Thursday June 30, 2011
Adam Knudsen, chief of operations at the Dynapower Corporation, likes a stiff breeze to spin the blades on the company’s two 98-foot wind turbines, but he doesn’t count on it. And although a 101-kilowatt solar array lines the roof of the South Burlington manufacturer, he doesn’t depend on long midsummer days of unbridled sunshine.
“Wind and solar are non-controllable generation,” he explained. “To have full solar or full wind is absolutely possible, but it’s not likely to be occurring one hundred percent of the time.” For a company that depends on an average 600 kilowatts of steady power for daily operations, the unpredictable nature of sun and wind keeps it at least partially dependent on a 480-volt connection to the Green Mountain Power grid.
By the end of the year, however, Dynapower will complete construction on its renewable energy storage park, enabling it to channel power gleaned from solar and wind into industrial-size batteries. On, say, a cloudy day, or during times of peak energy usage, like an August heat-wave when Dynapower’s day-time energy usage may contribute to a strained electrical grid, the company can flip to battery power.
“That’s clearly helpful in managing Dynapower’s overall power usage,” said Knudsen. The solar array and the two wind turbines are representative of his company’s commitment to renewable energy, Knudsen explained—they can produce about a third of the 600kW needed when running at full capacity—but they’re really meant to showcase Dynapower’s contribution to the future of renewable energy storage.
The entire system is a hydra-like web of technologies: The two wind turbines, one manufactured by Northern Power Systems of Barre and the other by Atlantic Orient (since bought by Entergy), and the solar panels, built and installed by Alteris Renewables, feed into a central hub called a PowerSkid. Green Mountain Power, Dynapower, and the batteries also feed lines into the PowerSkid, what Knudsen describes as an outdoor power cabinet.
Central to all of this is Dynapower’s product, a so-called “bi-directional inverter” that cobbles all the feeds together allowing power to flow both to and from batteries, enabling the company to bank energy. The climactic ups and downs of solar and wind generation are smoothed over with stored energy. “Basically, they become predictable,” said Knudsen, a necessity in commercial power generation.
The original 55kW wind turbine, installed in 1995, was buttressed last July by the 100kW turbine and 101kW rooftop solar array, both running around $500,000. A $250,000 grant from the Clean Energy Development Fund earmarked for the energy storage component contributed to the project’s $2.7 million overall price tag.
If Dynapower’s recession-era construction and rampant hiring since last fall are any indication, the company’s tapped into a burgeoning market within the field of renewable energy. Knudsen, who says they’re still in need of new employees, attributes the growth to the stability guaranteed by banking power.
So those wonkish-sounding bi-directional inverters wired to the base of the wind turbines, explained Knudsen, are at the heart of “a major movement to store power world-wide.”
SOURCE: Eric Blokland, Correspondent