Capture solar for use at night.

Jayboy · June 2015

Hi, we use 40kw per day for a 24hour period.
The challenge is that he we using about 12kw of power out of sun hours,
Early morning and night.

We might be totally off the rails here ( long hours are getting to us,
hehe). But we want to know if he can capture the solar power for use
for his appliances during the evening and the early morning out of the
sunshine window. I imagine this is a heavy battery investment and not
worth it?Grid power will be cheeper here vs battery.

If there is some magic that can be done please let know. Its either
that or asking the client to alter his lifestyle so if he cooks,
washes and uses heavy loads rather to when the sun is up.

I don't see a feasible way for him to store the solar for night time
use. Your thoughts?

Blackcherry04 · June 2015

You seem to be on Grid, This is where you use a Grid Tied system ( Inverter & PV Panels, no batteries ) and Net Meter if possible. The Power Company will allow you upon agreement and approval of you system allow you to push Solar power back into their system. There are several ways of paying you for that power or just Banking it and giving you credit and then allowing you to use it when you need it. It's a credit / debit accounting system for the power you use.

SolarPowered · June 2015

Net Energy Metering...
Its energy value for energy value, over production offers a true up credit.
43 states are in NEM, and you have to research what program will best suit the energy demands and needs.
I would start first by seeing where your consumption demands come from, and restructuring for lower consumption. LED lighting is a good way to start.

rclark · June 2015

Yup, this here is why going 100% "off the grid" isn't necessarily the best course of action, given the current status of solar power technology. You may even make money off the investment, depending on your consumption at certain times of year.

BB. · June 2015

In general... 3-10 kWH per day is somewhat reasonable to be off grid with solar... And if you can get to around 3-4 kWH per day or less, it can actually be somewhat competitive with grid power in some cases (if you have high monthly service charges, quite a distance from the power lines, etc.).

40 kWH per day or 1,200 kWH per month... That is a lot of power an a lot of solar power system. And remember, you pay much of the cost of off grid power up front and 5-10 years down the road again as batteries fail, inverters+charge controllers may need to be replaced, etc.

-Bill

SolarPowered · June 2015

40kWh a Day meets the 110% build rule.

That is the equivelant of a 8.5~9.6kWh system depending on angle of incedence and azimuth. If it can be built for under $3.80 per watt, and receive federal tax credit the system would pay itself off by year 6 of a 25year warranty and be free power with credit incentives for the last 19years of system life and depreciation.

My AVG 9.6kWh systems average 58kWh from mid spring to mid fall.

Photowhit · June 2015

SolarPowered wrote: »

40kWh a Day meets the 110% build rule.

That is the equivelant of a 8.5~9.6kWh system depending on angle of incedence and azimuth. If it can be built for under $3.80 per watt, and receive federal tax credit the system would pay itself off by year 6 of a 25year warranty and be free power with credit incentives for the last 19years of system life and depreciation.

My AVG 9.6kWh systems average 58kWh from mid spring to mid fall.

Much too much left out of this to say "If it can be built for under $3.80 per watt, and receive federal tax credit the system would pay itself off by year 6 of a 25year warranty and be free power with credit incentives for the last 19years of system life and depreciation."

What will be the user fees for those years? $5 or $100 a month?

Where is this located? Some where with an average 5.5 - 6 hours of solar isolation a day or some where with 3 hours of solar isolation a day?

SolarPowered · June 2015

User fees in California are $35 a year. That's nothing to the level of over production true up credits.

A true south bound 8.5kWh system will yield close to as a east/west 9.6kWh system with a AVG PV watts insolation of 5.5 hours.

The difference in the initial investment cost, or set back in the return in investment between a 8.5kWh and a 9.6kWh is literally 7 months in investment cost if the average utility bill is $285 per month prior to solar.

I will agree some of what I am stating is specious or arbitrary. These aren't hard numbers,every home is different, but based off static average calculations it is somewhat on par for realized costs.

Photowhit · June 2015

I'd guess the average home in the US has more like 4 hours of solar isolation, this will tack on many more months of paying that user fee, and if it's $35 a 'year', I'm a monkey's uncle! Maybe $35 a month?

