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declan_robertstoday at 3:06 PM25 repliesview on HN

The article is just wrong. And only mentions energy used for heating in passing. Heating requires MASSIVE amounts of energy.

I should know bc I have a whole house battery and solar system (almost 30 kWh battery and 24kW solar). It keeps the lights on, but not heating. I live in a mild climate.

The reality is that battery/solar requires major quality of life and activity time shifting trade-offs.


Replies

toasty228today at 3:27 PM

People still build houses like energy is cheap and abundant. A properly insulated house in any temperate climate require very little heating or cooling.

Spend 50k on insulation that will last the life of the building instead of 50k on heating and cooling devices which will need constant maintenance and replacement + fuel and end up costing 10x more over the life of the building.

A modern house with modern insulation in a mild climate shouldn't even need a central heating system. You can get by with 500w toaster heaters in each room for the coldest time of the year

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PyWoodytoday at 3:25 PM

I live in a northern climate and I know multiple people who are net zero with solar+basic battery.

Proper insulation and good windows go a very long way. For instance, I set my heat to 66F during the day and 60F at night. When I wake up in the morning, the register is usually still above 60F.

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jakewinstoday at 3:31 PM

Respectfully, 30kWh is not much in this context. In 10 years every modern 2-car home will have 200kWh on the driveway just from the EVs; add a 100kWh whole home battery at a price point close to a 10kWh battery today and the calculus changes in most of the world.

The cost of materials going into modern batteries easily leaves room for another 10x reduction in price, IMO where this all is heading is obvious. Zero marginal cost will win every day of the week.

FWIW we run our cabin on 15kWh battery today year around, though we do run a small wood stove to supplant the heat pump on cold winter days.

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minajevstoday at 4:01 PM

24kW solar "to keep lights on" is a funny way to underplay it. My house "summer" electricity usage is 60kWh per month, including water pump, DHW, septic and work from home for 2 adults. So 3h of your PV production would power my house for a month!

Regarding heating - I live in cold climate. We had average daily temperature of -10c this january, with multiple lows at -25c, and most nights at -15c. The house is 116sqm. Our heatpump COP for that month was above 2, and we used 787kWh total to heat the house, which is not a lot, actually. At 15 cents per kWh it is 118 euros for heating, for the coldest month in a decade! Considering also that we do not pay for electricity since april until october (solar panels).

We also paid less than those houses which use natural gas, wood pellets, etc. We also do not need to do anything to keep house warm. Also, during summer months we could "drive for free" in EV due to free solar electricity.

All that just to counter your take on "major quality of life and activity time shifting trade-offs".

FEELmyAGItoday at 3:37 PM

> I should know bc I have a whole house battery and solar system

This is not really a qualification to speak on how the grid works, at all.

Actually having panels on your roof doesn't give you unique insight into how solar panels operate - there is extensive data out there, any PV installation can become a data source trivially.

> The reality is that battery/solar requires major quality of life and activity time shifting trade-offs.

One residence powering itself is not representative of how the grid works, and is not a good way to evaluate any power generation technology whether its PV, coal, nuclear, etc.

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DanTheManPRtoday at 3:50 PM

This is basically correct in the sense that we cannot simply just force everyone in, say, Minnesota to install electric baseboard heating, rooftop solar, and a battery pack, and then expect them to stay warm. There are periods of extended extreme cold and low solar flux where you would simply not be able to warm everyone's house - that's just physics.

But there are a lot of extra things you can do as an intermediate steps to dramatically close the gap. The main ones are:

1. Homes can be renovated to improve insulation 2. Cold weather heat pumps can handle most mild winter conditions efficiently 3. Electricity doesn't all have to be locally generated - it can be transmitted from other parts of the country. 4. You can keep using fossil fuel peaker plants, and still have incredible reduced overall emissions

cbdumastoday at 3:12 PM

The article is about utility scale solar and storage I believe not home installations. It also mentions towards the end that in cold norther climates adding wind to the mix makes sense

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FuriouslyAdrifttoday at 5:54 PM

Heating is mostly affected by the roof insulation and really should not be done with electricity alone. It's just not efficient.

