Less than the sum of its parts: Rethinking “all of the above” clean energy

6 06 2015

Well, this is different.  If you needed more proof of why I think going 100% renewables is pure fantasy, this new way of parsing the facts using Capacity Factor should convince you.  Sometimes, even the obvious takes time to become obvious!  Mind you, I can’t agree with “build wind not solar”, because some places have no wind and loads of solar (and vice versa).  In the end, renewables are best in standalone systems, and even then, will only ‘solve’ our energy problems for only as long as we have fossil fuels to work the system, and we can’t afford to burn any more.  We can’t even afford the financial system to pay for it, and certainly not the nuclear grid these guys at Brave New Climate believe in……

Originally published over at Brave New Climate.

Guest Post by John Morgan. John is Chief Scientist at a Sydney startup developing smart grid and grid scale energy storage technologies.  You can follow John on twitter at @JohnDPMorgan.

The fastest path to decarbonization would seem to be combining every kind of low carbon energy available – the so-called “all of the above” camp of clean energy advocacy.  The argument runs that different kinds of clean energy are complementary and we should build as much of each as we can manage.  This is not in fact the case, and I’ll show that a mix of wind and solar significantly decreases the total share of energy that all renewables can capture.  The “all of the above” approach to emissions reduction needs to be reconsidered.

In a recent essay Breakthrough Institute writers Jesse Jenkins and Alex Trembath have described a simple limit on the maximum contribution of wind and solar energy: it is increasingly difficult for the market share of variable renewable energy [VRE] sources to exceed their capacity factor.  For instance, if wind has a capacity factor of 35%, this says it is very difficult to increase wind to more than 35% of electrical energy.  Lets look at why this is so, and extend the principle to a mix of renewables.

The capacity factor (CF) is the fraction of ‘nameplate capacity’ (maximum output) a wind turbine or solar generator produces over time, due to variation in wind, or sunlight.  Wind might typically have a CF of 35%, solar a CF of 15% (and I’ll use these nominal values throughout).

Jesse and Alex’s “CF% = market share” rule arises because it marks the point in the build out of variable renewables at which the occasional full output of wind and solar generators exceeds the total demand on the grid.

At this point it gets very hard to add additional wind or solar.  If output exceeds demand, production must be curtailed, energy stored, or consumers incentivized to use the excess energy.  Curtailment is a direct economic loss to the generators. So is raising demand by lowering prices.  Energy storage is very expensive and for practical purposes technically unachievable at the scale required.  It also degrades the EROEI of these generators to unworkable levels.

Jesse and Alex make this argument in detail, backed up with real world data for fully connected grids (i.e. not limited by State boundaries), with necessary qualifications, and I urge you to read their essay.

The “CF% = market share” boundary is a real limit on growth of wind and solar.  Its not impossible to exceed it, just very difficult and expensive. Its an inflexion point; bit like peak oil, its where the easy growth ends.  And the difficulties are felt well before the threshold is crossed.  I’ve referred to this limit elsewhere as the “event horizon” of renewable energy.

So if wind is limited to say 35% of energy, and solar to 15%, can we add them together and achieve 50% share?  The Breakthrough authors seem to think so, writing that “this threshold indicates that wind and solar may be able to supply anywhere from a third to a half of all electricity needs”.  That would be a very considerable addition of low carbon energy.  But unfortunately this is not the case.

Here’s the problem with adding solar: it produces about half as much energy as wind for the same capacity.  And the capacity factor rule sets a limit on total variable renewable capacity.  So at the limit solar capacity is not additive to wind, it displaces wind, while producing less energy.  Any amount of solar lowers the share of energy that wind and solar together can acquire, and the optimal mix for decarbonization is all wind and no solar.

This is a general corollary to the capacity factor rule – adding lower capacity factor generation to the mix reduces the potential share of variable renewable energy.  It is the energy equivalent of Gresham’s Law – “Bad energy drives out good”.  Far from targeting a “mix of renewables”, we are better off targeting just the one with the highest capacity factor.  We should build wind and not solar.

You can see this dynamic in the following figure, which plots the limiting share of wind and solar energy (VRE) in the grid as a function of solar’s share of wind and solar capacity.  Adding solar capacity cannibalizes wind capacity, and reduces the total amount of low carbon energy that these sources can ultimately provide.  Solar is not additive to wind; its subtractive.

The situation becomes even clearer if we shift focus from installed capacity to energy delivered.  In the plot below, the x-axis now shows the fraction of wind and solar energy that is produced by solar.

Introducing solar energy into the mix causes a rapid drop in the maximum grid penetration of all variable renewable energy.  Wind alone could potentially achieve 35% of grid energy share.  But with 50% solar, the maximum share that wind and solar together can achieve is just 21%.

