Power Storage in Your Building

by Luthin Associaties

It’s night. You’re riding the Ferris wheel, enjoying the view as you reach the top. Suddenly the power goes out all over the board-walk! There’s no back-up generator, but the ride’s lights are still on and the wheel keeps turning, letting every-body off safely. What’s going on?

This amusement pier is equipped with a power storage system that holds enough juice to run the facility’s critical systems for an hour. The same thing could be done at your building. Welcome to the near future.

For decades, R&D firms have been striving to bring down the cost of large scale batteries to be cost-effective for utility scale power storage. Units have already been installed at a handful of US utilities, with systems having 10-20 MW of peak output. All are designed mainly to help grids ride through brief problems, such as failure of a power plant or transmission line, while power is switched to other sources or lines.


Of interest to facility man-agers, however, is the trickling down of that technology to the end user level. Development of electric vehicles has brought down the cost of lithium-ion batteries, and some competing technologies (e.g., zinc-air) have also been going down in price and up in reliability.

Some are being scaled to capacities that could be used in:

  • storing renewable power (e.g., from photovoltaic [PV] panels or wind turbines) for later use, improving PV economics by 40% or more
  • peak shaving to counter brief high loads in buildings or manufacturing facilities
  • demand response programs, including frequency regulation and spinning reserve programs previously done only at utility levels because they require very fast response times in the range of seconds or minutes.
  • emergency backup power during utility outages (the vast majority of which last less than an hour), acting like a system or building-wide Uninterruptable Power System (UPS).

Several hotels in California, an apartment building in New York City, and part of a medical center in Philadelphia are already equipped with battery systems to help them perform such services. Prototypes will also soon appear in a NYC university and at some military installations. ‘

All this has not occurred without casualties, however. In the last year, a flywheel battery firm and a major lithium-ion producer both filed for bankruptcy. The big hurdle is producing a battery that can be recharged many times without losing capacity over its lifetime, all for less than $400 per stored kilowatt-hour (kWh).

For example, to be cost effective, a battery able to store and discharge 100 kWh per cycle cannot cost more than about $40,000 (i.e., $400 x 100 kWh = $40,000), doing so for at least several thousand cycles. So far, only a few very large batteries have achieved that goal. Some battery pioneers, such as Eos Energy (www.eosenergystorage.com), believe they can eventually create long-lasting units costing only $160 per stored kWh.

To help make this happen, significant financial incentives are becoming available. In California, utilities recently began offering funding to cover up to 60% of the installed cost of on-site power storage systems. In New York, NYSERDA has been funding prototypes and field testing both utility and customer level power storage systems. It’s presently supporting field testing of a 1,000 kW Eos system able to store up to 6,000 kWh. If successful, such a battery located in NYC could provide sufficient power to save over $250,000 a year in demand charges, yielding about a 4-year payback. A few power providers, demand response (DR) firms, and energy service companies have recently been dabbling in ways to apply power storage technology for their customers. By this time next year, expect to see several facilities in the New York metro area boasting of their power storage systems.

To achieve real dollar savings, it’s essential to automatically manage battery output and charging. Software and/or battery storage to accomplish this is offered by several firms, such as STEM, Inc, Demand Energy and Viridity.

(Article appeared in Luthin Associaties, 2013 Summer Newsletter)