That decision followed a moratorium imposed by energy regulator Tom Reeves on connecting output from new wind farms to the transmission and distribution network. Eirgrid, an ESB offshoot, controls that network, and had called for the move because of what it claimed was the inability of wind farms to provide stability of supply.

The decision caused consternation in Airtricity, which pulled the plug on Irish development.

Airtricity chief executive Eddie O'Connor has now reversed that decision. The company has raised an additional 130m in debt financing to help fund the construction of the four new sites over the next 18 months.

The new sites will double the company's generating capacity in the Republic and will have a combined output of 110 megawatts. According to the Irish Wind Energy Association, the total installed base of wind farms in Ireland at the end of June last year was 344 megawatts, versus total energy generation capacity of almost 6,000 megawatts.

It brings back into focus the capital-intensive nature of Airtricity's business and raises a question as to when Airtricity's 51% owner, toll road operator NTR, will make a move towards a flotation.

At last week's press conference, O'Connor said there are no plans yet for a flotation of the business, which this time last year was valued at 349m and which could now be worth in the region of 500m. But NTR chief executive Jim Barry has previously stated that, by 2007 or 2008, Airtricity is likely to be subject to an initial public offering.

The company may well be waiting until Airtricity has established a decent US presence before making any moves to entice institutional investors there. Before Christmas it announced that it acquired Texas-based Renewable Generation in a cash and stock deal. Renewable Generation has 1,000 megawatts of power at various stages of development and Airtricity is also working on its own developments in the United States.

At the moment, it is hard to put a true value on Airtricity.

Although the business is unlisted, its stock can be traded with NCB, which operates a grey market in the shares.

The 349m valuation placed on the firm last January was generated to value those shares, and not until an equity investment is made in the company, or until an IPO is set in motion, will its true worth be known.

Goodbody Stockbrokers estimated last year that Airtricity would report an operating profit of 31m for 2006 . . . substantially ahead of the 2005 figure of 7.4m. But with debt possibly as high as 300m on the books, Airtricity is likely to have a hefty interest bill, probably in the region of 18m, which would slash its profit number to close to 13m.

Taxed at 12%, that would leave Airtricity with net earnings of just over 11m. That would equate to a price earnings ratio of almost 31, which is certainly high.

Should Airtricity's number crunchers come up with a valuation of 500m, that would imply a price earnings ratio of more than 44, clearly a figure that would raise eyebrows for any potential investors.

The massive capital investments being made by Airtricity at present also makes it highly difficult to value the firm as of yet.

While a trade sale could be another route for Airtricity, it is highly likely that an IPO will be the favoured option.

Probably one more very significant debt fundraising can be expected before the company hits the markets though.

And of course any flotation will see NTR dilute its holding.

However, it could sell off a sizeable chunk of its stake . . .

perhaps 10% or 15% . . . and still retain overall control of the operation.

A flotation could also herald the apex of O'Connor's career at Airtricity. By 2007, he'll be 60, and taking Airtricity into new fiscal terrain could be a responsibility that will fall to new blood.

For now, O'Connor continues to extol the virtues of wind power, criticising government policy and predicting dire consequences unless wind power generation is increased in Ireland.

Other countries with similar population sizes . . . New Zealand, for example . . . are also getting twitchy about future energy supplies. A shortage of natural gas discoveries in New Zealand has prompted that country's four main power suppliers to consider building as much as 1,300 megawatts of wind power in the next five years to meet demand. That is eight times as much as is in place now.

O'Connor wants the Irish government to set a target for the amount of Ireland's energy needs produced from renewable sources (primarily wind) . . . possibly as much as 20% within the next 10 years.

It's a lofty target. Even greenorientated Germany can only produce 6% of its total electricity demand from wind turbines.