eVgo to deploy chargers with integrated battery storage

EV charging stations are an amenity that can help businesses attract good-quality customers. However, site owners may find, especially with DC fast chargers, that power spikes can trigger expensive peak demand charges from their electric company.

NRG eVgo has partnered with energy storage startup Green Charge Networks to add integrated battery storage to its growing network of Freedom Stations, enabling station owners to level out consumption and avoid demand charges.

EV charging stations and battery storage are a natural fit, according to Vic Shao, Green Charge’s CEO. “It’s really a symbiotic structure. We help enhance the value offering to the end customer – not only are they getting EV chargers, but they’re also getting power savings as well.”

MORE: Utility demand charges and electric vehicle supply equipment

The battery storage is not directly connected to the EV chargers, but is attached to the building load. The two appliances exist in parallel and join up at the host’s electrical panel.

Green Charge and NRG have been testing their joint system for several years. There are currently five NRG-Green Charge sites in California, including one at San Francisco’s Levi’s Stadium. According to Shao, the system has been shown to offer savings of up to 50 percent during peak summertime hours.

Other companies in the distributed storage market include Stem, Sonnenbatterie, Geli and SolarCity/Tesla. Shao thinks the successful companies will be those that venture outside of the Silicon Valley ecosystem and connect with more broadly focused players like Samsung or NRG. “Having these relationships and partners on your side – that’s the only way you’re going to make it in cleantech these days. It’s by pulling in the traditional guys and not being seen as a Silicon Valley outfit on the fringe.”


Source: Greentech Media

  • brian_gilbert

    Has flywheel energy storage been considered for this task? Its life is far longer than any batteries as far as I know. Even if not suitable for quiet locations it might be better for those where it would be in continuous use.

    • ned_plimpton

      Batteries used for stationary storage applications and peak shaving will have a very long life. The demands on the system can be controlled and mitigated much easier than in vehicles. And when hundreds of thousands (and then millions) of used large format batteries come out of the current generations of EVs and hit the stationary market, they will be incredibly cheap.

      How efficient is a flywheel at storing energy over long periods of time?

      • brian_gilbert

        here is a bit about it

        I have never found a lifetime. Boeing say greater than 20 years

        The reports just say it is still working at the end of the lifetime of the vehicle. Its disadvantage is its weight which makes it uncompetitive as the main source in a vehicle. However that is no problem with a stationary charger.
        The reason it is so reliable is that it usually has air bearings or similar so that no wear occurs. It is used for smoothing the demand of subway trains for example.

        Efficiency is covered here
        and I would expect the application in question to manage the higher efficiency which is 85%.

        • ned_plimpton

          “Flywheel energy storage systems using mechanical bearings can lose 20% to 50% of their energy in two hours.”

          Wow, that’s a lot of loss in a short period of time. I would assume that would disqualify it for most stationary storage applications. What if no one uses the charger for a few hours? It would be wasting a lot of energy.

          • brian_gilbert

            Yes, so you use magnetic or air bearings when you want longer-term storage as in this case. It is a matter of whether it is cost-effective.

          • brian_gilbert

            Use with Flywheel energy storage with air bearings.