Comment by PaulDavisThe1st | Hacker News Reader

Comment by PaulDavisThe1st | Hacker News Reader

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PaulDavisThe1st

It is interesting how this works out over time.

I've had my 6.7kW grid-tied array for about 3.5 years, long enough to be fairly confident that it generates between 90 and 95% of our annual electrical needs.

However, we heat with electricity (heat pumps), and so our array generates 3x what we need in the non-heating season, and 1/3rd of what we need during heating season.

In the first year, I paid very close attention to stats about the system. Now, I know if makes no difference, really. It doesn't matter when I run appliances, when I recharge batteries etc. Nothing is going to change the basic facts I've just mentioned.

HOWEVER ... jump ahead a little into the future. It is possible that it may make a lot more difference to a smart grid when and how I feed the excess generated power and suck the extra power I need, and they may well want more control over that. For example (as described in TFA), they may want me to have batteries on-site to hold the daytime excess and let it dribble back to the grid overnight. Or the opposite, because they have their own commercial scale storage. It's not hard to envisage a future that moves from "I (the owner) doesn't care much about timing" to "We (the grid) care a lot about timing".

depending on where you live, that's where grid pricing comes from. I live in Italy and in my solar panels I have a kind of net-metering (not quite, since I need still to pay transports costs for the energy I buy back from the grid). In a year, they will phase out this regime and every person with a solar array will become a "producer". Energy company will pay the gross market price for the energy that you feed to the grid (and this price it's updated hourly if not more often). That will essentially do what you suggest: owners will start caring more about timing, and the grid will benefit. If you still don't care and want to feed the grid at the time when everybody else is also.. well the energy won't be paid much. And viceversa

I prefer the local 1:1 kW banking that my electrical utility company offers: rather than being paid, all my excess generation gets "banked" and I can use it during heating season.

Obviously, if you generate more than 100% of your needs, you're going to want to get paid.

Yes, that's what's called net metering: https://en.wikipedia.org/wiki/Net_metering

However, despite being convenient for the user, it isn't great for the grid nor scalable if all users were to have solar panels. (Here in Italy solar on rooftops are quite widespread).

You can see that a kWh on a sunny summer noon when all panels the area are working well, isn't worth the same as a kWh in the cold winter night, where non-renewables often supply the grid.

> You can see that a kWh on a sunny summer noon when all panels the area are working well, isn't worth the same as a kWh in the cold winter night

Often by a huge margin. Electricity prices on the spot market can go negative, and that will happen more and more often in the future on sunny, windy days. Net metering at constant $/kWh prices is unsustainable, economically.

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