In other words, building out solar effectively robs us of a whole climate stabilization “wedge”.

It should be remarked that this capacity factor rule sets too optimistic a limit.  The Breakthrough writers cite estimates that only 55%-60% of grid energy could be replaced by variable sources, due to stability requirements.  This means VRE share will struggle to exceed 60% of capacity factor, and the limits described above will be reduced by that factor.  So while wind alone could achieve up to about 21% of all electricity, a 50-50 mix of solar and wind is practically limited to only 12%.

This is a lot to give away.

So long as we only have a small amount of solar and wind we can build as much of either as we like.  The limit only becomes apparent at higher penetration.  But this happens much more quickly if there’s a lot of solar in the mix.

There may be good reasons to build solar in the early stages of a clean energy expansion.  The rate of emissions reduction matters, and while supply chains are developing, building both solar and wind might help.  But if this trajectory is to continue we will need to shift resources to wind fairly early on, and allow solar capacity to decline.

This should prompt a rethink of the simplistic “all of the above” response to emissions reduction, and the popular notion that there should be a mix of renewables.  If it doesn’t even work for wind and solar, does it work anywhere at all?  Its time to pick some winners, and support for renewable energy at scale should increasingly favour wind over solar.

And we should also think about how to decarbonise the remaining eighty percent of the grid that variable renewables can’t touch.


Wind Blowing Nowhere

24 01 2015

I’ve just found this amazing post on Euan Mears’ excellent Energy Matters blog that clearly demonstrates, with real data, that anyone who believes renewables can run Business as Usual are just plain dreaming.

In much of Europe energy policy is being formulated by policymakers who assume that combining wind generation over large areas will flatten out the spikes and fill in the troughs and thereby allow wind to be “harnessed to provide reliable electricity” as the European Wind Energy Association tells them it will:

The wind does not blow continuously, yet there is little overall impact if the wind stops blowing somewhere – it is always blowing somewhere else. Thus, wind can be harnessed to provide reliable electricity even though the wind is not available 100% of the time at one particular site.

Here we will review whether this assumption is valid. We will do so by progressively combining hourly wind generation data for 2013 for nine countries in Western Europe downloaded from the excellent data base compiled by Paul-Frederik Bach, paying special attention to periods when “the wind stops blowing somewhere”. The nine countries are Belgium, the Czech Republic, Denmark, Finland, France, Ireland, Germany, Spain and the UK, which together cover a land area of 2.3 million square kilometers and extend over distances of 2,000 kilometers east-west and 4,000 kilometers north-south:

Figure 1:  The nine countries

We begin with Spain, Europe’s largest producer of wind power in 2013. Here is Spain’s hourly wind generation for the year. Four periods of low wind output are numbered for reference:

Figure 2:  Hourly wind generation, Spain, 2013

Now we will add Germany, Europe’s second-largest wind power producer in 2013. We find that Spanish low wind output period 4 was more than offset by a coincident German wind spike. Spanish low wind periods 1, 2 and 3, however, were not.

Figure 3:  Hourly wind generation, Spain + Germany, 2013

Now we add UK, the third largest producer in 2013. Wind generation in UK during periods 1, 2 and 3 was also minimal:

Figure 4:  Hourly wind generation, Spain + Germany + UK, 2013

As it was in France, the fourth largest producer:

Figure 5:  Hourly wind generation, Spain + Germany + UK + France, 2013

And also in the other five countries, which I’ve combined for convenience:

Figure 6:  Hourly wind generation, nine countries combined, 2013

Figure 7 is a blowup of the period between February 2 and 15, which covers low wind period 2. According to these results the wind died to a whisper all over Western Europe in the early hours of February 8th:

Figure 7: Wind generation, nine countries combined, February 2013

These results are, however, potentially misleading because of the large differences in output between the different countries. The wind could have been blowing in Finland and the Czech Republic but we wouldn’t see it in Figure 7 because the output from these countries is still swamped by the larger producers. To level the playing field I normalized the data by setting maximum 2013 wind generation to 100% and the minimum to 0% in each country, so that Germany, for example, scores 100% with 26,000MW output and 50% with 13,000MW while Finland scores 100% with only 222MW and 50% with only 111MW. Expressing generation as a percentage of maximum output gives us a reasonably good proxy for wind speed.

Replotting Figure 7 using these percentages yields the results shown in Figure 8 (the maximum theoretical output for the nine countries combined is 900%, incidentally). We find that the wind was in fact still blowing in Ireland during the low-wind period on February 8th, but usually at less than 50% of maximum.

