Concentrated solar power in the USA: a performance review

26 04 2017

I have written before about the concentrated solar power stations in the US beforehere. Roger Andrews (put glasses on him, and he looks just like me!) has just written a damning exposé on the excellent Energy Matters website you should all be following too……. can I say “I rest my case”?

 

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A review of concentrated solar power (CSP) plants operating in the US reveals that they are costly, heavily-subsidized, generally performing below expectations and no more efficient than utility-scale PV plants. The need to jump-start them in the morning can also require the burning of substantial quantities of natural gas. And although CSP’s sole advantage over PV is that it can store energy for re-use only one of the plants considered has built-in storage capacity. As discussed in the earlier concentrated solar power in Spain post , however, it is unlikely that enough storage could be installed at a CSP plant to provide more than short-term load-following capability when the sun is not shining. (Inset: Ivanpah Unit 2 tower catches fire, May 2016).

This review originated from a comment posted by correspondent “Thinks Too Much” (T2M) on the Blowout Week 172 thread which bewailed the lack of publicity being given to the poor performance of the Crescent Dunes CSP plant. After further exchanges T2M sent me a copy of a spreadsheet he had painstakingly constructed from the EIA’s Electricity Browser monthly data, which, supplemented by Wikipedia data on the Genesis plant I have used to develop the data presented here. So a thank you and a hat tip to T2M.

The locations of the six CSP plants reviewed (Mojave, Solana, Genesis and the three units at Ivanpah – Crescent Dunes is discussed later) are shown in Figure 1. Installed capacities are Mojave 250 MWe, Solana 250 MWe, Genesis 250MWe and Ivanpah 392 MWe (126 + 126 + 133). Nameplate capacities (MWp) are about 10% higher. Only the Solana plant has storage capability (reported to be 1.68GWh), but no details are available on its performance. Mojave, Genesis and Solana are “parabolic trough” plants and Ivanpah and Crescent Dunes “solar tower” plants. Additional details on CSP plant design are given in the “concentrated solar power in Spain” post post linked to in the introduction.

Figure 1: Plant location map

All plants except Crescent Dunes have monthly production data for the two-year period from January 2015 through December 2016. Over this two-year period Solana generated 1,363GWh, Ivanpah 1,355GWh, Mojave 1,128GWh and Genesis 1,246GWh, for a total of 5,092GWh. This represents less than 1% of the electricity consumed in Arizona, Nevada and Southern California in 2015 and 2016.

A plot of monthly generation from the plants is not very instructive, so we begin instead with a plot of capacity factors. Figure 2 shows average capacity factors by month. Solana leads with an average of 31.1%, followed by Genesis with 28.4%, Mojave with 25.7% and Ivanpah with 19.7%. The weighted average capacity factor for all four plants is 25.4% (calculated using MWe; calculated using MWp it’s around 23%). This, however, is not significantly higher than the capacity factors achieved at conventional utility-scale PV plants in the Southwest US. According to the EIA data I reviewed in solar capacity factors in the US, which yielded values of 28.7% in California, 27.0% in Arizona and 26.7% in Nevada, it is in fact lower:

Figure 2: Monthly capacity factors

A question that arises here is why CSP plants located in the same desert environment don’t give more consistent results. The most likely reason is malfunctions in plant operation, with the Ivanpah plant the most seriously affected. Figure 3 plots capacity factors for the three Ivanpah units:

Figure 3: Monthly capacity factors for Ivanpah Units 1, 2 and 3

The three Ivanpah units cover an area of only about 10sq km, so there is no meteorological reason why any one unit should outperform any other – so long as the units are working properly. But they generate comparable amounts of electricity only about half the time. There are large discrepancies in early 2015 and also between April and June 2016 (partially but not entirely explained by the Unit 2 tower catching fire in May, a result of misaligned mirrors). Other features of Figure 3 are also not credible, such as higher solar generation in February 2016 than in May 2015. Seasonal variations are less pronounced and more erratic than one would expect from a properly-functioning solar plant, and the capacity factors (21.1% for Unit 1, 17.9% for Unit 2 and 20.2% for Unit 3) also seem implausibly low. The implication is that the Ivanpah plant is not working as planned, with problems both in the solar side of the operation and probably also in the power generation circuit, which is a complicated system that uses heat exchangers to produce the steam that drives the generators from the molten salt.

Problems with Ivanpah operations other than the May 2016 fire have also been reported by the media:

Wired Magazine: Ivanpah initially struggled to fulfill its electricity contract, and it would have had to shut down if the California Public Utilities Commission didn’t throw it a bone this past March, approving without discussion  agreements that would give the owners of the plant, NRG Energy, BrightSource Energy and Alphabet’s Google, up to a year to work out the problems.

Wikipedia: In November 2014, Associated Press reported that the plant was producing only “about half of its expected annual output”. The California Energy Commission issued a statement blaming this on “clouds, jet contrails and weather”. Performance improved considerably in 2015 — to about 650 GWh, but ownership partner NRG Energy said in its November quarterly report that Ivanpah would likely not meet its contractual obligations to provide power to PG&E during the year, raising the risk of default on its Power Purchase Agreement.

Greentechmedia: The (Ivanpah) plant….. kicked off commercial operation at the tail end of December 2013, and for the eight-month period from January through August, its three units generated 254,263 megawatt-hours of electricity, according to U.S. Energy Information Administration data. That’s roughly one-quarter of the annual 1 million-plus megawatt-hours that had been anticipated. Output did pick up in the typically sunny months of May, June, July and August, as one might expect, with 189,156 MWh generated in that four-month period. But even that higher production rate would translate to annual electricity output of less than 600,000 MWh, at least 40 percent below target.

Even Solana, the best-performing of the plants, had its problems:

Phoenix New Times: (Solana) was knocked out by a microburst for a few days in late July and won’t generate power normally for months, a new report reveals. The severe problem comes on top of generally poor performance from the $2 billion project over the past two years. As New Times reported in November 2014, in its first year the plant produced only about two-thirds of the power that its former owner, Spain’s Abengoa Solar, said it would. The company and Arizona Public Service, which is contracted to buy the electricity the plant generates, said at the time that performance would improve. Publicly available production figures reviewed by New Times this week showed that Solana did generate more electricity in its second year but is still well below its advertised potential. The plant also did worse in the second quarter of 2016 than it did in the same period in 2015, the numbers show. And considering the new report on the July microburst, the plant’s third-quarter results for this year — which haven’t been released yet — are likely to be abysmal.

(Note that Figure 2 confirms a large drop in capacity factor between July and August 2016.)

No specific malfunctions have been reported at Mojave or Genesis, but the fact that the capacity factors at these plants are lower than at Solana suggest that they also had their share of them.

Next on the agenda comes natural gas. The Genesis, Solana and Ivanpah plants (but not Mojave) need to burn it to get the plant warmed up in the morning. Again this is a particular problem at Ivanpah:

Wikipedia: The plant requires burning natural gas each morning to get the plant started. The Wall Street Journal reported: “Instead of ramping up the plant each day before sunrise by burning one hour’s worth of natural gas to generate steam, Ivanpah needs more than four times that much.” On August 27, 2014, the State of California approved Ivanpah to increase its annual natural gas consumption from 328 million cubic feet of natural gas, as previously approved, to 525 million cubic feet. In 2014, the plant burned 867,740 million BTU of natural gas emitting 46,084 metric tons of carbon dioxide, which is nearly twice the pollution threshold at which power plants and factories in California are required to participate in the state’s cap and trade program to reduce carbon emissions.

How much natural gas is actually consumed in the warm-up process? According to T2M’s spreadsheet Ivanpah consumed 1.29 trillion btu in 2016. If this much natural gas had been consumed in a typical CCGT plant (heat factor 7,650 btu/kWh according to EIA) it would have generated 169GW, almost a quarter of the 703GWh of solar electricity Ivanpah generated in that year.

And as shown in Figure 4 there is a fairly strong correlation between the amount of gas Ivanpah burns and the amount of solar generated (R^2 = 0.51). Clearly the more gas the plant burns in the morning the more solar energy it generates later in the day. (Although it’s only fair to note, as the WSJ reports, that Ivanpah is a particularly bad example. As far as I have been able to determine Genesis and Solana burn significantly less gas.)

