“It is disappointing that 2009 looks likely to show such a significant fall in new investment in clean energy,” says Michael Liebreich, chief executive of New Energy Finance. “However, the good news is that it does look as though the worst is past.”

Second-quarter clean energy investment will total at least one-third more than the “disastrous” first quarter of $13.3bn, the firm said in a report 'Green Investment: Towards a Low-Carbon Energy Infrastructure'. About $28.3bn was invested in the second quarter of 2008.

Liebreich noted that investment in clean energy companies via public markets has rallied sharply, with well over $2bn of completed secondary issues done by high-profile companies such as Evergreen Solar, Q-Cells, SunPower, Suntech Power and Vestas.

In a research note to its clients this week, New Energy Finance describes bankers active in the sector as being optimistic about a gradual improvement in the availability of project debt during the remainder of this year.

Although spreads on debt finance for wind farms and solar PV projects have risen sharply from their lows in 2007, this change has been almost entirely offset by falls in central bank interest rates, says the report.

Investors are also awaiting details on how major countries will spend an estimated $184.9bn in economic stimulus funds for clean energy. The US and China have attracted the most attention, with President Barack Obama’s administration funding research and development of all forms of renewable energy.

New Energy Finance estimates that 15% or less of that amount will be spent this year, with most of the remainder in 2010 and 2011.

“The bulk of it is likely to arrive next year thereafter, by which time the clean energy sector may be well on the way to recovery under its own steam,” Liebreich says.

From January to March, new global investment in clean-energy projects totaled $13.3bn, down 53% from the $28.3bn invested in the same quarter in the previous year, New Energy said.