Powerful developments

Today I received my latest bill from my electricity company. It was a good one—a very good one. This whole thing is getting very interesting—to me, anyway.

The image above is what I posted to my personal Facebook. I added in a comment:

This bill was so very low because my credit for solar production not only paid the charges for what I consumed from the power grid (mostly nighttime), it also partially offset the fixed charges that everyone pays. In technical terms, in summer I'm mostly self-sufficient in electricity, and this past month I was completely self-sufficient. This fascinates me. I'll be VERY interested to see how costs work out this year because it'll be my first full, calendar year with solar power.

That pretty much explains it, but there’s a little more to it, especially about the self-sufficiency thing. In my comment, I was referring to the fact that in summer I’ve needed very little power from the national grid, and that last month I needed none at all: I sold more power than I bought. But that’s only part of the story.

As I said back in October, “I do electricity-heavy things—like running the dishwasher, running the clothes dryer, even ironing clothes or recharging batteries—during daylight hours, ideally on sunny days.” This is important because I pay more for electricity from the grid than I’m paid for the power I send to the grid. This means that it makes more economic sense for me to use the power I generate during the day, rather than run those things at night when I have to pay for power. In summer, I still have a lot of power to send to the national power grid—even after using what I can—and that offsets the cost of the power I buy. This month it more than paid for the power I bought.

There’s a device attached to my photovoltaic cells that measures and controls solar power in and power sent out. It reports “self-sufficiency” as a daily thing, and as using only solar power to run the house. If I use less power than I’m generating, it says I’m 100% self-sufficient, and that can happen on any sunny day, regardless of the time of year.

However, the effects in winter aren’t as dramatic as in summer because I don’t generate as much power in the first place, let alone having as much to send out to the grid. In winter, it makes even more sense to “do electricity-heavy things… during daylight hours”.

The reason all this fascinates me so much because it’s real-life results, what I get living my ordinary day-to-day life. Until now, I’d ready a lot of generalised information about how solar power works in a home, and I saw results that were both far better and far worse than what I’ve actually experienced. But, how would it work in my own situation, without doing anything unusual? That’s what I’ve been fascinated to see.

Apart from running things in the daytime, I don’t do anything even remotely special, because all that is stuff I’d do in the daytime, anyway. My experience of this is so very ordinary, in fact, that I even have my two heat pumps running 24-hours a day, every day, and despite that—and very hot weather this summer—my power was basically free last month. That’s pretty cool, so to speak.

I’m fascinated by this because I get to see how the system affects my household under real-life, and real-world conditions, and not based on mathematical models and engineers' projections. The results for this past month were clearly very good, however, saving money was never my prime motivation for doing this. Saving money is always a good thing, of course—duh!—but for me the whole point was to live more sustainably and to reduce my burden on the planet. And all of that is why this whole thing is getting very interesting—to me, anyway.