Guy Sorman’s The End of Green Ideology begins:
The meltdown at the Fukushima nuclear plant has sent political aftershocks racing around the globe. More often than not, however, the shocks have been ideological, with no basis in science.
I’ve been reexamining the case for nuclear power for a while now. I still think we’ll probably need to keep developing it, improving it, and including it in the mix. But I’m willing to be convinced otherwise and I’ll watch Germany’s forthcoming nuclear exit with great interest. In any case, I agree with Guy Sorman: let’s make sure our energy future is based on science not ideology.
So I was puzzled to find this assertion in the middle of his critique of green ideology:
If California were to rely on solar power for its electricity consumption, the entire state would have to be covered with photovoltaic cells.
Really? That seems wrong. According to an infographic called Surface Area Required to Power the World (with zero carbon emissions and with solar alone), assumptions and methodology here, it looks like a California of solar panels could more than power the world.
For reasons Sorman alludes to — cost, environmental impact — it probably wouldn’t make sense to build a California of solar capacity, regardless of how it’s distributed around the world. But let’s just focus on the assertion that California would need all of itself to keep the lights on using solar photovoltaics. Is that really wrong? If so, how wrong? What’s the right answer? And how can we find out?
Before the advent of WolframAlpha I would sometimes idly speculate about these kinds of questions, but I wasn’t able to effectively analyze them. Now I can. From various sources, I think I know that a PV panel can produce on the order of 10 watts per square foot. So we can ask WA directly:
How can we think about 45 terawatts? I recall from Saul Griffith’s Climate Change Recalculated that the whole world runs on about 16TW. This confirms what I gleaned by eyeballing the infographic: Solar California could more than power the world.
But where does Saul’s 16 TW number come from? Can we cross-check it? The infographic assumes that we were running at 500 quadrillion BTU in 2008, projected to rise to around 680 quadrillion BTU in 2030. The US Energy Administration’s International Energy Outlook 2010 cites similar numbers. I’m not good at unit conversions, but WA is:
500 quadrillion btu in watt years / 1 year = 16.73 TW
This matches so closely that I wonder about the provenance of the number. Do all these analyses use the same source, or are there independent estimates that converge? But anyway, let’s assume that 16 TW is in the ballpark. How much electricity does California use? (Recall that this was the quantity of energy Guy Sorman thinks would require a California-sized solar panel to produce.) A couple of sources say that California uses about a quarter million gigawatt hours of electricity in a year. How much is that? WA provides useful comparisons:
a quarter million gigawatt hours = 1/15 total production of electrical energy in US in 2001 = 2 * electricity consumption of Norway in 1998 = 28 * daily electric energy production of all nuclear power plants
a quarter million gigawatt hours /
1 year 2000 hours = 28.5 125 GW
45 TW is about
1600 360 times more than that, so I think that’s how wrong Sorman’s claim is.
If a California-sized solar panel could produce 45 TW, then how much of California would be needed to produce
28.5 125 GW? Let’s ask:
area of California /
1600 360 = 102 455 square miles = 1/15 1/3 area of Rhode Island = 2.2 * area of Walt Disney World 1.1 * land area of Hong Kong
As with other essays in my energy literacy series I am mainly interested here in how tools like WolframAlpha can help us reason our way through a thicket of quantities and unit conversions. Hundreds of people liked Guy Sorman’s essay on Facebook. Dozens tweeted it and the one comment I can retrieve calls it a “balanced and scientific assessment of world’s current and future energy outlook.”
I don’t know enough to agree nor disagree with Guy Sorman’s conclusion:
Future energy supplies will most likely rely more and more on miniaturized nuclear plants and shale gas — a mix capable of responding to a rapidly urbanizing world population’s growing demand for electricity.
But I do know that we need to be able to verify and reproduce analyses that purport to be scientific. WolframAlpha has become the View Source button that helps me do that.