Scientists working in Rutland, Vermont have installed a massive lithium ion battery at the Green Mountain Power, Stafford Hills solar farm. The battery charges up during the day when the installation’s 7,722 solar panels are producing power at full blast. The power can then be fed back into the grid when the sun has set.

Grid battery storage is something like a “Holy Grail” for power companies. Electricity is mostly a “use-it or lose-it” commodity, and planning generation around fickle renewable power sources like solar and wind can make it hard on utilities to operate.

The research being done at Green Mountain Power could prove that utility scale power storage is viable. Having the option to store power overnight would change how utilities approach renewable power forever.

Ken Wells writes in The Wall Street Journal:

Green Mountain’s project puts it in the vanguard of power companies that are showing that utility-scale battery storage can be technologically and economically viable—depending on the scale and how it is used.

Like all utilities, Green Mountain faces issues meeting “peak demand,” the high-use period, typically in the early evening, when people return from work and school and crank up air conditioners and energy-hungry appliances.

Many U.S. utilities fire up natural-gas-powered generators to help their baseload plants meet peaks, often imposing hefty surcharges on customers to offset the extra generating costs. Green Mountain instead stores energy from its solar-and-battery combination to meet peaks—shaving as much as $200,000 an hour off demand charges for its 265,000 residential customers, according to the utility. Green Mountain, which says it invested $12.5 million in the project and received a $285,000 government grant, benefits in that it doesn’t have to build additional plants to meet peak demand and gets a public-relations boost among its green-leaning customer base.

Read more here.