The US is set to overtake Germany as the world¡¯s biggest wind market in 2009 on the back of an investment boom which saw wind power generating capacity jump 45 per cent last yearNow is a pivotal moment for renewable energy in the United States,¡± says Peter Duprey, chief executive of Acciona Energy North America, a subsidiary of the Spanish infrastructure group Acciona. ¡°

This is a real opportunity here for companies to stake a major claim in the market because there has been a pent-up demand.¡±

Not only is there demand among the public for more environmentally friendly fuels, but the wide open US plains are enticing given far more expensive offshore options to expand in Europe. Last month Royal Dutch Shell sold its stake in what would have been the world¡¯s biggest offshore wind farm, the London Array, saying that Europe had been ¡°built out¡± and wind¡¯s future was in North America.

US wind plants are expected to generate just over 1 per cent of US electricity supply this year, but a study from the US department of energy last month said this could rise to 20 per cent by 2030 ¨C even if electricity demand grows by 39 per cent from 2005 to 2030, as estimated by the US Energy Information Agency.

No technological breakthroughs are needed to reach the objective, and the price of wind power has already come down with improvements in technology that have made wind more reliable.

Ten years ago, says Vic Abate, vice president for renewables at GE Energy, North America¡¯s largest wind turbine manufacturer, it would be normal to see two out of three turbines not spinning in California¡¯s wind farms. Reliability now is at 97 per cent. ¡°We believe wind power is becoming a mainstream power source,¡± he says.

Unsubsidised wind energy costs 8-10 cents a kilowatt hour, he says; solar is more than 30 cents/kWh, while coal, gas and nuclear are in the 5 cents to 10 cents range.

But the US government notes that major challenges remain. In particular, there is uncertainty over the production tax credit, the primary federal incentive for wind power, which expires at the end of the year. In the past, when the credit has lapsed ¨C 1999, 2001 and 2003 - installations have dropped by as much as 93 per cent the following year.

Gabriel Alonso, chief operating officer of Portugal¡¯s EDP Renov¨¢veis, a leading renewable energy company, says component suppliers have said they may invest in China and India before the US because the potential lapsing of the credit makes it difficult to make long-term investment decisions.

But Kenneth Westrick, chief executive of 3TIER, a provider of global renewable energy assessment and forecasting, says that given the US presidential candidates¡¯ dedication to alternative energy, he expects the new administration may be able to offer more political commitment to wind power.

¡°We put a man on the moon ¨C we can do this,¡± Mr Westrick says.

The rise in the oil price to almost $140 a barrel in recent days will only increase that incentive. ¡°I can tell you what the fuel cost for wind will be in 20 years: It¡¯s going to be zero. That¡¯s a guarantee.¡±