And the next Solyndra is . . . Beacon Power

Flywheel maker Beacon Power declared bankruptcy on Sunday, first reported by Reuters, after winning a $43 million loan guarantee from the Department of Energy in the summer of 2009. This is the second company to declare bankruptcy that had a loan guarantee from the DOE program, following solar maker Solyndra’s bankruptcy about two months ago.

Beacon Power makes flywheels, which are energy storage devices in the form of large spinning discs contained in a vacuum that keep electricity flowing over the power grid at a steady frequency. The technology has struggled to reach a mainstream market, but the idea is that flywheels can help stabilize the grid and allow it to run more efficiently. They also need little maintenance over their 20-year-plus life span, and they don’t have some of the toxic chemicals found in many batteries. Flywheels are most commonly used as backup power for emergency power systems — what’s called uninterruptible power supply, or UPS — and facilities like data centers sometimes use them when grid power is halted.

Beacon Power received the $43 million loan guarantee to help build a 20 MW flywheel energy storage plant in Stephentown, N.Y. — the first full-scale commercial deployment of the company’s technology. The Stephentown energy storage plant was built to absorb and discharge energy to the electric grid, making it possible to use more variable renewable energy sources like solar and wind.

Reuters reports that Beacon drew down on $39 million of the loan for the Stephentown plant, and it reports that the plant is still operating. Unlike in the case of Solyndra, where private investors are set to get paid back a portion of the funds first (before the government), Beacon Power will be paying back the government first, says Reuters.

Flywheel technology has struggled for years, and Beacon in particular has continued to face problems. In late 2008, Beacon said it was delaying expansion of its commercial project, and back in 2006 the company faced technology malfunctions. Flywheels have had difficulty finding the right market and have faced competition from batteries, which have received a good amount of funding and support.

Earlier this month Beacon Power received a notice for potential delisting from the Nasdaq for trading under $1. Reuters reports that Beacon has $72 million in assets and $47 million in debt and that Beacon blamed its bankruptcy partly “on its inability to secure additional investments due to the financing terms mandated by the Department of Energy.”

No doubt House Energy Commerce Committee Republicans and right-leaning media will have a field day with the bankruptcy of Beacon Power. Already, electric car maker Fisker has been deemed the next Solyndra. But it turns out Beacon Power is actually the next Solyndra.