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Tribunus_Plebis t1_isyhzr7 wrote

Reply to comment by AnonymousWritings in Investment in wind and solar is set to outpace oil and gas drilling for the first time this year by Frubanoid

Thanks for the explanation. Now I'm all for wind instead of gas but I have a question here.

Isn't a big downside of wind power that it cannot be planned? I.e. you might not get the power you need when you need it. Is that an issue and if so, how would that be mitigated so we can rely more on wind power?

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AnonymousWritings t1_isyjpl8 wrote

You're right, this is often talked about as a power source being 'dispatchable' or not. Gas generator, particularly peaker plants, are dispatchable because you can easily turn them on and off as needed, and quickly ramp up and down.

Wind turbines, on their own, aren't really dispatchable because they depend on wind conditions.

Ways to make wind power into a pseudo-dispatchable source include:

  1. Overbuilding wind turbines. If you overbuild them enough such that you always (or almost always) generate at least the required amount of power, you can just activate / de-activate some of your wind turbines to modulate your power output as needed depending on wind conditions . Conceptually this really isn't that different from having a whole load of gas peaker plants in existence, which only operate on average 15% of the time. On average a lot of 'idle' capacity sitting around with both situations.
  2. Building long distance transmission lines to link up grids with wind turbines that experience different weather conditions. This will work well in conjunction with 1) because it means that a smaller fraction of your wind turbines are expected to be seeing calm weather (and hence low generation) at the same time, meaning that your required over-building factor becomes lower.
  3. Pair wind turbines with energy storage. Batteries, compressed air storage, pumped hydro, possibly hydrogen storage, etc. Wind provides the (uncontrolled variable) power input, storage systems let you modulate when you release it to the grid.
  4. Pair wind power up with other renewable generation (e.g. solar) which typically has favorable weather conditions when wind is low. This reduces the over-build factor required to maintain the needed energy output.

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Wind turbines do need to get a bit cheaper for 1) to be realistically viable in large scale, but they are certainly tending in that direction. Locally it kind of already happens in some areas; wind power is routinely curtailed in Scotland because at peak wind times there is more installed capacity than the grid can use, which means a higher fraction of the time where wind can cover the demand (This situation will change if and when more north-south transmission lines are installed to let southern England use more of the Scottish wind power, but still).

All of these increase the cost of renewable electricity over the base cost of wind power itself, but with wind and solar power dropping south of $40 / MWh, and gas power rising north of $100 / MWh, the economics are still quite attractive

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Tribunus_Plebis t1_isyp068 wrote

Thanks a lot for that. I suppose it's in the end gonna be a combination of all those factors you mentioned. I don't know why I never considered just over-deploying. Seem like an obvious answer now that you point it out.

By the way, what is your source for the cost figures? I'd like to learn more about what those numbers include.

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AnonymousWritings t1_isyv6z3 wrote

Lazard levelized cost of energy analysis a nice place to look at summaries overall of the cost of different energy sources.

For off-shore wind, you can also take a look at recent UK off-shore wind contracts, which are coming in at <40/MWh GBP (37.5GBP which is $42 USD). That's the guaranteed price the wind producers are contracted to sell their electricity at, so the actual pre-profit cost is absolutely lower than that.

Can also see back here discussion of on-shore wind purchase agreements in the US for $20 / MWh in 2019, which was noted as being more expensive than just the natural gas fuel itself per MWh (before this whole Russian gas crisis skyrocketed the prices), without considering actually amortizing the cost of building the gas power plants.

I'll admit though, my 'north of $100 / MWh' number for gas is a bit fluffy. It's true if you look at peaker plants in general (which are expensive because of such low capacity factor meaning ammortized capital costs / MWh generated are high), or if you look at current natural gas prices for gas generation in general, but for pre-crisis CCGT baseload, costs were definitely still well under $100 / MWh.

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Global-Date t1_iszgqrs wrote

>>wind power is routinely curtailed in Scotland because at peak wind times there is more installed capacity than the grid can use,

This isn't completely true. If you look at where 'constraint payments' are paid in the UK a lot more go to Scottish farms, and hardly any to the modern offshore farms

Some of this is because the wind farms in Scotland are connected to the grid really badly. Grid infrastructure was not upgraded and so they need to be turned off more regularly. There is rumblings that this was done on purpose as the old old subsidy schemes paid a very high price to wind turbines if they needed to be shut off.

That incentive is gone in the more modern turbines so it pays for companies to ensure solid grid connectivity.

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