Why I am a double atheist

28 11 2017

For years and years – at least 15 – I argued with Dave Kimble over his notion that solar energy production was growing far too fast to be sustainable, let alone reduce greenhouse emissions.  I eventually had to relent and agree with him, he had a keener eye for numbers than me, and he was way better with spreadsheets!

The whole green technology thing has become a religion. I know, I used to have the faith too….. but now, as you might know if you’ve been ‘here’ long enough, I neither believe in god nor green tech!

This article – to which you will have to go to for the references – landed in my newsfeed…….  and lo and behold, it says exactly the same thing Dave was saying all those years ago…….:

How Sustainable is PV solar power?

How sustainable is pv solar power

Picture: Jonathan Potts.

It’s generally assumed that it only takes a few years before solar panels have generated as much energy as it took to make them, resulting in very low greenhouse gas emissions compared to conventional grid electricity.

However, a more critical analysis shows that the cumulative energy and CO2 balance of the industry is negative, meaning that solar PV has actually increased energy use and greenhouse gas emissions instead of lowering them.

The problem is that we use and produce solar panels in the wrong places. By carefully selecting the location of both manufacturing and installation, the potential of solar power could be huge.

There’s nothing but good news about solar energy these days. The average global price of PV panels has plummeted by more than 75% since 2008, and this trend is expected to continue in the coming years, though at a lower rate. [1-2] According to the 2015 solar outlook by investment bank Deutsche Bank, solar systems will be at grid parity in up to 80% of the global market by the end of 2017, meaning that PV electricity will be cost-effective compared to electricity from the grid. [3-4]

Lower costs have spurred an increase in solar PV installments. According to the Renewables 2014 Global Status Report, a record of more than 39 gigawatt (GW) of solar PV capacity was added in 2013, which brings total (peak) capacity worldwide to 139 GW at the end of 2013. While this is not even enough to generate 1% of global electricity demand, the growth is impressive. Almost half of all PV capacity in operation today was added in the past two years (2012-2013). [5] In 2014, an estimated 45 GW was added, bringing the total to 184 GW. [6] [4].

Solar PV total global capacitySolar PV total global capacity, 2004-2013. Source: Renewables 2014 Global Status Report.

Meanwhile, solar cells are becoming more energy efficient, and the same goes for the technology used to manufacture them. For example, the polysilicon content in solar cells — the most energy-intensive component — has come down to 5.5-6.0 grams per watt peak (g/wp), a number that will further decrease to 4.5-5.0 g/wp in 2017. [2] Both trends have a positive effect on the sustainability of solar PV systems. According to the latest life cycle analyses, which measure the environmental impact of solar panels from production to decommission, greenhouse gas emissions have come down to around 30 grams of CO2-equivalents per kilwatt-hour of electricity generated (gCO2e/kWh), compared to 40-50 grams of CO2-equivalents ten years ago. [7-11] [12]

According to these numbers, electricity generated by photovoltaic systems is 15 times less carbon-intensive than electricity generated by a natural gas plant (450 gCO2e/kWh), and at least 30 times less carbon-intensive than electricity generated by a coal plant (+1,000 gCO2e/kWh). The most-cited energy payback times (EPBT) for solar PV systems are between one and two years. It seems that photovoltaic power, around since the 1970s, is finally ready to take over the role of fossil fuels.

BUT the bit that caught my eye was this…..:

A life cycle analysis that takes into account the growth rate of solar PV is called a “dynamic” life cycle analysis, as opposed to a “static” LCA, which looks only at an individual solar PV system. The two factors that determine the outcome of a dynamic life cycle analysis are the growth rate on the one hand, and the embodied energy and carbon of the PV system on the other hand. If the growth rate or the embodied energy or carbon increases, so does the “erosion” or “cannibalization” of the energy and CO2 savings made due to the production of newly installed capacity. [16]

For the deployment of solar PV systems to grow while remaining net greenhouse gas mitigators, they must grow at a rate slower than the inverse of their CO2 payback time. [19] For example, if the average energy and CO2 payback times of a solar PV system are four years and the industry grows at a rate of 25%, no net energy is produced and no greenhouse gas emissions are offset. [19] If the growth rate is higher than 25%, the aggregate of solar PV systems actually becomes a net CO2 and energy sink. In this scenario, the industry expands so fast that the energy savings and GHG emissions prevented by solar PV systems are negated to fabricate the next wave of solar PV systems. [20]

Which is precisely what Dave Kimble was saying more than ten years ago.  To see his charts and download his spreadsheet, go to this post.

His conclusions are that “We have been living in an era of expanding energy availability, but Peak Oil and the constraints of Global Warming mean we are entering a new era of energy scarcity. In the past, you could always get the energy you wanted by simply paying for it. From here on, we are going to have to be very careful about how we allocate energy, because not only is it going to be very expensive, it will mean that someone else will have to do without. For the first time, ERoEI is going to be critically important to what we choose to do. If this factor is ignored, we will end up spending our fossil energy on making solar energy, which only makes Global Warming worse in the short to medium term.”

