Monthly Archives: July 2014
A popular notion that has driven a lot of thinking on ‘green energy’ is that the entire world’s demand for energy is equivalent to (or can be met by) the amount of sunlight falling on a relatively small area of land. For instance, this image has done the rounds recently:
The image is taken from this thesis, which explains,
…an area of 254 km x 254 km would be enough to meet the total electricity demand of the world. The amount of electricity needed by the EU-25 states could be produced on an area of 110 km x 110 km. For Germany with a demand of 500 TWh/y an area of 45 km x 45 km is required, which concerns 0.03 % of all suited areas in North Africa (BMU, 2004b).
Hmm. There’s something… I can’t quite put my finger on it… about this carving up of Africa… to exploit its resources… It seems eerily reminiscent of something… But let’s put that to the side, and just consider the technical practicalities.
A 254km x 254km space would require 64,516,000,000 1 metre square PV cells to cover it. Or, in other words, just over nine square meters per person in the world. But this is assuming that we all use the same amount of electricity. We don’t. Greens want us to cut the amount of electricity we use. But I don’t see any virtue in this at all. The minimum people in the future should expect is the same as people living in the highest income countries today. That is to say it would be a good thing if commodities such as electricity become cheaper and more abundant, making it possible for people to do more of a greater number of things.
So what would such a world look like? According to the world bank, the per capita consumption of electricity is 8,905 kilowatt hours in ‘high income’ countries. Multiplying this by 7 billion gives us 62,335 terawatt hours. The thesis referred to above says that a 1km sq area can produce 250GWh of electricity a year. Therefore, we’d need around a quarter of a million square km, or an area 500 km on each side. That’s 250 billion solar panels, or 36 per person. And this is before we have considered other energy uses — heat and transport, in particular.
8,950kWh only gives you 118 hours in a 75kW car. Even if each person only used the equivalent of around 2 hours a week, we’d now need an area twice as big as the one proposed by the thesis. Let’s give future generations an hour a day in a 75kw car (or some vehicle, which has not been invented yet). That’s 27,375kwh per year.
And we must consider flight. This article suggests that “a 747 flying five hours from San Francisco to Washington D.C. consumes 700,000 KWhs of energy”. According to British Airways, a 747-400 can carry 345 passengers. So that’s 2,029kWh per passenger for a five hours flight. 4,058 if we include the return journey. Now, let us be generous to future generations, and afford them a minimum of three such journeys a year each. That’s 12,174kWh per year each.
It is much harder to estimate how much future generations might depend on controlling their temperature. For this, I’m going to use the UK figure, assuming that it’s roughly between a hot and a cool place. And that where, in warmer climes, people will use this much on cooling, in colder climes the same will be used for heating. The average UK home uses around 16,000 kWh of gas, used mainly to heat space, according to DECC. And the UK’s 63 million people live in 28 million homes. So that’s an average of 7,111KWh per person.
This gives us a total of 55,565 kWh per person. And we should factor in population growth. Let’s say 10 billion at some point. That’s a requirement of 555,650,000 gWh, which in turn would require an area of 2,222,600 square KM, or an area just shy of 1,500km on its side, encompassing some 2,222,600,000,000 solar panels. Here’s the thesis image, compared with what I imagine the future to look like:
Now, of course, some if this is unfair. Solar PV will become more efficient. And so will our use of energy. But it is naive to think that becoming more efficient with our use of a thing means we use less of a thing. For one very big example, we might begin to stop relying on natural processes such as the weather and sun to produce crops. We might start to grow crops indoors, lit artificially. And we might at last begin to take transport seriously, such that a daily commute of a thousand miles or more is possible and even comfortable. And it is naive to only see future energy demand only in the terms of current energy demand. Everything is likely going to be powered by electricity in the future, rather than by fuels as such, so we should not discriminate between energy used to power iPods, and energy used to power jet planes. Energy is energy. In spite of the obvious problems with such back-of-an-envelope of estimations, I believe my estimate is much safer. It demonstrates that as simple as carving up north Africa sounds — it’s been tried before, of course — it belies a great deal of complexity which the thesis’s graphic neglects.
