Connecting to the Grid: Working with Your Local Utility

If you are installing a grid-connected system, you’ll need to contact your local utility company to obtain a copy of their interconnection agreement. You’ll need to assure them that the electricity you will be providing will be of the same quality as the power they supply to their customers. Utilities may have questions about what happens if the grid goes down and they need to send a lineman to work on it. They don’t want their linemen getting shocked by a wind system that’s operating while their system is down.

You won’t need to agree on compensation for surplus electricity you will supply to the grid. The amount is stipulated by state law. All utilities in the United States are required by federal law (the Public Utility Regulatory Policy Act of 1978) to accept surplus electricity produced by their grid-connected customers. However, federal law only requires utilities to pay the “avoided cost” for monthly or annual surplus. Avoided cost is what it costs the utility to generate the power, which is usually one-fourth to one-third the amount they charge customers. If you are paying 8 cents a kilowatt-hour, the avoided cost may be as low as 2.5 cents. That’s all the utility is required to pay.

Most states have enacted net metering laws that require utilities to reimburse residential customers at the avoided cost. Many others do not pay anything for the net energy generation. A few pay the same rate they charge customers — the retail rate.

Before they sign an agreement, your utility may require you to submit simple electrical drawings that indicate where components will be located. Its two most important concerns, however, will be an assurance that you have liability insurance and that your equipment includes some sort of system for automatically discon necting the wind turbine from the grid should there be a power outage. This is a standard feature on grid-connected inverters. Even so, the utility may require a demonstration or an inspection.

Utilities may also require you to install a visible, lockable AC disconnect — a manually operated switch that allows utility workers to disconnect your wind system from outside your home in case they need to work on the lines. This is required even though gridconnect inverters automatically terminate the flow of electricity to the grid when they detect a drop in line voltage or a change in frequency. Do not fight your utility on this redundancy. While you may be in the right, keep in mind that the utility is a lot bigger than you are, with much more legal expertise and practically unlimited
financial resources to fight your installation. In a case of irreconcilable differences, your best bet is to contact the public utility commission for help. If you go into the process with the proper knowledge, however, it is unlikely ever to come to that.