News & Views item - August 2008

 

 

Electricity Without Carbon. Nature Publishes a Special Issue to help Rationalise the Debate. (August 14, 2008)

The editorial in today's issue of Nature A task of terawatts introduces the journal's assessment of the challenge of producing man's future use of electrical energy without marked destruction of the planet's milieu.

 

We're told "The Sun shines down on Earth with a power of 174,000 terawatts [174,000 x 1012 watts, 174,000,000,000,000,000 watts]". Then in the news feature the journal notes: "In 2005, 18,000 terawatt-hours of electricity were generated. With almost 9,000 hours in a year, that averages out at a constant 2 TW or so," i.e. 0.0012% of that shone on the Earth by its Sun.

 

Now you might think that a species that can produce an Einstein and a Brunel could develop clean methods to harvest solar energy without debasing its nest, but up to now, you would be wrong.

 

Nature then examines seven forms of carbon-free production of electrical energy and gives its verdict, here we give a summarising table of the eight page article.

 

Source Verdict
Hydropower A cheap and mature technology, but with substantial environmental costs; roughly a terawatt of capacity could be added.
Nuclear Fission 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.
Ocean Energy Marginal on the global scale.

 

 

But it hasn't neglected carbon capture and storage (CCS).

 

After analysing what would be involved it concludes: "The probability of CCS being widespread in 10 or even 20 years is very low unless the technology is promoted much more aggressively. The biggest problem is scale. Capturing 60% of the CO2 from US coal-fired power stations would mean handling a volume of CO2 daily that rivals the 20 million barrels of oil moved around by the oil industry, according to a 2007 Massachusetts Institute of Technology study. Creating such an infrastructure is not impossible, but setting it up in a decade or two is a tall order."