I was lucky enough to spend last weekend at this year’s SciFoo, and took in a number of sessions on climate and energy. There was a lot of sometimes quite heated debate, but what was struck me most forcefully was the common ground that the optimists and pessimists share — specifically, a belief that the challenge in front of us is utterly huge. I almost said mind-numbingly huge, but people like Dan Schrag and Saul Griffith and Chris Uhlik have minds too active and well-exercised to numb easily…
In Nature this week we had a look at that hugeness with a big feature on ways of generating electricity that involve no intrinsic fossil-fuel emissions. Though I say so myself, it’s a pretty good look at the options, from those that are already significant (hydropower and nuclear) to those that people like Chris and Saul are trying to make significant (solar and wind). Here’s what we came up with as take home verdicts:
Hydro: A cheap and mature technology, but with substantial environmental costs; roughly a terawatt of capacity could be added.
Nuclear: Reaching a capacity in the terawatt range is technically possible over the next few decades, but it may be difficult politically. A climate of opinion that came to accept nuclear power might well be highly vulnerable to adverse events such as another Chernobyl-scale accident or a terrorist attack.
Biomass: If a large increase in energy crops proves acceptable and sustainable, much of it may be used up in the fuel sector. However, small-scale systems may be desirable in an increasing number of settings, and the possibility of carbon-negative systems — which are plausible for electricity generation but not for biofuels — is a unique and attractive capability.
Wind: With large deployments on the plains of the United States and China, and cheaper access to offshore, a wind-power capacity of a terawatt or more is plausible.
Geothermal: Capacity might be increased by more than an order of magnitude. Without spectacular improvements, it is unlikely to outstrip hydro and wind and reach a terawatt.
Solar: In the middle to long run, the size of the resource and the potential for further technological development make it hard not to see solar power as the most promising carbon-free technology. But without significantly enhanced storage options it cannot solve the problem in its entirety.
Wave and Tidal: Marginal on the global scale.
Feel free to disagree with any or all of those; what the article I think makes clear, as the discussions at the ‘foo did is that it doesn’t matter which is best — you need a portfolio of as much as you can get from as many as necessary. If you’re going to try and retire as much as possible of today’s carbon infrastructure, you will need dams and nukes and photovoltaics by the football field being spread out in every desert every day. If I remember Griffith’s presentation at the ‘foo, in the past 25 years 6TW of capacity have been built, and to get rid of the fossil fuels will take twice that in the next 25. So the scale of the infrastructure is not out of all historical bounds; it’s just doing it with far less familiar technologies that’s the challenge.
In this contex, the news of a close-to-a-gigawatt solar project in California is pretty darn welcome. If we can get a couple of thousand more of them built in the next 15 years or so we’ll be sitting fairly pretty. But that’s one a month…