[ZeroGravitas]

It's always interesting to see what ridiculous limitation they place on these to make them not work out.

Popular ones are:

Refusing to allow energy to be traded with neighbours.

Refusing to allow demand response.

Refusing to allow over building (so the installed capacity exactly matches the yearly required energy and storage needs multiply).

Refusing to target efficiency measures.

Refusing to use existing low carbon power sources (hydro, biogas).

Often they use low volume prices for a massive rollout but at least in this case they're estimating storage capacity rather than price so they won't have done that one.

edit: reading through it now, they cite other people who didn't do the above, and then state that they know some of their choices will overstate things:

> the fact that we model Germany as an island may lead to an overestimation

Guess that bit didn't fit in the tweet.

I don't fully understand this next one, but their headline number is based on running biogas as a constant baseload, which seems utterly ridiculous. They also claim that allowing that to flex with supply and demand has this impact:

> "Adding other sources of flexibility for the example of bioenergy, the duration of period that defines storage requirements lengthens to more than one year."

That's a very strangely worded sentence, with a very counterintuitive plain reading. Are they trying to intentionally confuse people? I'm not sure, can't figure out anything reasonable from the article. How can adding 8GW of flexible biogas generation increase storage requirements? Are they counting the storage of biogas?

[cm2187]

I am not trying to defend the study, but I don't think any of your points actually mitigate the issue of volatility.

1. trades with neighbours: most european countries face similar weather conditions at the same time. The french will need their own nuclear capacity to make up for their own lack of wind.

2. demand response: switching off factories or heating when you need it? That's no solution

3. over building: the problem is that the volatility of wind is massive, if you look at the uk grid website [1], it can go to nearly zero for more than a week. If the volatility was smaller, over provisioning could be a solution (provided the economics work).

4. efficiency measures: you only make the size of the problem slightly smaller, but you still have a volatility problem. And with cars going electric and us not relying on russian gas for heating, I don't see the demand for electricity going down

5. hydro, biogas: there is only so much hydro you can build. And the places where you can build some (Sweden, Norway) leave you at the mercy of a russian submarine cutting the cable. Biogas: isn't that co2 emitting?

[1] https://gridwatch.co.uk/

[ZeroGravitas]

Biogas is carbon negative, since you make it with manure and food waste that would otherwise give off methane.

EVs and heat pumps are over 4x the efficiency. 75% of your energy just not needed anymore to do the exact same work.

The real clincher is that most of the storage they predict is hydrogen and at the end they calculate that the crazy amount of storage required for Germany as an island is in fact, the same size as the existing gas storage facilities which can be reused for that purpose.

Which I think really rams home how utterly boring this allegedly insurmountable challenge is.

[imtringued]

I am so tired of pretending things that aren't impossible aren't. Just do it and then reach the next level of civilization. Honestly the only reasoning I can come up with is that a handful of individuals would rather be kings than let everyone live a more advanced life.

[imtringued]

>2. demand response: switching off factories or heating when you need it? That's no solution

It's a solution for charging the batteries inside your vehicles.