Figure 8:  Percent of maximum wind generation, February 2013

But even Ireland was not blessed with much in the way of wind at the time of minimum output, which occurred at 5 am. Figure 10 plots the percentage-of-maximum values for the individual countries at 5 am on the map of Europe. If we assume that less than 5% signifies “no wind” there was at this time no wind over an area up to 1,000 km wide extending from Gibraltar at least to the northern tip of Denmark and probably as far north as the White Sea:

Figure 9:  Map of percent of maximum wind generation, February 2013

During this period the wind was clearly not blowing “somewhere else”, and there are other periods like it.

Combining wind generation from the nine countries has also not smoothed out the spikes. The final product looks just as spiky as the data from Spain we began with; the spikes have just shifted position:

Figure 10: Spain wind generation vs. combined generation in all nine countries, 2013 (scales adjusted for visual similarity)

Obviously combining wind generation in Western Europe is not going to provide the “reliable electricity” its backers claim it will. Integrating European wind into a European grid will in fact pose just as many problems as integrating UK wind into the UK grid or Scottish wind into the Scottish grid, but on a larger scale. We will take a brief look at this issue before concluding.

Integrating the combined wind output from the nine countries into a European grid  would not have posed any insurmountable difficulties in 2013 because wind was still a minor player, supplying only 8.8% of demand:

Figure 11: Wind generation vs. demand, nine countries combined

But integration becomes progressively more problematic at higher levels of wind penetration. I simulated higher levels by factoring up 2013 wind generation with the results shown on Figure 12, which plots the percentage of demand supplied by wind in the nine countries in each hourly period. Twenty percent wind penetration looks as if it might be achievable; forty percent doesn’t.

Figure 12:  Percent of hourly demand supplied by wind at different levels of wind penetration using 2013 data

Finally, many thanks to Hubert Flocard, who recently performed a parallel study and graciously gave Energy Matters permission to re-invent the wheel, plus a hat tip to Hugh Sharman for bringing Hubert’s work to our attention.

Where is the electric grid headed?

19 11 2014

Followers of this blog will know my enthusiasm for solar power as a silver bullet for our future energy predicaments has waned, and in particular, my love affair with grid tied solar is over.  I have also been doubting for quite some time that the future of the electric grid is secure, and have on occasions discussed stand alone solar power as a possibility for those of us who are aware of the coming dilemmas to stretch their energy horizon a little further and make the inevitable energy descent less painful.  Well, it seems, this theme is catching on, even making it to what I consider to be mainstream internet sources.

Recently, on the Climate Spectator website (an arm of Alan Kohler’s straight as a die Business Spectator financial website), an article titled “Solar wins! Zombie-grid a dead man walking” began with this paragraph:

The grid financial model will collapse within 10 years, as millions of Australian households flee for the new, disruptive and cheaper alternative. This change will be as big as the conversion from horse and cart to motor vehicle, film to digital camera and the typewriter to the laptop.

I nearly fell off my chair…… because let’s face it, if the collapse of the grid financial model is not soon followed by total collapse, I would eat my hat.  The reasons the author – Matthew Wright CEO of Beyond Zero Emissions – gives for this prediction are:

Modeling by Zero Emissions Australia shows that an ordinary, but all-electric, household using off-the-shelf efficient electric appliances could be off the grid for between $30,000-$40,000 today and $12,000-$20,000 in 2024.

This is based on the following representative example of electricity demand charted below for an all-electric five-person household in Melbourne.

Example: One year of average monthly demand for all electric household in Melbourne (5 occupants).



Source: Powershop, Zero Emissions Australia

Households can install and size their off-grid solar system now and change their redundant gas appliances (stove top, gas hot water and gas heating) over later. Or, given that the price is going to be right to leave sometime in the next 10 years, they can start their electric conversion journey now. Ditching gas and the power grid starts by installing an oversized solar system (11-15kW) on the north, east, west and possibly even flat-racked. Indeed you can place it on the south face which captures diffuse light when its cloudy – which contributes over half of all generation during the middle of winter (more on that in another article).

10kW PV System

10kW PV System

I’m frankly AGHAST!  I wonder if Matthew has even ever seen a 10kW PV system (let alone a 15 kW one…)  One of my neighbours has such a large system on his roof, installed before Energex put their foot down and limited grid tied systems to 5kW, and it looks like the photo opposite.  Bear in mind this house was designed for solar to begin with, faces true North, built with a skillion roof, and is bigger than our place by some margin at 250m².  And yet, its roof is completely covered….  Try that on a standard McMansion hipped roof….

