Our Suntech display panel congratulated us the other morning on five years of generating solar power. We've made over 60 Megawatt hours. That would keep a 60 watt light bulb going for over a hundred years. But we don't have any 60 watt light bulbs, they're all low-power leds.
In the same period we've used under 30 Megawatt hours. Around 45% of what we have generated. We sold around 90% of the electricity we generated, and bought around 75% of the electricity we used. I'm not sure how much sense this makes in environmental terms or for overall energy usage, but economically it makes sense since we only pay 11 yen for off-peak electricity, and they have been paying us 48 yen per KiloWatt hour for our solar power, totaling over 3 million yen.
Our contract lasts for another five years, and we will see what is available at the end of that. In the meantime I can start working on my plan to use the hot air under the panels for our atmospheric heat pump, rather than the frigid night air. I think it will take that long to find a brave enough heat pump engineer to tackle the project, or to learn enough about heat pumps to try it myself.
(Corrected 10th January: originally said "Gigawatts", changed to "Megawatts". We're not a nuclear power station!)
