Neat breakdown with data + some code.
What I want to do is find out what the maximum size battery I would need in order to store all of summer’s electricity for use in winter.
I mean, I think that it’s probably not a good idea for this guy to try to go fully off-grid if he has access to the grid, but for the sake of discussion, if one were honestly wanting to try it and one is in the UK, I’d think that one is probably rather better off adding a wind turbine, since some of the time that the sun isn’t shining, the wind is blowing.
https://www.statista.com/statistics/322789/quarterly-wind-speed-average-in-the-united-kingdom-uk/
Wind speed averages in the United Kingdom are generally highest in the first and fourth quarters of each calendar year – the winter months.
The UK is one of the worst places in the world in terms of solar potential:
https://globalsolaratlas.info/
But it’s one of the best in terms of wind potential:
Right but he’s not serious, he’s just doing a “in theory, what would it look like?”
I could probably get away with putting solar panels on my roof but I think my neighbours would have something to say about a wind turbine. They’re pretty loud.
Small wind turbines are really, really poor. You need to go high to access the good air-streams and wide to get useful efficiency out of the turbine. Any wind turbine you put on your roof will vastly under-perform for the cost spent on it.
I’d be pretty comfortable saying that buying enough battery storage to power-shift a year of power is more expensive.
O, absolutely. The reality is the only reasonably economic way to do off-grid is with solar, battery, and a diesel or propane generator to top off the batteries when solar isn’t cutting it.
There is another option. Reduce your energy usage so much that you barely need anything. Cabin in the woods with wifi?
Bio-chemical reactor toilet?
Sure, why not. But I was thinking a 4/5G router takes very little power, then a steam deck doesn’t take that much either. If that is all you need, few hundred w solar panels and a decent sized camping battery will probably do just fine. You don’t need to store a years worth of energy in one go if you can produce more than you use which helps during lower output times.
Then if your employer is mandating return to office, charge the battery there. Make the fuckers pay for it.
Something very important that anti-nuclear but otherwise environmental minded people should realize is this sentence: " There’s no practical way to build domestic batteries with this capacity using the technology of 2025."
Also applies to grid storage. There does not exist a chemical energy storage solution that can substitute for “baseload” power. It’s purely theoretical much like fusion power. Sure maybe in 50 years, but right now IT DOESN’T EXIST. Economically, practically, or even theoretically.Why do I bring this up? Because I’ve seen too many people think that solar and wind can replace all traditional power plants. But if you are anti-nuclear, you are just advocating for more fossil fuels. Every megawatt of wind or solar, has a megawatt of coal or gas behind it and thus we are increasing our greenhouse gas emission everytime we build “green” generation unless we also build Nuclear power plants. /soapbox
It’s very infuriating talking to people about this because they never really accept that nuclear power is necessary. They spend all their time complaining about how it’s dangerous (it isn’t) and how it’s very expensive, and how you don’t have a lot of control over its output capacity. And yeah, all of those are true, but so what, the only other option is to burn some dead trees which obviously we don’t want to do.
Just because nuclear has downsides doesn’t mean you can ignore it, unless of course you want to invent fusion just to spite me, in which case I’ll be fine with that.
The new tack is to conflate nuclear energy with fossil fuels. As in assuming that nuclear energy is “legacy” power generation, and that obviously we need to use modern gernation like solar and wind, and magical grid-level storage technologies that don’t exist. Also ignore that baseload power is still required, and is currently fulfilled with Natural Gas and Coal.
Pumped hydro exists.
Do some quick math. How much pumped hydro in terms of acre-feet would be required to power a hypothetical city like Chicago at night? Where would this theoretical reservoir be built?
acre-feet
I can’t stop laughing at this as a unit of measurement
But is extremely limited to specific areas with the right geography that are also relatively close to a population centre.
It isn’t so much limited by the geography but is made far more cost effective because of it. A long valley with a narrow exit means you don’t need to build much dam and store a vast amount of water.
As far as distance from populated areas, I dunno, I live in the UK so its kinda close enough not to matter too much.
I agree with this assessment of battery technology, I’m curious what your thoughts on storage through other means, such as dams, kinetic batteries, heat batteries, that style of thing? I understand that it’d be a massive undertaking, but if we really put our nose to the grindstone we might be able to pull off a good amount of power storage through methods that already exist.