Consumption is consumption, whether it’s PVs or whatever, and at least KC exports 90% or more of what power his system produces, he doesn’t actually need it to run his house!  Any household that needs 11 to 15kW of solar has a serious efficiency problem that needs to be solved before spending “$30,000-$40,000“, and if Matthew believes such schemes are ways of dealing with Carbon emissions, he is seriously mistaken.

Then, he pushes heat pumps for water heating rather than solar……  I thought the title of this piece was “solar wins!”?  Why buy an electricity consuming gadget, even if very efficient, when there are alternatives that do not?  Matthew doesn’t even seem to understand the physics of energy with the statement “achieves Coefficient of Performance (COP) of ~4.0 or (400% efficient, yes that is possible)”  NO Matthew, 400% efficiency is NOT possible, COP is not efficiency…..  And you wonder why I have so many doubts about BZE’s green wet dream of 100% renewables for Australia?

But back to our grid problems.

“Industrialized countries face a future of increasingly severe blackouts, a new study warns, due to the proliferation of extreme weather events, the transition to unconventional fossil fuels, and fragile national grids that cannot keep up with rocketing energy demand” says Motherboard….

The paper published this September in Routledge’s Journal of Urban Technology points out that 50 major power outages have afflicted 26 countries in the last decade alone, driven by rapid population growth in concentrated urban areas and a rampant “addiction” to high-consumption lifestyles dependent on electric appliances.

Study authors Hugh Byrd and Prof Steve Matthewman of Auckland University, a sociologist of disaster risk, argue that this escalating demand is occurring precisely “as our resources become constrained due to the depletion of fossil fuel, a lack of renewable energy sources, peak oil and climate change.”

Blackouts, they warn, are “dress rehearsals for the future in which they will appear with greater frequency and severity,” they find. “We predict increasing numbers of blackouts due to growing uncertainties in supply and growing certainties in demand.”

The relentless growth in demand, 1300 percent from 1940 to 2001 in the US (and likely much the same here), is the obvious culprit with aircon requirements at the forefront.  And let’s not forget the coming new fad…..

Adding further pressure to future electricity demand is the rise of the electric vehicle, driven by efforts to mitigate climate change. Byrd and Matthewman note that in higher-income regions, switching entirely to electric cars would increase electricity demand by 15-40 percent. Even if we replaced all our petrol-guzzling cars with “highly efficient” electric cars, the new models would still consume about “twice as much electricity as residential and commercial air-conditioning combined.”

And as climate change brings warmer Summers and more intense rains to regions of North America and Australia, people resort to more and more air-conditioning to stay cool, another climate positive feedback loop maybe?

Worldwide, overall energy demand for air-conditioning “is projected to rise rapidly to 2100,” to as much as 40 times greater than it was in 2000. New York alone will need 40 percent more power in the next 15 years partly because the city will contain a million more people, aided of course by electrical appliances, elevators, and air-conditioning.

Yeah right….  like that‘s going to happen, with a failing grid model….?  The article even goes further saying “But in a slow-growth global economy hell-bent on austerity, the prospects for large government investments in grid resilience look slim. According to the global insurance company Allianz in an extensive report on blackout risks in the US and Europe, “privatization and liberalization” have contributed to “missing incentives to invest in reliable, and therefore well maintained, infrastructures.””

A new report by the French multinational technology firm CapGemini warns of a heightened risk of blackouts across Europe this winter due to the shut-down of gas-fired plants, competition from cheap US coal, and the big shift to wind and solar. Ironically, electricity surpluses from renewables have led to a fall in power prices and crippled fossil fuel utilities, which in turn has reduced the “electricity system’s margin to meet peak demand in specific conditions such as cold, dark and windless days,” according to the report.

So it seems the grid’s financial model in Europe is in just as deep a hole as Australia’s.  The more I think of the terminology ‘disruptive’ used to describe renewables, the more I think it’s accurate!  The increasing shift to renewable energy sources has, it appears, exacerbated the blackout risk not because they are bad at generating power, but because of the difficulty in integrating volatile, decentralized energy sources into old power grids designed half a century ago around the old fossil fuel model.  Something the BZE people just don’t seem to understand.

Take this for example:  Our friend Matthew Wright is at it again with “Imagine 1000 gigafactories – that’s what’s coming”

No doubt you have all heard of El on Musk, the CEO of Tesla, the electric car company.  “Tesla is everyone’s favourite motor car company, a darling of investors large and small. Rev heads who have driven a Tesla give it the nod” writes Matthew.  Well of course they’d give it the nod…. just like anyone who drives a brand new Range Rover would give that car the nod; after all, after driving our old bombs around, I’m sure I would be mighty impressed with a car worth some $70,000 too……

Musk’s gigafactories will be the world’s largest lithium-ion battery factory, and is expected to generate as much renewable energy as it needs to operate — and then some.  But is that thin line at the bottom right of the photo a road, or a mighty big cable going to Bolivia’s Lithium mines…?

