Net metering is claimed to be the great savior of renewable energy. One gets a separate meter, makes electricity and is billed for the difference. It sounds wonderful.
My views are a tempered by the reality of dealing with several electricity supply companies, the government and reality. Like many laws, the laws regarding producing your own energy and making it available to others are normally complex. The 'public safety' must be protected, the power must be compatible with the existing power and the electric company's service structure employees must be protected from stray shocks.
These requirements mandate a grid-tie inverter, separate meter, a power-panel interlock, insurance requirements and a battery bank if one expects to have power when the grid goes down. One should consider the requirements individually, and as a group, before deciding to have the local electrical supply company as a partner in power.
The grid-tie inverter can be represented buy the $ symbol. These things are more expensive than standard inverters. They will also have a limited lifespan. The cost of these seem to be between $700 and $1000 a kW. This is a non-productive cost and must be deducted from power output to have an honest assessment of the system. For the purposes of this discussion I will use $20 or, about 1% of the cost of the inverter per month and we will believe the sales folks claims they will last forever (sure). We shall also assume one can live on a 2kW energy budget (not likely).
In the states I have checked the separate power meter was $15- $20 a month. As it was illegal to connect without this feature, the cost must be included in any discussion of legal connections. We will use $15.
One would need to put in that little special power panel if this is to be an honest discussion. It will be put in by a certified electrician and we will considerate ourselves fortunate if costs less than $500. 1% of that cost will be $5 added to our little reality fund a month to service that 'debt' or replace that amount we might have had invested. Either way, it is a cost to the system.
As one would 'normally' have insurance and if one is truly off-grid these two items will be ignored for simplicity. It's not fair, but to prove my intemperate thoughts, not necessary either.
Our fixed costs are now $40 a month to play with our wonderful electricity company and we must now produce to offset those costs. Rates here are $0.14kWh. In Ohio, they were $0.08kWh. If one uses $0.10 a kWh, they would need to produce 400kWh a month of power offset costs. It will be prudent to see what kind of system that will take to produce that.
Our figures say we will need 13kWh production a day to 'break even', before we start saving any money. Figuring 8 hours of full output a day, and ignoring we didn't put in a MPPT and a solar tracker in our figures, we will need about 1600 watts of solar panels. In reality, it will probably take closer to 2kW. But, this is play and pixels, not writing a check to the various vampires of one's monetary resources. We need about $6,400 to achieve this kind of output. Oh, installation is extra.
Personally, I would rather spend the monies on things other than to enrich my local electric supply company. It appears to me they all drive cars of more recent vintage than mine, they are all provided health insurance and retirement benefits, the buildings seem to be built with little expense spared and all their tools and toys, from lineman's tools to computers, seem to be better than I can afford.
Ron