Another myth is that hydroelectric is “green.” It’s absolutely not. The huge amount of land required to build something like the hoover dam or the three-gorges dam is massively destructive to the existing ecology. It’s often overlooked, but land use has to be part of any environmentally sound analysis.
I would say that while the Hoover Dam, or the Three-gorges dam by themselves are acceptable, they are wholly impossible solutions for grid level storage for the entire united states/China. How practical do you think it would be to build thousands of hoover dams?
Other options like kinetic batteries etc, all come down to energy density. The highest energy density options that humans can harness are nuclear Isotopes like Uranium 238, or Plutonium 239 (what powers the voyager probes) After that is lithium batteries at ~<1% density of a nuclear battery. Everything else is fractions of a percent as efficient. Sure there are some specific use cases where a huge fly-wheel makes sense to build (data centers for example) but those cases are highly specific, and cannot be scaled out to “grid-level.” The amount of resources required per kilowatt is way too high, and you’d be better off just building some more power-plants.
Unclear if you’re misinformed or disingenuous.
Hoover Dam does generate power, but it’s not an energy storage project to time-shift intermittent clean energy generation to match grid consumption. That’s known as pumped hydroelectric energy storage, and it requires having paired reservoirs in close geographic proximity with a substantial elevation difference. It’s not an ideal technology for several reasons, but it’s the largest type of grid-scale storage currently deployed. Fundamentally it’s gravitational potential energy storage using water as the transport medium.
A higher-efficiency but not yet fully proven technology also uses gravity and elevation differences, but relies on train rails and massive cars. Here’s one company leading the charge, as it were.
Nuclear isn’t a good option to balance out the variability of wind and solar because it’s slow to ramp up and down. Nuclear is much better suited to baseline generation.
There are plenty of other wacky energy storage ideas out there, such as pumping compressed air into depleted natural gas mines, and letting it drive turbines on its way back out. That might also be riddled with problems, but it’s disingenuous to claim that chemical energy storage is the only (non-) option and therefore increasing wind and solar necessarily also increase fossil fuel scaling.
Again, i’m talking energy density. All those other wacky ideas aren’t viable at all. Yes I know that the hoover dam is for generation, but the idea of pumped reserve power is literally identical to hydroelectric generation. The only difference is we would have a man-made solar/wind powered pump fill the resevoir, instead a natural source of solar power fill the resevoir. Either way, it’s a huge amount of land use for it to be considered “green.”
Additionally I never claimed nuclear power should be used as a peak generation, it should 100% used for baseload replacing all of our fossil fuel generators, with huge taxes being applied to carbon generators.
As an aside:
A higher-efficiency but not yet fully proven technology also uses gravity and elevation differences, but relies on train rails and massive cars. Here’s one company leading the charge, as it were.
This idea is trash and as far as I can tell the hypothetical existence of this is an oil industry fud campaign. The only viable version of this is pumped hydro, which has the land use problem I’ve already described.
Pumped hydroelectric storage obviously works with the same kind of turbines as dams located on rivers, but the land use is far from “literally identical”. For one, I agree with you that damming rivers is generally a bad thing. Large dam sites are chosen to min-max construction effort and reservoir capacity, and usually double as flood control. A grid storage project only needs to hold enough water for its daily power use, and it doesn’t need to be located directly on a water course. That’s not to say that there are unlimited suitable sites, but it’s more flexible.
Pumped hydro storage is quite green in its lack of carbon emissions and ability to time-shift green generation capacity to match grid demand timing. Land use is a consideration, but large anything requires land. You haven’t actually attacked the weakest part of pumped hydro, which is that there just aren’t very many geographically suitable locations for it.
You’ve also neglected to acknowledge the pesky spent nuclear fuel storage problem, which is unsolved and distinctly not eco-friendly. There are potentially better paths available such as the thorium fuel cycle, but they all either have no economic traction or are actively opposed by various governments (which don’t have any good solutions for existing spent fuel).
First of all nuclear energy is a fossil fuel.
Yikes. If words have no meaning, then sure. But there is no world where radioactive elements that come from stars have anything to do with fossil fuels that come from decayed biomass.
