This energy experiment is playing out behind the smokestacks of an old brick coal power plant in Johnson City N.Y. on a small, snowy lot.

The storage facility, which is contained in a row of shipping containers elevated on stilts. John Zahurancik is overseeing its deployment for AES Energy Storage and shows his visitor inside a container.

"All the way down the side, these are racks of batteries. There's 80000 batteries in here, more or less," explains Zahurancik.

Bear with me now, because at this point in our story we need to stop for a short physics lesson. Our existing power system uses what's called "AC current". AC current is always switching directions, going back and forth. And that back and forth has to be kept steady, or else - things break.  In the past keeping the rate of that back and forth regular has been managed with coal or gas in plants, like the one next door.  But Zahurancik's facility could change that, with their batteries, making the whole process a
little greener.

"They're sending us a signal to either charge or discharge the unit to help them manage the balance on the grid," he says.

The warmth inside this container is welcome on a cold winter day - a little bit of heat released as the power is converted to be stored. But it¿s much less waste that in created by the alternatives according to Jonathan Silver, from the Department of Energy. The DOE helped to finance the Johnson City plant, as part of an effort to green not the coal power plant but the system itself that delivers energy.

"They're much cleaner. In fact this technology results in savings of about 70% of carbon dioxide emissions," says Silver.

The DOE's backing is important because despite its promise, this technology is still in its infancy in the grid.

Research on battery technology has been going on for consumer electronics and electric cars for years. But as batteries got cheaper and more efficient, people who worked on the grid started looking for ways to make battery technology work for their needs.
Researchers started looking for ways to make that tech work for the grid.

Rajit Gadh asks a crucial question for an important emerging technology, "Is it going to spread and is it going to become a standard way of storing energy?"

Gadh believes the answer is yes. Gadh researches making so-called 'smart' changes to the grid at UCLA. Just like there are not outlets for electric cars in all our garages, there is not the infrastructure in place to plug all the wind turbines and solar panels we want into the grid. For now, balancing the grid is mostly about tweaking the output of a couple of power plants to keep up with people turning their lights on and off. But in the future, utilities will have to cope with more finicky solar and wind generators whose output changes with the wind, or as clouds cover the sun.

And Gadh says the real unknown but exciting possibilities for batteries on the grid will be in long term storage ¿ not just balancing the grid minute to minute, but storing energy from wind turbines or gas power plants to use later.

"The other things that we're looking at here, is at night typically utilities have a lot more energy available. We all know on a hot summer afternoon when temperatures hit 100 degrees, that's when energy prices start to rise. You can take very very cheap energy at night, and store the energy in these batteries across the country," Gadh says.

"In the future now we're saying, the power system itself has to get smarter, more responsive more flexible," says Zahurancik, has an eye on those possibilities too on behalf of AES.

The technology is still in its infancy. But as we head back indoors, Zahurancik notes that things are progressing. Just a few years ago, this facility was just theories and diagrams a few years ago.