So, to summarize. Our solar PV system is working fine, after a few roof issues, and after we made some green choices in our lighting and our habits, we are routinely making about 1,000 kWh of electrical power MORE than we consume each year. Our Utility, Southern California Edison, will be paying us for the extra power we make.
End of Story? You don't know me very well, do you?
Tracking our Solar Power
I was excited about our new solar PV system, and when I get excited, sometimes I build a spreadsheet.
I wanted to make sure that our new solar panels were making the amount of power that they were promised to make. Then I wanted to make sure that they kept making the same amount of power each year going forward. I found it was easy to track this information, as well as our power usage each day, by taking two readings each evening at sunset: A reading from our solar inverter and one from our electric meter.
So I've taken and recorded these readings every day for the past three plus years. This is how I've been able to track the gains we've made by greener choices in our home. And tracking the excess power we make got me excited about using that excess to power an electric car. LOTS more about that journey in future posts.
Digital Power Tracking
One of my regrets about our solar PV purchase is that our inverter (the box that converts the DC power from the solar panels to AC power to use in our home) does not have the ability to provide data to a computer. It also shuts off its display when the sun goes down. So I have to take my readings manually, each day before the system shuts off. Or else I have to get up early enough the next morning to take a reading before the system makes more power for the day. I'd LOVE to have a digital capable inverter, but it wasn't available at the time we ordered, at least I didn't know about it.
I'm looking into a TED (The Energy Detective) product to solve this problem.
http://www.theenergydetective.com/
Influencing and Helping Others
One great thing about being an early adopter is having an impact on the choices of others. [I know that I'm not really an early adopter for solar electric power. Many real pioneers have been putting solar panels on their homes, either tied to the electric grid, like ours is, or off-grid, using storage batteries to save the power made during sunny periods for use at night or on cloudy days. Me and my neighbors are following in the footsteps of these true early adopters.] Two neighbors across the street have added solar PV systems to their homes within the two years after we added ours. I was glad to be an information resource for them and a trail blazer with our HOA architectural committee.
While state incentives are getting smaller, prices for the panels are going down, and federal incentives are now higher. So it is even more affordable now to go solar than it was when we did it. There are also financing plans that allow one to gain the benefits of going solar without coming up with the full cost up-front. I recommend starting your research at Go Solar California: http://www.gosolarcalifornia.org/
Next Blog Post: Can Your Refrigerator Power Your Electric Car?
Saturday, August 21, 2010
Saturday, August 14, 2010
Things we've learned about Solar
Hi again. I'm back to blogging after some busy weeks and some fun-filled travel to the Puget Sound area.
Living with a solar PV system is simplicity itself. You have it installed, set up a Net Metering Agreement with your utility and forget about it. The system wakes up each morning and puts itself to bed each evening and you don't have to pay any attention to it. Your electric meter will run backwards on sunny days and forwards at night, and it may even stand still on cloudy days. When it runs backwards (which is GREAT FUN to watch at first), power is going to the electrical grid for other people and businesses to use. This is great for your power company and your region, because you are making extra power at times when most people are using it to run their business or their air conditioner, etc., the so-called "peak hours".
The Net Metering Agreement is a good idea if your solar PV system is large enough that you'll make more power than you use during some months. Basically, the power company monitors your meter each month. For months when you make more power than you use, they bank those kilowatt hours (kWh) for you. For months when you use more than you make, they take those kWh out of your bank. At the end of 12 months, the power company calculates whether you owe them money or whether they owe you money. You get only one bill or one check each year, except for a monthly bill of maybe $5 for their costs to deliver power to you and monitor your meter.
Living up to the promises: The Solar PV installer companies try to estimate for you how much power your system will make. This is dependent on several factors, and they have computer programs and experts that make the estimates for you. The factors are: The number of solar panels you install; The power output (in watts) of each panel; The compass orientation (N, S, E, W) of the roof or other surface where you are installing the panels; The degrees of angle that your roof is from horizontal; any Shading caused by trees or structures during any part of the day; the Latitude and Longitude of your home (which allows them to predict the "insolation" or the amount of sunlight to expect to hit your roof); and Whether or not your system has motors to allow the panels to track the sun during the day (very rarely done because of expense and complexity).
As for compass orientation, the best direction is South for those of us living in North America. This places the panels facing toward the sun for the largest part of the day. The next best alternative is West, followed by East, and North, as I am fond of quoting Monty Python is "RIGHT OUT" (meaning if you only have a north facing roof tilt, don't waste your money, such a system won't be cost effective.). Our main roof faces slightly West of South. If you don't have a South or West facing roof or if you have major shading of the roof area, you are probably NOT a candidate for solar PV unless you have a large area of ground where you can place a slanted structure for the panels.
Our installer predicted that our system would produce 8,724 kWh of electrical power per year. Our usage for the previous 12 months was 10,278 kWh, so we would produce almost 85% of our power needs from our system. In fact, after the first 12 months of use, the system had produced 8,666 kWh. So the company was very close in their estimate. Exact predictions are impossible because nobody can predict weather patterns in exact detail. We learned quickly that cloudy days can make a huge difference. A rainy, gloomy day can reduce your output to almost nothing for a full day.