 

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A crisis of stupidity

6 10 2017

Through sheer stupidity, I gave myself a couple of days of un necessary stress…… As you may, or may not know, I chose Nickel Iron batteries for my standalone solar power system because they will operate at voltages other battery chemistries cannot even dream of, and all without destroying them. By some weird coincidence, someone on a FB group I belong to called Aussies living simply posted how she was having difficulties with her NiFe battery setup, which frankly had nothing to do with the batteries, and everything to do with dodgy wiring and inappropriate peripherals…….

To cut to the chase, debate over whether NiFe was better than Lithium occurred (and boy they chose the wrong person to pick a fight with!). As a result of this discussion, I ended up ringing Andrew Bartlett who sold me the batteries, and we started nattering about this and that. I mentioned that I had seen my batteries go down to 44V – I occasionally turn the solar power off to ‘flatten the batteries’, as this is supposed to increase their storage capacity. Andrew said I should actually take them down to below 40V, but as I had had problems with resetting the inverter with my laptop because I don’t use windoze, I wasn’t certain what settings I had actually used….

Anyhow, on the last night I had the solar power off, I checked how things were going, and the voltage was still above 50V, so I decided to leave it. Unbeknownst to me, the weather was about to do its Tasmanian thing and turn to you know what. In the morning, it was just pouring, so I stayed in bed, watching the news and such like, there really was nothing for me to do in the deluge…….

At lunch time, feeling a bit stir crazy, I walked up to the power station to find the inverter had turned itself off, with the red low battery voltage glowing quite brightly in the sombre environment of a container on a rainy day……

Even in the poor light, the battery voltage was above 48V (can’t remember now), so having closed the solar array breakers I switched the inverter back on. The freezer, which had now been off for an indeterminate length of time cut straight back in, but with the solar array barely generating 90 Watts – or 4.5% capacity – and the freezer needing about 120W, it didn’t take too long before the battery voltage was below the inverter’s operating range. Which to my amazement was in fact 32.6V!

20171005_092747

The red light is FLASHING, the green one is still on, but at 10V below the battery bank’s nominal voltage, it’s all about to go pear shaped!

A few trips back and forth (a good 400m at a time) between the shed and the power station in my oilskin managed to keep the contents of the freezer frozen. One good thing, it wasn’t exactly hot, the thermometer seemed stuck on 9C all day and night long……. the unusual weather was coming from the East, and we were basically in thick wet fog for the duration.

The following day was not much better, the fog was gone, but there was still no sunlight to speak of. It’s actually quite amazing how well our eyes adapt to the lack of light, solar panels unfortunately do not come with irises…!

That day – yesterday – during which the array was on full time, saw just 0.6kWh of energy generated. And the freezer needs about 0.8 in a 24 hour period. Any other kind of batteries would have keeled over, and I would have lost the content of the freezer. Having said that….. I would also not have turned the solar array off if I was using more conventional batteries…!

I only had myself to blame, but at least I learned something (like I won’t do this again!) and I now know how the inverter ticks.

This morning, by 9:30AM, more than twice as much energy had already been squeezed into the batteries as had been generated all day long the day before, and the freezer was cycling normally; as of later this afternoon, no less than ten times as much energy had gone into the batteries as did yesterday, and they now look very healthy, thank you very much for caring…..

And some people still refuse to believe how intermittent renewables can be…….





Blindspots and Superheroes

14 05 2017

I haven’t heard much from Nate Hagens in recent times, but when he does come out of the woodwork, his communications skills certainly come through….. We who follow the collapse of the world as we know it probably know most of what’s in this admirable presentation, but it is absolutely captivating, and you will learn something new, or see it in a different perspective. It’s an hour and twenty minutes long (I actually drove down town to use the library’s free wi-fi to download it, my mobile phone data allowance won’t stretch to a quarter Gig for one video!), so make yourself a cup of your favourite poison, and enjoy the show……

Nathan John Hagens is a former Wall Street analyst, turned college professor and systems-science advocate. Nate has an MBA with Honors from the University of Chicago and a PhD in Natural Resources/Energy from the University of Vermont. He is on the Boards of Post Carbon Institute, Institute for Integrated Economic Research, and Institute for the Study of Energy and our Future. He teaches a class at the University of Minnesota called “Reality 101 – A Survey of the Human Predicament”.

Nate, partnering with environmental strategist DJ White, has created the “Bottleneck Foundation”, a nonprofit initiative designed to help steer towards better human and ecological futures than would otherwise be attained. The “Bottlenecks” are the cultural, biological, and technological challenges which will arise as energy and terrestrial biomass begin their long fall back toward sustainable-flow baselines this century. The “Foundation” part of the name is a tip of the hat to Asimov’s “Foundation” series of novels, about an organization designed to mitigate the negative effects of societal simplification. BF is dedicated to making “synthesis science” accessible to a new generation of engaged people, through educational materials and projects which demonstrate that reality is a lot different from our culture currently thinks it is.





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……

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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.