Battery prices have enjoyed a very steep decline in costs, and according to the National Renewable Energy Laboratory and Bloomberg New Energy Finance, more improvements are expected. That begs the question: Have prices reached the point where batteries are a viable alternative to backup generators?

Well, sort of. It’s not an easy question to answer and depends on two very important parameters:

  1. Your location; and
  2. Your tolerance for outage risk.

If your facility is in Massachusetts, New York, or California, the state and local incentives for batteries are excellent, making batteries the cheaper solution for short-term backup. Note that we said “short-term”.

Outages follow a declining exponential curve: the probability of a short outage (that lasts only a couple of hours) is vastly higher than the probability of a multi-day outage. To illustrate, in Massachusetts a battery backup with three hours of capacity eliminates about 48% of all outages, and at a cost 40% less than a backup generator. Unfortunately, if the outage lasts longer than three hours, then you will be down. Since batteries are expensive, the backup generator becomes the better investment if you need protection from outages longer than three hours.

Exergy did a deep-dive video into this subject where we also covered solar-plus-battery installations. You can view that video here (no registration required):

If you would like to learn more about backup power options, from generators to batteries to Backup Power-as-a-Service, please visit us at, or simply email or call.

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