The crisis rocking the U.S. financial sector is rippling into the clean-energy business, bruising more mature industries like wind while leaving young start-ups relatively untouched so far.

The unraveling of debt-heavy investment banking firms–including the demise this week of Wall Street icons Lehman Brothers and Merrill Lynch–means that financing for large-scale renewable energy projects will get harder and more expensive, according to analysts.

“This isn’t good news for anybody–it’s going to have an impact economy-wide,” said Ethan Zindler, head of north American research at New Energy Finance.

New Energy Finance’s clean-energy stock index is down about one third so far this year–lower than the Dow–and the sector has been volatile, Zindler noted.

Lehman and Merrill Lynch were involving in financing clean-energy deals, but to a far lesser extent than Goldman Sachs, JP Morgan, and General Electric’s renewable-energy financing arm.

“If you look at the other investment banks, their survival is probably more critical to clean energy,” Zindler said.

Because it is the most mature, wind energy will likely get hit hardest by a squeeze on credit. Wind farms rely on project finance from banks or other institutions to fund construction and development.

But with fewer investment banks offering financing amid strong demand, wind project developers may get less favorable terms, ultimately making the energy from those projects more expensive.