BB. · June 2015

My PG&E (Northern California) minimum TOU + Net Metering Bill is ~$4.44 per month or ~$54 per year.

If you want to the details (believe me, you really don't want the details):

http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_E-7.pdf

-Bill

SolarPowered · June 2015

BB. wrote: »

My PG&E (Northern California) minimum TOU + Net Metering Bill is ~$4.44 per month or ~$54 per year.

If you want to the details (believe me, you really don't want the details):

http://www.pge.com/tariffs/tm2/pdf/ELEC_SCHEDS_E-7.pdf

-Bill

This is the E7 TOU rate for electric car.

I've actually requested my clients that even if they do own an electric car to either schedule E1 or E2, it shouldn't be the utility providers business what the client uses their power for unless its something illegal.

This rate looks like it was amended for the SanFrancisco and Oakland Territories, I don't do business in those territories.

My last 3 clients that signed into NEM paid $35 for the year.

The NEM rates do change from different NEM contracts.

BB. · June 2015

Actually, E7 (as I remember) is one of the early GT Solar / Net Metering TOU rates from 10+ years ago. And, it had, for solar a nice noon-6pm peak rate. I have it because I am (for now) grandfathered. I love it because the plan is pretty simple to explain to family members (avoid using lots of electric power between noon and 6pm summer weekdays).

E8 is (was?) the electric vehicle rate.

E6 (is?) the present TOU rate and the partial/full peak runs quite a bit after the sun has set (and a couple hours before noon). A lot more complex rate plan (and may not be better than an E1 or E2 plan--If new/current GT solar folks can sign up for them.

And, at one point (again something like a decade ago), having solar plus Ex + E8 was bad--The way they allocated the tiered rate plans and how they credited between the two meters and such--It was a mess.

-Bill "as I recall" B.

SolarPowered · June 2015

BB. wrote: »

Actually, E7 (as I remember) is one of the early GT Solar / Net Metering TOU rates from 10+ years ago. And, it had, for solar a nice noon-6pm peak rate. I have it because I am (for now) grandfathered. I love it because the plan is pretty simple to explain to family members (avoid using lots of electric power between noon and 6pm summer weekdays).

E8 is (was?) the electric vehicle rate.

E6 (is?) the present TOU rate and the partial/full peak runs quite a bit after the sun has set (and a couple hours before noon). A lot more complex rate plan (and may not be better than an E1 or E2 plan--If new/current GT solar folks can sign up for them.

And, at one point (again something like a decade ago), having solar plus Ex + E8 was bad--The way they allocated the tiered rate plans and how they credited between the two meters and such--It was a mess.

-Bill "as I recall" B.

Yeah its all kind of a scam, to skim off the top of the solar producer. On the NEM form it can allow you to check either E-7, E-8, E-9A, E-9B, however it says those TOU's are closed to all PG-E NEM applicants at this time, so it should just be deleted from the NEM checklist.

Previous consumers in standard E-2 TOU, swap over to E-6 TOU in NEM, then for electric cars that were on an "experimental " E-7, E-8, or E-9 car charging are now moved into the EV-A and EV-B rates.

Its all a sick joke, sign an agreement for E1, its energy for energy with over production and it isn't the utility companies business how people use a watt no matter what time it is to differentiate a "credit".

The only one that works is E1, because the exchange has to be energy for energy production/consumption with the overproduction at .0397kW. The other rates "skim off the top of the producer".

In TOU the utility company essentially tries to fool the producer that using the nightly $ .09kW for car charging is practical. Its really just a loss of healthier voltage, and ultimately a longer hour charge rate due to that lower voltage.

Grid Tied Solar has voltage rise into the grid between the peak hours so utilities such as PG&E want that healthier voltage power. I've measured VMP at the point of main being as high as 248~252V during solar production, at nightly off peak at the $.09kWh rate voltage is as low as 238~240V. That is really a big difference in the investment value.

I've recommended to all my clients for car charging that were in E-2, whihc is now E-6, or EV-A/EV-B, if possible to charge during the solar insolation peak hours, to get the solar value before it is sent to the grid, and ultimately the charging station uses the healthier higher voltage, rather than the lower voltage at night.

Capture solar for use at night.

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