[IshKebab]

The problem with solar isn't the night. Getting enough batteries to cover that is totally doable. The issue is the winter. And not even because of fewer daylight hours - on sunny winter days there is usually still a good amount of solar.

The problem is its often very cloudy in the winter. In the UK in winter we regularly have periods of 5 cloudy days in a row where solar output is virtually zero.

I don't know what the answer to that is. In a calm cloudy winter week all renewables and battery storage are totally screwed. Space based solar is a scam. Maybe we just have to live with it until fusion works (if it ever does).

(But it's still academic at the moment because we're still far from the point where building more renewables is a bad idea.)

[MakersF]

It's unfair you're being down voted, you're right. I used to think that we could get by with just solar wind and batteries, but then after collaborating with people on an ideal energy mix the numbers were obvious: there is a (small) fraction that cannot be covered. Not with storage (the discharge cycles are so few that the cost is prohibitive. How can a battery pay for itself with 10-20 discharges a year? And this applies to any kind of battery that needs to be built, including hydro). Likely there will need to be some baseload nuclear (which then increases average prices, since to make it economical you need to buy all the electricity it produces, and so it partially displaces renewables). The alternative is overbuilding solar+wind+battery something like 5/8 times the average need. Maybe if the prices drop enough that could be feasible.. The big win would be if there is some way to get predictable power at a lower cost than nuclear (e.g. tidal), which could be used to smooth the troughts, or alternatively a low capex but potentially high opex solution which is turned on only when needed (gas is an option, but not co2 free. And sizing the power needed is not super cheap, although now it's not a problem since we have enough gas capacity which is going to be displaced, so it won't be needed to be built)

[blackjack_]

Yeah but we are nowhere near the end of the scaling curve. For now, we can use the natgas plants during the unexpected outages while solving for green hydrogen / whatever backup plants. Like when a household has one EV and one gas car, they can always just take the gas car when they have range anxiety and don't know about chargers. NBD.

[jopsen]

Falling back on gas 10-20 times per year sounds very reasonable.

It's not net zero, but nearly zero will probably do fine?

Politicians like to say net zero, but when we are 90% there will we maybe not stop caring and find other more pressing problems?

[tsimionescu]

Net zero is barely enough to help with climate goals, given how late we are. It's not a huge goal, it is the absolute bare minimum to avoid >2 degrees of warming.

[lambdaone]

Achievable near-future net-nearly-zero in the near future is a lot better than waiting longer until we can achieve full net zero. Don't let the perfect be the enemy of the good.

The real issue is the cost of keeping gas peaker stations around that are mostly idle and fire up only a few days a year, but that's an economic issue, not an engineering one.

In the longer term, you could even run them off net-zero renewable syngas that you make the rest of the year using low-cost electrical power at peak solar generation times; you only need to store a relatively small amount of it, and old fossil fuel reservoirs are ideal for this.

[jopsen]

Also once we're nearly-net zero, we should focus on airlines, shipping, industry, etc. not the last 5% of electricity.

[pfdietz]

> Likely there will need to be some baseload nuclear

Baseload nuclear is entirely feckless as a backup for a renewable grid. You either go with a long term storage technology (and then don't need nuclear), or you go to an entirely nuclear grid. Wind/solar and nuclear don't mix well.

[TheSpiceIsLife]

Forget tidal, it’s dead in the water.

Everyone who’s tried it suddenly realises that anything you put in the ocean is almost immediately covered in marine growth, or destroyed by the ocean itself.

And that wave / tidal energy is very diffuse, or that where it isn’t diffuse it’s also extremely destructive.

[kieranmaine]

Regarding long term storage keep an eye on the UK's Cap and Floor scheme which offers guaranteed revenues to long term storage technologies [1].

Page 7 of https://www.ofgem.gov.uk/sites/default/files/2025-09/LDES%20... lists the technology types of the project applications. The majority are Li-Ion BESS, but there are also other battery chemistries and Liquid/Compress Air Storage

1. https://www.ofgem.gov.uk/press-release/super-battery-project...

[TheSpiceIsLife]

> offers guaranteed revenues

Government picking winners?

When did that ever work out well?

[kieranmaine]

I think in this case it's because LDES can't compete in the UK energy market, but it's a capability that needs to be developed, so this scheme address that by providing a guaranteed revenue.

