The future of interconnection of solar arrays to the utility grid in NH, net metering, is being taken up by the State Legislature this session. As the Utilities have met their minimum (“solar cap”) and are not required to allow interconnection of solar arrays to the grid, the natural question of what is next for solar automatically arises.
First it is important to understand why we need the grid. The power grid provides electricity to many customers across a large region. The grid has the ability to supply power even if there are shading constraints or electric demand is too high for what a solar array can produce. In New England this is even more true as the winter months provide significantly less solar energy. The more customers that are connected to the grid the easier it becomes to manage costs of providing power to all customers. Keeping customers on the grid helps to keep the overall cost of providing power to everyone low.
With the advances in battery technology the ability for people to defect from the grid and go off-grid is becoming increasingly possible both from a technological and economic perspective. As customers leave, the utilities lose revenue but have the same infrastructure to pay for, so rates will go up for those who stay, encouraging more to leave. More customers connected to the utility helps keep the costs down and provide electricity to the largest number of people. Just as with insurance the larger the group the greater the ability to spread the costs for all.
Now, what about the solar on my house? With smaller home systems the excess electricity that generated will be used locally. The electrons will travel through the grid to find the nearest load most likely the neighbor’s home or local business and be used there. The advantage of this is that the electric company often needs to start up a large fossil fuel power sources to meet business and summertime (air conditioning) daytime demands. With distributed solar on homes that aren’t being used in the middle of the day, they may be able to avoid starting a new generation plant. Since solar arrays produce power during peak times the residential solar arrays are feeding into the grid at the same time demand is high.