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CA Solar Use Falling Because of Economics
mdsolar writes "The LA Time reports that California is seeing a big drop off in rebate applications for solar power systems. It seems that to get a rebate you have to also switch to a time of use rate with your utility. The math is not working out, especially for smaller systems that don't fully cover use during peak hours. The result: homeowners are reluctant to go with solar energy. 'The difference between peak and off-peak rates is particularly large in the 11 counties of Central, coastal and Southern California, where Edison provides electricity service to 13 million customers. Edison charges summer time-of-use rates that range from 29.7 to 35.9 cents per kilowatt-hour between 10 a.m. and 6 p.m. on weekdays. It drops to a range of 16.3 to 18.6 cents per kilowatt-hour from 10 p.m. to 6 a.m. weekdays and all weekend days and holidays, according to documents filed with the PUC.' There is likely an optimal system size that reduces consumer costs, but with things in flux you'd want some flexibility in your system."
I'm in exactly the situation described in the article. I've gotten my first quote on a solar system, and will get my second quote next week. I'm trying to figure out if the whole thing makes sense financially, and the TOU requirement certainly doesn't help. Data on the quote I have:
- 5.2 kW nominal power, 4.4 kW output from the inverter
- estimated yearly output of 7600 kW.hr
- $40,900, lowered to $28,100 by rebates
- 468 square feet
Last year we used about 12,000 kW.hr, which cost us $2,400. We've instituted a bunch of conservation measures, which should make that figure a lot lower in the future. The critical thing is the summer months, when we'd sometimes been using 1500 kW.hr per month. This is partly the pool pump (which you have to run longer when the water temp is higher), but mainly AC. Actually although we're in Southern California, our house stays pretty cool naturally, and often we go a whole summer without turning on the AC for more than a few days, but there's always the temptation just to turn on the AC because it feels more comfortable. We just signed up for a voluntary program where Edison installs a remote control on your AC and turns it off at peak times, in return for which they give you some money. We've also started using the pool pump for fewer hours per day, which seems to be working OK as long as I'm very careful about all other aspects of pool maintenance.If we hadn't instituted any conservation measures, and if the legislature doesn't backstep on the TOU thing (which seems to have been simply a mistake), then I'm estimating we'd only save about $1,250 per year with the solar system, which isn't much of a return on a $28k investment. Judged purely as an investment, we'd have been better off just putting the money in the bond market or something.
On the other hand, if we do the conservation measures, then the TOU might not be such a big deal, because we wouldn't be buying much energy at the summer, peak rate of $.36/kW.hr. My estimate is that if we hardly ever turn on the AC (which we've done in some summers), then the TOU thing becomes financially irrelevant to us, and the system saves us about $1,500/year, which is somewhat better. It becomes an investment sort of similar to a standard real estate investment, where you pay a bunch of money up front, and then get a steady for a long time. One big issue is that you want to make sure your system lasts long enough so that it pays for itself, and that means you want to have confidence in your warranty. The good news is that the companies I'm getting quotes from have been in business for 40 years. The bad news is that the LA Times is quoting them as saying that unless the legislature reverses the TOU requirement, they'll all go out of business within 100 days.
The real issue is global warming. If it's reasonably neutral in investment terms, then I'm inclined to do it, but it's worrisome to have this cloud of uncertainty.
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I don't know what is causing the drop-off. However, I do have solar energy system that was installed in 2003. I was not required to install a time of use meter (the E7 tariff in California) but I moved to that tariff because it makes great sense.
The normal baseline rate for electricity on the standard residential tariff (E1) is 11.4 cents/kWh rising to 36.4 cents/kWh for usage over 300% of baseline. On the E7 tariff, during summer peak time (noon to 6pm) the baseline cost is 29.4 cents/kWh rising to 52.8 cents/kWh for over 300% of baseline usage. However, off-peak cost is 8.6 cents/kWh to 32.1 cents/kWh at 300% usage.
What do all these numbers mean? My solar array generates a high percentage of the total amount of electricity generated during peak time. I know this because a data monitor was installed on my solar array and I have detailed numbers on the performance of the panels and inverters. I think it was well worth the $1500 additional cost.