Here’s the first problem with celebratory headlines over renewables: record renewable energy growth hasn’t stopped record fossil fuel burning, including record levels of coal burning. Coal use is growing so fast that the International Energy Authority expects it to surpass oil as the world’s top energy source by 2017.  And building gigafactories is only worsening the problem.

Mabe, the 1,500 gigawatts of electricity produced from renewables worldwide have prevented a further 1,500 gigawatts of fossil fuel power stations? Who can tell?  It’s just as possible that renewables have simply added 1,500 gigawatts of electricity to the global economy, fuelling economic growth and ever-greater industrial resource use. That being the case, far from limiting carbon dioxide emissions worldwide, renewables may simply have increased them because, as I’ve written many times before, no form of large-scale energy is carbon neutral.

And no one mentions the looming economic crisis having an effect on the grid’s reliability.  The future is taboo.  Watch this space…

The Electricity Industry’s Death Spiral revisited

10 07 2014

I know I only wrote about The Electricity Industry’s Death Spiral just a couple of days ago, but the speed at which things are now moving is almost bewildering.  The subject of disconnecting from the grid and moving to battery storage actually made it to the evening news last night……  I wish I could post a link to this video clip, but it looks like the ABC isn’t playing ball.  In truth, the owner of the system did such a bad job explaining how it works I doubt installers will be rushed off their feet just yet.

This from The Examiner, a Tasmanian online news outlet….

Energy specialist Lucy Carter of the Grattan Institute outlined the horror scenario for suppliers while launching a new report to be released on Monday about why we are paying too much for power.

She says network charges account for most of the increase in electricity prices. The carbon tax is small by comparison.  [the Carbon tax repeal act has just been knocked back in the Senate as I type this…  The motion was defeated 37 votes to 35.]

”The risk for the companies is that when people get the option of putting solar panels on their roofs and installing batteries and cutting the cord, demand will fall sharply. The people who end up left on the network will be the only ones left paying.” They will be stuck with extremely high network charges, forcing even more people off the network, pushing network charges higher still. It is what Ms Carter calls ”your death spiral scenario”.

She says it is not upon us yet, but if battery storage improves and network costs keep rising, it will be.

Part of Ms Carter’s proposed solution is for power companies to charge for network costs differently. At the moment customers who put very little strain on the network [like us…] pay the same fixed charge and the same amount per kilowatt as those whose peak usage necessitates extra spending on high-grade wires and substations.

Those peak users account for about one-third of the extra spending on infrastructure over the past five years, Ms Carter says.

She wants to charge users for the pressure they put on the network rather than for being part of it. Someone who comes home to a McMansion and whacks on all the airconditioners or heaters puts far more pressure on the network than someone who is at home all day using the same amount of power more steadily.

It can properly happen only with smart meters that report usage to retailers. Victoria has them and could adopt the proposal immediately. In other states such as NSW, Ms Carter says, the ability to levy variable charges could build a business case for suppliers paying to install smart meters.

Her other solution is even bolder: a peak usage warning to be delivered by SMS or broadcast on TV the day before extreme peak demand due to events such as heatwaves. In France it is done using a red, white and blue colour code. ‘’Red’’ means the next day is facing an extreme peak and that for that day only electricity will be more expensive. Throughout the rest of the year users will be given rebates to make sure they are not charged more overall.

The system would apply only in locations where the network was under pressure and the alternative was new infrastructure.

If it was in operation over the past five years, the Grattan Institute believes it would have saved $7.8 billion of the $17.6 billion spent on new infrastructure.

Data on household electricity use provided by the Victorian government suggests the change would be unlikely to affect disadvantaged families.

And now this from REneweconomy…

Wholesale electricity prices this week in Queensland have fallen below $30/MWh – see graph below – far below the levels of other states as mild weather and sunny condition reduced demand and generated a large amount of solar electricity.  [that’s 3c/kWh….. or 10% of the new retail price..]

aemo qld prices

The Energex network, which operates in the south-east corner and Brisbane, added another 13.7MW of rooftop solar in June, to take their total installed in the Energex network to 843MW on 261,500 homes and businesses.

Another 3,563 homes added solar in the south east corner in June, despite the fact that they would only get paid 8c/kWh for electricity they export back into the grid.

From Tuesday, that payment by the network ceases and falls to retailers. But the payment is voluntary, and has to be negotiated between the customer and the retailer. More than 59,000 houses – with some 200MW of rooftop solar – now find themselves in this situation.