Figure 4: Natural gas consumption vs. solar generation in 2016, Ivanpah Units 1, 2 and 3, monthly data

Last but one on the agenda is the question of project costs. Based on data from a number of sources, not all of which are necessarily reliable, I have put together the following table. It contains Crescent Dunes for completeness:

The five listed plants, which between them generate less than 1% of the electricity consumed in Arizona, Nevada and Southern California, cost over $8 billion to construct, and over 70% of this cost was covered by federal loan guarantees. All of the projects were also eligible for a 30% federal tax credit. With these generous subsidies and a bit of creative wheeling and dealing it might well have been possible for the developers to complete construction without forking out any of their own money at all.

Of particular interest is the ~$6,430/kW installed cost, which is in the same range as the 3.2GW Hinkley Point C nuclear plant. According to NREL’s 2015 cost estimates it also exceeds the cost of installing the same amount of utility-scale PV capacity by a factor of over three.

Another consideration is electricity sales price. Electricity from the plants is sold to various Southwest US utilities at cents/kWh rates and reliable data are again hard to come by, but the following numbers indicate a range of between 12 and 20c/kWh, or $120-200/MWh:

These rates equal or exceed the all-sector rates that local utilities charge in Arizona and Nevada, which according to EIA data are presently 9.62c/kWh and 8.02c/kWh respectively. After addition of transmission charges, administrative charges, taxes etc. Arizona and Nevada utilities will therefore lose money on each kWh of CSP energy they buy. With the all-sector rate at 15.02 c/kWh California utilities will probably lose money too, although not so much. And ultimately the consumer will finish up paying.

Last on the agenda is Crescent Dunes, the project that gave birth to this post. As shown in Figure 5, Crescent Dunes started operations in October 2015 and took its time ramping up, but by the late summer of 2016 it was achieving respectable capacity factors of between 30 and 40%. But then in early October a leak developed in the molten salt circuit and the plant was shut down, and it has stayed shut down in the five months since (probably now for six months. On March 2 of this year it was expected that it would be “another few weeks” before operations recommenced. But as of the time of writing there are no reports of the plant restarting, so presumably it’s still down):

Figure 5: Monthly capacity factors since startup, Crescent Dunes

Now there’s nothing unusual about a power plant shutting down, but it’s not often that a “low-tech maintenance issue” shuts one down for six months:

PV Times, March 2, 2017:  “We expect to be back online in a few weeks,” CEO Kevin B. Smith said. A hot salt tank issue “took a while to get it fixed, but it’s a pretty low-tech issue,” Smith said …… I understand you guys have got to figure out what’s going on, but you just seem so infatuated with this hot salt tank issue. It’s a maintenance issue ….”

One has to wonder how long a real breakdown might shut the plant down for.





Not happy, Jan…….

8 04 2017

If you’ve been following this blog, you will know I’ve been saying for quite some time that out of the ludicrous Lithium battery rush happening right now as a ‘fix it’ for all and sundry energy problems, a lot of disappointed people will surface. Well, one just has, and he’s one of the most high profile person in the sustainability movement.

I met Michael Mobbs almost certainly before 2010, which is the year I went working for the solar industry. He gave a public lecture about sustainability in Pomona at the Rural Futures Network; I wonder how that’s going now..? Mobbs has undertaken converting an old terrace house in Sydney to ‘sustainability’ by disconnecting from the water grid and sewerage. He also went grid tied solar, the whole project is well documented on his website, and you have to give him credit for doing the almost impossible…. in Sydney no less. I for one would never undertake such a project, it’s so much easier to start from scratch in the country! And that’s hard enough, let me tell you….

It now appears, Mobbs decided to also cut himself off from the electricity grid…. and it seems that didn’t go so well….

mobbsbatteriesOn Mobbs’ website, there is an “invitation to install & supply an off-grid solar system” It seems he had one installed in March 2015, but it’s not working as it should, or at least as Mobbs thought it should…..

Firstly, let’s start with what he got……. It’s a bit hard to tell from the photo, apart from the fact it is an Alpha ‘box’. From the blog, I also established that this comes with a 3kW inverter, itself a problem, it appears to be too small. Going to Alpha’s website, I cannot find the system Mobbs appears so proud of in the above photo; and let’s face it, two years is a long time in the world of technology. All the products on display say that the output of these cabinets is 5kW, but nowhere does it say it even features an inverter.  Solarchoice’s website shows a 3kW Storion-S3 cabinet, but not even it looks like what Mobbs has in the photo – it only has one door, the ‘new ones’ have two….. The inverter is called an AEV-3048, and perhaps the A stands for Alpha, and 3048 means 3000W/48V, but it’s all guesswork because finding information is a problem.

So why is a 3kW inverter a problem in a house with a claimed baseload of 86W, very close to what we achieved in Cooran actually…..

Another huge flaw with the Alpha system that I’ve recently become aware of also stems from the fact that all the energy first goes through the batteries: the Alpha system’s output is always limited to 3,000W regardless of the solar size; it can’t deliver above this. This is an extremely important point to understand because it affects the way I live and how I’m able to use my appliances. I’ll break it down in a way that’s practical and simple; prepare yourself to be blown away by this outrageous system limitation.

We’ve already established that the base load of my house is 86W. Let’s say I wake up in the morning, turn on a couple of lights in the kitchen because it’s still dark (20W), turn on the toaster because I’m in the mood for toast with butter for breakfast (1,200W), and my daughter (who happens to be staying with me) turns on her hair dryer while getting ready (1,500W) and she decides she needs to put on a load of laundry before she leaves the house (500W). Doesn’t seem too out of the ordinary, right? Well, we would be in trouble: all of the power would cut off, and the Alpha system would shut down because we would have exceeded its 3,000W limit. Regardless of the size of my solar system, I can NEVER exceed 3,000W of power consumption in my house while using the Alpha system. This was very hard to swallow.

Oh Michael…….  welcome to living off the grid!

Mobbs gives a brief description of how he worked out this baseload….

Step one, determining my total base load, wasn’t as easy as I expected, especially given the fact that I have three different monitoring systems that could provide me with the information. The Efergy and Wattwatchers systems confirmed what I already knew: my house’s base load was about 86W (60W for the aerator and roughly 20W for the fridge occasionally turning on).However, where I ran into problems was with the Alpha ESS reporting system: it was saying my base load was 257W, which is three times larger than the base load reported for the house.At first I thought this difference of 171W was the base load of the Alpha system itself, but their numbers just didn’t add up.

I do have a theory here, he may have got the sums wrong because he used to be grid tied, and maybe, just maybe, his figures did not include what was exported. But I’m only guessing. My main reason for thinking this is that he is running a conventional fridge, while we achieved our low baseload using a freedge which consumes 20% of the energy a conventional fridge does…. make no mistake, a conventional fridge’s ‘baseload’ is half or more of his 86W. He’s claiming 20W for his fridge (480Wh/day, 20W x 24 hrs), but I have never seen any fridge perform that well…. Most fridges today still consume a whole kilowatthour a day. So there could be another error there.

But it gets worse……

Now you see why I said that I probably made a huge mistake by purchasing the Alpha system when going off-grid. The simple truth is that the Alpha system is not designed to be used in an off-grid setting, and they have not implemented the necessary retrofits to make it work in that environment. However, during my recent research, I came across a product that is designed specifically to be used off-grid and shows great promise for high efficiency and effective energy management: the SMA Sunny Island system.

Bad news Michael……  the SMA Sunny Island is not designed for off the grid either, it’s made to work with other SMA grid tied units in a hybrid grid/backup batteries system.

Worse still, he also seems to have storage issues….

For the last few weeks, in the particularly cloudy and rainy weather Sydney has had to endure, Mobbs had to turn off his fridge (bloody fridges, they are a curse…) during the day to ensure that the house, which he shares with two others, has enough power for a “civilised life” at night-time. Worse than that, the system has a bug in it that causes it to trip out every couple of days. It seems flashing digital lights have become part of his life….!

“I’m running short of power,” Mobbs said complaining that the system that he has in place is delivering 1kWh/day less than he expected. “I thought this would be a walk in the park, but I appear to have tripped over.”

