Phil Timmons
Silver Member
- Joined
- Mar 18, 2008
- Messages
- 179
2. No battery required, nor really desired. It is called Grid-Tie? You must have heard of this? Solar Folks send the surplus up to the Grid during the day (high grid demand time), and then get electricity back at night (surplus grid time). Win-Win for all sides.
In the East, it's called net metering. We had it and it worked great. fast forward to today, some electric companies are shutting that option down. I'm guessing here, but their profits are higher if they shut it down. It wouldn't have made sence for us to go solar when we did if net metering wasn't a factor.
It is called Net Metering here, and most of the US, as well -- generally when Full Credit is given on a 1:1 send and receive at full retail both ways. So that is sort of a sub-set of overall Grid-Tie.
Some areas do what is called "Avoided Cost" (for the Utility) when the small local Solar PV is credited at wholesale price when Solar is sent UP to the Grid, and then charged full retail price for Electricity is taken FROM the Grid.
And then a few areas, only charge Full Retail from the Grid and give NO Credit for Solar sent UP. For many folks, even in this condition, continue Grid Tie to use the Grid as a back up, or small use overnight.
But even those are not the end of complications. To figure out what is the BEST method -- folks still need to consider Time-of-Use plans, and how meter fees and connection fees tie in.
But with all those combinations -- no local batteries are required, but some folks want batteries as a back-up system. Thinking about it all, we have even done some Solar PV sites - without batteries - but add a small local generator, because the customer needs that level of backup around the clock.
In an ideal world, folks would figure out what is best for everyone, and learn to share from their surplus, and accept help as needed. True "Give-and-Take" as it were. However, that tends to cut at least some "Cash Flow" from the Bottom-End to the Top-End investor(s) at the Central Plant(s).
The severe outcome of that is called "Grid Defection" when local folks decide to just disconnect from the Grid (called "Off Grid"), even where the Grid is available. We are starting to see this in California. The severe outcome of this is if the Utility runs off about 10% or more of their customers the Utility may become unprofitable -- and raise prices on the remaining customers -- running off more customers. This is what is the real "Utility Death Spiral."
In the Grid Defection Case, (as well as less than "Net Metering") folks may often try to align their own Time-of-Use with their local Time-of-Production. At most sites we do this with -- easily hit around 70% alignment. That means about 70% of the site's daily use occurs during the 6 to 8 hours of Solar PV production. Doing some projects this Spring Semester at school where we are targeting 90% alignment or more.