However, my intention is not to pour water on the thesis, which is why I haven’t referred to it by name. I am agnostic about solar, even if it means we need a panel the size of a country to make it work.
What concerns me is the extent of solar evangelism, and the excesses of its proselytisers. What caught my eye recently was this bold claim in the Guardian.
Solar has won. Even if coal were free to burn, power stations couldn’t compete
As early as 2018, solar could be economically viable to power big cities. By 2040 over half of all electricity may be generated in the same place it’s used. Centralised, coal-fired power is over.
The basis for Giles Parkinson’s claim is not in fact a revolution in solar technology, but merely an artefact of a distorted market. This is how Parkinson explains it:
Last week, for the first time in memory, the wholesale price of electricity in Queensland fell into negative territory – in the middle of the day.
For several days the price, normally around $40-$50 a megawatt hour, hovered in and around zero. Prices were deflated throughout the week, largely because of the influence of one of the newest, biggest power stations in the state – rooftop solar.
Negative prices sounds like a good thing. Better even than free food, food that you get paid to eat. But just as there’s no such thing as a free lunch, there’s no such thing as a lunch you get paid to eat. But negative prices in fact mean there is trouble on the grid — it is at risk of becoming unstable. Paying people to consume it means paying people to take away a dangerous surplus.
The links provided by Parkinson all refer to his other articles, which provide only slightly more information. This article contains the following graphic of electricity demand and price in Queensland over a 48 hour period.
On Tuesday this week, the wholesale price of electricity (in red in graph above) skirted around zero for several hours in the afternoon, and on Wednesday they plunged to minus $100/MWh at 2.20. (They were back at zero on Thursday morning between 11am and noon).
As an inspection of the graph reveals, the graph starts on Tuesday 1 July, at 11pm. So it seems that Parkinson is at best confused about the point at which the graph shows the wholesale price of electricity ‘skirting around zero’, apparently confusing early morning prices for the previous afternoon prices. Here is a graph of the price data, from 00:00 on 1 July 2014 through to 23:59 on Wednesday 2 July, so that we can be clear that what Parkinson claimed to have happened did not in fact happen.
To the best of my understanding — and I hope Australian readers will forgive me for my ignorance of their country’s geography (I hope one day to be able to afford the price of a ticket) — Queensland does not typically experience sunlight between the hours of 2 and 4 AM. So the notion that solar PV pushed the price of electricity down during this time seems far-fetched indeed.
Then there is the matter of the low/negative prices later on Wednesday. The sample rate of this graph is 30 minutes. And as we can see, there are no negative prices at this scale, meaning that the price was negative perhaps for about 5 minutes. During that 30 minute window, yes, the average RRP was much closer to zero, as it had been 12 hours earlier. But how significant is this?
A clue as to Parkinson’s misconception is given in both articles. In the Guardian, he says,
That’s not supposed to happen at lunchtime. Daytime prices are supposed to reflect higher demand, when people are awake, office building are in use, factories are in production. That’s when fossil fuel generators would normally be making most of their money.
And at the other article, he explains,
Daytime electricity prices have historically been the “cream” on the cake for electricity generators because that is when demand is usually the highest, and prices too.
But this idea of there being a difference between day and night energy demands — for Queensland, at least — is very much an oversimplification, as this graph of price and demand shows.
Here, there are not two features of demand throughout the day — night and day — but four: an early morning trough, a late morning peak, an afternoon trough, and an evening peak. It is true that many electricity suppliers offer day and night rates to consumers with the right equipment. But the idea that prices are highest in the day because that is when demand is greatest misunderstands this pricing strategy. Cheaper rates were offered at night because supply exceeded demand. There is an important difference. The backbone of an energy grid — the bit that does the heavy lifting — are its ‘baseload’ generators. These are typically large coal-fired plants, which cannot easily be ramped up and down to follow demand. (In fact, cyclying them up and down reduces their productivity over time). It would be more expensive to turn these generators off overnight than it is to keep them running.