I’m seriously starting to think a lot of installers have no idea what they are doing. I recently related the story of my friend Bruce whose inlaws replaced a perfectly good system (because of a fridge no less!), and they were sold a Sunny Island, with I was told over the phone just two days ago, gel cells for storage……… completely not what either Bruce or I would have bought. Solar companies (including this well known one who shall remain nameless) have simply turned into salespeople selling whatever it is they have in stock off catalogues…….

Mobbs then writes……

The main difference between the Alpha and Sunny Island system: Sunny Island can send solar energy directly to the house when it is needed and completely bypasses the system’s batteries. SMA’s Sunny Island system not only extends battery life by not cycling all loads through them, but using solar directly into loads means items can be set to run on timers during the day, (washing, dishwasher etc) to maximise the benefit of an abundant afternoon supply of solar. It also has a larger peak design capacity than Alpha. For example, if you have a 4kW solar system, with the SMA units that would allow a potential delivery of 4kW of solar (in optimum conditions) directly into the house’s load + the 4.6kW of power from the batteries delivered by the Sunny Island controller (they can run in parallel to each other).  That’s a big potential 8.6 kW of continuous capacity to loads.  As I’ve already pointed out, in contrast the Alpha output is always limited to the 3,000W delivery of the battery inverter regardless of the solar size.

More bad news Michael…… this only works that way if you are grid tied with a hybrid system!

Michael also doesn’t seem to understand how off the grid works…

Alpha has an inefficient way of managing my solar energy (by diverting all of it through my batteries first), which decreases my battery life by constantly charging and discharging them…

Errr…..  Michael, that’s how battery storage works! Which is of course exactly why Lithium batteries are not good at this. Mobbs also wrote…:

Like any system that transfers and converts energy from one form to another, there are going to be losses. No system is perfect. However, as I started doing more research, I became aware of a key element of the way the Alpha system operates that may mean my decision to purchase it was a huge mistake: the Alpha system transfers all its incoming solar energy through the batteries before it delivers it to the house. When I learned this, I was devastated. One of the most important figures of merit in a system such as mine are the battery losses. If you put 1kWh into a battery it doesn’t all come out! There are losses associated with both charging and discharging. The higher the charge/discharge rate, the greater proportion of energy is lost and the shorter my battery life becomes. So, I repeat, all my energy is getting charged and discharged through the batteries before I ever even see it in the house. For someone living off-grid, this level of energy loss and battery depreciation is unacceptable, and I was never made aware of it by the installer.

This is why I know there will be a lot of disappointed grid disconnectors. They have swallowed the idea that living off grid is just like living on it hook line and sinker, when it cannot possibly be. How long have I been saying solar has shortcomings?

If you’re going to go off the grid, first, you need to know exactly how much energy you’re consuming. Then you need to know what your peak power demand will be so you can size your inverter. Then, you must size your battery bank so that you can go on living through a series of cloudy days without your batteries falling over. Accurate climate data is really important. And if you ask me, any off the grid system should be tailor made for the household, not all fitted in a box…..

The comments on Mobbs’ blog are interesting, including one from Alpha who obviously can do without the bad publicity and are suggesting entering into consultation….. well if you ask me, the time for consultation is before installation, not after it’s established the gear does not perform as needed….

Furthermore, and this is most important, get batteries that can be flattened and recharged for as many times as you like, almost forever if you go the way of Nickel Iron batteries……

At least Mobbs is aware of what his system is doing, but most consumers don’t. They will buy these cabinets, not understand what the monitors tell them, and the Lithium batteries will be cycled to death, failing early without a doubt, driving incompetent solar companies broke and giving solar power a really bad name. Plus, let’s face it, by the time all these systems die, you won’t be able to get replacement bits in a post collapse world….

There is one more issue…… on his blog Mobbs shows..:

In 1996, I installed 18 solar panels, each with 120-watt capacity. It reduced the amount the house took from the grid by more than 60%. Since then, I have installed 12 additional panels, bringing my home’s total system capacity to just over 3.5kW. mobbs panels

In addition to the roof solar cells, the house uses sunlight to heat water through a standard solar hot-water system. The environmental savings achievable by using solar hot-water heaters are summed up by Gavin Gilchrist in his book, The Big Switch:
“If all the electric water heaters in Australia were replaced with solar ones, greenhouse gas emissions from Australia’s households would be cut by one-fifth.” One fifth is one mighty big saving!

The Bottom Line… I am saving hundreds of dollars every year not paying electricity bills by powering my household appliances using the Sun. 

I totally concur re the solar water heaters. Amazingly, I have friends in Geeveston who have one, and they hardly ever boost, which is astonishing considering how everyone was telling me how poorly solar would work in Tassie.

BUT…… all those original PVs were replaced when Mobbs cut the cord and increased his array size from 2kW to 5kW…… they were only ten years old, and as Prieto pointed out recently, the early retirement/replacement of PVs and balance of system can drive the ERoEI of solar to negative territory….. I can’t find mention of what happened to the obsolete 120W panels for which it might be hard to find compatible equipment.

One last thing……  his baseload of 86W is clearly wrong if a 3.5kW array can’t drive it. Our electricity habit was run for years on just 1.28kW, and I intend to now do it in Tassie with just 2kW. I rest my case.





PV ERoEI may be negative…

16 01 2017

Well THIS will stir the hornet’s nest……. Pedro Prieto now thinks many solar panels won’t last 25-30 years, EROI may be negative……

pedro

Pedro Prieto

It must be remembered that Pedro, whose work has been published here several times, has vast experience in this, having been involved in large scale PV and wind installations in Spain. I don’t know if this article is how he wrote it in English, or whether it was poorly translated from the Spanish, but it is often difficult to read, even when you have the technical knowledge to know what he’s talking about. I had a go at editing it, see what you think… This piece certainly didn’t make me feel good about my new power station, especially after seeing ads on Tasmanian TV by someone who thinks he sells better equipment showing blown up inverters and burnt out connectors on the front face of panels….. there is a lot of rubbish out there, that’s for sure, I’ve had first hand experience of this myself, but if even best quality gear won’t last 25 years, then we will be going back to the stone age……

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Our study concluded that, when what we called “extended boundaries energy inputs” were analysed, about 2/3 of the total energy inputs were other than those of the modules+inverters+metallic infrastructure to tilt and orient the modules.

So even if the cost of solar PV modules (including inverters and metallic infrastructure) were ZERO, our resulting EROI (2.4:1) would increase by maybe 1/3.

Without including the financial energy inputs (you can easily calculate them if most of the credits/leasing contracts at 10 years term with interests of between 2 and 6% were included, even if you consider energy input derived from the financial costs, only the interests (returning the capital, in my opinion, would theoretically only return the previous PREEXISTING financial (and therefore, energy) surplus, minus amortization of the principal, if any (when principal is tied to a physical preexisting good, which is not the case, I understand in most of the circulating money of today, but you know much better than me about this).

We also excluded most of the labor energy inputs, to avoid duplications with factors that were included and could eventually have some labor embedded on it. And that was another big bunch of energy input excluded from our analysis.

As I mentioned before, if we added only these two factors that were intentionally excluded, not to open up old wounds and trying to be conservative, plus the fact that we include only a small, well-known portion of the energy inputs required to stabilize the electric networks, if modern renewables had a much higher or even a 100% penetration,  it is more than probable that the solar PV EROI would have resulted in <1:1.

And I do not believe we can make solar modules with even 25 ~ 30 years lifetime. There are certainly working modules that have lasted 30 years+ and still work. Usually in well cared and maintained facilities in research labs or factories of the developed world. But this far away from expected results when generalized to a wide or global solar PV installed plant. Dreaming of having them 100 or 500 years is absolutely unthinkable.

Modules have, by definition, to be exposed more than anything else, to solar rays (to be more efficient). Just look at stones exposed to sun rays from sunrise to sunset and to wind, rain, moisture, corrosion, dust, animal dung (yes, animal dung, a lot of it from birds or bee or wasp nests on modules) and see how they erode. Now think of sophisticated modules  exposed to hail, with glass getting brittle, with their Tedlar, EVA and/or other synthetic components sealing the joints between glass and metallic frames eroding or degrading with UV rays and breaking the sealed package protecting the cells inside, back panels with connection boxes, subject to vibration with wind forces and disconnecting the joints and finally provoking the burning of the connectors; fans in the inverter housings with their gears or moving parts exhausted or tired, that if not maintained regularly, end failing and perhaps, if in summer, elevating the temperature of the inverter in the housing and provoking the fuse to blown or some other vital components, etc.

