California Encourages West-facing Solar Panels

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Rooftop solar panels in North America face south. That’s just the way we do it. But*California*recently began to incentivize west-facing panels over south-facing solar. New guidelines from the California Energy Commission call for a 15 percent higher rebates for west-facing solar arrays than for south-facing solar panels. While solar panels collect

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westbranch

Re: California Encourages West-facing Solar Panels

Interesting numbers...

According to the Pecan Street study, south-facing systems produce more energy, but west-facing systems produce the most usable energy. About 42 percent of the electricity generated by south-facing solar panels is sent back to the grid. However, 75 percent of the electricity produced by west-facing panels is consumed on site.

and

Facing rooftop solar panels toward the setting sun, can increase late-day energy production by as much as 50 percent, according to recent studies.

inetdog

Re: California Encourages West-facing Solar Panels

Yes!
But rather than looking only at the amount sent back or consumed on site, an equally important number to look at is the total demand as a function of time of day to see where the PV energy will have the greatest effect on reducing the need to operate peaker plants to supplement the generally more efficient base load plants.
It turns out that the overall load starts to increase in the early evening as people return from school, work, and other activities and start consuming more power.

westbranch

Re: California Encourages West-facing Solar Panels

Yup, I've heard it called the 'Gamer/Dinner Peak' .... as soon as little Johnny get home on goes the 52" plasma and the ?? Watt gaming machine and stays on till he is sent to bed.... then Dad takes over! And in between Mom has the kitchen heated up....It's all in the timing...the fact that those West facing PV s can supply 75% of demand says to me that not much more PV is needed for that portion of the day...no?

inetdog

Re: California Encourages West-facing Solar Panels

westbranch wrote: »

the fact that those West facing PV s can supply 75% of demand says to me that not much more PV is needed for that portion of the day...no?

NO!

That means that for those houses that have PV, 75% of their panel output is consumed on site. It does mean that if 100% of the households had PV in the same size ranges, there would be a pretty large export to the grid that would have to supply loads elsewhere. During the day, that would include offices and other commercial. By evening those loads would be winding down.

It does tell us that the average PV system for those houses that have them is pretty well sized, since it will have to net out the whole night and morning period when PV is not available.

inetdog

Re: California Encourages West-facing Solar Panels

Oh, and one more detail: It is a somewhat moot point, since in most of CA the state rebate money (allocated through the POCOs) has run out, and I have not seen any predictions for when the legislators may add more funding.
The change has no effect on Federal tax credits. And CA has no SREC system.

westbranch

Re: California Encourages West-facing Solar Panels

inetdog wrote: »

NO!

That means that for those houses that have PV, 75% of their panel output is consumed on site. It does mean that if 100% of the households had PV in the same size ranges, there would be a pretty large export to the grid that would have to supply loads elsewhere. During the day, that would include offices and other commercial. By evening those loads would be winding down.

Agreed

inetdog wrote: »

It does tell us that the average PV system for those houses that have them is pretty well sized,

Agreed, particularly if they sized for the heaviest loads. Or is it the 10Kwh max size of the array that most go for?

inetdog wrote: »

since it will have to net out the whole night and morning period when PV is not available.

Disagree somewhat, if there are smart meters and TOD metering which I believe California has. I read that as saying that while the 'gamer demand' is up, the PVs are supplying that demand, but after sundown there may still be a need for 'peakers' until the lights start going off...

The writer missed out on 'the rest of the story' which is more dispersed storage is needed generally for solar /wind to fill in some of the gaps currently filled by the peakers.

inetdog

Re: California Encourages West-facing Solar Panels

Agreed on peaker need, but although it would be nice not to keep the peakers in service at all, it will still be beneficial to reduce the required run time on them.

westbranch

Re: California Encourages West-facing Solar Panels

We (BC) appear to be so different from California, in that I am aware of only one peaker in the province, it is called the Burrard Thermal Plant and is located just outside the City of Vancouver, runs off Nat Gas. was built back when I was a kid, first unit online 1962, 900MW, slated to be offf line in 2016 as capacity will be replaced by Hydro generation ~ 600 miles away...
Locally we have a waste wood generation unit that runs full time, really cleaned up the air shed starting day one of operation...