Factorio has prepared me for þis challenge…
You can plug your system into a free platform like opensolar, which allows you to play with the design to see what the effect of upgrades would be during the course of the year.
they generate about 3,800kWh per year. We also use about 3,800kWh of electricity each year
Obviously, we can’t use all the power produced over summer and we need to buy power in winter. So here’s my question: How big a battery would we need in order to be completely self-sufficient?
O, god, it’s going to be huge. You really can’t do the off-grid thing unless you have enough power production to satiate you over any given 3-day moving window. Trying to store power from summer until winter is going to be too expensive, instead buy more panel.
This isn’t even going into the fact batteries lose charge slowly. So any power generated in summer will be much diminished by winter, even if you have big enough batteries.
they generate about 3,800kWh per year. We also use about 3,800kWh of electricity each year.
Holy shit. I think we used that much last month, which is higher than average but not that high for August around here.
How ? Is it just AC ?
We oscillate between 300 and 800kwh per month and it’s with an old water heater, an electric car charged at home, a dryer and electric oven.
You leave 5,278 LED light bulbs on 24/7?
glad I’m not the only one that noticed that.
last time I checked I was using around 4600-5800kwh from May to August. the rest of the year its 3300-4200.
I live in a dual zoned 5200sqft home and my average power bill is around $900.
I’ve had solar sales try to talk me into solar panels but once they see my consumption they stop answering my calls lol. could be because I told them I’ll buy once I can get net zero.
could be because I told them I’ll buy once I can get net zero.
I’m not following your logic. You aren’t willing to accept any savings unless you can completely zero out your power bill? Judging from your consumption I’m assuming a good chunk of that is for cooling your home? If so that means you’re likely in a pretty great place to harvest solar power. You’d reach payback of your investment on your array much faster than most, and be saving money for probably 35 years or more with little to no additional investment.
Making some guesses for how much your electricity rates are, and how much you’re consuming (assuming much from cooling), you might be a full payback in less than 7 years if you took advantage of the tax credit. Then, every month after that you’d be gaining money back.
my house is over 120 years old. it still has knob and tube in half the house. I have even found gas lines for the old sconces, that were “conveniently” used as grounds for said knob and tube in some places. the house is a nightmare, electrically speaking. the only new-ish electrical are the HVAC systems, the 200amp panel, and the basement (where the rack lives).
for me to get proper solar installed, it would cost more than the house cost to buy. For me to find it in any way cost effective, I would need my $900 a month power bill to pay for the $200k loan on top of my mortgage.
That house sounds like a terrible investment.
lol. all houses are terrible investments, too volatile.
Wtf?? Are you running a crypto farm or something?? $900 is insane
that’s an average btw. last months bill was $1100.
this month is already at $960 and we’re only halfway through the month.
this year has been lower than previous. I had new insulation installed last November.
highest bill I have ever seen was around $2200 which is over my monthly mortgage.
no crypto farm. though it would probably be higher if I was.
I have personally never seen a bill of more than 60€ per month. I have some friends living in bigger houses, not apartments, and they tell they can get over 100 fairly frequently, the bigger ones more in the North can get over 200 in the winters, but even still, I’ve never even heard of anything reaching 300.
But I’m in my thirties and don’t really know anyone from beyond upper middle class. That might help explain my experience if it happens to be the outlier, but just reading the responses to this, I might not be the outlier here.
Anything four figures is just crazy surreal to me. I can not even imagine what it takes to reach that kind of electric usage. Or maybe it’s just extremely expensive, not the usage itself being crazy? I would think living in a place where sustaining one’s existence requires that kind of resource usage would be very hostile against settling and building in general?
But if it’s just personal usage rather than the regional climate or whatever, and an insane price of electricity isn’t the main reason, then I don’t even know what to say. That’s crazy.
it’s kind of a mix of everything.
I grew up poor. like, “take a nap for dinner” poor. I was afforded great opportunities that allowed me to become comfortably wealthy, as in I can freely go to the store and just buy groceries without concern. This is important because I always promised myself that when I grew up I would live comfortably.