I have seen many examples of different manufacturers of all types of modules (single/mono, multi/poli, amorphous, thin film high concentration with lenses, titanium dioxide, etc.) in the test chambers, after warranty claims by the clients to the manufacturers. I have attended test fields of auditing companies contracted by retailers, detecting hot spots in faulty internal solder joints straight from the factory to the customers.

I have seen a whole batch from a promising leading US brand specializing in thin film modules(confidentiality does not permit me to name, as yet) having to return it because it did not comply with specs. Now, as I mentioned, I am in contact with a desperate retailer, seeking replacement modules or reimbursement (the manufacturer is broke and has disappeared) that will last a little loger than those he purchased (not Chinese) about 6 years ago and of which about 2/7 of the total have failed, without a practical replacement being available because present modules in the market have higher nominal output power than those originally contracted for and with different voltage and currents that do not permit unitary replacements in arrays or strings, being forced to a complex and costly manipulation to reconfigure arrays with old modules and creating new arrays with new modules and adapting inverters to the new currents and voltages delivered (Maximum Power Point Tracking or MPPT)

We mentioned many other examples of real life affecting functionality of solar PV systems in our book. The reality, 2 years after the publication of the book, proved us very optimistic. Imagine when you install a solar village in a remote area of Morocco, or Nigeria or Atacama in Northern Chile and the nearest replacement of a single broken power thysristor or IGBT that is stopping a whole inverter from operating, plus the entire plant behind it (not manufactured in the country) and about 2,000 Km -or more- from the factory that needs to pass customs like the one in Santos (Brazil), where tens of thousands of containers are blocked for more than one week (plus the usual 6 to 10 weeks custom procedures) because of a fire in a refinery close to the only motorway leaving the Santos port to Sao Paulo..

100 or 500 years lifetime? ha, ha, ha.





White man’s magic……

8 10 2016

20160418_163158Now that our power station has been commissioned, is actually powering stuff, and because it’s been an evolutionary thing over many months, I’ve decided to chronicle how our rather unique stand alone power system is built in one post, for the benefit of all mankind…. as it were!

The solar power is generated by eight 260W monocrystaline photovoltaic panels, for a 20161008_131339total of 2080 Watts. They are mounted on a custom made steel frame, installed by the first wwoofer I had working for me here… They are connected in two strings of four with each string producing 1000W at 150V DC maximum. The two pairs of wires are fed underground and through the container’s floor in that orange conduit, to the DC circuit box where two 20 Amp circuit breakers protect the system against short circuits or serious malfunctions. Each circuit breaker is dipole, and simultaneously breaks both the positive and negative circuits.

dcsector

DC Circuits

From this box, the solar power is fed to the MidNite Classic Maximum Power Point Tracker. This magic black box manipulates the incoming electricity so that it is fed into the batteries at the optimum voltage/amperage combination needed to maximise the amount of energy fed into the batteries to keep them charged. I had never used one of these before, but they are well worth the $900 , because it does all sorts of other tricks, like boost charging, battery equalising, floating, and even monitors the amount of energy fed into the batteries, logging all that information where it can be accessed later…… If I decide to later add a wind turbine, I will get a second one to control its output.

The power going into the batteries (and out of them for powering things with the inverter) go through a fuse box with two 160A slow burn fuses. Batteries are capable of producing spectacular amounts of current (think big sparks and fire!) and in the unlikely event of something seriously bad happening to the batteries, these fuses will burn and save the rest of the system. The fuse box is also designed such that it can be used to disconnect the batteries from everything else in an emergency, or for maintenance. There’s one fuse for the positive cable, and one victronfor the negative……

Once charged, the energy contained within the batteries can be extracted back out (through the aforementioned fusebox) by the Victron inverter, which converts the 48V (nominal) DC from the batteries into 230V AC for powering all the things we take for granted in houses, like lights, fridges, TVs and washing machines etc……

This inverter has now had its settings altered to operate at between 64V and 37.5V. It’s because Victrons can be reprogrammed to do this that I opted for this technology, as the Nickel Iron batteries are able to work safely at an even greater voltage range. The blue digital voltmeter is something I added to the inverter to get an instant readout of the battery bank’s voltage.

Just as there is a series of safety devices on the DC side of the system, the AC sector is also wired up to protect the wiring and the people using the electricity! You will also notice the green/yellow striped earth wires to/from the MidNite Classic and the inverter, all connected to the earth in the AC switchboard, all grounded to the container itself.

acsectorBefore going into the AC circuit box, I wired in an old energy meter I have had for years to monitor how much energy we will be consuming in the house (as well as outside to pump water for the gardens etc…). I used to use it for doing energy audits, and they sure don’t make them like this anymore…!

The 230V output is split into three, with another dipole circuit breaker (one for the active and one for the neutral) taking power to where the house will be built, currently permanently switched off. Another 10A circuit breaker takes current to a power point inside the container for running the freezer and charging cordless tool batteries (so far), while a 15A breaker takes power to an external 15A all weather power point outside the container where I currently plug the new pump in (more about this in a later post).

The two power points are protected with safety switches which are now built into the circuit breakers. It’s amazing how fast technology changes/improves these days….

The battery bank consists of forty 1.2V Nickel Iron cells (to make the nominal 48V). You can read about why I selected this battery chemistry here……

20161023_103049

Earth/Ground wire to stake

 

The container is earthed with a copper stake, and everything involved in this system is also earthed through the steel container, one advantage of having a steel building! The safety switches test just fine, the whole system is very safe. To vent the potentially explosive hydrogen gas that bubbles from the batteries, two whirlybird extractors were put into the container’s roof, and six vents at floor level on the western end of the container were also added. It’s where the wind usually comes from, and it will no doubt assist in keeping everything cool, even in summer….

vents

Floor level air vents

 

batterybankI’m really stoked at how well it’s all working. Even on really rainy days, the solar array was able to feed 4.7kWh of energy into the battery bank, and even on the very worst day when the sky was inky black and it just poured all day long, 1.7kWh was absorbed by the batteries, almost enough to power our old house for a whole day…. The design electricity consumption for the new house is 2kWh/day, though at this stage it’s still unknown how much energy I will need to pump water for the market garden.

I’m finding adjusting to the NiFe batteries a little tricky. Unlike conventional Lead Acid batteries, these prefer to be worked hard. I’m told by people who run them that the harder you cycle them, the more capacity they build up, and the longer they last between electrolyte replacement. Because I’m (so far) only pulling 0.9kWh/day out of them with the freezer, the batteries haven’t been worked enough. So I recently turned the solar power completely off for eight or nine days, just to ‘flatten’ them. They were fully charged again within two days…. Nickel Iron batteries, unlike the other technologies sold everywhere, can be ‘flattened’ as often as you like….. you just need to always make sure there’s enough left to start the freezer again, or else lose the contents!

Now the container sports a 1000 litre IBC for gravity fed water storage….. but you’ll have to wait for the next installment.

 





Eight Pitfalls in Evaluating Green Energy Solutions

4 07 2016

Does the recent climate accord between US and China mean that many countries will now forge ahead with renewables and other green solutions? I think that there are more pitfalls than many realize.

Pitfall 1. Green solutions tend to push us from one set of resources that are a problem today (fossil fuels) to other resources that are likely to be problems in the longer term.  

The name of the game is “kicking the can down the road a little.” In a finite world, we are reaching many limits besides fossil fuels:

  1. Soil quality–erosion of topsoil, depleted minerals, added salt
  2. Fresh water–depletion of aquifers that only replenish over thousands of years
  3. Deforestation–cutting down trees faster than they regrow
  4. Ore quality–depletion of high quality ores, leaving us with low quality ores
  5. Extinction of other species–as we build more structures and disturb more land, we remove habitat that other species use, or pollute it
  6. Pollution–many types: CO2, heavy metals, noise, smog, fine particles, radiation, etc.
  7. Arable land per person, as population continues to rise

The danger in almost every “solution” is that we simply transfer our problems from one area to another. Growing corn for ethanol can be a problem for soil quality (erosion of topsoil), fresh water (using water from aquifers in Nebraska, Colorado). If farmers switch to no-till farming to prevent the erosion issue, then great amounts of Round Up are often used, leading to loss of lives of other species.

