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Cybiote | 4 years ago

Renewables are indeed vital. At the same time, it feels counterproductive that every discussion on nuclear or renewables ends up casting things as an either or proposition. Nuclear as baseload remains very useful. What's more, we don't just seek to replace current capacity but also to quickly increase generation.

While costs of transmission infrastructure required for country scale (larger distances for lower correlation) energy dispatch are recognized, its more abstract challenges are less well acknowledged. Dispatch at this level is not just about developments in grid integration or hardware like solid state "transformers", it also has a complex routing coordination aspect requiring research in control and even game theory [1].

A lack in wind and solar can sometimes occur simultaneously. Analysis of German wind turbines data observed that experiencing a stretch of almost a week with generation as low as 10% installed capacity was likely within a given year [2]. Surprising/extreme weather events like Europe's recent "wind drought" are rare but there remains a large amount of uncertainty in how changes in climate will affect the tail of this distribution. Tools such as coordinating distributed generation and improvements in storage tech will surely help smooth generation, nuclear is another powerful tool in that toolbox.

[1] https://www.nrel.gov/docs/fy15osti/63037.pdf

[2] https://iopscience.iop.org/article/10.1088/1748-9326/ab91e9/...

https://www.sciencedirect.com/science/article/pii/S096014812...

https://www.nature.com/articles/s41561-017-0029-9.epdf

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rsj_hn|4 years ago

> Nuclear as baseload remains very useful. What's more, we don't just seek to replace current capacity but also to quickly increase generation.

The problem is that Nuclear may not be economical if it is only used when both solar and wind run out. Nuclear has large fixed costs. And almost zero marginal costs. So the average costs -- what needs to be charged in order to avoid bankruptcy, increase as you use it less.

That means every solar panel you add makes the nuclear power a bit more expensive. And that incentivizes adding more solar. Up until you drive the nuclear out of business, and then suddenly you don't have reliable power anymore.

Then you are faced with a situation of

a) only having nuclear power which can provide for all of your needs, in which case adding solar is an unnecessary expense

b) only having solar+wind and an unreliable grid, which means you need to add batteries to cover solar+wind. And the price of those batteries may be more than the price of the nuclear plant.

c) having nuclear and solar both, with enough subsidies given to the nuclear plant to keep it in business so that the total solution is more costly than just going with nuclear.

So yeah, there really is a tension between nuclear and solar.

This is not the situation, however, with solar and coal. Because coal plants are damn cheap, and they have higher marginal costs. Thus solar can coexist with coal or with gas much better than with nuclear.

Therefore the economics is such that as people promote solar the result is a decrease in nuclear and an increase in coal and gas.

Retric|4 years ago

Your model is overly simplified. Nuclear runs into the exact same issues in the other direction as you try to scale it to take over more of the grid. Frances nuclear reactors where at 70% capacity factors vs 90% in the US even with France exporting and importing vast amounts of electricity with the rest of Europe. It’s really not Nuclear vs Solar it’s simply Nuclear’s high cost and thus inflexibility that’s at issue.

Current electricity demand is heavily biased to daytime use even with cheap nighttime prices causing people to shift demand to use that. Start to ramp up solar to the point where daytime demand is higher and a great deal of nighttime demand drops off.

Grid storage isn’t cheap enough to store energy at current nighttime rates, but it’s cheap enough to have a balanced grid backed by hydro, wind, and solar even with zero fossil fuels. The tipping point to cheap daytime rates and expensive nighttime rates isn’t inherently better or worse, it just reflecting the future economic reality.

Retric|4 years ago

Lack of wind and solar can happen but at scale there is plenty of hydro energy stored to cover significant edge cases. Rivers can handle significantly more flow than current hydro releases without causing flooding, we just need to retro fit existing dams and then reduce their generation most of the time to reserve that capacity for when it’s needed. Aka averaging 6.6% over 365 days a year ~= 80% for 30 days.

Also, be careful when looking at wind and solar minimal percentages. It’s the difference between median output and minimum output that matters not maximum output. Long term it’s likely something like 30 to 50% of all solar generation is going to be wasted simply because it’s just that cheap.

themaninthedark|4 years ago

Aren't we removing dams because of the damage that they do to fisheries? Also doesn't new dams create a large amount of greenhouse gasses?