The floor is a minimum revenue guarantee, to protect investors at times when the wholesale price is low and the cap is a maximum revenue limit to protect consumers when the wholesasle price is high.

It seems like these limits haven't been set yet, so I don't know what the potential impacts on energy prices will be.

[lambdaone]

Airbus.

[micwag]

> In a calm cloudy winter week all renewables and battery storage are totally screwed. Hydro doesn’t really care about a calm cloudy winter week and is the reason my state was 100% renewable last year. So it’s definitely not a problem for ALL renewables.

[TheSpiceIsLife]

Effectively all renewables.

When was the last time a new dam and hydro electric power plant was built in your country?

Either all of the favourable geography has already been dammed, or good luck getting environmental approval.

[lambdaone]

Alas, this is absolutely right. It's trivial to find places to put hydropower using global elevation data and GIS tools, but almost all of the good ones are already either being exploited, or in the process of being readied for use, or facing barriers such as the side-effect of destroying cities or heritage sites.

[kilroy123]

Just over build the solar. Build out solar so demand in winter is met.

Use the excess power in summer for some kind of industrial use.

[pfdietz]

This can lead to a solution, but at high latitude it becomes infeasibly expensive. Insolation varies too much from summer to winter. Low round trip efficiency long term storage becomes much cheaper than doing (just) this.

[kilroy123]

This assumes prices for the solar panels and batteries continue to fall as this build-out happens. I don't think it should or could happen in a single year, but slowly over the next 5-10 years.

[lambdaone]

Syngas (infinitely better than hydrogen, which was always a stupid idea), or huge-scale Carnot batteries (the square-cube law is your friend) would do the trick nicely in both cases.

[pfdietz]

Syngas has the problem of where do you get the carbon. With hydrogen, the exhaust (water) just gets released to the atmosphere. Syngas would require capturing and storing the CO2 of combustion for reuse in making more syngas, which adds to the cost.

But yes, resistively heated ultra low capex thermal storage ("hot dirt") is very attractive.

[IshKebab]

You would have to overbuild by a factor of 20 at least. Not at all practical or economical.

[aitchnyu]

Citation? We get 25 units in the sun and 5 in heavy rains.

[IshKebab]

I'm in the UK. I covered my whole roof with 6.5kW of panels (it's pretty ideal south facing etc.)

I just checked our stats. Average consumption 16kWh/day. Sunny summer day we get 30-40kWh. Sunny winter day 10-20kWh. Cloudy winter day it's 0.5-2kWh.

Also that's without a heat pump... Which you mainly use in the winter.

And without an electric car but I doubt they're as big of an issue because you can charge them from cheap overnight power anyway.

[ViewTrick1002]

Keep some of the existing natural gas plants around as an emergency reserve. Run them on hydrogen or hydrogen derivatives for zero carbon fuel, if the emissions are large enough to matter.

[PunchyHamster]

that costs a lot of money

[ViewTrick1002]

Not really. That is how the grid works today. Especially open cycle turbines, which are essentially stationary aircraft engines.

Lowest possible fixed costs, high operating costs.

[pfdietz]

This just shows batteries shouldn't be the only storage technology, at least at high latitude. There needs to be a complementary long term storage technology with low capacity capex, even if its round trip efficiency is bad. Examples: green hydrogen, ultra low capex thermal storage.

To see the effect of including such, go to https://model.energy

Using a long term storage technology (in addition to wind/solar/batteries) can cut the cost in half at high latitudes.

[neilwilson]

The most sensible solution is synthesised natural gas. Then we can use the existing LNG storage and plant.

It’s a lot easier to store and transport than hydrogen and the capital items already exist.

Curtailment fees should be replaced with purchases of green LNG.

[ViewTrick1002]

The problem with that is how dispersed carbon atoms are in the atmosphere.

Another option is ammonia, which is quite nasty to deal with.

[PunchyHamster]

We can start with non-dispersed carbon atoms coming off industrial processes. Green hydrogen and CO2 into methane

[pfdietz]

This is just one-time repackaging of the CO2 from fossil fuel combustion. It's not an answer.

[PunchyHamster]

there is no "answer". We will have industrial processes producing CO2. We have to deal with it, and that is one way.

[pfdietz]

It's more expensive than hydrogen because you need to capture and store the CO2 of combustion. Extracting CO2 from the atmosphere as part of the cycle would be even more prohibitively expensive.

