The Reality-Based Community

The endless GOP hostage theatre over US budgets succeeds in one of its main purposes: to distract attention from issues that matter. Like the race against the clock to avoid complete climate breakdown. We already have the trailers.

So here comes a fat Victorian-novel style doorstopper weekend post with as many nutritious links as a Christmas pudding has currants.

Renewable energies are still only a drop in an ocean of climate-busting fossil fuels:

Spreadsheet here.

What hope is there for my granddaughters? A change of heart by billionaires? A popular insurgency, a Main Street Spring? A miracle discovery?

The one solid basis for optimism is the prospect of terawatts of solar energy. If you just extrapolate the global trend of the last 12 years – an average growth rate of 43% a year – , the world will reach its first cumulative terawatt of solar PV in 2020. Its expansion would cross the world’s full energy demand soon after 2030. That’s fast enough even for James Hansen.

Plenty of experts say it won’t happen. But their reasons are unconvincing.

For some time semiconductor experts have been offering very good reasons why Moore’s Law of transistor density must come to an end. But so far it hasn’t, and looks OK for a good few cycles yet. In comparison, the trend doubters on solar PV are running on empty.

Exhibit A: Steven Davis et al., the credentialed authors of a recent scholarly paper on “Rethinking wedges” – my italics:

Existing solar, wind, biomass, and energy storage systems are not yet mature enough to provide affordable baseload power at terawatt scale.

Baseload? What’s that, Grandpa? Well, sonny, in the days before the Deluge we used to have big coal and nuclear power plants running all the time, that’s baseload, and gas plants running only at times of high demand, that’s peak lopping. Now we have wind and solar running when they can, because they are the cheapest, as primary load; but they are variable, so we need despatchable capacity to make up the difference, peak and off-peak. There isn’t any baseload now.

You can’t believe experts who are still trapped in an obsolete paradigm.

Exhibit B, the IEA, the born-again intergovernmental think tank, and semi-penitent former whore cheerleader of the oil industry. They project that solar PV will flatline around 26GW of Solar PV a year, below its current rate. But their assumptions are plain wrong. They predict that utility PV installation costs will gently fall from $2.6 to to $1.65 a watt in 2035. Terje Osmundsen, author of the blog post I got this from, works for a company that will quote around this today. (Independent confirmation from another solar entrepreneur, Jigar Shah, here.) The IEA shows in-depth ignorance by expecting 130 GW of PV to be «retired» by 2035. Osmundsen points out that 25 years is just the maker’s guarantee for 90% performance; the gear lasts much longer, 30-40 years at least.

The only way I can make sense of the IEA’s absurd predictions (I’m not going to shell out good money on a dud report to check) is that they think past growth has been entirely driven by policy, which is now going into reverse, as in Spain. Neither proposition is globally true. The learning curve (a steady 22% since 1955) is driven by technology; policy just enables or obstructs it. And the number of countries with reasonably supportive policies and targets keeps growing: Brazil, Mexico, Chile (for the policies of these three, see also here), South Africa, Turkey, Saudi Arabia, France, India, Thailand and Indonesia …) These are following in the footsteps of the rapidly growing big deployers of China – its latest target is 10 GW this year -, the USA, Australia and Japan. Germany has stopped growing, but at a very high annual level of 7 GW and a stock of 30 GW. Only Greece and Italy have run out of money and are in retreat. In developing countries, the boom is driven by simple economics, not subsidies.

What’s more interesting is that solar boosters like EPIA and Greenpeace also won’t trust the trend. In a joint report, they predict a steady slowdown in the pace of cost reduction and installation, and their optimistic scenario comes out at half the trend number in 2020. I can’t find any considered argument for this. It’s basically herd caution in the consultaverse, reflecting the risk aversion of its client investors. McKinsey is an honourable exception.

Distinguish between the intrinsic characteristics of the technology, and its deployment. Clearly any given process, like the currently dominant polycrystalline silicon cell, will reach an intrinsic cost asymptote some day. If DARPA and its industrial partners think this is below $1/watt installed, who am I to quibble? The current wholesale module price is 65$c per watt (cyclically ahead of the trend), so 50c/watt is pretty certain in the next few years, and BOS costs will surely follow on the German model.

When the current scheme stalls, there is an extraordinary variety of potential relays being investigated, ranging from 3D light-trapping geometries to 44% efficient multijunction cells (on sale now for satellites and military backpacks, at a price) to the ultimate long shot, artificial photosynthesis mimicking the near 100% efficiency of leaves as solar cells achieved by evolution using weird quantum effects. I have no more idea than you which of these will make it to market success. But it would be very surprising if none of them were able to take over the torch, and we were stuck as it were with 5¼” floppy discs for computer memory. In any case, we don’t need any of them to get to tens of terawatts.

The other aspect is the environment for deployment. Successful game-changing innovations like TVs and mobile phones don’t follow the technological learning curve, but a steeper sigmoid: slow acceptance by pioneers, then explosive growth, then a slowdown to saturation. Since solar PV has now hit grid parity in many places, I predict growth will actually accelerate, for example when cheap consumer-friendly plug-and-play AC-PV modules become widely available from the likes of WalMart, this year or next. This market effect, plus ordinary economies of scale and learning, should mask any slowdown in underlying innovation for much of the decade. So I’m predicting 1 TW solar by 2020, without big policy changes. (An early disconfirmation test: if solar PV doesn’t exceed 30 GW in 2013, I’m wrong.)

