More than five months after its signing, key parts of the American Recovery and Reinvestment Act’s grant and loan programs are still being hashed out by officials at the U.S. Department of Energy, much to the chagrin of anxious executives counting on public money for big projects. While some funding is beginning to trickle out from state and federal projects, the deadlines for others are still several weeks away and winners may not receive their funds for months.

Yet the tension between the urgent needs of clean tech companies and the grinding nature of government bureaucracy is not unexpected, industry watchers say.

“The prevailing wisdom out there is that the money isn’t moving as fast as people would like,” said Nick d’Arbeloff, executive director of the New England Clean Energy Council. “I think you’d need a crystal ball to know exactly what programs will release how much money when.”

That has some local technology companies looking to use stimulus dollars for major projects playing the waiting game.

“Our facility in Massachusetts is pending stimulus funding or winning some other federal grant,” said Christina Lampe-Onnerud, CEO of Boston-Power Inc.

The Westborough company is hoping to receive $100 million in funding through the advanced battery manufacturing grant program to build a battery manufacturing plant in Auburn.

“The fact is we need to offset the capital cost of the project. We’re still in a framework where the private finance community doesn’t believe you can build manufacturing in the United States,” she added. “We haven’t heard anything yet, but we’re eagerly awaiting word and I trust that we will get funding.”

The stimulus act also was looked to by renewable energy developers as a way to open up the project finance market shuttered since the collapse of credit markets last fall. While guidelines from the U.S. Department of Treasury on how wind, solar and other projects can apply for 30 percent investment grants instead of tax credits were seen as a step in the right direction, many insiders say it will take months to move the needle.

“I think the stimulative effect of those programs are ahead of us,” said Carol Grant, senior vice president of external affairs for Newton wind developer First Wind Holdings Inc.

First Wind expects to apply for the grant program when it begins accepting applications next month, as well as a yet-to-be outlined program to guarantee loans for commercial scale energy projects.

“It’s not going to make it easy, but it’s going to make it possible for more projects to move forward,” Grant said.

A substantial number of clean tech firms join Boston Power and First Wind in line for ARRA funding. About 39 companies are applying for 64 ARRA-funded projects, including a handful looking to receive research and development funds and two for smart grid demonstration projects, according to data collected by the Massachusetts Clean Energy Center. Another 100 entities bid for stimulus projects and programs administered by the state Department of Energy Resources.

Application deadlines loom for companies looking to get into the stimulus competition, including programs for solar research and project deployment and geothermal systems that close this week. How long it will take the energy department to review and award grants is unknown.

One company with funding already in its pocket is American Superconductor Corp. The Devens maker of energy transmission components received $12 million to manufacture superconductor wires for smart electrical grid demonstrations. While the large scale pilot projects would have proceeded with or without the funding, “these fit perfectly under the smart grid aspect of the stimulus program,” said AMSC spokesman Jason Fredette.