[KaiserPro]

> In the UK in winter we regularly have periods of 5 cloudy days

True, but then for the UK solar power isn't the right thing for winter, hence why we need a massive mix of other stuff.

Also we have the advantage that france isn't that far away.

In the UK battery is about grid stabilisation, as in making sure that it hums at 50hz rather than 49.

[kieranmaine]

Battery revenues are shifting away from stabilisation now from https://cn-cob.com/info-detail/2026-uk-energy-storage-market...:

> the focus of energy storage has shifted from frequency services to energy arbitrage. Due to market saturation, the share of frequency services in the revenue stack has significantly declined, from 80% in 2022 to just 20% in 2024. Looking ahead to 2030, we expect energy arbitrage to dominate the revenue stack, with most revenue coming from participation in the balancing mechanism.

[KaiserPro]

Indeed, in the same way that solar has now peaked in spain/portugal in its current config. They are moving to solar+battery to absorb solar mid day and replay that in the morning/evening. (that doesn't really apply in the UK because of the rain)

As more renewables come on stream and the grid gets more complex, batteries are going to plug holes.

Energy Arbitrage is usually a good thing, so long as its regulated to for the customer, not the battery people. the point is that battery capacity is being deployed to even out the 5-9pm peak, which means that we are much much less dependent on gas turbine generators (which means less price pressure linked to LNG prices, if you're not into the co2 aspect)

[TheSpiceIsLife]

> (which means less price pressure linked to LNG prices, if you're not into the co2 aspect)

No it doesn’t.

The arbitration is only possible because the battery storage providers can ever so slightly undercut the gas peakers.

The price pressure is still linked to the LNG price.

[KaiserPro]

> The arbitration is only possible because the battery storage providers can ever so slightly undercut the gas peakers.

I think you underestimate the cost of running a grid battery, you need to be able to undercut significantly to make profit.

Its not like you can practically keep the battery at 98% for 7 days waiting for the right time to discharge, its not that simple.

The aim is to make as much money, but the markets you can join are regulated (in the UK)

You can be a grid stabilisation service (paid to be at % percent battery and turn on/off in milliseconds to keep the frequency from going too high or low)

You can be intra day, or day ahead. but you're not likley to be dayahead because you're rated at x Mw for n hours. The stuff that I know about in iberia is ~100-300Mw for 3 hours. Again spain is a special case because the market is peer to peer through PPA.

I digress.

The point is sure last year there wasn't really enough battery to affect peak price(in the UK), but now there is 19 gwhr. assuming its all rated for 3 hours, that around 18 % of total generating capacity for 5-8pm.

Now as there is a mix of cfd and other financial things that actually affect price, it doesn't quite work like that in the UK.

[TheSpiceIsLife]

Your answer to renewables being intermittent is: France!.

Good, we agree the solution is: Nuclear!.

[KaiserPro]

well yeah, I wanted tony blair to have allowed EDF to build those 10 nukes at 2004 prices.

[tremon]

Space based solar is a scam

It's not a scam, it's a weapon. The same proliferation arguments that have been used against nuclear also apply to space-based solar.

[hexbin010]

Try 2 weeks of seemingly endless cloud up this way lol. This winter has been seriously depressing so far

[lambdaone]

Remarkably, even most cloudy weather still lets a suprising amount of sun in. And it doesn't stop the wind from blowing. The threat is when the wind stops blowing at the same time it's very, very cloudy and in the middle of winter (short days). This happens, but it's very intermittent.

However, as seen above, there are lots and lots of ways to store (or equivalent) power over long periods, it's just the economic incentive to build them that is needed - and is now on the way. Renewable-gas low-duty-cycle gas peakers, Carnot batteries, and sodium-ion batteries are top candidates, with the first being the low-hanging fruit because they already exist.

[hexbin010]

> Remarkably, even most cloudy weather still lets a suprising amount of sun in

Lol give over. Who told you that - solar panel companies? Companies selling holidays to the UK?

You ever been to England?

[IshKebab]

> even most cloudy weather still lets a suprising amount of sun in

It really doesn't. Clouds absolutely kill solar. In the winter we get 10-20kWh/day on sunny days and 0.5-2kWh/day on cloudy days.

I dunno where you got that info but it's dead wrong.