> What is the end game here?

Getting off fossil fuels. Specifically, it's something called the "European Grid Vision" [1]

The short version is advances in long range power distribution using DC transmission lines mean we can transmit power further with less loss than traditional high voltage AC lines. ABB has done wonders in rolling out HVDC technology [2].

But what does this have to do with the variable duty problem you ask? Alternative energies are hard to grid precisely because they are so variable as you observed. But with efficient transmission you could, for instance, collect solar in North Africa to provide power to the continent as well as pump up water into dammed fjords in Scandinavia which can be drained at night to through hydro-electric supplies. Wind in Germany or Tarifa can supplement dams one week, which can be drained the next. And of course there is always geo-thermal and nuclear.

So yes, today one needs the backup coal/gas/nuclear plants but not by 2040 in the updated roll-out schedule.

[1] https://www.youtube.com/watch?v=Uir-BPoTN88#t=0

[2] http://renews.biz/109437/abb-transforms-chinese-grid/

Depending on North Africa which is extremely politically unstable is a horrible idea. Germany is phasing nuclear energy out. EGV is just a vision: reality is Germany routinely overloading their neighbors' grids(Czech, Polish) transmitting electricity from northern wind farms to southern and Austrian industrial centers. The neighbors are quite upset about it and are taking legal and technological(expensive investments on borders, without any German participation).

The endgame for Germany is wind + Russian gas, see Nordstream2.

> France: 17 cent per kwh vs Germany: 29 cent per kwh

You can't really compare that. The 17 cent are not real prices in a competitive market. In France electricity production is mostly monopolistic & state owned - some kind of deregulation start last year. ;-) EDF is state owned. Increasing the electricity price to cover real costs is not an option, the population will vote against it. Guess who pays for keeping the old reactor fleet alive? Costs for maintenance are rising to an estimated 45 billion Euros in 2025. Guess who pays for the super-expensive new reactors like the EPR? Without government money the company which builds it would have been imploded long ago.

Germany OTOH makes electricity expensive: there are taxes, investments in renewable energy, investments in decentralized grid, research, etc.. This also keeps consumption low and creates incentives to invest in new and efficient infrastructure and electricity consuming devices.

Note also that large commercial and industrial customers in Germany get much cheaper electricity rates than domestic consumers.

Although they consume 70% of Germany's grid energy, they are exempt from (or receive rebates for) much of the green energy taxes/levies.

Briefly:

- distribute regenerative sources geographically to have a better average production; there's always wind somewhere in Europe

- increase storage capacity through various means; e.g. pumped storage, chemical batteries

- make electricity consumption match production through various means; e.g. have (industrial) cooling and heating work in excess if there is an excess of "free" energy, charge electrical car batteries

- reduce electrical capacity requirements through gains in efficiency; e.g. improve home insulation

It's also not just a matter of production capacities: we're throwing away huge amounts of regenerative energy because we don't have the technology to a) adjust other production sources fast enough, b) store excess production and c) we don't have the infrastructure to transport it.

Don't forget dynamic pricing.

I know it is due to historic energy markets and old metering technology, but the fact that a kWh costs the same no matter the time of day is a situation that cannot continue.

And throw overcapacity at the problem. If a bad day gives you 5% renewables with the current capacity then you "only" need 20x more capacity. Combining with other solutions this overcapacity factor goes down significantly.

And once you have intermittent excess energy that is essentially free some opportunities to use it might spring up, e.g. run various electrochemical processes for free and store the products or smelt aluminium or something like that.

Being German living in France I don't think an absolute comparison like this is telling. The EEG in Germany ( https://de.m.wikipedia.org/wiki/Erneuerbare-Energien-Gesetz) fosters development of alternative energy sources at the real cost of guaranteed purchasing prices. A good investment (see adoption https://de.m.wikipedia.org/wiki/Photovoltaik_in_Deutschland) but borne by all through increased electricity costs. I never liked the price hikes but I do think it will spur further innovation in network anf storage while here in France I pay more for access than consumption and rent from owners not interested in changing windows to anything resembling insulation.

How expensive would electricity be if we could somehow factor in all the environmental costs?

I pay 25 cent per kwh, in munich;

End game? Trying to produce as much wind and solar as possible.

Those numbers are only getting better and better with every year.

I pay 29c/kwh in a country with abundant solar, wind, coal and uranium. Perhaps there is something more at play here?

Public education about grid engineering and its challenges would be a good thing.

How inefficient and/or environmentally unfriendly would it be to store the excess in batteries of some sort? I've heard that scheme pitched for solar quite a bit, so why not use the same strategy of buffering for wind?

Better than batteries is pumping water uphill into reservoirs when there is a power surplus, then recovering it as a normal hydropower plant when there is a deficit.

One infrequently discussed but very real issue with pumped storage is biogenic methane. In some cases, reservoirs can make more greenhouse gas per kWh than coal(!). Earlier we thought this was just bad in tropics but more recent studies indicate it may be most strongly correlated simply to reservoir size. If these are even moderately accurate, pumped storage for significant energy storage is not an option for a carbon-free system.

[1] http://pubs.acs.org/doi/abs/10.1021/es401820p

[2] http://journals.plos.org/plosone/article?id=10.1371/journal....

That's really interesting. Methane is pretty bad, but at least biogenic methane doesn't increase the total amount of carbon in the atmosphere.

Methane is far worse than CO2 though, about 30x. A process that converts one to the other while staying carbon neutral isn't what we need.

