The one good thing about a log jam of any persuasion is that when it breaks it tends to be pretty spectacular.

That will certainly be the hope for growing numbers of clean tech firms, who after 18 months staring at an IPO window that has been frozen firmly shut are beginning to wonder if floatation may once again represent a good way of financing expansion plans.

According to figures from the Cleantech Group, globally there were just four clean tech IPOs during the first quarter of this year, but since then there have been definite signs that the IPO market could be warming up once more.

As reported today, Canada-based geothermal specialist Magma Energy has raised double the C$50m it originally anticipated through its Toronto IPO, while energy efficient lighting outfit CRS Electronics also completed an IPO on the increasingly popular Toronto Exchange back in May.

SolarWinds, the US-based networking software specialist with sizable smart grid interests, also raised over $150m with an IPO on the New York Stock Exchange in May, and The Clean Tech Group has reported that a further 11 clean tech firms are currently undertaking IPO application processes on Canadian exchanges.

Meanwhile, across all industry sectors Morgan Stanley has predicted up to 40 firms could float in Europe over the next two years, Thomson Reuters reckons there are nearly 150 IPOs now being planned globally, and everyone is anticipating a surge in IPO activity in emerging markets such as China and Brazil.

It is as safe bet as Andy Murray choking in the Wimbledon final, that there are plenty of clean tech firms amongst those companies preparing to be in the first wave of IPOs that will mark the true onset of economic recovery.

The recession may have dealt a major blow to clean tech firms looking to scale up their operations, but for those planning an IPO the recovery could yet come at the perfect time.

It is easy to envisage a (perhaps optimistic) scenario where the IPO markets start to really hot up early next year, just as clean tech firms are in the perfect position to release compelling prospectuses detailing increased demand for low carbon technologies and the roll out of tough new environmental legislation in the wake of an international climate change agreement.

Given how long it can take to plan a well executed stock market floatation, any firm interested in following the IPO route would be wise to get their skates.