Cooling, on the other hand, is brutally expensive without living in basically an air tight Styrofoam box (or underground).

dv_dttoday at 3:33 PM

Beyond the other better insulation comments, pairing electric with heat pumps that are SEER 10+ goes a long way to improve heating efficiency. Old resistive heaters are 1:1 on energy to heat, while newer heat pumps operate to much lower temperatures, and give you 1:10 or 1:15 electric:heat energy ratios.

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jacquesmtoday at 3:58 PM

House heating does not require massive amounts of energy. What it requires is efficiency. I've seen a house in Canada that was heated with a single candle when not occupied. Triple wall, reflective foil in between the wall layers, vertical movement of air in the walls interrupted every 30 cm or so. Absolutely amazing. And it still had sizeable windows. If your house doesn't leak energy like a sieve you don't need to replace as much either. Between passive solar and some augmentation you can do fine on an extremely modest energy budget.

And Canada is not exactly the warmest country on the planet.

Epa095today at 3:20 PM

What's the actual effect you get out of that? Even half, 12 kW, would be an absolutte beast of heating (for a home), even with 'dumb' convection heating. With heat pumps 2-3 kW should really be enough.

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j16sdiztoday at 3:15 PM

The insulation matters a lot in home heating.

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iamjake648today at 3:11 PM

Do you have a high efficiency heat pump, or how are you heating?

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ethagnawltoday at 5:05 PM

The article should have explored that aspect further but it's not all or nothing. For example, a geothermal setup could significantly offset the amount of energy required to heat a home.

ZeroGravitastoday at 4:30 PM

Note that the article title has "the world" in it, immediately limits his specific claims to 80% of the world nearer the equatorr as most of the people in the world have more need for cooling than heating.

He even has a map that covers this and multiple paragraphs of discussion about high latitudes and wind in winter.

panstromektoday at 3:18 PM

As far as I understood it, it only talks about electricity, so that doesn't seem like a contradiction to me. I think some electrification of heating is expected in 2030, but not that much bigger than it is now.

amlutotoday at 3:43 PM

Do check that your heater isn’t doing something ridiculous. A while back I helped someone debug a Mitsubishi Electric system on which the installer had set the fan speed control to high instead of auto (it’s an easily accessible setting on the thermostat). I forget exactly how much power was saved, but IIRC it was well over 30kWh/day.

I don’t know where all that energy was going. I expected some improvement but not anywhere near that much.

daneel_wtoday at 6:00 PM

Gonna go off on a limb and guess that you live in North America where the state of the art in single-family homes is double-pane windows and thin outer walls made of cardboard and pressboard, clad with "luxurious" vinyl siding. I mean no offense to you guys. It is what it is.

mapmaptoday at 3:24 PM

This is a large pv system for what I assume is a single family home. Do you have resistive in floor heating or an electric boiler feeding radiators? I imagine you could easily run a half dozen mini-splits drawing 500-1000w each, or a centralized heat pump. Happy to help if you can give more details.

dyauspitrtoday at 3:29 PM

Is a 30 kWh battery considered massive? My F-150 lighting has a 143 kWh battery.

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Faaaktoday at 3:47 PM

Heat pumps help quite a lot, thanks to Carnot's law

abengatoday at 3:30 PM

If you need to heat/cool your home, is that really mild?

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fooblastertoday at 3:21 PM

where are you? that is a massive amount of solar in any place at a reasonably low latitude. Is your house enormous or are you heating your house with resistive heating?

LogicFailsMetoday at 4:54 PM

My house in the bay area runs at <1kW per hour most of the time and the sunlight is more than enough to keep it above 65F most of the year. Maybe you need LED lights because when I'm not there, it's ~150W per hour.

Of course actual data like this is downvote heresy! Go for it! Also, bite me.

Rover222today at 3:26 PM

Well obviously lights aren't using up much of that power, you're powering everything else too.