Two isn’t quite zero

Here’s a first-world “problem” for you.

On Sunday, our bidirectional PG&E electricity meter read 2 (preceded by a bunch of zeros).

But that was before doing a bunch of laundry and cooking.

Today, it turned dreary (not “bad” weather by any means, just dreary): Overcast and rainy. Which means very little generation from our photovoltaic system (5.42 kWh, which is better than I expected but one-third of a really good day)–and also using a little more power for lights. Right now, the PG&E meter is at 16.

Trivial numbers, but a target

My wife really wants to hit zero–to see the PG&E reading be all zeros. That would mean we’d essentially used the grid as a giant battery all year–sending surplus electricity out on sunny days, getting it back on overcast days and at night.

Technically, zero wouldn’t do it: We were at -22 at last year’s “truing up,” the annual point at which PG&E will actually charge us for the electricity we’ve used, if any. (Or, starting this year, theoretically pay us a little if we’re net negative.)

If we’d forgone baking & laundry on Sunday, we would have been there–but that’s silly.

Not done yet

The truing-up reading will be taken somewhere between October 15 and October 18. Right now, the ten-day forecast (ha!) says rain today through Wednesday, but clear from then through October 11. (The three-day forecast is probably right. The seven -day Weather Underground forecast is plausible. AccuWeather’s 10-day forecast? Really? 10 days ahead in the weather biz is a very long time.)

Chances are, if it’s clear almost every day from Thursday through October 15, we’ll wind up at zero at some point. Maybe.

Silly in a way

This has very little to do with money–after all, we’ll wind up paying for, say, 10 to 50 kWh for the year, at the lowest rate, which means a bill of around $5 (for 50 kWh). For the year. (Well, plus the $4.50/month metering/grid connection charge we’ve been paying along with our gas bills.)

It’s just a number, but it’s an interesting one.

I should note that our next-door neighbor is having a photovoltaic system installed. Little by little, these rooftop installations do make a difference.

That’s an odd topic: Turns out UC Berkeley is working with SolarCity, our vendor, on a study of the actual impact of household solar on electricity loads–which involves changing the frequency with which our system’s output is reported to SolarCity via wifi from once every 15 minutes to once every minute. The study’s just getting going…it will be interesting to find out the results.

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