[badpun]

How much would it cost to build out batteries which cover entire continent's electricy needs for say three weeks (as there can be 2-3 week lulls of no wind and no sun in Europe in the winter)? Cause that sounds like a lot of batteries. Not to mention, if a freak 4 week lull occurs, we'll go back to Middle Ages for a week.

[pydry]

You would likely get to 97% green energy first with 5-8 hours of storage: https://reneweconomy.com.au/a-near-100-per-cent-renewables-g...

(for Australia it is 5, for other countries it might be 8)

Once you get to that "nice to have" problem of what to do about the remaining 3% of power needs it would probably make most sense to synthesize and store gas (methane/hydrogen) from electricity when solar and wind is overproducing. Gas can be stored cheaply for long durations. The roundtrip efficiency is poor but it's still cheaper than nuclear power on the windiest sunniest day.

The nuclear + carbon lobbies would of course prefer to model green energy transitions by pretending that the wind and sun simultaneously turn off for 2 weeks at a time every year and that electricity can only be stored in very expensive batteries. This is not realistic.

[laurencerowe]

It might not be quite that good in less sunny countries. Similar modest overbuilding of wind and solar in Denmark is simulated to get to about 90% with 12h of storage. This is still good enough though.

https://xcancel.com/enn_nafnlaus/status/1565923581246091264

[energy123]

Australia's CSIRO studied this for Australia, renewables were half the cost of nuclear, factoring in storage and transmission for both renewables and nuclear (yes, nuclear also needs storage because energy demand varies with time). Australia is uniquely endowed with sun and land, so other countries/regions may arrive at different results.

[blitzar]

If you live in Australia, have a house and roof, you're a bloody idiot if you didnt install solar.

[bot403]

You don't even need a roof. If you have enough land then a ground mount system is more convenient and easier to maintain.

[pibaker]

I think by having a roof GP meant lives in a house instead of an apartment. If you don't have your own roof you probably don't have land either.

[leonidasrup]

Australia is also well endowed with coal and no carbon pricing, so for Australia the cheapest form of electricity production is a mix of solar + battery + coal.

[ricardobayes]

Solar still produces even in overcast conditions, during the day. If it's light/medium overcast, most of which Germany usually is it still produces 50-80% of nominal. It only really doesn't produce anything at night or when it snows.

[bot403]

Yes this is one thing that surprised me owning solar. Some days its pretty cloudy and I can still get 2kw or so from my 7kw max.

[crote]

"But what if thing thing that never happens were to happen?"

We'd probably go deep into hydro, fire up every gas peaker plant, and through skyrocketing prices incentivize everyone to switch to emergency diesel generators where possible.

You're talking about a once-in-100+-years event. We'll deal with it the same way we dealt with the various oil crises.

[leonidasrup]

Those once-in-100+-years events are called crises because they have large impact on economy and loss of human life.

For example a short event in US with duration 2 hours–4 days, depending on location, affecting 55 million people.

Deaths: Almost 100

https://en.wikipedia.org/wiki/Northeast_blackout_of_2003

The Economic Impacts of the August 2003 Blackout

"Based on the much-studied 1977 New York City blackout. ICF Consulting estimated the total economic cost of the August 2003 blackout to be between $7 and $10 billion"

https://www.nrc.gov/docs/ml1113/ml111300584.pdf

Short blackout: 2025 Iberian Peninsula blackout

"The employers' organization CEOE estimated that the outage resulted in economic losses valued at €1.6 billion."

https://en.wikipedia.org/wiki/2025_Iberian_Peninsula_blackou...

[XorNot]

You can't fire up capacity you don't have. Your scenario implies a massive idle stock of power plants.

Who's going to build and run them? They'd be enormously expensive because they'd almost never sell power.

(Of course the answer is if you build 3 weeks of battery storage you can pretty obviously build 4).

[oezi]

But what do we do when the sun isn't shining?

Well what are we doing if the straight of hormuz isn't hormuzing?

Demand will adapt via price signals. Same story as in every market.

[gpm]

> (as there can be 2-3 week lulls of no wind and no sun in Europe in the winter)

This is simply entirely untrue. Europe's a big place, there's not a single day ever where there is no sun in it.