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by aagd 1704 days ago
In Germany renewables are at over 42% in 2021, despite a 'conservative' government that for decades has blocked the development of windfarms and solar for the benefit of the coal and nuclear lobby. That kind of lobby-work is the actual problem here. The way forward is renewable energy. The huge difference is that the source of renewable energy is free and basically limitless.
4 comments

The problem is that only a fraction of power consumption is electric. The rest is burning fossil fuels.

In order to get away from these, we have to increase electricity production significantly. And we have to build a better electricity grid.

It is completely unclear how renewable energy should provide this in the short or medium term (i.e. until 2050). Without nuclear, we’ll just continue burning fossil fuels.

Renewables paired with batteries can improve grid resilience, actually. Distribution of generators means less loss in the wires travelling, batteries paired with renewables to provide overnight power and load-smoothing, these are good things. Renewables also are very predictable, so you can use a little natural gas to supplement at night while you build out batteries and more wind. Solar will take care of our day-time needs no problem, it's the overnight stretches and the wind-less winters where nuclear would really shine.
How much batteries and renewables do you need to provide baseline power on the level of a single 1000MW nuclear plant?

And how will you construct all that sooner than constructing those plants?

Batteries are a bit of a red herring. The combination of pumped storage plants, overgeneration, and demand response already has you covered for at least two decades even in Germany. The minimal cost solution calculated for Germany assumes 1.6 GWh of storage for your 1000 MW nuclear equivalent for a 60% RE penetration scenario, only some of which needs to be batteries (Germany is currently at ~45% or so, many other countries are considerably behind). At the expense of extra costs, lower storage could be compensated for by higher overgeneration (= by not consuming all the power you produce).

However, this was all calculated for current grid conditions. Spread of BEVs would likely put dedicated grid storage needs lower, since in Germany, for each of your 1000 MW nuclear equivalents, there's 700k cars which already have ~600 MWh of storage capacity even just in form of lead-acid batteries, and even replacing just 10% of these cars with 40 kWh BEVs would give you a whopping 2.8 GWh of capacity per your 1000 MW nuclear equivalent, necessitating higher overgeneration to provide the vehicles with motive energy and lowering grid storage capacity because of demand response ("smart charging"). For reference, a 100% replacement of ICE cars with BEVs in Germany would require a ~25% increase in average power generation - by around 250 MW of average power per your 1000 MW nuclear equivalent.

Electrolytic hydrogen production would do exactly the same thing to grid storage - require more generators, and with demand response, lower grid storage capacity. Just replacing German ammonia with "green" ammonia using electrolysis would necessitate another 60 MW of average power generation per your 1000 MW equivalent that could be subject to demand response.

> (= by not consuming all the power you produce).

This is a bit of a nitpick, but this is a physical impossibility. On a AC electric network, if the power input is higher than the power output, the frequency of the current goes up quite quickly, until the grid collapses (because there are security to avoid frequency deviation). You cannot “not consume all the power you produce”, all you can do is not producing as much as you could.

Btw, I'm interested by the sources of your “1.6 GWh of storage for your 1000 MW nuclear” because it sounds really low to me. I did a simulation[1] a while ago based on French data, for a 100% RE scenario and my calculation arrived at around 250GWh per GW of installed capacity. For sure it's not the same country, and a 60% vs 100% RE is a huge step, but the differences between those two results is a lot more than what I would expect.

A mistake I've frequently seen with people discussing wind power storage, is taking the average capacity factor and calling it a day. The storage need for wind-based power generation is enormous because (at least in France, but given the geography of Germany I'd expect it to be even worse there) you can have severe wind deficit which can last for weeks!!

[1]: https://bourrasque.info/images/20180116-moulins-%C3%A0-vent/...

> This is a bit of a nitpick, but this is a physical impossibility. On a AC electric network, if the power input is higher than the power output, the frequency of the current goes up quite quickly, until the grid collapses (because there are security to avoid frequency deviation). You cannot “not consume all the power you produce”, all you can do is not producing as much as you could.

I probably should have said "all the power you could produce", since for example with photovoltaics you can produce at any moment any amount of power from zero up to the MPPT point on the I/V curve, depending on how much charge you remove from the panel. I hope this clears it up.

> Btw, I'm interested by the sources of your “1.6 GWh of storage for your 1000 MW nuclear” because it sounds really low to me

I used the figures in the 2018 Zerrahn et al. article: https://www.sciencedirect.com/science/article/pii/S001429211...

> I did a simulation[1] a while ago based on French data, for a 100% RE scenario and my calculation arrived at around 250GWh per GW of installed capacity.

Maybe you've just taken Sinn's approach instead of Zerrahn's? That number would seem to fit it.

I'm not sure there are (can be?) enough batteries in the world, to support the grid for any length of time.
There was a project to try this: https://www.greentechmedia.com/articles/read/german-utility-...

Unfortunatly this project was cancelled since Germany taxes electricity from batteries two times: Once when charging the battery and once when discharging it (since it is then seen as "producing" electricity).

Why wouldn't this be solved by co-locating the battery with its own generator?
There are not now but there may be a solution in the future eg "Seasonal energy storage in aluminium for 100 percent solar heat and electricity supply" https://www.sciencedirect.com/science/article/pii/S259017451...
Not completely unclear. Renewable energy can be even more local than nuclear plants. A good grid is a valueable tool, but not the only solution. The zero-energy-house is a working example for self-sufficient development. Large office buildings or small residential houses are already being build this way. It's a matter of where to put the subvention money - to the big old coal companies (and their lobbies) or the innovative smaller engineers.
You don't get points for using Nice Green power, you get points for not releasing more CO2 in the atmosphere. Right now, France's electricity is at 30g CO2 per kW.h (the figure includes the whole lifexyle), while Germany's is at over 400g.

Sure, we have to deal with the waste ourselves, but you're just dumping yours in everyone's air.

Those 42% percent in Germany include Bio-mass. A Bio-mass 'plant' is a wood chip furnace, it is only renewable based on the weak principle that the burned mass and C02 emissions can be captured 'because we can just plant trees'.

The energy needs we have and the land avaialable in Europe for forest makes this impossible without importing 'bio-mass' wood pellets at which point the ecological argument goes out the wind. [0]

[0] https://www.researchgate.net/publication/302972714_Tracking_...

And despite 42% of renewables Germany CO2 emissions have increased in the last years, and Germany will obviously miss its 2030 target (which is already not enough). Just look at electricitymap.org to see how that strategy is going. Also nuclear is kind of renewable too so that distinction is not really relevant regarding climate. That view needs to be updated with 2021 reality, we need a baseline production that always work, and choosing fossile for that like Germany (Coal, Gas) is irrational (nuclear issues pale in comparison of climate change for future generations).