Princeton Power: Plugging the Power Grid Into Electric Cars

By Bill Moore

Princeton Power co-founder and Chief Strategy Office Darren Hammell sits down with EV World to talk about vehicle-to-grid bidirectional charging and what it means for the future of electric vehicles in his 30-minute MP3 interview.

Who knew there was a U.S. Air Force Base in Los Angeles? It's located in El Segundo, not far from LAX. It is the home of SMC, the Air Force's Space and Missile Systems Center. The personnel there, both military and civilian, are "responsible for research, development, acquisition, on-orbit testing and sustainment of military space and missile systems," says Wikipedia.

In keeping with its 'out of this world' mission, it now can claim to another important distinction: it also is the home of the Air Force's first V2G fleet experiment in which 13 Nissan LEAFs can now share their combined 300+ kWh of energy storage capacity with the base's power grid.

One of the key players in this demonstration program is Princeton Power, co-founded over a decade ago by our guest today, Darren Hammell, who with some engineering classmates started the company while still undergraduates at Princeton University.

Back in the early 'oughts' (2001), the company began with doing some work on shipboard micro grid applications for the U.S. Navy and then migrated to developing inverter technology for renewable energy applications: wind and solar.

Today, one of the primary focuses of the company is development and manufacture of bi-directional charging stations. There are two models at present: a home-scale unit and a industrial/commercial unit; and this is where LA AFB enters the picture. Those charging stations lined out on the base in the above photo are Princeton Power DC fast chargers that, unlike other manufacturer EVSEs, enable the movement of energy both ways: from the grid into the car and from the car back into the grid by doing the conversion of the grid's AC power into DC on the charger instead of on the car. This allows for much more rapid charging capability, as well as the management of energy flowing both ways.

For this to work, of course, both the car and the charging station have to be capable of this bidirectional energy flow and at the moment, only Nissan's LEAF has been engineered to make this possible through their CHAdeMO charging standard. This is why all the cars in the LA AFB vehicle-to-grid (V2G) fleet are LEAF electric cars.

And why would you want to share power from your car back into the grid? Certainly in a car-to-home situation, having this ability can mean keeping the lights on and the power flowing at home should your local power grid go down. Depending on how much current the house might draw, the homeowner could run from a few hours to a couple days on the 24 kWh battery in the LEAF.

In the Air Force's more commercial-level application, the idea is to monetize this energy storage capacity, at least in theory, so that the local grid operator pays the car owner for being able to access the car's battery; not so much for its electric storage capacity, but for its grid stabilization capability by providing frequency management and surge buffering, especially from renewable sources. Having just a handful of cars with this ability won't make much of a difference, but when there are someday millions of EVs hocked up -- most as much as 23 hours a day -- it can start to have a significant impact on the power grid in a good way. This is what Princeton Power is counting on.

The interview with Mr. Hammell is just over 30-minutes in length. You can listen to it using the embedded MP3 player or by downloading it for playback on your favorite MP3 device.

Times Article Viewed: 9872
Originally published: 22 Dec 2014


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