UPDATE 2-US green energy projects get $59 mln in guarantees

* Beacon Power storage project to get $43 mln guarantee

* Nordic Windpower gets $16 mln guarantee to expand plant

* Part of $6 bln stimulus funds to boost renewable energy (Recasts, updates throughout)

By Ayesha Rascoe

WASHINGTON, July 2 (Reuters) - The U.S. Energy Department on Thursday offered loan guarantees worth $59 million to two renewable energy companies as the agency tries to quickly boost green energy production with a windfall of funding from the economic stimulus package.

Energy storage company Beacon Power Corp (BCON.O) was awarded a $43 million loan guarantee for building a 20-megawatt flywheel energy storage plant in Stephentown, New York.

The department also offered Nordic Windpower a $16 million loan guarantee to help expand the company's assembly plant in Pocatello, Idaho.

"These projects represent the innovative technologies that will help America reduce its dependence on fossil fuels and fight climate change," Energy Secretary Steven Chu said in a statement.

U.S. President Barack Obama has touted clean energy development as a way to boost the economy, pledging to double renewable energy production in three years.