We lost power again the other day. It wasn’t a big problem, but once again, it reminded me how dependent we are on that electrical current coursing through our overhead power lines. In our case, we lost power even though our home is net-zero-energy, meaning that we generate onsite all of the energy we consume on an annual basis—we even have enough left-over solar electricity to power our plug-in electric-hybrid Chevy Volt.
But living in a solar-powered, net-zero-energy, net-metered house doesn’t solve the problem of being without power when the grid goes down—which can happen for any number of reasons, from a tree falling over a power line to an equipment malfunction hundreds or even thousands of miles away, to an earthquake.
So what are our options for providing back-up power in homes?
The table below (also available as a download: Backup Power Options for Houses) presents a fairly comprehensive range of options for backup/emergency power. There are some others, but these represent the vast majority of solutions you will come across. With each option, the main features are described, followed by pros and cons, and special notes. Note that one of these options isn’t quite ready for prime-time, but still offers huge promise.
For commercial buildings and groups of buildings, other backup power options exist, including combined heat and power (CHP) systems and microgrids. Those options are not covered here.