I am searching for information about a grid tied wind-electric system that also has battery backup. There doesn’t seem to be a lot of information out there on this particular setup. Have you heard of people doing this?
Zac Luhellier • via email
Any battery-charging wind generator can be part of a grid-tied battery-backup system, and this is very common. Models that show 48 volts as an option will be best for a modern North American home.
Perhaps you are already familiar with batteryless grid-tied systems, which couple a specific wind generator to a specific inverter—the two must be matched. Only a handful of wind generator manufacturers have done the design work to customize a specific inverter to work safely and effectively with their wind generators. Batteryless wind is definitely not a situation where you can buy a wind turbine and then go shopping for an inverter. You should buy the two together, from a reputable source.
But you asked about battery-based grid-tied systems, which is a very different situation. In that case, the charging source is not directly matched to the inverter. It simply charges a battery bank. You’ll want to size your battery bank for your backup needs, and make sure the charge controller for your charging source has an output voltage compatible with your battery bank.
The inverter in a battery-based grid-tied system is not directly coupled or matched to the charging sources. It only needs to be large enough to handle the total charging wattage of your sources, so it will be able to send excess energy back to the grid even in times of peak production. The inverter, of course, also needs to be able to have the capacity to run all the backup loads you might want on at one time (see “Sizing a Battery-Based Inverter”).
You could have multiple charging sources putting energy into the battery bank and one inverter selling to the grid. You could also have one charging source and multiple inverters selling to the grid. The specific configuration will depend on your situation.
Batteryless systems require expertise and education to design and install; battery-based systems need even more of both, since these systems and their electronics can be quite complex. Work with an experienced designer and installer to get what you want.
Ian Woofenden • Home Power senior editor