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Installed wind power capacity will total 1067 GW in 2030 under the IEA's 450 scenario, a prognosis of how energy markets will look that year if countries co-operate to stabilise atmospheric concentration of greenhouse gas emissions at 450 parts per million of carbon dioxide equivalent.

The wind figure, published in IEA's World Energy Outlook (WEO) report released in November, is slightly higher than the 1000 GW in last year's report and reflects growing hopes for the technology, says IEA senior energy analyst Marco Baroni. "Wind is by far one of the most viable options," he remarks. But the most optimistic advanced scenario from the Global Wind Energy Council (GWEC) for 2030 envisages that nearly 2400 GW of wind could be installed. That trajectory would mean wind supplies around 12% of the world's electricity by 2020. In the past, the wind industry has made cautious projections and then surpassed them by broad margins, GWEC says (“uåX˜äŠÊ˜·³Ç, November 2009).

The difference in the outlook of the two organisations' outlook is at its starkest in North America. While 223 GW are installed in the region under IEA's most optimistic scenario, GWEC's advanced scenario foresees 520 GW. In Europe, the figures are 320 GW and 353 GW, respectively; 257 GW and 451 GW in China; 59 GW and 235 GW in India; 22 GW and 201 GW in Latin America; and 28 GW and 52 GW in Africa (see map).

Fundamental differences

Baroni cited the high cost of expanding electricity transmission as a hurdle to more wind in the US. Under the IEA's 450 scenario, firm support for grid improvements is expected to boost wind's portion of overall power generation to around 20% in Europe by 2030. "Thanks to the investment in transmission, it is feasible and obtainable," says Baroni. By contrast, for penetration in the US to reach even 10.4% by 2030 - the figure under the 450 scenario - will require huge investment based on a commitment to international carbon reduction agreements and a cap-and-trade system placing a price on carbon emissions. "There must be both policy action and price signals," says Baroni. "If these are there, I think investment will follow." Legislation to cap emissions is wending its way through the US Congress but faces an uphill battle.

The IEA and GWEC differ in their view of the potential energy mix in 2030. Baroni believes GWEC's vision for wind comes at the expense of other renewable energy sources. "To go with the additions of GWEC would mean that all of the other options would not be there," he says. "In my opinion, solar would still have a lot of support, geothermal would have a role to play, biomass would have its role, as would hydro." Also, the IEA includes nuclear power and carbon capture and sequestration (CCS) as key components of the 450 scenario's energy mix.

Under CCS, carbon dioxide is separated from other gases contained in industrial emissions then compressed and transported to isolated locations for long-term storage. CCS and nuclear power each prevent the emission of 1.4 billion tonnes of carbon dioxide under the 450 scenario. Combined, they slightly exceed the 2741 GW of carbon emissions prevented by all renewables put together. In its Energy Technology Perspectives Blue Map scenario, an assessment of strategies for reducing greenhouse gas emissions, the IEA sees wind contributing 12% of carbon emissions cuts by 2050, compared to CCS's 26%.

"I know that a lot of people do not like nuclear," says Baroni. "But in some regions of the world and in some states of the US, support for nuclear will be there, in particular if you have a penalty (for CO2 emissions)." And while acknowledging that CCS is a technology whose potential remains to be proven, in the US it stands a good chance of gaining acceptance due to the country's reliance on coal, says Baroni, adding: "In a country that has so much coal capacity nowadays and so much cheap coal, it makes (CCS) a possible and viable option for a number of generators."

GWEC's scenario, however, is in line with Greenpeace's Energy Revolution Scenario, "which shows how all renewable energy sources can meet 77% of the world's electricity generation by 2050 without an increase in nuclear and without the use of CCS", explains GWEC communications director Angelika Pullen. Greenpeace says it excludes nuclear energy for multiple safety and environmental reasons and that the overall cost of CCS could serve as a major barrier to its deployment.

GWEC calls the IEA's US forecast unnecessarily conservative. "Recent strong growth has not been taken into account, which leads to unrealistically low expectations," it says. "The US wind market has been experiencing unprecedented growth and experts predict this boom will continue well into the future. The IEA's forecast does not reflect this, predicting a sharp drop in market growth up to 2030, with only 7.5 GW of new capacity added annually, i.e. smaller than the 2008 US installations of 8.5 GW."

Meanwhile, Pullen disputes any notion that GWEC's advanced scenario marginalises other renewables. In the Energy Revolution scenario, hydro and wind would each occupy about a third of all installed renewables generation in 2030, solar photovoltaics would cover about 20% and a combination of other clean energy sources would fill the remaining 15% gap. Coal and lignite would together supply less than 20% of total power generation and nuclear only 1%. "In our view, (our scenario) would be at the detriment of nuclear and the detriment of fossil fuels production," Pullen says, "but not at the detriment of other renewable sources, because those would be contributing a great share of the rest of the energy mix."