The federal government should make it easier for colleges and universities to finance big sustainability projects on their campuses, three higher-education groups recommend.

In recent years the government has offered grants, loan guarantees, and tax credits to support energy efficiency and renewable energy, says a report by the groups, but those programs have been limited mostly to corporations and have excluded nonprofit colleges. Even so, many colleges have moved to make buildings and programs more sustainable, adopting energy-efficiency standards and pledging to reduce carbon emissions.

"Many colleges and universities have already attacked the low-hanging fruit—they've changed their light bulbs, installed motion sensors," said Elizabeth L. Clark, who worked on the report and is director of Congressional affairs at the National Association of College and University Business Officers. The proposals outlined in the report, released Thursday by Nacubo, the sustainability-education group Second Nature, and the American College & University Presidents' Climate Commitment, are aimed at promoting larger capital investments in sustainability, she said.

The three groups offer several policy proposals to create incentives for colleges to pursue large-scale energy-efficiency projects, such as retrofitting laboratories and developing renewable energy sources to power their campuses.

Since switching to renewable energy often doesn't begin to pay off for five to 10 years, one suggestion is to allow colleges to use the money raised from low-cost capital bonds to buy a 20-year supply of green energy. Another proposal is to establish a federal loan-guarantee program and a revolving loan fund for energy-efficiency and renewable-energy projects.

The government should also extend existing tax benefits and create new ones for the suppliers of biomass and bio-methane energy. the report says, arguing that doing so would provide more certainty for institutions contemplating whether to build bio-digester plants.

Despite the challenges of asking Congress for money as spending cuts loom, Ms. Clark said, colleges should press for those programs over the next few years, as lawmakers look to overhaul the tax code.

"We have a larger calling than just managing our resources. We have an obligation to provide moral leadership on this," said Timothy P. White, chancellor of the University of California at Riverside, one of more than 100 campus leaders attending a climate-commitment meeting in Washington this week.

Wim Wiewel, president of Portland State University, said at the meeting that institutions of higher education were ideal candidates for more federal support in sustainability. "We can make the long-term investments that don't pay back until 10 or 20 years in ways that companies just can't," he said.

"Students are profoundly impacted by the environment in which they go to school," Mr. White added, arguing that investments in sustainability at colleges can shape the perspective of future generations.