Net-Metering, or Net Energy Metering, is the policy where an energy producer, such as a solar electric system owner, produces energy that is used directly by the home, exporting any excess power generated out to the grid, while importing any extra needed power from the grid. Typically, a home with solar will produce more power during the day than the home uses, exporting that extra power to the grid, which makes the electric meter count down. At night, when the solar array stops producing power, the home draws electricity in from the grid and the meter counts back up. The home owner then pays the utility each month for the “net” amount of electricity imported from the grid over what they have exported. If the home has exported more electricity than it has imported in any given month, the credit is carried forward to the next month. In Rhode Island, a net-metered customer is allowed to generate up to 100% of their electricity usage annually.

The goal is to design a PV (Photovoltaic or solar electric) system that will produce, on average, the same amount of power that the home will use annually. In this scenario, the home’s PV system will produce more power than the home uses over most of the summer and that credit will be used in the winter when the days are shorter and the nights are longer.

Here in Rhode Island, when the PV system produces more power than the home uses in one month, National Grid still charges the home owner a few fixed charges. These fixed charges add up to about $8 a month. Some say that this is not fair to non-solar customers because the solar customers still use the grid, but do not pay the same amount to support the grid as non-solar customers. Solar advocates argue that solar customers give a net benefit to the grid, but these benefits are not fairly accounted for. With the utility business model being over 100 years old, and the utility guaranteed a certain profit, the debate is heating up. In fact, this debate is playing out in a serious way in California and Arizona with studies now being done by the utilities, solar advocates, the Public Utility Commissions and Government agencies.

Of course the studies by the utilities claim a net loss from solar customers, but the non-biased studies, those from Universities and Government agencies, tell a different story. Meanwhile there are costs and benefits from both renewable sources and fossil fuel sources that are not always taken into consideration. Some costs of fossil fuels that are not taken into consideration by the utilities are the negative health effects of burning fossil fuels and the tax breaks and subsidies given to the extraction industry. They also ignore the fact that solar energy is being put on the grid when it is needed most, in the daytime during peak load, reducing the need to bring extra power plants online.

Solar advocates also sometimes forget that most PV systems do not have battery storage and depend directly on the grid to absorb excess power generated, and provide power at night when the system stops producing.

The two sides will eventually have to come to some fair conclusion on how to charge all rate payers, but in the meantime the debate makes for some interesting spectating!