jhm
Well-Known Member
@JHM a clarification. is virtual net metering the same or similar to Virtual power plants (VPP) where groups of local batteries are aggregatee into small to large power plants, avoiding some of the T&D (transmissions and Distribution) costs and losses
Not the same thing. The difference between net metering and virtual net metering is that in the former surplus solar power is sold to the utility, but in the latter, surplus solar is sold to any other buyer using utility owned power lines. So ordinary net metering forces the utility to be a buyer, but in virtual net metering it is up to the seller to find a willing buyer at whatever price buyer and seller agree to. It may be reasonable for the utility to receive some compensation for use of the distribution network.
Community solar is a form of net metering. Here there are community owned solar resources the send power to subscribers via the grid. The local utility is neither a buy or seller, but merely a grid access provider.
Virtual net metering can go even further. Suppose you have a big southfacing solar installation, I have a westfacing installation, and our neighbor has a Powerpack. In the morning you feed us power to use. Midday our neighbor is charging up the Powerpack. In the late afternoon, my panels feed power to the others, and after sunset we are all drawing power from our neighbor's Powerpack. Between the three systems we can come pretty close to covering our 24 hour power needs. We can share or trade this power as needed, and pay only a small amount to the local utility for use of grid and backup power.
This concept is really a virtual microgrid. A microgrid would generally include its own power lines, but in this virtual form it is merely renting powerlines. So aggregation services aimed at balancing the supply and demand can happen within the virtual microgrid. With enough storage the net flow between the virtual microgrid and the macrogrid can be as smooth and rate sensitive as the utility is willing to pay for. So grid seizes happen within the virtual microgrid and between it and the macrogrid.
So once we obtain virtual net metering, all these other things start to become possible. The exciting thing about SolarCity entering Mexico is that Mexico has a federal virtual net metering law that appears flexible enough to support all this.