Part of a series on new energy storage solutions being developed in Massachusetts

FORT DEVENS — These days we plug in everything: phones, flashlights, cameras — sometimes even our cars. We keep recharging them because, with electricity, you either "use it or lose it" unless you store power in a battery.

"The electric grid is the only supply chain in the world where you need to generate electricity and consume it at the exact same time," says Massachusetts Department of Energy Resources Commissioner Judith Judson.

By 2020, DOER is requiring electric utilities in the state to procure large-scale storage systems for some of the electricity they generate. Just how much is yet to be decided. What technology they use is up to them.

Now, a novel liquid battery is potentially offering unlimited storage capacity.

Power From A 'Goddess'

If beauty is in the eye of the beholder, you can see it by the truckload parked behind an Army Reserve building at Fort Devens. Inside, two 53-foot-long shipping containers are huge tanks filled with vanadium — the element named after the Scandinavian goddess of beauty.

"The vanadium, the beautiful part about it is the liquid changes color," says Vionx Energy CEO David Vieau. "It's like a rainbow goes through as you charge it. It changes. We can actually tell charge state by the color of the liquid."

Vieau's Woburn-based company has been testing a novel kind of battery at Devens for the military that stores energy in liquid form.

"This was an early system that the Army wanted to do to begin to understand from a microgrid standpoint how could they get an independent energy capability," Vieau explains. "Could you get something that would allow them to get separated from the grid?"

The answer is "yes."

For the U.S. Army, which is one of the largest consumers of energy in the world, the ability to always have access to electricity is a matter of national security.

"This battery system is getting energy that comes in off of the grid and it stores the energy in off-hours and then allows it to deliver it during peak times," Vieau says. "And you can actually provide enough energy to run the entire facility off this. You can run the meter backwards."

Field engineer Michael McNeely demonstrates the mechanics of the Vionx energy storage system.

"You'll see inside we have these huge storage tanks which basically hold all the electrolyte," McNeely says, "and that's obviously the magic to the system."

Vionx Energy field engineer Michael McNeely stands in the engineering house where the monitoring of the vanadium redox flow battery occurs. (Bruce Gellerman/WBUR)

Giant tanks contain vanadium in a solution of weak sulfuric acid. The liquid, or electrolyte, allows the flow of the electrical charge between tanks.

"We take that electrolyte, we bring it in with pumps and push it up through the stacks, and then just kind of let it fall back into the tanks through the top," McNeely says,

The electrochemical vanadium redox reaction, capable of storing grid-sized energy, is hard to explain. Just ask President Obama.

But the flow battery just might transform the nation's energy supply.

A Potential Energy Game Changer

U.S. Secretary of Energy Ernest Moniz says his department has invested tens of millions of dollars funding the novel design in its search for the energy storage holy grail.

"Flow batteries is one of the most interesting directions for storage," Moniz says, "because, roughly speaking, the energy is stored outside the battery rather than inside."

If you need to store more energy just add more big tanks filled with the electrolyte.

"Energy storage is a game changer if we get the cost down," Moniz says. "One principal reason is to be able to manage the variability of wind and solar."

High capacity rechargeable batteries make it possible to store renewable energy when the wind is blowing and the sun is shining and release electricity when they're not, to even out fluctuations in supply and demand.

McNeely, CEO David Vieau and Director of Business Development Jonathan Milley stand in front of the Vionx Energy vanadium redox flow battery. (Bruce Gellerman/WBUR)

"The beautiful part about this is there is no degradation," says Vionx's Vieau. "It's a chemical reaction. A hundred percent reversible."

And Vieau says the Vionx storage system can recharge and run for decades and vanadium is environmentally safe. The electrolyte is 70 percent water.

"This is the beginning. What you're seeing here is an opportunity," Vieau says. "When you think about Massachusetts and New England and the availability of power and say, 'Well, what have you got?' If you've got offshore wind, at relatively large scale, you can create energy around the clock. Think of it as a power plant but without the fossil fuel."

The Vionx storage system puts the search for the renewable energy holy grail within sight, except for one thing: the cost.

"It's about $400 per kilowatt-hour for a DC [direct current] system. And that's going to go down by a third over the next few years," Vieau says.

Still, that's nearly three times the cost the Energy Department has set as the renewable energy storage holy grail. But, according to Vieau, if you spread out the upfront costs over decades and attach the system to a solar farm, the redox flow battery will be able to store and generate electricity at half the price of burning diesel. And, says Vieau, the core components — tanks, controls and energy conversion system — are future proof.

"As new technologies develop that have alternative chemistries," he says, "they can be deployed in systems like this. But the one that works today and works really well — that's this — vanadium. It's proven. It works."