Encouraging use of forest products because they are renewable can lead to loss of forest cover, as more trees are made into wood chips. There can even be a roundabout reason for loss of forest cover: if high-cost renewables indirectly make citizens poorer, citizens may save money on fuel by illegally cutting down trees.

High tech goods tend to use considerable quantities of rare minerals, many of which are quite polluting if they are released into the environment where we work or live. This is a problem both for extraction and for long-term disposal.

Pitfall 2. Green solutions that use rare minerals are likely not very scalable because of quantity limits and low recycling rates.  

Computers, which are the heart of many high-tech goods, use almost the entire periodic table of elements.

Figure 1. Slide by Alicia Valero showing that almost the entire periodic table of elements is used for computers.

When minerals are used in small quantities, especially when they are used in conjunction with many other minerals, they become virtually impossible to recycle. Experience indicates that less than 1% of specialty metals are recycled.

Figure 2. Slide by Alicia Valero showing recycling rates of elements.

Green technologies, including solar panels, wind turbines, and batteries, have pushed resource use toward minerals that were little exploited in the past. If we try to ramp up usage, current mines are likely to deplete rapidly. We will eventually need to add new mines in areas where resource quality is lower and concern about pollution is higher. Costs will be much higher in such mines, making devices using such minerals less affordable, rather than more affordable, in the long run.

Of course, a second issue in the scalability of these resources has to do with limits on oil supply. As ores of scarce minerals deplete, more rather than less oil will be needed for extraction. If oil is in short supply, obtaining this oil is also likely to be a problem, also inhibiting scalability of the scarce mineral extraction. The issue with respect to oil supply may not be high price; it may be low price, for reasons I will explain later in this post.

Pitfall 3. High-cost energy sources are the opposite of the “gift that keeps on giving.” Instead, they often represent the “subsidy that keeps on taking.”

Oil that was cheap to extract (say $20 barrel) was the true “gift that keeps on giving.” It made workers more efficient in their jobs, thereby contributing to efficiency gains. It made countries using the oil more able to create goods and services cheaply, thus helping them compete better against other countries. Wages tended to rise, as long at the price of oil stayed below $40 or $50 per barrel (Figure 3).

Figure 3. Average wages in 2012$ compared to Brent oil price, also in 2012$. Average wages are total wages based on BEA data adjusted by the CPI-Urban, divided total population. Thus, they reflect changes in the proportion of population employed as well as wage levels.

More workers joined the work force, as well. This was possible in part because fossil fuels made contraceptives available, reducing family size. Fossil fuels also made tools such as dishwashers, clothes washers, and clothes dryers available, reducing the hours needed in housework. Once oil became high-priced (that is, over $40 or $50 per barrel), its favorable impact on wage growth disappeared.

When we attempt to add new higher-cost sources of energy, whether they are high-cost oil or high-cost renewables, they present a drag on the economy for three reasons:

  1. Consumers tend to cut back on discretionary expenditures, because energy products (including food, which is made using oil and other energy products) are a necessity. These cutbacks feed back through the economy and lead to layoffs in discretionary sectors. If they are severe enough, they can lead to debt defaults as well, because laid-off workers have difficulty paying their bills.
  2.  An economy with high-priced sources of energy becomes less competitive in the world economy, competing with countries using less expensive sources of fuel. This tends to lead to lower employment in countries whose mix of energy is weighted toward high-priced fuels.
  3. With (1) and (2) happening, economic growth slows. There are fewer jobs and debt becomes harder to repay.

In some sense, the cost producing of an energy product is a measure of diminishing returns–that is, cost is a measure of the amount of resources that directly and indirectly or indirectly go into making that device or energy product, with higher cost reflecting increasing effort required to make an energy product. If more resources are used in producing high-cost energy products, fewer resources are available for the rest of the economy. Even if a country tries to hide this situation behind a subsidy, the problem comes back to bite the country. This issue underlies the reason that subsidies tend to “keeping on taking.”

The dollar amount of subsidies is also concerning. Currently, subsidies for renewables (before the multiplier effect) average at least $48 per barrel equivalent of oil.1 With the multiplier effect, the dollar amount of subsidies is likely more than the current cost of oil (about $80), and possibly even more than the peak cost of oil in 2008 (about $147). The subsidy (before multiplier effect) per metric ton of oil equivalent amounts to $351. This is far more than the charge for any carbon tax.

Pitfall 4. Green technology (including renewables) can only be add-ons to the fossil fuel system.

A major reason why green technology can only be add-ons to the fossil fuel system relates to Pitfalls 1 through 3. New devices, such as wind turbines, solar PV, and electric cars aren’t very scalable because of high required subsidies, depletion issues, pollution issues, and other limits that we don’t often think about.

A related reason is the fact that even if an energy product is “renewable,” it needs long-term maintenance. For example, a wind turbine needs replacement parts from around the world. These are not available without fossil fuels. Any electrical transmission system transporting wind or solar energy will need frequent repairs, also requiring fossil fuels, usually oil (for building roads and for operating repair trucks and helicopters).

Given the problems with scalability, there is no way that all current uses of fossil fuels can all be converted to run on renewables. According to BP data, in 2013 renewable energy (including biofuels and hydroelectric) amounted to only 9.4% of total energy use. Wind amounted to 1.1% of world energy use; solar amounted to 0.2% of world energy use.

Pitfall 5. We can’t expect oil prices to keep rising because of affordability issues.  

Economists tell us that if there are inadequate oil supplies there should be few problems:  higher prices will reduce demand, encourage more oil production, and encourage production of alternatives. Unfortunately, there is also a roundabout way that demand is reduced: wages tend to be affected by high oil prices, because high-priced oil tends to lead to less employment (Figure 3). With wages not rising much, the rate of growth of debt also tends to slow. The result is that products that use oil (such as cars) are less affordable, leading to less demand for oil. This seems to be the issue we are now encountering, with many young people unable to find good-paying jobs.

If oil prices decline, rather than rise, this creates a problem for renewables and other green alternatives, because needed subsidies are likely to rise rather than disappear.

The other issue with falling oil prices is that oil prices quickly become too low for producers. Producers cut back on new development, leading to a decrease in oil supply in a year or two. Renewables and the electric grid need oil for maintenance, so are likely to be affected as well. Related posts include Low Oil Prices: Sign of a Debt Bubble Collapse, Leading to the End of Oil Supply? and Oil Price Slide – No Good Way Out.

Pitfall 6. It is often difficult to get the finances for an electrical system that uses intermittent renewables to work out well.  

Intermittent renewables, such as electricity from wind, solar PV, and wave energy, tend to work acceptably well, in certain specialized cases:

  • When there is a lot of hydroelectricity nearby to offset shifts in intermittent renewable supply;
  • When the amount added is sufficient small that it has only a small impact on the grid;
  • When the cost of electricity from otherwise available sources, such as burning oil, is very high. This often happens on tropical islands. In such cases, the economy has already adjusted to very high-priced electricity.

Intermittent renewables can also work well supporting tasks that can be intermittent. For example, solar panels can work well for pumping water and for desalination, especially if the alternative is using diesel for fuel.

Where intermittent renewables tend not to work well is when

  1. Consumers and businesses expect to get a big credit for using electricity from intermittent renewables, but
  2. Electricity added to the grid by intermittent renewables leads to little cost savings for electricity providers.

For example, people with solar panels often expect “net metering,” a credit equal to the retail price of electricity for electricity sold to the electric grid. The benefit to electric grid is generally a lot less than the credit for net metering, because the utility still needs to maintain the transmission lines and do many of the functions that it did in the past, such as send out bills. In theory, the utility still should get paid for all of these functions, but doesn’t. Net metering gives way too much credit to those with solar panels, relative to the savings to the electric companies. This approach runs the risk of starving fossil fuel, nuclear, and grid portion of the system of needed revenue.

A similar problem can occur if an electric grid buys wind or solar energy on a preferential basis from commercial providers at wholesale rates in effect for that time of day. This practice tends to lead to a loss of profitability for fossil fuel-based providers of electricity. This is especially the case for natural gas “peaking plants” that normally operate for only a few hours a year, when electricity rates are very high.