Beyond that, the environment will begin to impose constraints, and policy will become critical to a successful transition. It’s most unlikely that 50 TW of solar PV will meet world energy demand in 2031, even if it’s by far the cheapest option. What are the possible constraints?

One: running out of land. A world total of 50 TW of solar panels, the upper bound in my thought experiment, corresponds to 25,000 km², or a square about 100 miles on a side. That’s less than the roofspace of a bundle of megacities. So land take is not a killer. The WWF has just released some pretty maps making the same point.

Two: intermittency. We will need a lot of balancing power for solar in a zero-carbon world. (Actually we will probably have to go carbon negative, and build a few TW for sequestration, but never mind for now.) Some of it should be be wind, which is nicely complementary at night and in winter (Fraunhofer here, slides 15, 23, 58) but also variable. So we must have a lot of more expensive despatchable power. This can be either substitute primary sources, in the forms of hydro, geothermal, CSP, and biomass; or additional storage for time- and mode-shifting, as distributed and utility batteries and heat tanks, synthetic fuels catalysed from the air, and load management with price incentives.

Now all of these except the last are going to be more expensive than solar PV. The optimisation problem is to start from 100% solar PV, which is mismatched to demand, and add the other things so as to match demand at least additional cost. Wild guess for a seed solution: for 10TW continuous demand, the primary energy could be 5 TW solar (installed 33 TW), 3 TW wind (9TW installed), 1 TW geothermal (2 TW installed), 0.6 TW biomass (1.2 TW installed), the 0.4 TW of hydro (0.8 installed or under construction) we have now, and 5 TW (?) installed storage. You can shift between wind and solar, and between storage and the despatchables. (To pacify Brett, we should throw in nuclear power, but in fact it’s not going to be more than a footnote, for reasons explained here and here.) A terawatt is 1000 nuclear reactors, which will never be built.

Even in this very crude form it stands out that the policy problem lies not with wind and solar but with despatchable energy. Load management is a no-brainer, but its scope is necessarily limited. We do not have deliverable technologies for storage, geothermal, and biomass on the required scale. That’s where the funding should go.

Three: transportation, iron, and cement. These are the main areas where solar electricity is not yet a technical solution. Electric cars are slowly on the way to mass deployment, but not trucks, ships, and planes. Absent technological breakthroughs, it will have to be sustainable bio- or synthetic fuels. Cement-making inherently releases carbon dioxide, even with solar calcining. A lot more work needs doing here.

Four: backlash. Cheap solar PV is disruptive because it’s going to be very cheap, and will destroy value embedded in defeated competitors on a heroic scale. The shift will not be controllable by incumbents. Solar PV doesn’t only come in the unthreatening shape of multi-megawatt utility solar farms. It also arrives in distributed form on residential and commercial rooftops – turning millions of passive electricity consumers into an activist army of prickly producers armed with social media and votes. Some rough and noisy politics is in store before the oil and coal industries die.

Germany is the laboratory for the future here, as solar is already below grid parity and renewables are having a major impact on electricity supply. Merkel’s conservative government, pushed by incumbent utilities and heavy industry, is increasingly hostile to its lusty and disruptive solar cuckoo. It favours expensive offshore wind to replace the rashly closed nuclear power stations. In Spain, rooftop solar was strangled in the cradle, so there’s no lobby to defend it, just marginal bloggers. But in Germany the solar producers are a large and strong lobby.

What’s more, the government has lost the technocratic control of the situation it had when the FIT was a subsidy and could be tweaked. The official target for solar PV installation in 2012 was 2.5-3.5 GW; the result was 7.6 GW. The FIT will expire above 53 GW, but why should German households and warehouse-owners stop? The payoff is less and less the miserable FIT, more the saved consumption, valued at the full retail price of 25c€/kwh. Local storage, as low-tech as the venerable storage heaters being dusted off and as high-tech as electric cars, will stretch the self-consumption payoff. What’s sold to the grid will have some market price.

Some German solar people, including Professor Volker Quaschning, are already proposing 200 GW of solar PV in Germany, four times the government target, and a 300 GW yearly worldwide installation rate by 2025.

Can we get there? I’ve said it before: we are witnessing, and in many cases taking part in, a technological revolution. Governments can obstruct it as in Spain or help it along as in Germany, but they are not in the driving seat. Current policies are favourable enough for the revolution to happen.

Will it happen fast enough to save our climate? Even with my optimistic scenario, solar PV doesn’t really vanquish fossil fuels till the 2020s. If carbon emissions have to peak in the next five years, the heavy lifting will have to be done by conservation – meaning carbon pricing – and wind energy. Wind has a lower historic growth rate than solar – 28% over the last 15 years, and slowing as the technology matures; but it has a much higher installed base, around 280 GW nominal to solar’s 100 GW. Since wind’s capacity factor is twice as high, the effective ratio is five to six times. There’s a strong case for differential medium-term support for wind. On conservation, the air pollution crisis in China and coal chaos in India offer more hope than US policy, still in hock to denialism like Noah’s neighbours.

Credit: Greenpeace BP logo competition post-Deepwater

• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 

Posted: Friday, January 18th, 2013 at 8:41 am
19 Comments »