Monday, December 27, 2010

Solar Power - More panels and Nissan Leaf

Solar City will triple our solar power output in February, and we just ordered a Leaf, which they say is deliverable in the April-July timeframe.

We are adding 6.5KW of net delivered AC capacity (gross is about 7.5KW DC) to the garage roof. This time we are leasing it, and there are several options for how much downpayment vs. recurring payment to make.

There was a power cut last night for about two hours, and the automatic generator that runs off our propane tank kicked in after about 20 seconds. When the power came back, there wasn't a glitch, everything kept running. That was the first real test. We have a Generac 17KW unit that powers most of the house. With hindsight, it would have been better to get the 20KW generator that can power a whole 200Amp distribution panel rather than routing individual circuits. The extra cost would be offset by a simpler installation. We hope to replace the propane furnace with a heat pump at some point, then the generator will be the only thing running on propane, and since our solar system is grid-tied, it needs to work well to keep an all electric house going.

We were originally looking a geothermal heat pumps, but the extra cost of digging wells to get a more efficient heat pump is not cost effective versus adding extra solar panels to make up the difference. In climates where it is colder and there is less solar irradiance available, it makes more sense to use geothermal.

During 2010 we generated about 60% of the electricity we consumed, and also greatly reduced our propane consumption by switching appliances from propane to electric. In 2011 we should be almost 100% solar powered electric, and reduce our gasoline usage as well.


  1. What do you use to heat water? I just picked up a GE Geospring runs on about 700W in heat-pump mode and seems pretty slick and ideal for a solar electric setup.

    (I was at Sun in the late 90s and your work there was a huge help for me...Now I'm enjoying following your work on other platforms).

  2. We must make sure we have the necessary safeguards in place so we don't harm the environment, while trying to save it. Solar seems the safest as wind needs to come up with a design or method of keeping bats and birds away from the turbines. I know this will all get worked out in the end, we just need to make sure it doesn't get left out.