Terence Eden
@Edent@mastodon.social  ·  activity timestamp last week

What would it take for our home to be Solar Self-Sufficient?

Work in progress, but I think I have the answer.

🏠 I live in an ordinary house in suburban London.
☀️ Our solar panels generate 3,800kWh per year.
🔌 We use the same amount of electricity per year.

After crunching the numbers:

🔋 Capturing all our solar excess needs a 1 MegaWatt-hour battery.

#Solar#SolarPunk

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mau 🏳️‍🌈#EndFossilFuels
@mzedp@mas.to replied  ·  activity timestamp last week
@Edent ...I think your math is wrong. Here's a reference, they calculate that most places can be served by a 17kWh battery and a 5kW solar system.

Even if you have the worst location in the world, there's no way you need a 1 MWh battery.

https://ember-energy.org/latest-insights/solar-electricity-every-hour-of-every-day-is-here-and-it-changes-everything/

Key takeaways 01 24-hour solar generation is possible – just 17 kWh of battery storage is enough to turn 5 kW of solar panels into a steady 1 kW of 24-hour clean power. On an average day in a sunny city like Las Vegas, US, providing 1 kW of stable, round-the-clock power requires 5 kW of fixed solar panels paired with a 17 kWh battery. This combination can deliver a constant 1 kW of solar electricity every hour over a full 24-hour period – and this amount of battery will be sufficient for most regions across the world. 02 It is possible to get 97% of the way to constant solar electricity every hour of every day of the year (24/365) in the sunniest cities. Cloudy days mean that 24/365 solar generation – maintaining the same constant solar output every hour of every day of the year – would need so much solar and battery that it is likely uneconomical. However, in sunny cities it is possible to get more than 90% of the way. Las Vegas can reach 97% of the way to 1 GW constant supply and Muscat in Oman – 99%, using 6 GW solar panels and 17 GWh battery. Even cloudier cities like Birmingham can get 62% of the way to a constant supply every hour of every day across the year. 03 The economics are great in sunny cities – just $104/MWh to get 97% of the way to 24/365 solar, 22% lower cost than just a year earlier and cheaper than new coal or new nuclear. In a sunny city like Las Vegas, the estimated Levelised Cost of Electricity (LCOE) at this 97% benchmark is $104/MWh. This
Key takeaways 01 24-hour solar generation is possible – just 17 kWh of battery storage is enough to turn 5 kW of solar panels into a steady 1 kW of 24-hour clean power. On an average day in a sunny city like Las Vegas, US, providing 1 kW of stable, round-the-clock power requires 5 kW of fixed solar panels paired with a 17 kWh battery. This combination can deliver a constant 1 kW of solar electricity every hour over a full 24-hour period – and this amount of battery will be sufficient for most regions across the world. 02 It is possible to get 97% of the way to constant solar electricity every hour of every day of the year (24/365) in the sunniest cities. Cloudy days mean that 24/365 solar generation – maintaining the same constant solar output every hour of every day of the year – would need so much solar and battery that it is likely uneconomical. However, in sunny cities it is possible to get more than 90% of the way. Las Vegas can reach 97% of the way to 1 GW constant supply and Muscat in Oman – 99%, using 6 GW solar panels and 17 GWh battery. Even cloudier cities like Birmingham can get 62% of the way to a constant supply every hour of every day across the year. 03 The economics are great in sunny cities – just $104/MWh to get 97% of the way to 24/365 solar, 22% lower cost than just a year earlier and cheaper than new coal or new nuclear. In a sunny city like Las Vegas, the estimated Levelised Cost of Electricity (LCOE) at this 97% benchmark is $104/MWh. This
Key takeaways 01 24-hour solar generation is possible – just 17 kWh of battery storage is enough to turn 5 kW of solar panels into a steady 1 kW of 24-hour clean power. On an average day in a sunny city like Las Vegas, US, providing 1 kW of stable, round-the-clock power requires 5 kW of fixed solar panels paired with a 17 kWh battery. This combination can deliver a constant 1 kW of solar electricity every hour over a full 24-hour period – and this amount of battery will be sufficient for most regions across the world. 02 It is possible to get 97% of the way to constant solar electricity every hour of every day of the year (24/365) in the sunniest cities. Cloudy days mean that 24/365 solar generation – maintaining the same constant solar output every hour of every day of the year – would need so much solar and battery that it is likely uneconomical. However, in sunny cities it is possible to get more than 90% of the way. Las Vegas can reach 97% of the way to 1 GW constant supply and Muscat in Oman – 99%, using 6 GW solar panels and 17 GWh battery. Even cloudier cities like Birmingham can get 62% of the way to a constant supply every hour of every day across the year. 03 The economics are great in sunny cities – just $104/MWh to get 97% of the way to 24/365 solar, 22% lower cost than just a year earlier and cheaper than new coal or new nuclear. In a sunny city like Las Vegas, the estimated Levelised Cost of Electricity (LCOE) at this 97% benchmark is $104/MWh. This
Sheddi
@sheddi@mstdn.party replied  ·  activity timestamp last week
@Edent
More like £100k, if you buy 30 of these:
https://www.fogstar.co.uk/collections/solar-battery-storage/products/fogstar-energy-32kwh-battery?variant=55157091205497

As I'm sure others have commented, it would be more cost effective to add extra PV panels so you don't need to save the midsummer peak all the way through to midwinter. I've not modelled it but I suspect adding 10kWp of PV somewhere (carport? conservatory? gazebo?) for £10k would let you halve the battery size.
Daniel Durrans
@dan@mastodon.durrans.com replied  ·  activity timestamp last week
@Edent I wonder what used EV batteries will do to the market. The percentage of EVs in company fleets continues to increase and while we have gone through a few replacement cycles, those vehicles are likely still in the second hand market. But in another 5 years? 10 years? We should see a reasonable volume of EVs at end of life... but those batteries will still have life left in them for non-transport use.
Terence Eden
@Edent@mastodon.social replied  ·  activity timestamp last week

To be clear, I've no idea if this is possible. Maybe there are fundamental limits to the size, cost, and capacity of batteries.

But it shows that it is technically feasible for homes in the SE of England to use rooftop solar to generate all the electricity they need across the year.

Yeah, it doesn't account for getting an electric car or heat-pump. But panels should also get more efficient as well.
gary
@gary_alderson@infosec.exchange replied  ·  activity timestamp last week
@Edent right now you need like 4 pv panels to power a small mini pc ai cluster - it helps productivity and is also much more efficient and faster to keep most (not all obviously) compute local - you will upgrade less and just add a node or two when you need them but it is easily scalable so good for the smb sector. you are basically paying for 5 years of elec upfront and then it is free - that's reasonable. battery tech and materials science will help speed things along and catalyze advancements, the hardware is starting to be fast enough and cheap enough (unified mem) that we see a host of tech related trends manifest/outperform
DamonHD
@DamonHD@mastodon.social replied  ·  activity timestamp last week
@Edent My challenge was to cover all our heat (now c/o a heat pump) also. We are about carbon neutral and energy neutral in an EPC A house. My CAPEX guestimate was a bit lower last time I had a go, but another issue is that the battery would take up 50% of the volume of the house, so I'd need to dig a basement at least. Which is tricky as we are poised over much of the local sewage system...