I keep my house between 68F-72F year round. I don’t open my windows because I have terrible allergies (that my kids have also inherited). at least half of my bill is just heating and cooling. the other half is likely a mix of the servers and the regular appliances.
I have family ranging from 30-60 years old. when I told them how much I spend on power their eyes popped out. they don’t run their hvacs as much as I do, and actually use their windows and attic fans. they also don’t have the allergic reactions I have either so 🤷.
in my old home, 1600sqft, our highest bill was around $300, and that was still high for the area. our neighbors were average between $100-$150. they were in their 70s though, so likely they didn’t use their hvac as much either, nor the technology I was running.
Fair enough, that’d explain it. I did expect air conditioning to be a big part of it, kind of makes a lot of sense that you do run servers as well.
Still, that’s a huge bill to eat each month.
is that per-month, or for the whole span?
per month.
Seems to me his panel capacity is to small anyway.
We have 11 kWh panels, and yes in the summer we routinely produce 4 times more than we use, and we have a 7.5 kWh battery But November December and January it’s not even close to enough.In the Winter you can easily have a week with near zero production:
Our Import / export from grid last year:
November 215 / 59 kWh
December 300 15 kWh
January 268 / 34 kWhDespite we have almost 3 times the capacity, and produce more than twice what we use per year, and we have a decent battery and believe it or not, even the shortest day we can produce enough power for a whole 24 hour day if it’s a clear day! But we can also have clouds for 14 days!
But for those months we imported 783 kWh and exported 108 that could have been used with bigger battery. But the net import was still 675 kWh!! For those 3 months, and that’s the minimum size battery we could have managed with, and then we even need 10% extra to compensate for charge/discharge losses.TLDR:
Minimum 740 kWh battery in our case, and that’s without heating, because we use wood pellets.That means it would require at least the equivalent of 10 high end fully electric car batteries. But also a very hefty inverter, which AFAIK ads about 50% the price of the battery.
PS: Already in February we exported more than we imported.
(Author here) As I say in my post, our roof is full. We have 16x 320 Watt panels - 8 on each side of the roof.
Damn, those winter numbers mean full off-grid is quite difficult with pure solar. A propane or diesel generator to occasionally top off the batteries would be required for winter.
It is not remotely close to economically viable to go off grid, and the exports of solar power to the grid pay for the connection anyway.
The reason to have a battery is that it lasts through the night, or even with a smaller system, it can handle dinner time, which is the most expensive time of day to buy electricity.
Now if you live in some remote area without a grid, a generator is a way better option than a huge battery.
Maybe if you live somewhere very sunny, like Spain and especially southern parts of USA you can probably do it with a modest battery that can handle a couple of days.
In the summer we can make enough electricity on by far the most cloudy days, but in the winter, the sun can’t penetrate the clouds nearly as well.
Admittedly London is south of where I live, which is close to the most southern part of Denmark, but on the other hand London is infamous for grey weather with heavy clouds.You could probably get by with a gas generator and only run it 2-3 times/year in many areas. It’s not 100% green, but it could get you off grid for a fraction of the price.
Power the generator with vegetable oil. There are multi fuel generators that are designed to work well with that kind of fuel. You could also use them for heating which is very useful in Northern regions where you usually need heating and electricity during winter.
Diesel generatorsare significantly better on fuel consumption than a gas one and diesel takes alot longer to go bad than gasoline.
Diesel generators run fine on heating oil, which is cheaper since no fuel tax and has longer shelf life.
Stabil 360 additive to fuel.
You also lose some energy to heat while charging and discharging. And depending on load profiles, you might not be able to load all of your excess solar power at once (depends on how many Watts the battery can be charged at) or fulfill your power requirement with battery alone (depends on how many Watts your battery can deliver).
I’m a fan of small scale wind, if there’s climate and space for it. 20hrs a day of a (small) 500w adds up really quickly compared to more panels, especially in grey winter weather. The problem is that there’s a bigger difference between megawatt scale solar vs homeowner scale, and megawatt scale wind vs homeowner scale, so there’s limited investment.
Wind isn’t great small scale. You rarely can get high enough for constant wind energy. They are noisy. They don’t produce a lot. In many or even most cases solar will be better than wind.
I’d go so far as building both sun oriented and a solar “fence” line going north/south to get more non-peak solar before putting up small-scale wind.