Germany has been adding wind and solar, in an attempt to offset reductions in nuclear power production. Germany is now running into difficulty with its pricing approach for renewables. Some of its natural gas providers of electricity have threatened to shut down because they are not making adequate profits with the current pricing plan. Germany also finds itself using more cheap (but polluting) lignite coal, in an attempt to keep total electrical costs within a range customers can afford.

Pitfall 7. Adding intermittent renewables to the electric grid makes the operation of the grid more complex and more difficult to manage. We run the risk of more blackouts and eventual failure of the grid. 

In theory, we can change the electric grid in many ways at once. We can add intermittent renewables, “smart grids,” and “smart appliances” that turn on and off, depending on the needs of the electric grid. We can add the charging of electric automobiles as well. All of these changes add to the complexity of the system. They also increase the vulnerability of the system to hackers.

The usual assumption is that we can step up to the challenge–we can handle this increased complexity. A recent report by The Institution of Engineering and Technology in the UK on the Resilience of the Electricity Infrastructure questions whether this is the case. It says such changes, ” .  .  . vastly increase complexity and require a level of engineering coordination and integration that the current industry structure and market regime does not provide.” Perhaps the system can be changed so that more attention is focused on resilience, but incentives need to be changed to make resilience (and not profit) a top priority. It is doubtful this will happen.

The electric grid has been called the worlds ‘s largest and most complex machine. We “mess with it” at our own risk. Nafeez Ahmed recently published an article called The Coming Blackout Epidemic, discussing challenges grids are now facing. I have written about electric grid problems in the past myself: The US Electric Grid: Will it be Our Undoing?

Pitfall 8. A person needs to be very careful in looking at studies that claim to show favorable performance for intermittent renewables.  

Analysts often overestimate the benefits of wind and solar. Just this week a new report was published saying that the largest solar plant in the world is so far producing only half of the electricity originally anticipated since it opened in February 2014.

In my view, “standard” Energy Returned on Energy Invested (EROEI) and Life Cycle Analysis (LCA) calculations tend to overstate the benefits of intermittent renewables, because they do not include a “time variable,” and because they do not consider the effect of intermittency. More specialized studies that do include these variables show very concerning results. For example, Graham Palmer looks at the dynamic EROEI of solar PV, using batteries (replaced at eight year intervals) to mitigate intermittency.2 He did not include inverters–something that would be needed and would reduce the return further.

Figure 4. Graham Palmer's chart of Dynamic Energy Returned on Energy Invested from "Energy in Australia."

Palmer’s work indicates that because of the big energy investment initially required, the system is left in a deficit energy position for a very long time. The energy that is put into the system is not paid back until 25 years after the system is set up. After the full 30-year lifetime of the solar panel, the system returns 1.3 times the initial direct energy investment.

One further catch is that the energy used in the EROEI calculations includes only a list of direct energy inputs. The total energy required is much higher; it includes indirect inputs that are not directly measured as well as energy needed to provide necessary infrastructure, such as roads and schools. When these are considered, the minimum EROEI needs to be something like 10. Thus, the solar panel plus battery system modeled is really a net energy sink, rather than a net energy producer.  

Another study by Weissbach et al. looks at the impact of adjusting for intermittency. (This study, unlike Palmer’s, doesn’t attempt to adjust for timing differences.) It concludes, “The results show that nuclear, hydro, coal, and natural gas power systems . . . are one order of magnitude more effective than photovoltaics and wind power.”

Conclusion

It would be nice to have a way around limits in a finite world. Unfortunately, this is not possible in the long run. At best, green solutions can help us avoid limits for a little while longer.

The problem we have is that statements about green energy are often overly optimistic. Cost comparisons are often just plain wrong–for example, the supposed near grid parity of solar panels is an “apples to oranges” comparison. An electric utility cannot possibility credit a user with the full retail cost of electricity for the intermittent period it is available, without going broke. Similarly, it is easy to overpay for wind energy, if payments are made based on time-of-day wholesale electricity costs. We will continue to need our fossil-fueled balancing system for the electric grid indefinitely, so we need to continue to financially support this system.

There clearly are some green solutions that will work, at least until the resources needed to produce these solutions are exhausted or other limits are reached. For example, geothermal may be solutions in some locations. Hydroelectric, including “run of the stream” hydro, may be a solution in some locations. In all cases, a clear look at trade-offs needs to be done in advance. New devices, such as gravity powered lamps and solar thermal water heaters, may be helpful especially if they do not use resources in short supply and are not likely to cause pollution problems in the long run.

Expectations for wind and solar PV need to be reduced. Solar PV and offshore wind are both likely net energy sinks because of storage and balancing needs, if they are added to the electric grid in more than very small amounts. Onshore wind is less bad, but it needs to be evaluated closely in each particular location. The need for large subsidies should be a red flag that costs are likely to be high, both short and long term. Another consideration is that wind is likely to have a short lifespan if oil supplies are interrupted, because of its frequent need for replacement parts from around the world.

Some citizens who are concerned about the long-term viability of the electric grid will no doubt want to purchase their own solar systems with inverters and back-up batteries. I see no reason to discourage people who want to do this–the systems may prove to be of assistance to these citizens. But I see no reason to subsidize these purchases, except perhaps in areas (such as tropical islands) where this is the most cost-effective way of producing electric power.

Notes:

[1] In 2013, the total amount of subsidies for renewables was $121 billion according to the IEA. If we compare this to the amount of renewables (biofuels + other renewables) reported by BP, we find that the subsidy per barrel of oil equivalent in was $48 per barrel of oil equivalent. These amounts are likely understated, because BP biofuels include fuel that doesn’t require subsidies, such as waste sawdust burned for electricity.

[2] Palmer’s work is published in Energy in Australia: Peak Oil, Solar Power, and Asia’s Economic Growth, published by Springer in 2014. This book is part of Prof. Charles Hall’s “Briefs in Energy” series.





When it rains it pours…..

18 05 2016

And I mean literally, as well as metaphorically.  We’re just half way through May, and Tasmania has already tallied more than its average May rainfall, following months and months of well below average rain.

On the metaphorical side, while the sawmilling is still happening (when the rain pauses), the excavator turned up.  In total darkness, and drizzling rain, with a huge truck that almost didn’t make it through our driveway which is flanked by two deep ditches at the

digger

Dawn of a new era…?

roadside.  Because the guy who normally floats Trevor’s excavator let him down, he had to use this oversized low loader, which then got immediately bogged almost to the axle behind my shed after unloading the digger….. which had to be used to pull the truck out.  Trust me, it was more excitement than I could wish for at dinner time.

That very evening, I get an email saying my batteries were at a depot 20km North of Hobart, so I spent a fine day driving to the big smoke to pick them up, over 500kg….  After so much rain, the farm is getting very slippery for my two wheel drive ute, and reaching some of the places I’ve been taking for granted is getting much harder, but I managed to get to the container in one go without getting bogged!

20160517_145235The batteries came in crates meant to be used just once, there was no way of dismantling them carefully for reuse; they were solid enough for the job, but totally fell to pieces when prized apart.  And so many nails and screws, it was unbelievable.  The crate labeled ‘accessories’ had the electrolyte powders (caustic), heavy duty rubber aprons and gloves, eye protection, battery hydrometer, thermometer, insulated spanners for bolting the things together with the links supplied, terminal protectors, and even a special tool for removing the filler caps.  You’d think there would be instructions for mixing the electrolyte (as promised), but that was not the case, a minor issue I’m sure as I will 20160517_160653certainly get them as necessary from Ironcore.

The first thing you notice when lifting them up is how light they are.  Each 1.2V battery is the size of a heavy duty car battery, but easily half the weight.  Less actually, because I eventually started moving them into the container two at a time, one under each arm! Even filling them up with electrolyte would only increase their weight by one kg, so it wasn’t why they were this light, they simply don’t have lead in them.

These Nickel iron batteries were originally designed over 100 years ago to be used in electric vehicles, and now it’s got me thinking about using them for doing this too if I ever get around to converting one of my utes to EV status.  Ironcore sell 1.2V 10Ah batteries that weigh just 1.2kg each, which would be a good size as an EV would need at least 400 of them to reach a working voltage of 480V DC; such a battery bank would cost ‘only’ $6000, and with a capacity of 4kWh should give the ute a range of maybe 50 km….. enough to get from here to Huonville……..