Whats more, new rules have been introduced which allow the network operator to require that no exports can be made back to the grid for new rooftop solar systems. Ergon Energy explained its reasoning here, saying it wanted to prevent “reverse flows” and encourage more solar and energy storage on its network.

So if people in Qld lose what paltry feed in tariff they were getting, what incentive is there to stay connected?  Watch this space….

The 5 key elements of sustainable transport

13 04 2014

The 5 key elements of sustainable transport, or rather ‘so called’ sustainable transport makes for interesting reading.  Some of this info doesn’t really make much sense to me…. like the C intensity of different flights (business and economy, short and long) as a function of emissions per kilometre.

Interestingly, the difference between a ‘small car’ (a car that can only do 35MPG is NOT a small car!  But then, this is written in/for the USA….) and a grid charged electric car is only 15g CO2e/km, or just 9%.  By that measure, the Suzuki Alto I drove in Tasmania emits far less than an electric car, unless that car is 100% solar recharged.  And then I’m doubtful, because since we now know solar has a shockingly low ERoEI, it might be even closer than we think.  I’m also surprised cycling’s numbers are as high as they are shown here.  Does a cyclist really consume a whole lot more food than a motorist?

The article also states “People who live in cities have lower transport emissions.  Fuel economy may be lower in city traffic but that is more than made up for by the fact that city dwellers drive far less.”  Well that depends……  since moving from the city to the country, I’ve actually halved how much I drive!  Then it continues with “In 1950 less than 30% of the world’s population lived in cites, by 2010 that figure was over 50%, and by 2030 it is expected to surpass 60%. This natural trend to urbanization is a huge opportunity to for lowering both distance travelled per person and the carbon intensity of that travel.”  Whoever wrote this has obviously no idea cities will eventually be abandoned for being too far from their food sources, and due to the fact that when grids go down, none of the lifts will work!  Nor the sewerage……..

Shrink That Footprint


Transport is responsible for around a seventh of greenhouse gas emissions globally. Of these emissions almost two thirds are the result of passenger travel while the rest is due to freight.

So passenger travel is a big deal for climate.

In the chart above, which comes from our new eBook Emit This, we compare carbon intensity of different types of passenger transport on a per passenger kilometre basis.  Using it we can explain some elements important to the development of a sustainable transport system.

1) Fuel Economy

Our chart today compares the carbon intensity of different transport modes, per passenger kilometre.  The better fuel economy gets the lower emissions go.  If you just look at the cars you’ll see the large car (15 MPG) has emissions almost three times that of the hybrid car (45 MPG).

By improving fuel economy we can get the same mileage while generating fewer emissions.  Something that is achieved by making engines more efficient, vehicles lighter and bodies more aerodynamic.  But even then combustion engines remain relatively inefficient and produce emissions at the tailpipe, so improving them is really just a stop-gap en-route to sustainable transport.

2) Occupancy

The cheapest and simplest way to lower the carbon intensity of a passenger kilometre is to stick more people in the vehicle.  In each of the figures above car occupancy is assumed to be an average of 1.6 passengers (including the driver).  But most cars are designed for 5 people.

If you take a look at the bus examples the importance of occupancy becomes even more stark.  The local bus example has emissions seven times higher than the school bus.  While there routes may vary a little they are both diesel buses.  The main difference is that the school bus has very high occupancy.

With notable exception of flying public transport tends to have quite low carbon emissions, due largely to having relatively high occupancy.

3) Electrification

In the absence of breakthroughs in second generation biofuels electrification is the most important pathway to low carbon transport.

Electric cars using low carbon power have footprints less than half that of the best hybrid, even after you account for their larger manufacturing footprint.  Right down the bottom of our chart is the high-speed EuroStar rail which used low carbon French electricity. Though not on our chart the lowest carbon transport on earth is probably electrified public transport in a place like Norway where electricity generation is almost carbon free.

While there is a natural tendency to obsess about the electrification of cars, there are lots of interesting innovations occurring in the electrification  of rail, motorbikes, scooters and bikes.

4) Pedal power

They may be a bit low tech for some, but when it comes to carbon emissions bicycles are pretty cutting edge.  Even when you account for the foodprint of excess energy used when cycling, the humble bike is incredibly low carbon.

Bikes have obvious limitations around speed and distance, but for short trips in places with good infrastructure they are hard to beat in terms of carbon. They also have a great synergy with public transport systems like intercity rail.

5) Urbanization

Each of the first four elements we have described above refers to improving the carbon intensity of transport.  But emissions are a function of both how we travel and how far we travel.  One thing that tackles both of these issues is the trend towards urbanization.

