Grid Connect Your Wind Machine

Federal utility regulations make it worth you while to grid connect a home wind machine, if you have one.


| September/October 1984



grid connect wind machine - illustration of wind generator on tower

A grid connected wind machine allows you to generate your own electricity and have a ready backup supply.


Illustration by MOTHER EARTH NEWS Staff

In the last five years, the use of wind energy has enjoyed a powerful resurgence in the United States. And the proliferation of machines that employ moving air to generate electricity can largely be attributed to two pieces of federal legislation, both of which resulted from the recognition of our nation's energy predicament back in the 1970's. These two important incentives can actually turn a wind system that costs as much as $3,000 per kilowatt of capacity into a wise financial investment.

You, the Friendly Local Utility

In 1978 Congress passed the Public Utility Regulatory Policies Act (PURPA), which contains a provision, Section 210, that among other things requires utilities to buy power from (and sell power to) independent producers of electricity who utilize renewable sources of energy. Under PURPA, if you own a wind machine your local utility must grid connect it, guaranteed.

The wind systems of a couple of generations ago had battery banks to store their excess production. These plants were designed to be electrically independent, simply because there was no centralized source of power in the form of a utility grid. Admittedly, windplants of the 20's and early 30's were far better than the alternatives: motor generators or no electricity at all. But when the wind stopped blowing for extended periods, their battery banks did eventually go flat. And, until the wind came up again, the residents either had to fire up a backup generator or go without electricity.

Today the utility grid can offer a wind machine owner an essentially unlimited source of backup power. And the utility's interconnection charge — which the system owner must bear — is far less than the cost of buying and maintaining a battery bank.

Hooking into the grid provides another important benefit, in the form of a constant customer for excess electrical production. Since a wind machine's capacity will sometimes be greater than the amount of power that's needed (in the middle of a windy night, for example), it's very convenient to have someone around to purchase the excess.

PURPA requires utilities to buy electricity from qualifying independent producers at rates based on what is called avoided cost. This figure is determined by what it would cost the utility to produce that electricity. Because there's a tremendous variation in the actual avoided costs of different power companies, and because there are a number of different ways to go about calculating them, buy-back rates vary from about 1¢ per kilowatt-hour (kwh) in some midwestern states to as much as 10¢ per kwh in California and parts of the Northeast.





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