Random thought: Why don’t we have a server rack that runs at home but is managed by a company, then people or businesses rent them? Th important use case is that the heat generated can be used for home. Like property managers, business maintaining them are heat managers for home.
I feel like this idea would work better at a somewhat larger scale, like a small to medium datacenter heating an apartment or office building. The downside is for any of these systems is that when it's too hot outside that heat becomes a liability so you'd have to have the infrastructure to divert heat as well. The other downside is that you'd be replacing a very well understood technology with minimal maintenance requirements with a relatively complex technology with more extensive and complex maintenance requirements.
A lot of us live in older homes without good insulation. Somewhere in the mid 1900s we simply forgot that "plaster interior wall directly on brick exterior wall" does not provide insulation.
1920s era homes are even worse, single hung windows in wooden frames, no insulation, no conception of managing airflow.
Modern homes are much more efficient, but they're a bit impractical to buy these days, and are increasingly built so shitty that their lifespan is less than their inhabitants.
https://www.eia.gov/energyexplained/use-of-energy/electricit... - This shows a breakdown. HVAC is not the most [edit: as in majority, it has the largest share though], but it is a significant amount. Also my household is apparently well below average (though still higher than you) for the US and our region in the US.
I think it would just about break even on an economy 7 night rate saving about 17p/kWh shifting load to the overnight rate. (Might save more on a smarter tariff.)
A 12kWh system costs £5880 including VAT. Assume 95% round trip efficiency and 80% cycle each night gives savings of £565 annually.
That's about the same as the cost of a loan at 5% for the total amount paid back over an estimated useful life of 15 years.
This assumes it doesn't need servicing in that time and you can DIY install.
I don't know whether home systems like this will get much cheaper as the batteries themselves probably only make up about 20% of the system cost.
There are huge economies of scale for utility scale storage with all in project costs now down to $125/kWh meaning 12kWh would cost just $1500 rather than $6600 for this home system. So I wouldn't be confident the price differentials between day and night rates will remain as high over its expected lifetime.
My night tariff is 6.67p/kWh compared to 28.36p/kWh for daytime.
I don’t think these differentials will last either but I do like the idea of smart charging when there is too much wind. I suspect these grid storage systems currently being built won’t handle these peaks and will be designed for the average case so there will still be periods of cheap electricity.
My supplier already controls my car this way and charges it on a schedule it defines each night and also ad-hoc during low demand.
There is also some benefit to have a backup system for when the power goes out which happens a few times a year.
30 kWh per day sounds about right. I have resistive heating and holy heck is it expensive in the winter months, which are short and mild. I plan to replace it soon.
But yes, most of that would be heating and cooling single family homes. Many built during a time when insulation was an afterthought. Now homes are well insulated, but they are larger.
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