Now the batteries are on the floor, I’ve decided that they are not staying there, and I will have to build or buy some shelving to raise them up.  There’s no way I’m going to be bending over to maintain this many cells on a regular basis at floor level… Shelving’s always handy for storing tools etc anyway, so now I have something else to keep me occupied!  No time to get bored around here……





Another study on the ERoEI of solar PV

10 05 2016

Originally posted by Euan Mearns on his blog Energy Matters, this study makes Pedro Prieto’s look very good….. the differences in ERoEI between the two studies must be a function of the difference in latitude between Spain and the UK, and even possibly by the fact that as the ERoEI of fossil fuels drops like a stone, the ERoEI of renewables must follow suit, as they rely entirely on the former.  Is Mearns a fan of nuclear power?  You make up your mind….

As Fort McMurray burns, and its smoke plume reaches the East coast of the USA, it’s occurred to me that the inevitable efforts and energy smoke-plume-from-fort-mcmurray-fire-reaches-us-east-coastrequired to rebuild it once the fire is out (IF, that is, it doesn’t reach the tar sands and sets them alight…), should be included in the ERoEI of fossil fuels.  Whilst it’s impossible to say Climate Change caused the fire in Alberta Canada, it’s impossible to not make the connection that the only reason it was over 20°C when the fire started was entirely down to the jetstream going haywire because of the arctic melt……  in fact, the energy spent rebuilding destroyed infrastructure caused by Climate Change anywhere should now be included in the ERoEI of fossil fuels….

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

A new study by Ferroni and Hopkirk [1] estimates the ERoEI of temperate latitude solar photovoltaic (PV) systems to be 0.83. If correct, that means more energy is used to make the PV panels than will ever be recovered from them during their 25 year lifetime. A PV panel will produce more CO2 than if coal were simply used directly to make electricity. Worse than that, all the CO2 from PV production is in the atmosphere today, while burning coal to make electricity, the emissions would be spread over the 25 year period. The image shows the true green credentials of solar PV where industrial wastelands have been created in China so that Europeans can make believe they are reducing CO2 emissions (image credit Business Insider).

I have been asked to write a post reviewing the concept of energy return on energy invested (ER0EI) and as a first step in that direction I sent an email to my State-side friends Charlie Hall, Nate Hagens and David Murphy asking that they send me recent literature. The first paper I read was by Ferruccio Ferroni and Robert J. Hopkirk titled Energy Return on Energy Invested (ERoEI) for photovoltaic solar systems in regions of moderate insolation [1] and the findings are so stunning that I felt compelled to write this post immediately.

So what is ERoEI? It is simply the ratio of energy gathered to the amount of energy used to gather the energy (the energy invested):

ERoEI = energy gathered / energy invested

Simple, isn’t it? Well it’s not quite so simple as it appears at first sight. For example, using PV to illustrate the point, the energy gathered will depend on latitude, the amount of sunshine, the orientation of the panels and also on the lifetime of the panels themselves. And how do you record or measure the energy invested? Do you simply measure the electricity used at the PV factory, or do you include the energy consumed by the workers and the miners who mined the silicon and the coal that is used to make the electricity? Ferroni and Hopkirk go into all of these details and come up with an ERoEI for temperate latitude solar PV of 0.83. At this level, solar PV is not an energy source but is an energy sink. That is for Switzerland and Germany. It will be much worse in Aberdeen!

Why is ERoEI important? It is a concept that is alien to most individuals, including many engineers, energy sector employees, academics and policy makers. The related concept of net energy is defined as:

Net Energy = ERoEI – 1 (where 1 is the energy invested)

Net energy is the surplus energy left over from our energy gathering activities that is used to power society – build hospitals, schools, aircraft carriers and to grow food. In the past the ERoEI of our primary energy sources – oil, gas and coal – was so high, probably over 50, that there was bucket loads of cheap energy left over to build all the infrastructure and to feed all the people that now inhabit The Earth. But with the net energy equation for solar PV looking like this:

0.83-1 = -0.17

….. Brussels we have a problem!

So how can it be possible that we are managing to deploy devices that evidently consume rather than produce energy? The simple answer is that our finance system, laws and subsidies are able to bend the laws of physics and thermodynamics for so long as we have enough high ERoEI energy available to maintain the whole system and to subsidise parasitic renewables. Try mining and purifying silicon using an electric mining machine powered by The Sun and the laws of physics will re-establish themselves quite quickly.

In very simple terms, solar PV deployed in northern Europe can be viewed as coal burned in China used to generate electricity over here. All of the CO2 emissions, that underpin the motive for PV, are made in China. Only in the event of high energy gain in the PV device would solar PV reduce CO2 emissions. More on that later.

Energy Return

The calculations are all based on the energy produced by 1 m^2 of PV.

Theoretical calculations of what PV modules should generate made by manufacturers do not take into account operational degradation due to surface dirt. Nor do they take into account poor orientation, unit failure or breakage, all of which are quite common.

The actual energy produced using Swiss statistics works out at 106kWe/m^2 yr

We then also need to know how long the panels last. Manufacturers claim 30 years while empirical evidence suggests a mean scrapage age of only 17 years in Germany. Ferroni and Hopkirk use a generous 25 year unit life.

Combining all these factors leads to a number of 2203kWe/m^2 for the life of a unit.

Energy Invested

The energy invested calculation is also based on 1 m^2 of panel and uses mass of materials as a proxy for energy consumed and GDP energy intensity as a proxy for the labour part of the equation.

Two different methods for measuring energy invested are described:

  • ERoEI(IEA)
  • ERoEI(Ext)

Where IEA = methodology employed by the International Energy Agency and Ext = extended boundary as described by Murphy and Hall, 2010 [2,3]. The difference between the two is that the IEA is tending to focus on the energy used in the factory process while the extended methodology of Murphy and Hall, 2010 includes activities such as mining, purifying and transporting the silicon raw material.

In my opinion, Ferroni and Hopkirk correctly follow the extended ERoEI methodology of Murphy and Hall and include the following in their calculations:

  • Materials to make panels but also to erect and install panels
  • Labour at every stage of the process from mining manufacture and disposal
  • Manufacturing process i.e. the energy used in the various factories
  • Faulty panels that are discarded
  • Capital which is viewed as the utilisation of pre-existing infrastructure and energy investment
  • Integration of intermittent PV onto the grid

And that gives us the result of ERoEI:

2203 / 2664 kW he/m^2 = 0.83

The only point I would question is the inclusion of the energy cost of capital. All energy produced can be divided into energy used to gather energy and energy for society and I would question whether the cost of capital does not fall into the latter category?

But there appears to be one major omission and that is the energy cost of distribution. In Europe, about 50% of the cost of electricity (excluding taxes) falls to the grid construction and maintenance. If that was to be included it would make another serious dent in the ERoEI.

This value for ERoEI is lower than the value of 2 reported by Prieto and Hall [4] and substantially lower that the values of 5 to 6 reported by the IEA [5]. One reason for this is that the current paper [1] is specifically for temperate latitude solar. But Ferroni and Hopkirk also detail omissions by the IEA as summarised below.

IEA energy input omissions and errors

a) The energy flux across the system boundaries and invested for the labour is not included.
b) The energy flux across the system boundaries and invested for the capital is not included.
c) The energy invested for integration of the PV-generated electricity into a complex and flexible electricity supply and distribution system is not included (energy production does not follow the needs of the customer).
d) The IEA guidelines specify the use of “primary energy equivalent” as a basis. However, since the energy returned is measured as secondary electrical energy, the energy carrier itself, and since some 64% to 67% of the energy invested for the production of solar-silicon and PV modules is also in the form of electricity (Weissbach et al., 2013) and since moreover, the rules for the conversion from carrier or secondary energy back to primary energy are not scientifically perfect (Giampietro and Sorman, 2013), it is both easier and more appropriate to express the energy invested as electrical energy. The direct contribution of fossil fuel, for instance in providing energy for process heating, also has to be converted into secondary energy. The conversion from a fossil fuel’s internal chemical energy to electricity is achieved in modern power plants with an efficiency of 38% according to the BP statistic protocol (BP Statistical Review of World Energy, June 2015). In the present paper, in order to avoid conversion errors, we shall continue to use electrical (i.e. secondary) energy in kW he/m2 as our basic energy unit.
e) The recommended plant lifetime of 30 years, based on the experiences to date, must be regarded as unrealistic.
f) The energy returned can and should be based on actual experimental data measured in the field. Use of this procedure will yield values in general much lower than the electricity production expected by investors and politicians.