Have we gotten Greener?: Well yes we have. In 2005 and before, we paid only average attention to our electrical use, turning off lights when we remembered to. During 2006, we got "the message". We saw the film "An Inconvenient Truth", and that really got us thinking. No matter that Bruce Willis showed up on David Letterman that month and joked that he was making a movie called "An Unappealing Hunch", we decided to see what we could do to reduce our energy usage.
By replacing almost all of our light bulbs with compact fluorescent designs, replacing our Christmas lights with LED lights, switching computer CRT screens and TVs to LCD screens, and being more careful with leaving lights on when not needed, we have steadily reduced our usage so that instead of the 10,278 kWh that we used in 2005, we used only 7,051 kWh in 2009. That is more than a 31% reduction.
As a result, our solar PV system has regularly made at least 1,000 kWh MORE than we have used each year.
What are we going to do with that extra power? Well, right now, we are selling it back to our power company. In the first years that we had solar, California didn't require the utility companies to pay us for the extra power that we made and sent to them. So: THEY DIDN'T PAY US A DIME. Is there anyone else left out there who still thinks that we don't need government telling companies what to do? Now there is a law requiring the power companies to pay us for the extra power we make. So next year sometime, we'll get a check. It may only be $100 or a bit more, but it's something, and they really do owe it to us. After all, we are now a power generation station!!
Next Blog: More insights on Living Solar
Living with a solar PV system is simplicity itself. You have it installed, set up a Net Metering Agreement with your utility and forget about it. The system wakes up each morning and puts itself to bed each evening and you don't have to pay any attention to it. Your electric meter will run backwards on sunny days and forwards at night, and it may even stand still on cloudy days. When it runs backwards (which is GREAT FUN to watch at first), power is going to the electrical grid for other people and businesses to use. This is great for your power company and your region, because you are making extra power at times when most people are using it to run their business or their air conditioner, etc., the so-called "peak hours".
The Net Metering Agreement is a good idea if your solar PV system is large enough that you'll make more power than you use during some months. Basically, the power company monitors your meter each month. For months when you make more power than you use, they bank those kilowatt hours (kWh) for you. For months when you use more than you make, they take those kWh out of your bank. At the end of 12 months, the power company calculates whether you owe them money or whether they owe you money. You get only one bill or one check each year, except for a monthly bill of maybe $5 for their costs to deliver power to you and monitor your meter.
Living up to the promises: The Solar PV installer companies try to estimate for you how much power your system will make. This is dependent on several factors, and they have computer programs and experts that make the estimates for you. The factors are: The number of solar panels you install; The power output (in watts) of each panel; The compass orientation (N, S, E, W) of the roof or other surface where you are installing the panels; The degrees of angle that your roof is from horizontal; any Shading caused by trees or structures during any part of the day; the Latitude and Longitude of your home (which allows them to predict the "insolation" or the amount of sunlight to expect to hit your roof); and Whether or not your system has motors to allow the panels to track the sun during the day (very rarely done because of expense and complexity).
As for compass orientation, the best direction is South for those of us living in North America. This places the panels facing toward the sun for the largest part of the day. The next best alternative is West, followed by East, and North, as I am fond of quoting Monty Python is "RIGHT OUT" (meaning if you only have a north facing roof tilt, don't waste your money, such a system won't be cost effective.). Our main roof faces slightly West of South. If you don't have a South or West facing roof or if you have major shading of the roof area, you are probably NOT a candidate for solar PV unless you have a large area of ground where you can place a slanted structure for the panels.
Our installer predicted that our system would produce 8,724 kWh of electrical power per year. Our usage for the previous 12 months was 10,278 kWh, so we would produce almost 85% of our power needs from our system. In fact, after the first 12 months of use, the system had produced 8,666 kWh. So the company was very close in their estimate. Exact predictions are impossible because nobody can predict weather patterns in exact detail. We learned quickly that cloudy days can make a huge difference. A rainy, gloomy day can reduce your output to almost nothing for a full day.
Have we gotten Greener?: Well yes we have. In 2005 and before, we paid only average attention to our electrical use, turning off lights when we remembered to. During 2006, we got "the message". We saw the film "An Inconvenient Truth", and that really got us thinking. No matter that Bruce Willis showed up on David Letterman that month and joked that he was making a movie called "An Unappealing Hunch", we decided to see what we could do to reduce our energy usage.
By replacing almost all of our light bulbs with compact fluorescent designs, replacing our Christmas lights with LED lights, switching computer CRT screens and TVs to LCD screens, and being more careful with leaving lights on when not needed, we have steadily reduced our usage so that instead of the 10,278 kWh that we used in 2005, we used only 7,051 kWh in 2009. That is more than a 31% reduction.
As a result, our solar PV system has regularly made at least 1,000 kWh MORE than we have used each year.
What are we going to do with that extra power? Well, right now, we are selling it back to our power company. In the first years that we had solar, California didn't require the utility companies to pay us for the extra power that we made and sent to them. So: THEY DIDN'T PAY US A DIME. Is there anyone else left out there who still thinks that we don't need government telling companies what to do? Now there is a law requiring the power companies to pay us for the extra power we make. So next year sometime, we'll get a check. It may only be $100 or a bit more, but it's something, and they really do owe it to us. After all, we are now a power generation station!!
Next Blog: More insights on Living Solar
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