Bottom line: last year I used 16,345 KWh of electricity, 12,096 kWh generated by the solar panels and 4,249 provided by the utility company. However, I ended the year $191 in credit with the utility. This is because they credit me at the current rate when I send electricity back into the grid, and I'm delivering electricity at the time when I get the highest credit, and I'm using electricity at night when the price is lowest. So, last year I received 4,249 kWh of electricity from the utility that I didn't have to pay for. Without the E7 tariff I would have received ~$1,200 less credit for peak time generation and I would have paid ~$160 more for the electricity I did use.
Obviously, mileage will vary for different installations. For me, time of use has been, and continues to be, a great financial benefit. It also contributes to home comfort: I sent my home thermostat to a minimum of 72 degrees and a maximum of 76 degrees, and that's how the thermostat stays 24/7 all year. Extravagant maybe, because I could have saved more electricity with different thermostat settings, but I like my comfort. And saving electricity doesn't do me any good because all it gives me is a larger credit with the utility company (and I can't convert that to cash).
You're obviously not a Californian. Post Proposition 13, improvements to your house that increase its value don't make your property tax go up. Only the homeowner by voting a special assessment, the local government State Legislature can and only then with a super-majority vote. If you sell the house, however, the next buyer's tax bill will get the full benefit of your improvements. Remodeling the kitchen has the same effect. Which one has a better possibility of lowering your electric bill?
Environmental fuzzy save the birds you're killing from the reflection of your solar panels tax .2%
Does this happen? A quick google seems to indicate that birds have a better chance of getting killed by chasing light on the other side of glass windows than being par-cooked by reflected light. The neighborhood cat kills more birds than the solar panels ever will.
The SEGS plants at Kramer Junction in the Mojave Desert have been operating since the 1980's and are the largest solar plants in the world producing 354 MW.
Nevada Solar One is 64MW of solar thermal (3rd largest solar plant) and set to come online this year.
Stirling Energy Systems has a CPUC approved contract with SCE for a 500MW parabolic stirling solar thermal plant.
This document details a lot of the 100 year history of solar thermal attempts.
SHPEGS is our not-for-profit design project to adapt solar thermal to moderate climates by combining it with geothermal and heat pump technology. There is more information and links here.
Off-peak here is 11 hours per day, so I'd need to sustain something like 1kW (at a guess) 13 hours - let's call it 15 for a bit of slack. No, sod it, let's go for a full 24-hour supply at an average of 1kW (I don't have a lot of heavy electrical appliances that run during the day). So that's 24kW/h - and I suspect I'm guessing high there.
Right, let's consider our power delivery system. Forget 12v, to reduce the current draw I'm going to use 24v electrics. This page has a range of 24v to 240v inverters. They run at around 90% efficiency (inverters are very good these days). Lets assume a full load draw of 50A - that's 1200Ah. LED lighting tends to be easier to get in 12V form, with GX53-type replacements being cheap and easy to get. They put out about the same light as a halogen lamp (maybe a little less) for an input power of less than 2W. At most they're going to pull down maybe 15A for a houseful. Let's for argument's sake say it's 10W, because that gives us a total load on the batteries of 60A. We'll split the lights across the batteries to even the load.
Still with me? Good. We have a total power requirement of 60A at 24v, for 24 hours. This is 1440Ah (it's also 1440kW/h, but that's just co-incidence. 24 volts, 24 hours). Let's go look at batteries.
A quick Google suggests the Elecsol 125 batteries might be the way to go - they're relatively cheap, small enough to be handled by one man (28kg - they're not light!) and not too expensive (a little below the £1/Ah price point). With 125Ah capacity, we'll need 24 to cover our day's requirements.
These are 34x17x24cm, and this is where my crappy arithmetic and geometry fails me. I could arrange them on a special stand about 102x68x80cm, or very roughly the size of a small chest freezer. You'd need a bit more room for the services board, and some switchgear, the inverter and the regulator. You'd still easily fit it in your garage, though.