People who live in cities have lower transport emissions.  Fuel economy may be lower in city traffic but that is more than made up for by the fact that city dwellers drive far less.  Electrification of public transport is more economic and practical in cities.  Occupancy on public transport systems is much higher.  And access to infrastructure for both cycling and walking is often better.

In 1950 less than 30% of the world’s population lived in cites, by 2010 that figure was over 50%, and by 2030 it is expected to surpass 60%. This natural trend to urbanization is a huge opportunity to for lowering both distance travelled per person and the carbon intensity of that travel.

Those are our five elements of sustainable transport: fuel economy, occupancy, electrification, pedal power and urbanization.

Check out our free new eBook Emit This for more ideas on getting more life out of less carbon.

Source: Shrink That Footprint. Reproduced with permission.

Why our next project is off-grid

17 10 2013

“Off-grid” or “off the grid” can mean lots of things to different people, especially if they are as diverse as Americans versus Australians.  I think the term probably started in the US.  I’ve always thought of the term as meaning not involving or requiring the use of mainstream sources of energy, but some definitions have wider meaning….

Off-grid is a new adjective which describes the situation of not using public utilities such as electricity, gas, water and mains sewerage. A truly off-grid home or building is completely autonomous in that it operates independently, not relying on any central supply of power or water.

I have to say that after seeing how much it costs now to be connected to the water grid and sewerage, I am very pleased we are not hooked up to either of those…  According to the definition above, we already are off-grid to a large extent, but for the purpose of this essay, I will mean not being connected to the electricity grid.

When we first connected to the grid with our first solar array, I wanted  to make a point.  Being the 400th grid tied solar house in Queensland makes us pioneers.  Today, there are 285,000!  Had we built at Mt Nebo as originally planned for the system which I bought before I even started building, we would have been even further up he list.  Compared to the cost of solar today, back then it really was an extravagance.  Like $500 for 64W panels, when today that sort of money will buy you 500W!  Or a 1500W inverter (that admittedly was also a stand alone inverter and battery charger) costing $5000…. when today you can buy portable inverters of that capacity for under $100, and grid tied devices for $350…!

The main reason, however, for my wish to go off-grid after being a campaigner for grid tying, is that I can see the writing on the wall for the grid once the brown stuff hits the fan.

Recently, Tristan Edis wrote in Climate Spectator:

The ‘Declining Demand Death Spiral’ is a story that has captivated many involved in the electricity sector. Imagine a downward spiral where electricity businesses chase their tails increasing prices to recover large fixed investments, which prompts customers to install solar and reduce demand, which is followed by further price rises followed by further demand drops and ad infinitum until the rich start going off the grid with batteries leaving the poor like pensioners behind.

He then adds….

It is massively overblown for two reasons:

1) The foreseeable change in network charges due to solar demand reductions is not big enough to spur other people to spend several thousand dollars on solar and batteries;

2) The available evidence suggests a small difference in uptake of solar according to income levels.

That’s all very well, but I know quite a few people who hate the way Campbell “can’t do” Newman has trashed the Feed in Tariff in Qld, and the power companies themselves so much, they are already contemplating waving their middle fingers at the grid very soon….  One commenter who is obviously also an installer left this comment”

I’ve received numerous enquiries from rural households wanting to disconnect from the main-grid. Interestingly, even when advised it is not economic, some households still want to proceed as they ‘dislike’ their electricity provider so much that they are prepared to pay a premium to not have to deal with them anymore. Hopefully, the retailers will continue to confuse and annoy consumers, so this niche market keeps growing.

For me who wants to move to Tasmania, however, the clincher was this little news item which I have seen nowhere else:

THE state government must consider selling Hydro Tasmania ahead of costly maintenance demands and sliding profits, a Tasmanian energy consultant has warned.


Despite posting a record $238 million profit last week, Mr White said the business was likely to soon be faced with huge repair bills for its ageing infrastructure and had already flagged a drop-off in profits due to plans to axe the carbon tax.

But will this be a problem for just Tasmania?  As the financial system grinds to a halt over the next few years (boy I wish I had a crystal ball…) and fuel, or rather cheap fuel runs out to power the helicopters which fly the HT power lines in the valley below us all the time to monitor potential high tension grid problems,  how long will the grid remain reliable?  Of what use is a grid tied solar array when the grid is down?  What is the point of generating all that power, the costs of which you have already paid for, if you can’t use it when you need it most?