The afternoon dip in demand is not quite as pronounced as the early morning dip. But it is not far off. Between 8.30 am and 1.30pm in Queensland on Wednesday 2 July, demand fell from 6699MW to 5222MW. During this time, however, the output from the region’s solar panels increased, as the sun rose in the sky. Then, as the sun begins its descent again, and so output from solar falls, demand rises to the evening peak. So solar supply happens to correspond inversely to demand. But Parkinson ignores the demand curve with four features, and uses the day-night understanding of demand, to make the claim that ‘The influx of rooftop solar has turned this model on its head’.
What solar in fact turns on its head is a sensible grid design that responds to need. In the UK, renewable sources of energy take priority on the basis that this will displace carbon-emissions. This takes the form of subsidies for renewable generators and obligations on suppliers to take it. I understand the situation is the same in parts of Australia. So the grid now has a harder job to follow demand, having to cope with excess of unwanted midday output from solar, while keeping baseload generators online, so that demand can still be met in the middle of the night. So if Parkinson is right to claim that “Even if coal were free to burn, power stations couldn’t compete”, it would be because solar, in spite of the sun being free, costs more than coal, and it is given priority on the grid.
The fact that solar power caused such disruption to a grid for five minutes on a Wednesday afternoon does not mean that solar is capable of displacing coal, gas, oil or uranium. The only way Parkinson could make such a claim would be a situation in which the grid was free to choose the best suppliers and solar PV was not given any subsidy.
The extraordinary claims made by solar evangelists require very little numerical investigation to be shown as so much bullshit. The Guardian, for obvious instance, couldn’t wait to reproduce Parkinson’s claims, apparently without any fact-checking or scrutiny. Yet anyone with an internet connection and a copy of Microsoft Excel can show that not only does Parkinson make significant mistakes confusing times of day/night, and in misunderstanding of the structure of the electricity market and its prices, his interpretation lacks any sense of proportion. And even the specialist press was not far behind the Guardian. Even the experts in the renewable energy sector at Business Green do not have their critical faculties engaged when a positive slant on solar energy is possible. In other words, the broader green energy sector is not capable of keeping its own members in check. Hubris and hyperbole is informing the public debate that is predominantly presented as one divided between scientists and ‘deniers’.
This all echoes the claims made by Bloomberg New Energy Finance back in April. “CHINA’S 12GW SOLAR MARKET OUTSTRIPPED ALL EXPECTATIONS IN 2013″ claimed the news-agency-turned-green-lobbying outfit. But as I pointed out, this revolutionary step amounted to no more than “0.89 watts of net capacity per person”. It’s not even enough to charge a smartphone, much less power a dynamic, growing, industrial economy.
Solar evangelists have convinced themselves, it seems, that we’re on the brink, if not in the middle of a ‘solar revolution’. Yet the evidence suggests that solar PV in particular is at best nothing more than an expensive and possibly even dangerous hindrance to the normal operation of electricity grids, yet. It is like marketing fruit flavourings and sugary water as a ‘health drink’ — the contents doing the exact opposite of ‘what it says on the tin’.
Technological revolutions past have important characteristics. They typically positively transform our lives, or at least create the possibility of a new way of life. Even though they may create new problems, the problems they do create are preferable to the problems they have solved. We have first world problems where we once had third world problems. Second, they make it possible to produce more for less. There is no such thing as a technological revolution which makes things more expensive or less abundant.
Even if solar energy ‘works’, or at least becomes economic feasible, it will never produce a ‘revolution’. It cannot transform our lives for the better by virtue of becoming more abundant and cheaper. The indeterminacy of sunlight means solar generation is in fact likely to be an irritation for our way of life, just as it is an impediment to the safe operation of the grid. And this has implications for price. Even if the holy grail of energy storage were to be found, such that massive batteries could store surplus energy until it was needed, this would not likely reduce the price of energy by any significant margin, but increase it. And even if solar panels could be produced cheaply, the key commodity would not be the price of panels, but the price of land. Even if it were possible to locate trillions of solar panels where the cheapest real estate in the world can be found, that real estate would do what all sought-after real estate does. We would exchange our putative dependence on fossil fuels with dependence on something far more fickle: land. And a vast area of land, at that.
