Tag Archives: power

Solar Power update (part 8)

(continued from part 7)

So here we are. February 2010. We had our solar array online for close to a year now.
What are the first year impressions of our life with a 1.2kw solar array in our front yard?

First, if you read the initial installment of my solar power posts you will notice that we built a post with a mount laid out to hold 12 panels. Because 200W panels aren’t cheap we only populated half of the array at first. These six panels were actually only 195W a piece, so to be correct they only add up to 1170w total. Since going online on February 11 2009 we made 1361kwh as of January 31 2010. The array has been producing power for just over 4010 hours. The power output during the course of a nice sunny day starts up around 8:30am (in the winter) with just enough wattage to turn the inverter on, typically 10 watts or so. Around 11:30am, when the sun clears our roof and hits the panels full on we are up to 800 watts which will quickly ramp up to 1050-1150 watts just around noon. It stays there until 2:30pm or so and slowly creeps back down to 50 watts around 5pm. On a sunny, cloudless day this will produce between 4.5 and 5.2kwh. In the summer we get up to 7.5kwh on some days. Of course if we have a very cloudy sky the power never exceeds 50 watts. January around here is like that sometimes. Total electricity usage in our first year with the solar panels was 14,320kwh. That means the panels contributed a little under 10% of the electricity used at our house.

As it turns out my installer, Alex Jarvis from Solar Systems of Indiana, helped me to sign up with a company by the name of Sol Systems which brokers SRECs (Solar Renewable Energy Credits). Based on the size of your system you get a yearly check for offsetting carbon output. I actually did get a check of a couple of hundred dollars for the first year. More than the $85 I saved on my power bills.

One other thing is that my system over-produces sometimes. In other words it makes more power than we use in the house and we get credit for it from our utility company. Unfortunately the credit that we get back is a little more than half of what we pay (we pay $0.0631 per kwh while we only get $0.03357 for a kwh that we feed back in.) Unless we overproduce during peak times – then we get a credit of $6.67 per kwh! During last summer we were actually able to still produce around 500 watts during evening peaks and it turns out it is a good time to turn off everything non-essential in the house for an hour to feed back as much as possible and get the peak time credit. If you can feed back half a kwh on 10 days in a month it adds up to a $40 credit on your power bill – pretty substantial.

Then, on January 5 2010 Alex came over and we added six more panels for a whopping 2370kw. This what our array looks like now:

Why, you ask, would I spend another $4,500 to add six more panels? I mean, I really *only* made about $285 last year. If nothing else happens, nothing changes, the price of electricity stays the same or the days become longer it will take me 33 years to break even, not counting at least one inverter replacement for about $2k in that time – and that calculation does already include a 30% tax break.

The answer isn’t exactly simple.

1) While looking at my power bills, we developed strategies to use electricity when we get it for free from the panels. We learned that dishwasher, washing machine, dryer, computer tasks involving multiple computers, etc. are better done during the day to use power from our solar panels rather than the grid.

2) With the help of a Kill-a-watt, which shows you how much energy a connected appliance draws over a given time, I was able to locate some real energy wasters in the house. For one, the dehumidifier in the basement is now turned off – that things sucks 300-400 watts! That’s about 3000kwh in a year! The solar panels make me really conscious about that stuff.

3) We have about 4-5 months in which we can actually overproduce and feed back power during peak times. With 12 panels we should be able to maximize our credits considerably.

4) While at the moment the 1/2 ratio between what we pay for a regular kwh ($0.0631) and what we get credited for ($0.03357) seems quite unfair, this will change eventually. Even in Indiana the law says utilities are required to pay retail rates for power fed back into the grid. It’s just that our power company is a coop and they are still excluded.

5) While our initial six panels were $1200 a piece and rated at 195w the new ones we put on just three weeks ago where $800 and are rated at 200w. So prices have dropped.

Today was really the first full day of sunlight since we installed the additional panels. Just before shutting down the inverter read 10.41kwh produced. And that’s pretty cool. Considering that on average we use about 39kwh in a day that’s about 1/4 of total electricity from solar. I am sure we will find more holes to plug in the walls and more ways to save energy. It should be an interesting year.

Solar Power (part 4)

(continued from part 3)

As a we are waiting to go operational I have some time to ponder the pros and cons of my $15,000 investment, alternative energies in general and solar in particular. Despite my feeling of doing something good for the environment and (maybe) for our bottom line I know that this technology is young, even though it has been around for decades, and like my computer the equipment I am installing might be outdated in a few years. Our calculations still show that we’ll break even after about 22 years. The system has a life span of 35-40 years. It is a very long term investment.

