Well, here (in middle of finland) the sun set at 14:30, so there wasn’t all that much solar energy available.

Also heat pumps are always at least as efficient as straight electric heating.

Solar is quite poor in Northern winters. Wind + solar + heat would be a better bet, but the battery required to heat your house for more than a day with low winds would be prohibitively expensive unless you added geothermal to the mix like a geothermal heatpump which is also very expensive. Betweem the gear, battery, geothermal, all installed your probably in the 80k$ range or more. A wood stove would be the best bet

Wow, air to air even?

But do you know what the COP is at -30?

And at one point, due to an error, it was tens of cents negative. You were literally getting paid to use electricity. Though, we’re paying it back now.

So not mildly infuriating, but fuckaroundandfindout?

I think the opposite. Price is usually high when demand is high because of cold temperature. Because of the high price, you’re motivated to consume less, and that’s a good thing for the grid. It’s also a good thing for the carbon footprint because usually this is when the most polluting plants are activated, gas first, then fuel and coal. This is where protecting the consumer too much from the wholesale market volatility can be a problem, a fix price doesn’t motivate the end consumer to adapt consumption base on supply/demand which is important to reduce carbon footprint, instead the country pollutes more than it would if people were more aware. The problem is rather the risk for personal finance. That’s why I thought mostly ecological activists would be motivated enough to take this risk. But I forgot the possibility of very low prices on average.

I’m in the UK on an agile tariff and I’m not quite so sure - it depends on a number of things. Sure my batteries were bought primarily to support my solar panels. but I’ve been making quite a lot of money this winter.

1. There are times when it is windy and there is low demand, when prices actually go negative - fill your batteries and make money
2. The differential between lowest and highest price per kWh is often 30p so filling up when it is 10p and using when it is 45p makes sense.
3. The grid will sometimes pay you large amounts of money with a few hours notice that they will pay you a premium to discharge your batteries when demand is predicted to be extremely high - to avoid them cranking up coal power stations. In November and December I made £90 just from this - and I only have 5Kwh batteries.

I haven’t run the figures on payback times if the batteries were just for shifting and not solar - but they might just pay themselves back.

In the UK domestic solar panels are quite common and new installations usually come with batteries. Agile 30-minute pricing tariffs are still new and fairly experimental, but people are rapidly realising that their batteries can be really useful when used to force charge/discharge based on grid demand. Octopus is probably the leader: https://octopus.energy/blog/agile-pricing-explained/

I live in the northeast US and we looked into batteries. Unless you’re rolling your own and have a very specific home/garage layout installing them is really difficult. They have to be outside the living space, away from flamingo wall coatings and windows. And they need to be relatively climate controlled (not great in direct sunlight or frigid temps).

Until we start designing battery systems that can mount outside (away from the house, like propane tanks) within their own heat pumps to manage temps built in, it’s not going to be popular in climates like ours (which are very similar to Swiss and lower scandawegian climates).

They should probably be bigger metal boxes with sodium flow batteries and heat pumps, like we have now for utility boxes in some places. They could incorporate the smart/net meters required to pump back into the grid too.