Re: Solar PV and ST - Share Experience
I have a friend just north of Knoxville, Tn who just flipped the switch on a 9600w solar array which ties to the utility through a pair of 4800w grid-tie inverters and a dedicated meter per TVA rules. It's been in service for about three weeks now, and the total yield is about 370kw/hrs. Considering the number of astronomic daylight hours for this time of year, and the fact that he's experienced a few rainy/overcast days, I'd say his yield looks pretty good.
The SYSTEM investment came out to around $30,000, and probably has another $16,000 in materials getting the support structure and additional service wiring all sorted out.
I don't remember his exact number statement, but the TVA contract was something to the effect that his normal power PURCHASE rate was something like $0.16 KW/hr, while he could SELL his solar energy TO TVA for $0.12 HIGHER ( $0.28/KW/hr)... so his total payoff, at yield estimation based on what we observed so far, was somewhere in the vicinity of 18yrs or so. I'm betting that our estimations were substantially lower than what we'll actually see during a clear sky day, with substantially longer daylight hours.
The issue with trying to do such a system, is that your local util co HAS to have policies in place to do such things, and some are much more profitable circumstances than others. Furthermore, doing a grid-tie setup is much easier to facilitate for utilities that have hydroelectric power, as having other sources on tap (such as yours) allows water to remain in the reservoir rather than running 'em down. With a locality that doesn't have hydroelectric, the local and regional system will be managing load with fossil-steam and nuclear, perhaps a NG co-gen plant... none of them will be as ready to respond as quickly as opening a valve on the hydro plant... so a dramatic loss of PV solar (eclipse, or overcast) would be much more of a grid-destabilizer in some locations.