Viewing post #635016 by Steve812
|Three years ago I believed that solar electric power was not a good economic choice; but last year my wife and I decided to put solar electric panels on the roof.
We saw a salesman at Costco who told us that their company had installed several large solar electric installations on the rooftops of Costco warehouses. We talked with him for an hour or two and a week later signed a contract with REC Solar for a 4 kW system. Several weeks later some people came out to evaluate our site. Turns out that our house is oriented axis E-W, and there is a large area facing about eight degrees west of true south. They told us it's a perfect orientation. They also evaluated the site for shading and found that not to be a problem. They filled out the rebate paperwork and submitted it to out local utility APS.
APS, at the time, was offering 50% of the initial cost of a system. After they had approved the application for rebate, we went to Costco to pay for the solar system. The checkout people were stunned to see someone putting $15,000 on their Amex card, especially when the cart was empty; but sometimes the best stuff doesn't fit neatly in a shopping cart. And by doing it that way we go our 1% cash back on the purchase.
The system was installed in July. Mostly, things went smoothly. They were supposed to install a monitoring system called TED, the energy detective. And they did. But the readings were all screwy - mostly because they installed one or more of the transducers backwards. They kept sending out technicians who were clueless. And it kept on being broken for about three months.
In September they sent out the only person in the organization who knew anything about the TED system and since then it has worked marvelously. It measures the output of the system and it measures electrical usage in real time. It stores the data, and it displays the information in a web browser window. When it works it is fantastic; it changes the way I think about electric power and gives me a great tool to manage usage. When it breaks, however, it can be breathtaking. At one point it reported that we had used $15million worth of electricity one minute. Then it went dead the next. It has a little trouble sometimes when electrical storms pass overhead. (There was not, however, any problem with metering by APS. It reported our usage correctly and we got the full economic benefit of the power we generated.)
The economics of the system really works for us. Besides the 50% rebate from APS we got a 30% tax credit on the balance. So the system cost us about 30% of the retail price, or about $10,000. It saves us a little more than $100 per month on electricity. That means we're getting something like a 12% to 14% return on investment. It should pay us back in seven or eight years. And if it lasts thirty years it will pay for itself almost four times over.
Part of the economic success is due to our power rate structure which is Time of Use. We pay $.15 or $.175 per kWh during daylight depending on the season, but just $.05 per kWh at night. For most of the year we generate more power during the day than we use, selling it back to the utility at the rate we would pay to use it. But even in the summer when we use more than we generate, the power we generate during daylight hours is worth $.175 per kWh because of the rate structure we're on. It turns out that this rate is no longer offered by APS, so not everyone will have quite so supportive a rate structure. (It's not a very friendly structure to people who have huge air conditioning loads but no solar panels. I suppose that is why it was discontinued.)
There are a few minor issues. The output has gone to zero during the day when the panels are covered in a few inches of snow. When it warms up, the snow melts and there is an avalanche. Our house is on the side of a hill and the panels are more than twenty five feet in the air. When the avalanche falls, it creates quite a racket. But when the snow is gone the system returns to normal. Another minor problem is that in December and early January the sun is low enough in the sky that there is some shading in the late afternoon. We had anticipated this and had REC Solar change their installation drawings to correct this problem, but the installers installed to the unrevised print. So we did not get quite as efficient a system as we would have wished.
We were asked by a neighbor about the system. He had a friend who had difficulty with the paperwork and a year or so after deciding to install a system has no panels on his roof. And of course there are horror stories about companies that took huge down payments and went bankrupt before delivering anything. We were fortunate enough to have chosen a reputable and financially stable company to do the work. I don't know if our approach might have been more expensive; but even if it was I think we got a better deal.
It seemed like a lot of money to spend, at the time. And it seemed like a scary proposition to take on a fairly new technology. But the system has been very reliable - even the inverter. We like the idea that even if the grid lost power for days we'd at least be able to run a couple of refrigerators and a computer or two. And recharge portable device - maybe one day even a car. We also like the idea that the power we generate does not create pollution or add to global warming. It seems like a socially responsible thing to do. We feel very fortunate that we can do the right thing and still get a good return on our investment.
Here in Arizona where sunlight is abundant at just about the same time that hot weather makes air conditioning necessary, solar electric is a great economic choice for "peak shaving." Solar electric power generation is an economical way for utility companies to postpone building expensive coal or gas powered generating plants and operating them for just part of the day. With the price of fossil fuels increasing and the price of solar panels falling, and with healthy rebates and tax credits being offered, this is a great time to consider adding solar electric panels to the roofs of a lot of houses, especially in the south and west, maybe even yours.
---- copyright S.R. Brubaker 2011 ----
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