Clipper plans huge new turbines by Ben Bland

"Clipper's latest turbine concept, which is expected to move into the testing phase in 2009 or 2010, is based around a 7.5 megawatt machine. The turbine, which would be placed on a 115 metre-high tower [377 feet] and have a diameter of 150m [492 feet]."

From ground to blade tip height would be 190 metres [623 feet]! This monstrosity would obstruct 17,662.5 square metres [57,949 square feet – 1.3 acres] of sky - a killing field of birds over water.

For much of the past year, Clipper Windpower proved to be something of a darling among the large City institutions whose forays into the world of Aim are generally few and far between.

But the wind-turbine developer soon found itself out on a limb after a series of production problems emerged. Clipper's share price had soared from under 200p shortly after its flotation in 2005 to a staggering 916p in June this year.

But two profit warnings related to production difficulties – the first in July, the second early this month – took the wind out of its sails and the stock tumbled to below 500p last week.

However, Jim Dehlsen, Clipper's chief executive and a veteran of the American wind-power industry, is undeterred and unapologetic about his shares' recent performance.

"It's a normal response to early stage activity," he notes. "We've indicated that we expect Clipper to be hitting bumps on the road."

Mr Dehlsen pins the blame for Clipper's difficulties on glitches with components supplied by outside companies. However, he stresses that Clipper is on its way to ironing out these problems as its manufacturing process matures.

"We're working our way through the supply problems," he says. "I think we're in good shape on building a global supply chain but it's a new process."

Despite the latest upsets, Mr Dehlsen says that he enjoys his relationship with Clipper's investors and the financial markets more generally.

He insists that he is happy with Clipper's listing on Aim, although he concedes that the frequent travel to London can be "a bit of a burden". (Clipper's headquarters are in California).

Mr Dehlsen was one of the pioneers of the wind-power industry in the US. He founded Zond Corporation, one of the early movers in modern wind-generated energy, in 1980 and grew the business until he sold it to Enron, the now-collapsed energy group, in 1997.

But, by the early part of this century, traditional wind turbine technology had hit the buffers in terms of scale, with most turbines only able to produce about one megawatt of electricity.

Mr Dehlsen says that Clipper has managed to attract so much interest from the financial community because it has come up with a design that will take the next generation of turbines beyond the 2.5 megawatt barrier.

Clipper's latest turbine concept, which is expected to move into the testing phase in 2009 or 2010, is based around a 7.5 megawatt machine. The turbine, which would be placed on a 115metre-high tower and have a diameter of 150m, is designed to be located offshore, where winds tend to be stronger and planning restrictions less strict. Each massive turbine should be able to power 3,000 houses over its 30-year life span.

But Mr Dehlsen is realistic about the limits of wind power to replace carbon-based energy sources such as coal, oil and gas.

"The US Department of Energy said that you would need to cover four states with wind farms to supply America's energy needs," he admits.

So while wind has a role to play, Mr Dehlsen accepts that any genuine attempt to tackle climate change must be much more holistic.

"It's going to take everything we can muster, from energy-efficient light bulbs to new types of car, and we need to do it very quickly," he adds.