And all these technological developments, which solar evangelists promise us are, like the revolution, just around the corner, are only pertinent to a discussion about choice of technique in the future if we consider them in relation to other potential developments. Fusion, perhaps. More fission. More fusion-fission hybrids. These are my favourites, because they promise ever less dependence on natural processes or goods light sunlight and land, and their enormous potential is described by Einstein’s equation, not by the comparatively paltry amount of sunlight falling on an area of land at the equator at noon.
Let us compare pipe dreams, then. The following presentation from Charles Chase of Lockheed Martin suggests that the company will have produced a 100MW fusion reactor with a footprint of just 8 square metres by 2017, and will be ready for commercial development by the mid 2020s.
Remember that 8 square metres of solar panels could, even if they were 100% efficient, only produce 8kW at noon, at the equator, on a cloudless day. The Lockheed Martin application would be 12,500 times more powerful. Over the course of 24 hours, the Lockheed Martin application would produce 125,000 times as much energy as the solar panels. Returning to our future scenario in which the world’s ten billion people require 555,650 TWH… this requirement could be met by 634,304 fusion reactors, which would have a combined footprint of just five square kilometres. And they would be capable of working 24/7. They would be mobile, operating on or off the grid, according to demand. The could be used to produce electricity, of course, but also they could power ships, and desalinate and pump water to where it is needed. They could produce fuels for vehicles that are not yet able to run on electricity.
So why are the solar evangelists not jumping up and down for joy that something even better than sunlight may have just been discovered, which requires little more than seawater as a fuel? Why are climate bureaucracies all over the world not demanding subsidies for this zero-carbon source of power? Why aren’t green politicians promising that a real energy revolution is just around the corner? After all, Lockheed Martin’s plans are as well developed as solar energy is. Solar panels work in principle. In practice, they have yet to contribute anything useful.
Indeed, why is it that discussions about Lockheed Martin’s prototype and other reactor designs are more easily characterised as an optimistic but sober treatment of the facts, whereas solar zealots quickly lose control of their faculties when as little as a megawatt is added to the grid anywhere in the world?
I don’t mean to propose here that those of us who understand the value of energy start behaving like solar evangelists, and to start creating unrealistic expectations of Lockheed Martin’s development. The point is rather that the virtues of the technology itself are not enough to explain the solar evangelist’s excitement. Something else must be going on, because solar energy is, quite simply, not at all exciting in any respect.
What is that something? Is it madness? Is it simple dyscalculia? Is it even really solar power that the solar evangelists want?
I was surprised by Queensland’s demand curve — though perhaps not as surprised as Parkinson. My understanding of demand in the UK, at least was similar to his — that there is a peak and a trough once per 24 hour cycle. So I had a quick check of the UK’s demand curve.
This is interesting. It seems that the UK and Australia have dissimilar demand patterns — which is born out by data from the other Australian territories. On the other hand, the UK has a much larger population than the whole of Australia, let alone just one territory. Furthermore, it seems possible that, perhaps by virtue of its size and by the nature of its industries, the UK may be able to better shape the demand curve. This notion seems to be at least partly supported by this weekend’s demand curve:
NB the Y Axis does not start at zero — I’ve moved the graph down to emphasise the signal. But it does show a pronounced 4-feature curve, rather than the more sinusoidal pattern of weekday demand.
There is an interesting implication here. Whereas the emphasis of many greens is in ‘decentralised grids’, in reality, a centralised grid is much better able to absorb the fluctuation of solar output (and other renewables). In other words, solar needs coal, gas and uranium. Lots of it.
But Parkinson doesn’t think so.
The next step, of course, is for those households and businesses to disconnect entirely from the grid. In remote and regional areas, that might make sense, because the cost of delivery is expensive and in states such as Queensland and WA is massively cross-subsidised by city consumers.
In other words, from madness to suicide in one step.