Tag Archives: energy

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 3)

(continued from part 2)

Together Alex and I started digging in my front yard in early October while our supplies were on their way. There was to be a big 3×3 feet hole, almost seven feet deep.

This was where our steel post was going.

The main hole soon got too narrow for two people and I started digging the 24 inch deep trench for the electric line going from the post to the house. You want to keep that as short as you can. The longer the cable the more power you loose on the way to the inverter. These are pretty hefty cables, too.

Of course, in the pretty Fall weather our two girls wanted to have a part in the fun.

Eventually the digging was complete. Most of the supplies had arrived. The first step was to set the post. This is one hefty piece of metal. Since we didn’t have a crane we devised a way to roll the 16 foot pipe with five people off the flatbed trailer, onto a four foot pipe of the same kind – so we could roll it towards the hole (it was a 20 foot post but since we needed only 16 feet we had one four foot piece left over). After the post was in the hole Alex started to prepare it for a concrete pour.

After that there were two days of electrical installations. There are actually two separate cable pairs going from the post to the house. Only one pair will be used at first. If we decide to add on a second row of panels all the wiring will be in place. These wires go into  the basement and connect to the inverter.

Made in Germany (I am proud to say). This piece of equipment turns the ~400V Direct Current (DC) coming from the panels into 110V Alternate Current (AC). After the actual solar panels the inverter is the most expensive piece of equipment needed. It’s also the one you will have to replace after ten years or so.

Then it got cold and we had to wait for the final paperwork from our power company. We will be the first grid tied solar installation of all their customers. I think they will watch us with great interest.

Currently (January 2nd) everything is ready to go. The panels are in the basement,

the mounting brackets are sitting under the deck,

and the post is waiting for a few days break in the weather.

(to be continued)

Solar Power (part 2)

(continued from part 1)

Alex, my solar assessor – his company is Solar Systems of Indiana – came over one cold winter day early 2008 with his Solar Pathfinder and a device called a Kill-A-Watt. The Solar Pathfinder is used to determine the best place on your property for a solar installation and how much sunlight you can actually harvest taking into consideration stuff like tree line and geographical location. The Kill-A-Watt is such a good investment that I got one myself and it makes the rounds through my friends’ houses. Do you know how much electricity your refrigerator uses in a day? Your computer? (with all attachments such as external drives and scanners etc. on?) How about your waterbed? Or your cell phone charger (which you probably leave plugged in even while you carry your cell phone around with you)? Even though I have been frugal in my power use all my life (and believe me, my wife and kids hate me for being after them all the time to turn the lights off when they leave the room), after Alex had measured the power usage of some stuff in my house I was able to cut back even more. In retrospect, the sheer process of measuring this stuff, and learning as you go, how much it costs to build power plants, etc. makes you very conscious about waste – and that’s a good thing.

Of course being the only Solar Assessor in my state means that this guy is busy. After his visit to my house he prepared a report for me. Pretty detailed. It turned out that my property had potential if we mounted the panels in the front yard on the ground or on a post – not on the roof. There are other considerations with roof mounting, especially penetration and possible weight issues. In the time from the assessment until Alex finally located some free time to start the actual planning of the installation (around June 2008) I went to a seminar at Indiana University dealing with many aspects of home solar technology. I learned a lot and thought for a while that I might actually learn some more, take a weekend seminar in Wisconsin, get certified and become the second Solar Assessor in Indiana. It didn’t go that way.

I spent most of July in Germany and then August, back home, writing down my energy usage to determine the base load to be able to size the system we were going to get. Base load is essentially all your power users which are on all the time such as refrigerator, computers, whatever. In the hot Indiana Fall, with the geothermal doing the AC,  I was able to determine the base load at just around one kilowatt. Then we started to devise a system.

  • 1)  We never had plans to go off the grid. I didn’t want an over sized six kilowatt solar array ($60,000) and a truckload of lead-acid batteries in the basement and then still face the possibility of running out of juice in the middle of February because of lack of sunlight.
  • 2) While utilities in Indiana are required to pay retail for what you overproduce and feed back into the grid our power supplier is a Co-op and they do not have to do that. They pay wholesale rates. So too much overproduction was not feasible. This pretty much sized our system at 1.2KW. Six panels, pole mounted, in the front of the house.

Then, in late September, came the $15,000 shopping list to the supplier. And early October Alex showed up at my house with a shovel and said: “Let’s dig!”

(to be continued)