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Comment by cm2187 | Hacker News Reader

The batteries mentioned in the article have only a few hours of capacity, and are designed to smooth the peak usage intraday. I think many people are confused and seem to think batteries are a viable way to address the volatility of wind, where you may deal with weeks with no/low wind, or solar, which in countries with cold winters is of little help.

I have yet to see a cheap scalable alternative to carbon to deal with that volatility. Hydro perhaps in a handful of smaller, mountainous countries (and if you are not too regarding of the environmental damages). Right now the UK is using LNG to compensate wind.

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Long-form storage is inherently unprofitable - a battery that's used daily will make 365x the sales of a battery that's used only once a year.

So inevitably, the first batteries will always prioritize daily arbitrage, and only once that market is capped out will some battery projects target weekly/monthly/yearly arbitrage.

In countries with cold winters, the obvious solution is heat-energy storage systems, which don't output electricity but instead store and output heat directly; they're basically just a big pile of sand/stones/bricks wrapped in a ton of insulation. Thanks to the cube-square law, they scale up unbelievably well and can easily store months worth of heat.

Due to that scale they don't make much sense without district heating, but energy storage is a numbers-game and lots of cold places already have district heating that could be quite easily retrofitted.

You don't need batteries with longer capacity in terms of power:energy ratio, you simply need more batteries.

Getting to France's level of nuclear decarbonization with batteries is cheap and easy with current prices. Using existing thermal plants for a few weeks a year and renewables for the rest is quite similar overall to France's mix.

What's challenging is the final 10%, 5%, and 1%. But it will take 15-20 years of deployment of our current cheap renewables+storage technology before we need to solve those final percents. In that time, technology will have advanced tremendously and we don't know what the cheapest solution will be, just that it will be cheaper than current tech. Plus it would take much longer than 15 years to even build nuclear in any significant quantity! France said a few years ago that they would be building handful of new reactors but I still have not seen progress!

The UK uses far more gas to heat homes than to generate electricity, and uses some for industrial purposes so it seems weird to attribute LNG use to wind, the technology that more than any other has reduced gas usage in the UK.

The increase in use of wind, being intermittent and non-dispatchable means there has to be 1-for-1 back up wind generation. That is gas.

We also have periods in the winter (so solar of little to no use), where we can have a week or two of no wind.

As the gas generators are not run constantly, they're more expensive than if they were. There are various (at least 3) UK "gridwatch" sites available, offering real time and historical generation mix. Maybe have a look.

From memory, so probably flawed, we still tend to depend upon nuclear and gas for around 40 - 50 % of our generation (nuke being low - say between 5 and 10).

you can actually see it live here: https://gridwatch.co.uk/

It illustrates both the volatility of wind (which regularly goes to zero for at least a week), and how it is currently pretty much 100% offset with gas.

Since year 2000 wind has gone from 0 to 30% of UK electricity generation

Coal has gone from 32% to 0.

Gas has gone from 40% to 30%

How do you square these numbers with wind being responsible for the amount of gas burned?

You are not going to observe that in annual averages. As mentioned in my other comment, you can observe that very clearly in the energy production charts: https://gridwatch.co.uk/

Let's boil this right down:

A new wind turbine is built and plugged into the grid. Does this cause more gas to be burned or less?

That's not what dfawcus is saying, he is talking about installed capacity, not consumption. If you build 1GW of wind, you need to also build 1GW of gas to make up for when there is no wind (and as you can tell from gridwatch, it's a common occurence). Otherwise blackouts.

[edit] and we might be talking at cross purpose here. I think most of the new capacity built now is to expand the production, rather than to reduce other forms of productions (in which case you might just keep around existing gas capacity if it was there, to your point).

Replying to myself because a new report came out saying the UK saved a net 104 Billion over a decade by replacing gas with wind.

The major factor was reducing the use of gas which lowers gas prices. As a result the main beneficiaries weren't electricity users but gas users paying lower prices and saving 133 Billion.

Normally this would be handled by a wider synchronized network. The EU has a continent wide synchronized network and the UK isn’t part of it.

There are also other ways to store energy. For polar regions sand batteries are capable of storing heat for months. High grade heat to the point they can siphon off that heat for power generation.

The interconnectors between UK and the continent are HVDC.

As such they are essentially massive switching-mode PSUs, and there is no possibility of having a synchronised connection, as the AC has to be synthesised, following the local spinning iron.

But also europe isn't that large. When there is no wind in the UK, there is no wind in France or Italy. Which means not only do they not provide diversification, they will import at the same time.

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