As is mentioned in the article 😉 What is also mentioned is the fact that battery prices are going down. Soon it seems they’ll be down to $10/kWh!
There’s also alot of new battery tech on the way.
There will be a market for batteries at home, and they will exist with the best suitable tech for it - and it’s probably not lithium.
How many years, I dont know. What will it be, and who will do it, no clue. Otherwise my stock portfolio would look better if I knew these things haha.
I wish the second-hand battery market were more lively. Using half-worn car battery packs seems optimal for home use.
Using half-worn car battery packs seems optimal for home use.
I’m not putting cobalt based (NMC or NCA) batteries bolted to the inside my house. Thats nearly exclusively what car battery packs are. Thermal runaway is too great a risk to bolt that much energy to a wall in the house. I am comfortable with LFP in the house though.
It is. Some of them are getting snapped up to help with powering factories.
I think this is car companies using the incoming battery packs from replacing worn out packs. Time to look it up…
https://www.autoblog.com/news/toyota-just-found-a-clever-new-use-for-old-ev-batteries
This is the article I was thinking of. It’s more of an idea than a common use case to use old packs to help power factories.
Sodium batteries?
BTW that’s the wish for trend line, $10/kWh right?
I mean… they are at ~$16/ kwh right now, so…
https://www.alibaba.com/product-detail/CATL-75AH-220Ah-Grade-a-Sodium_1600972483761.html
No?
I have seen some wild priced on Ali, in your link the 75Ah and the 210Ah are priced the same, so I guess it’s for the smaller one, 30€ for ~0.225kWh or 133€/kWh.
Could be wrong ofc, but it sort of fits what I thought it would roughly be.
I mean even ~133/kWh…
Whats an average, perhaps even gratuitous, level of consumption per household? 24kwh if you are running a clothes drier and an AC nonstop? Lets go nuts, say you are a DIY enthusiast and hosting your own servers, so 36kwh daily.
3192€-4788€ to be and you can be effectively energy independent with a small solar system.
Triple that and you are truly energy independent are any where south of the English channel. I mean obviously its money out of pocket, but its a fixed cost that you pay now, instead of a variable cost that continuously goes up. It just seems basic.
How big a battery would we need in order to be completely self-sufficient?
Exactly. Haven’t read all details of the link,so I react your comment, and have immersed myself a bit in this earlier.
You need to change your way of thinking and energy usage. Start with your daily energy supply and then change your energy consumption pattern to day time use Then, with for example a dynamic energy contract or if you can spare solar energy, buy or store cheap electricity in your storage ( battery ). The energy management system ( charge / uncharge and which cells) is very important.
Also, realize that battery life is tied to charge cycles and need replacing like every 10 years when talking about the better quality Lithium battery . Sodium systems could and maybe should be used in parallel, if you want more storage, safety and longevity (20 years).
It is yet all quite expensive, though imo having a half day reserve like 5 - 10 kwh, battery, would already create more independence (at around € 3K to € 10 K in Europe) .
Basically why the grid exists to begin with. You’re not supposed to be solving these engineering problems on a household budget inside a single home.
You’d be better off simply reducing your consumption or finding alternative methods of power (nat gas or maybe wind or geothermal) during the longer winter nights.
If you really want to go crazy, you should consider investing in a bigger home with better insulation and roommates. An apartment/condo block can at least leverage economies of scale, if you’re dead set on DIY. More people benefiting from the setup dilutes the cost per person.
I recently got a solar system and came to the conclusion that if you can sell power back to the grid (not everyone can) for some reasonable percentage of what it costs to buy it, then it will always be worth it to be connected (assuming you already are).
Quite simply, if you have enough solar capacity to get you through the winter (no house is going to have months of battery storage), then you will always be creating far more than you need in the summer. Selling this excess will easily cover any costs associated to being on the grid.
Also at current prices batteries are good for backup power only, it’s always cheaper to sell excess power to the grid in the day and buy it back at night than it is to have battery capacity to get through the night. I worked out it would take 40 years for our battery to pay for itself (assuming the battery kept a constant battery capacity for 40 years…) but less than 10 years for the rest of the system to pay for itself.