Until recently, we had back up batteries for the odd time this happened, and as luck would have it, no sooner had I sold the batteries, we had to endure a five and a half hour blackout while we waited for the power lines that were all over the road just a few hundred metres away to be fixed….  After nearly ten years of uninterrupted power, it came as a rude shock, believe me…!

All sorts of things go wrong in blackouts.  We couldn’t get water from our taps.  The fans in the compost toilet stopped working, slowly filling the house with unpleasant odours, and of course no lights apart from candles and torches….  Luckily for us, our fridges are so efficient that when the power came back on, the main fridge didn’t even cut in!  Imagine what might happen to the eggs in our incubator though if we suddenly had a lengthy blackout in the middle of an incubation?  How compromised would those eggs be if they were allowed to cool down for any length of time…..?  While I had good reasons to ditch the old battery/inverter system, I miss the security of uninterruptible power already.

As the price of grid power goes up, and renewables come down, Tristan’s “death spiral” may well become real.

And yes, I acknowledge that even if we do end up with a good stand alone system in Tasmania, eventually it will all end up being for nought as post collapse it will become impossible to repair or replace failing components.  That will be our children’s problem I’m afraid……..

A new era……

7 08 2013

Following on from the End of an Era, I have finally replaced my old inverter.  I found this old pic of it straight after it

SunProfi Inverter

SunProfi Inverter

was mounted on the wall with the original 17Ah 48V battery bank that I quickly discovered was being trashed by the SunProfi that never really worked properly.  Last year, I built a wall sized book case around it, with doors to hide it all.  It certainly was an interesting bit of kit in its day, acting as two inverters in one plus battery charger.  Heavy as lead too, pretty well a two person lift….

Sun Power (the makers of the inverter) went broke at some stage during the noughties, and getting any information on making their inverters work was nigh impossible.  A friend of mine has two of these, and even though they are later models than this one, he is not happy with his battery life either.

Just goes to show that just because something’s made in Germany, it doesn’t necessarily mean it’s any good.

When I had the batteries listed on Gumtree, this guy called Mal rang me up about purchasing them.  In conversation, it came out that he had a Latronics PV Edge 1200 lying around, near new and still under warranty.

To cut to the chase, he didn’t buy the batteries, but we struck a deal on me buying his inverter instead…..  life’s full of twists and turns!  Only trouble is, he’s one of those ‘fly in fly out’ workers who is based near Roma (Western Qld) to work on….  Coal Seam Gas operations…..  gulp!

New Latronics Inverter

New Latronics Inverter

Communicating turned out difficult, his wife even more so…..  and I can’t believe it took almost 2 ½ months to actually get my hands on the device….  He lives in Bundaberg, and in the end we met half way near Maryborough (a 140 km trip each way for me..) so I could pay him and collect the inverter.  Need I say I was starting to get desperate..?

It’s much smaller than the SunProfi, and because all its connectors come out the right hand side of the box instead of the bottom as it used to be, what I thought was going to be a twenty minute job became a three hour one.

I had to move the DC switch board to the right, and mount the new inverter where the switchboard was…..  it looks a bit unfinished because now that there are no batteries, fewer circuit breakers are needed, and I need a new cover to hide all the ugly stuff.  Plus the PV output now comes out the top instead of the bottom, and that dirty great big conduit that contains all the wires coming down from the roof needs a new hole in the bottom to tidy it all up.  That lead dangling down is for the PV Voltmeter, and I have to get longer wires to remount the meter in the new cupboard doors I now have to also make.  Never a dull moment around here, let me tell you……

With some trepidation, I switched the whole operation on at about 3PM, and I’m pleased to announce there were no bangs, and all the smoke that is normally trapped in electric circuits stayed there as it is trained to do……..

The downtime will have an impact on our next credit, but at least I can rest knowing that we’ve had terrible solar weather up until now, and that as we are no longer charging batteries and we have an inverter that’s behaving properly, we should make appreciably more money from the old array than we have ever done before.

Time for a well deserved beer…….

Finished installation

Finished installation


Having pondered what to do with the old DC Switch Board (which contained 7 circuit breakers and now only has 4), I decided to bite the bullet and buy a new box.  I also decided to not mount the digital voltmeter (which now meters PV input voltage rather than battery voltage) into the cupboard door again, and after carefully cutting a hole in it the new box it’s now mounted on its cover.  The whole installation looks much more professional and safer now, especially for someone wanting to buy this place.

As an aside, we are currently experiencing amazing cloudless weather (for a change!) and to my amazement, we produced 14.5kWhrs of energy yesterday which is about 2 more than we’ve ever produced in Winter while the batteries were being charged by the old inverter…..  I knew it wasn’t very efficient, but this bad?  Can’t wait to see what the new system will produce when the days get longer….