Of those I’d agree straight off with “a”, “c” and “f”. I’m not sure about “b” and “e” I’m sure this will be subject to debate. “d” is a complex issue and is in fact the same one described in my recent post EU and BP Renewable Electricity Accounting Methodologies. I agree with Ferroni and Hopkirk that units of electricity should be used throughout but if the IEA have grossed up the electricity used to account for thermal losses in power stations then this would increase their energy invested and suppress not inflate their estimates of ERoEI. Hence this is a point that needs to be clarified.

Environmental impacts

The main reason for deploying solar PV in Europe is to lower CO2 emissions. The European Commission and most European governments have been living in cloud cuckoo land allowing CO2 intensive industries to move to China, lowering emissions in Europe while raising emissions in China and making believe that importing steel from China somehow is emissions free.

The example of solar PV brings this into sharp focus. Assuming the main energy input is from coal (and low efficiency dirty coal at that) and with ERoEI <1, making electricity from solar PV will actually create higher emissions than had coal been used directly to make electricity for consumption in the first place. But it’s a lot worse than that. All of the emissions associated with 25 years of electricity production are in the atmosphere now making global warming much worse than it would otherwise have been without the PV.

And it gets even worse than that! The manufacture of PV panels involves lots of nasty chemicals too:

Many potentially hazardous chemicals are used during the production of solar modules. To be mentioned here is, for instance, nitrogen trifluoride (NF3), (Arnold et al., 2013), a gas used for the cleaning of the remaining silicon-containing contaminants in process chambers. According to the IPCC (Intergovernmental Panel on Climate Change) this gas has a global warming potential of approximately 16600 times that of CO2. Two other similarly undesirable “greenhouse” gases appearing are hexafluoroethane (C2F6) and sulphur hexafluoride (SF6).

And

The average weight of a photovoltaic module is 16 kg/m2 and the weight of the support system, inverter and the balance of the system is at least 25 kg/m2 (Myrans, 2009), whereby the weight of concrete is not included. Also, most chemicals used, such as acids/ bases, etchants, elemental gases, dopants, photolithographic chemicals etc. are not included, since quantities are small. But, we must add hydrochloric acid (HCl): the production of the solar- grade silicon for one square meter of panel area requires 3.5 kg of concentrated hydrochloric acid.

Comparison with nuclear

The paper offers some interesting comparisons with nuclear power. Looking first at materials used per unit of electricity produced:

  • PV uses 20.2 g per kW he (mainly steel aluminium and copper)
  • A nuclear power station uses 0.31 g per kW he (mainly steel) for a load factor of 85%

kW he = kilowatt hours electrical

Looking at labour, the authors observe:

The suppliers involved in the renewable energies industry advertise their capability to create many new jobs.

While of course the best forms of energy use as little labour as possible. At the point where ERoEI reaches 1, everyone is engaged in gathering energy and society as we know it collapses!

  • Solar PV creates 94.4 jobs per MW installed, adjusted for capacity factor.
  • Nuclear creates 13 jobs per MW installed covering construction, operation and decommissioning.

This may seem great to the politicians but it’s this inefficiency that makes solar PV expensive and kills the ERoEI. And looking at capital costs:

  • Solar PV needs CHF 6000 per kW installed (CHF = Swiss Franc)
  • Nuclear power CHF 5500 per kW installed

But normalising for capacity factors of 9% for solar and 85% for nuclear we get for effective capacity:

66,667 / 6471 = 10.3

Solar PV is 10 times more capital intensive than nuclear.

Energy transformation

When ERoEI approaches or goes below 1 we enter the realm of energy transformation which is quite common in our energy system. For example, converting coal to electricity we lose approximately 62% of the thermal energy. Converting coal and other raw materials into a PV panel may in certain circumstances make some sense. For example PV and a battery system may provide African villages with some electricity where there is little hope of ever getting a grid connection. Likewise for a mountain cabin. Individuals concerned about blackouts may also consider a PV battery system as a backup contingency.

But as a means of reducing CO2 emissions PV fails the test badly at temperate latitudes. It simply adds cost and noise to the system. In sunnier climates the situation will improve.

Concluding comments

The findings of this single study suggest that deploying solar PV at high latitudes in countries like Germany and the UK is a total waste of time, energy and money. All that is achieved is to raise the price of electricity and destabilise the grid. Defenders of RE and solar will point out that this is a single paper and there are certainly some of the inputs to Ferroni and Hopkirk that are open to debate. But there are reasons to believe that the findings are zeroing in on reality. For example Prieto and Hall found ERoEI for solar PV = 2. Looking only at cloudy, high temperate latitudes will substantially degrade that number.

And you just need to look at the outputs as shown below. Solar PV produces a dribble in winter and absolutely nothing at the 18:00 peak demand. There is a large financial cost and energy cost to compensate for this that RE enthusiasts dismiss with a wave of the arm.

Figure 1 From UK Grid Graphed. The distribution of solar production in the UK has grown 7 fold in 4 years. But 7 times a dribble in winter is still a dribble.  The large amount of embodied energy in these expensive devices does no work for us at all when we need it most.

Energy Matters has a good search facility top right. Insert solar pv and I was surprised to find how many articles Roger and I have written and they all more or less reach the same conclusions. I have added these links at the end of the post.

Figure 2 A typical solar installation in Aberdeen where the panels are on an east facing roof leaving the ideal south facing roof empty. This is a symbol of ignorance and stupidity that also pervades academia. Has anyone seen a University that does not have solar PV deployed? I’ve heard academics argue that orientation does not matter in Scotland, and they could be right. I dare say leaving the panels in their box would make little difference to their output. Academics, of course, are increasingly keen to support government policies. Note that sunny days like this one are extremely rare in Aberdeen. And in winter time, the sun rises about 10:00 and sets around 15:00.

Two years ago I fulminated about the random orientation of solar panels in Aberdeen in a post called Solar Scotland. And this random orientation will undoubtedly lead to serious degradation of the ERoEI. PV enthusiasts will no doubt assume that all solar PV panels are optimally orientated in their net energy analysis while in the real world of Ferroni and Hopkirk, they are not. A good remedy here would be to remove the feed in tariffs of systems not optimally deployed while ending future solar PV feed in tariffs all together.

But how to get this message heard at the political level? David MacKay’s final interview was very revealing:

The only reason solar got on the table was democracy. The MPs wanted to have a solar feed-in-tariff. So in spite of the civil servants advising ministers, ‘no, we shouldn’t subsidise solar’, we ended up having this policy. There was very successful lobbying by the solar lobbyists as well. So now there’s this widespread belief that solar is a wonderful thing, even though … Britain is one of the darkest countries in the world.

If the politicians do not now listen to the advice of one of the World’s most famous and respected energy analysts then I guess they will not listen to anyone. But they will with time become increasingly aware of the consequences of leading their electorate off the net energy cliff.

References

[1] Ferruccio Ferroni and Robert J. Hopkirk 2016: Energy Return on Energy Invested (ERoEI) for photovoltaic solar systems in regions of moderate insolation: Energy Policy 94 (2016) 336–344

[2] Murphy, D.J.R., Hall, C.A.S., 2010. Year in review-EROI or energy return on (energy) invested. Ann. N. Y. Acad. Sci. Spec. Issue Ecol. Econ. Rev. 1185, 102–118.

[3] Murphy, D.J.R., Hall, C.A.S., 2011. Energy return on investment, peak oil and the end of economic growth. Ann. N.Y. Acad. Sci. Spec. Issue Ecol. Econ. 1219, 52–72.

[4] Prieto, P.A., Hall, C.A.S., 2013. Spain’s Photovoltaic Revolution – The Energy Return on Investment. By Pedro A. Prieto and Charles A.S. Hall, Springer.

[5] IEA-PVPS T12, Methodology Guidelines on the Life Cycle Assessment of Photovoltaic Electricity – Report IEA-PVPS T12-03:2011.