We can’t, but we can do net metering, meaning we can offset costs but not get paid. So the best investment is to pay nothing through Dec. 31 and keep costs manageable at the start of the year (net metering ends with the calendar year).
Net metering is great, much better than being paid for the surplus.
With net metering the grid is basically an free, infinite, 100% effective battery.
Only while there’s a surplus. Our net metering arrangement effectively forfeits any surplus at the end of the year. It obviously can vary by region and how much you’d get from surplus vs specifics of the net metering policy, but I think getting paid for surplus is simpler and easier to plan around.
Net metering is potentially better, as you are effectively getting free night usage based ob day generation. My setup pays me, but I get paid 20c per Kw (NZ dollar) and pay about 30c to buy, so there’s a 10c difference. Just as long as whatever you lose on 31st Dec is not too high, you’d be better off than me.
Basically why the grid exists to begin with
Agreed this is the best option. Economy of scales and our consumers wishes should dictate the Grids plan to incorporate cheap energy ( and emergency) storages.
And, also like you said, change your energy life style and insulate your house wherever you can.
I’m very ignorant on this subject, but couldn’t you just sell excess to grid and get it back for a minimal markup? Seems like a good governmemt incentive to even supplement an even exchange program. Scaling things to everyone having their own giant batteries seems like a waste of the existing infrastructure.
(Author here) Yes, this is how it works in the UK. I sell my excess electricity back to the grid. The selling price is a bit smaller than the buying price.
I’m very ignorant on this subject, but couldn’t you just sell excess to grid and get it back for a minimal markup?
Sure, but it depends on the incentives in your country. Afaik, excess energy could be sold, but you’ll have to checkout your local incentives and energy suppliers for specifics. In most parts of Europe, the are scaling down the prices for excess energy. Therefore, battery systems are being forwarded in some cases as sort of solution for solar panels maintaining like ca. 80% +? integrity efficiency over 20 to 30 years.
For example, I read that in The Netherlands the solar panel market has crashed completely or is crashing. Note here that saturation of the market ( many existing solar panels) can also cause that.
You need to find out;
- energy usage
- insulation options and materials
- costs /benefits
- energy contracts and energy incentives.
- check out current physical electricity wiring and fuses in the house
- DIY or professional?
- budget etc
TLDR: dont buy solarpanels if you want to be rich. And buy them according and after you’ve done everything possible to insulate your house, whether in the colder or warmer climates. The efficiency, added value, and comfort reached by insulation outweighs everything else. Then , after doing that, check your kwh usage, and buy solars according to that.
Hope this is helpful, but seems you need to go outthere and do some exploration on the topic.
(Ed: layout)
And buy them according and after you’ve done everything possible to insulate your house, whether in the colder or warmer climates.
In the USA there are silly rules that you can only get 120% capacity of your last years worth grid consumption as solar installed. So if one were to follow your advice and do all the energy efficient improvement prior to solar, then you would be restricted to getting a much smaller array. I understand why they have the rule, but its easy to circumvent by just having artificially oversized consumption for a year in your house, and you can then get the larger array you want before then doing all the energy improvements post-array installation.
In the USA there are silly rules that you can only get 120% capacity of your last years worth grid consumption as solar installed.
Yes , I can see how that impacts the process. indeed checking the rules and doing some prior info digging is essential.
It’s also important to check whether solar overcacity is worthwhile in the UsA. Her3 it is not( anymore).
I don’t need to get through winter, I just need to get from dusk to when the cheap energy is starts. Currently that’s about 4kwh - or a small portion of my car battery before or recharges on the cheap rate.
battery and solar at the home level is what makes the most sense.
60% of the planet lives between the subtropics and tropics. There is way more than plenty of sunlight hitting our earth to support all of our energy demands, and any naysaying around battery technology is missing the forest for the trees.
Need to wire the whole world. Let’s go.
The most straightforward path to world peace is to increase the global supply of energy to the point of negligibly low prices
I like the idea that the real reason for all of the atrocities is that people don’t have enough power to play Xbox.
I believe it would attribute to cheaper of free energy and to more peace. I am agreeing with you.
And I imagined a all encompassing " worldgrid" across all continents and islands. We did it with phone networks, now we should do energy.