There is lots of talk these days about green energy and solar and wind are usually the first technologies mentioned. The problem with both of these is that you only get electricity when the sun shines or when the wind blows. There are really only two ways to have access to electricity when there is no sun or no wind: oversize your system and store surplus energy in batteries or a grid interconnect. Unless you don’t have access to the grid battery storage is really a bad idea. Electricity storage will have to be much more efficient than what is currently available to a homeowner. If you read Scientific American or MIT Technology Review or do a search on the internet you find many people doing great and promising research. Last summer I had a little test setup in my yard with a small solar panel electrolyzing water into oxygen and hydrogen. Nothing much came of it – maybe the plastic bag I used to collect the gases was leaky. More likely the electrodes were the wrong metal. At the same time I am not sure how safe I would feel if there was half a Hindenburg’s worth of hydrogen in a pressurized tank under my house. No storage then. But then each time the sun goes down you will draw power from the grid instead of your panels. So the power utilities can’t really scale down their power plants. Sure, if you work at home and most of your power is used during normal work hours you might be able to offset that with a solar array. But even if my whole street does what I do and nobody draws a single watt from the grid during the 4-8 hours of usable sunlight the power company still will have to keep their coal or nuclear power plant running. As far as I understand you can’t just flip a switch and turn them on or off. To my knowledge just gas power plants allow for relatively fast on/off cycling. At the same time changes in the electric infrastructure will take people like us into consideration.

Of course there are really cool proposals such as once we all have electric cars their batteries will function as energy storage while hooked up to the grid. One literally ‘cool’ idea I read about was to replace the current wires of the electric grid with superconducting material which is kept at very low temperatures by liquid hydrogen. Superconductivity means that electricity can flow through a conductor without resistance. Usually this is done by cooling certain materials to temperatures close to absolute zero. These would be pretty substantial ‘wires’ but they would function to deliver electric energy and hydrogen and could serve as giant energy storage reservoir. Not cheap, though. (September 2006  issue of Scientific American).

Then we also have the really huge stuff like solar power satellites in geosynchronous orbit around the Earth. Geosynchronous means the satellite is at such a distance from Earth that it appears to be hanging above the same point on the ground even as it is orbiting the planet at breakneck speed. Something like that could collect solar energy day and night. It would have to be huge (as in miles and miles of panels) and the energy would have to be transmitted to the ground using tightly focused microwaves or lasers. Since the US will lose manned orbital access for a few years after the Space Shuttle fleet is retired and NASA’s new rockets are not finished yet it doesn’t look too good for large cargo hauls to 36,000km orbits.

And, really why do I need to set solar panels up in my front yard if the payback is so long term that I can’t even be sure to still be alive to see it? Because it’s something that I can do now! This whole energy thing is made up of so many networked components that we can’t rely on one solution only. And we need to accept that it’s a moving target. Maybe more people would put solar panels or wind turbines up if you could buy them at Walmart. The fact that you can’t and that you have to actively make an effort to find skilled and knowledgeable people to help you with it forces you to learn about energy. I think that even if you end up not installing anything you will be much more conscious about your energy footprint and you will discover ways to waste less – or you stick your head in the sand (from what I understand ostriches don’t actually do this) and pretend that everything is fine and no change is necessary.

(to be continued)

Solar Power (part 1)

In the last year or so the term ‘alternative power’ has really come to the forefront again. High fuel prices, talk about peak oil and dirty coal. Good thing, too, because we need to talk about it. Especially during 2008 I kept getting emails from countless action groups and organizations such as the Sierra Club and the World Wildlife Fund mentioning it. The issue is actually on people’s minds….

For some reason it has been on my mind since I was a teenager. If you have read some of my other entries here you will be aware that big, complex engineering holds high fascination for me. All sorts of power plants fall into that category. From giant dams to nuclear power plants, from wind turbines to geothermal. And there are of course the more esoteric, fantastic or futuristic things such as fusion, solar power satellites, deep geothermal, tides, etc.

But what is an ordinary citizen supposed do to about all of that? Sure, you can contribute to some of the organizations who lobby for clean power and oil independence in Washington. But still, somehow somebody has to do the dirty work, build something, make something work. Only scientists get to do the cutting edge stuff. We consumers just have to wait until product becomes available at our local hardware stores – sometimes ten years after you first read about it in Scientific American, often never.

Here’s the first part of our ongoing story:
We bought our home in 1995. After paying rent all my apartment-life it came as quite a shock that not only could you do stuff to your house and garden but unless you wanted to call somebody to fix that drain or dig that hole YOU had to do it yourself.

When we moved into the house we had a brand new gas furnace installed. It was fairly efficient but a few really cold winters convinced us that some other heat source might be more economic. I spent the first half of 2001 looking for a local contractor who knew how to install a geothermal heating & cooling system. Around May I found somebody – 90 minutes drive south. In August, in the course of a few days, the system was installed. We spent a bit over $10,000 on it but it works much more efficient than the gas furnace. Since then the gas prices have gone up even more and my latest calculations show that we did break even already.

After that I started seriously looking into solar power. But, really, in the first years of this decade nobody wanted to hear about it. My car mechanic and my dentist both told me they had solar panels installed in the early seventies after the first energy crisis. Their experience was not a good one – non-standardized systems, no spare parts available and nobody close by to maintain it. So, for about six or seven years I kept looking around for somebody to help me. Sure, there was (and is) plenty of the needed material for sale at places on the internet. There are plans, layouts, articles. But I really wanted somebody to come to my house, look at the property and tell me whether this was feasible or a pipe dream.

In late 2007 there was a little press about a few houses being built in the city of Bloomington, IN (my hometown). Some of these houses had solar panels on their roofs. Through the real estate company I found the person who had put these on. And guess what. He lives about a mile from my house, is a well known rock drummer in town and happens to be the only certified Solar Power Assessor in the whole state of Indiana.

(to be continued)