Governments are hesitating to use this because pump storage has major environmental impact. It just needs _a lot_ of space. You also need mountains for that and not every country has those.

There is some research going into putting concrete spheres into the ocean and pumping water in and out of them. The principle is the same but it doesn't need hundreds of hectares of forest to be cleared.

I recently visited Cruachan ( https://www.visitcruachan.co.uk/ ) which does this, with four 120MW reversible turbines; it's great but requires very specific topology. Most countries don't have too many places they could build one.

Any hydro lake works as an energy storage system - it doesn't have to be pumped.

That's why you see energy being exported to hydro-rich Norway on windy winter days. It allows water to be retained in Norway's storage lakes for later use.

Even more efficient is to control the flow in a hydroelectric plant by stopping the generation when the demand is low. This removes the cost of pumping. If there is sufficient reserve water capacity it is done in places where the energy price depends on the market and economic incentives are there.

Hydro also has non-trivial enviromental impact - you are creating pretty big "lake" above the dam. And if you want to turn it on and off, you'll need one more to make the flow normal again.

And that reservoir can emit very significant biogenic methane. Large reservoirs for pumped storage are likely not a scalable option for climate change.

For the downvoters, here are scientific references [1,2]. I was shocked too.

[1] http://pubs.acs.org/doi/abs/10.1021/es401820p

[2] http://journals.plos.org/plosone/article?id=10.1371/journal....

One thing to note. While biogenic and thus "green", the methane is about 30 times as potent greenhouse gas (over 100 years), so we can not consider pure "carbon footprint" here. There are similar problems with restoring wetlands and undraining peatlands, which used to be carbon sinks, where biogenic methane production goes up for a while.

There are also problems with N2O emissions on the reservoirs, specially near the agricultural regions. And this is all without even talking about reducing biodiversity and destroying spawning areas for the fish by filling those with mud. So yes, efficiency is not always friendly.

This is true. High efficiency and low carbon emission are not always in the same boat.

Extremely. For instance, in Washington state, the BPA just had a 10-day wind lull. The 4 GWe of capacity was at a standstill. It would have taken batteries covering an American football field (with end-zones) 100 stories tall and costing $90B to fill that gap [1]. The mining and carbon footprint of that energy storage system would be very non-trivial. Pumped hydro storage is no good either due to biogenic methane in the reservoir.

[1] https://partofthething.com/thoughts/a-medium-length-primer-o...

There's individual Nuclear plants of that size and the grid already needs to plan for those to be out unexpectedly (far less predictably than wind in fact) so it doesn't seems to be that big a problem in practice.

At this size (4GWe) it was no big deal, the hydro plants can cover easily. But at 50 or 100% renewables it's much more challenging because entire regions can go down unpredictably. The 1 GWe nukes go down for outages generally in a staggered way (though not always, for instance in a common-cause design concern)

Don't forget that France is heavily relying on German electricity. Especially in the winter time, France needs to shut down some nuclear power plants due to frozen rivers and but still needs electricity for heating. In the summer some nuclear power plants have to shut down as well because the rivers and thus the cooling water is too hot. In those times, Germany's reliable power sources help France to avoid major blackouts.

France only imported electricity from Germany in 2016 because a good part of the reactors had to be shutdown at the same time to investigate a dfect risk. But every other year it's Germany that buys France's electricity

This doesn't really matter because there needs only to be a single day where the nuclear power plants need shut down and France goes dark in a lot of places. Over the whole month France still seems to be a net exporter to Germany but Germany only buys French electricity because its cheap.

France cannot react to a fluctuating power demand like Germany can and Germany simply takes over the French excess power. You cannot power down a (French) nuclear plant as quick as you can spin up a (German) gas turbine. So Germany operates on a stable power source of less than they actually need and import from France but if more power is needed, Germany quickly spins up their gas turbines for the time it takes to power up the coal plants. France' power plants normally run at full power and if the demand falls off, they are in a bit of trouble and rely on Germany to help them out. Be it by taking over electricity (most of the time) or delivering electricity (sometimes).

If Germany didn't take the excess electricity, France would have to burn it off.

France imports in hot/dry summers when the rivers are overheating from cooling the nuclear powerplants. France imports in cold winters when their nuclear reactors are not sufficient to power the electrical heating for the homes...

> However, this takes off-line about 40 percent of Germany’s nuclear capacity and Germany is one of the two countries along Great Britain from which France imports electricity during the high-usage months in the summer. The reason importing electricity from Germany and the U.K. will be particularly important for France during a drought is because 24 of its 58 nuclear reactors do not have cooling towers and purely depend on the flow of river water to cool the reactor cores. What this means is that if the level of water in rivers drops, it means that some of the reactors may have to be shut down especially those on the Rhone River in southwest France, where temperatures are expected to be particularly high due to its geographical location.

http://www.businessinsider.com/french-heat-wave-one-tumultou...

> France imports UK electricity as summer heatwave puts a third of its nukes out of action

https://thinkprogress.org/france-imports-uk-electricity-as-s...

> Germany powers France in cold despite nuclear u-turn

https://www.reuters.com/article/europe-power-supply/germany-...

> France was heavily dependent on power imports from Germany during the first cold spell of this winter, despite the fact that most of the country’s nuclear reactors are back online

http://energypost.eu/france-cant-meet-power-demand/

I don't know, but I can't find anything that would support that statement. It is pretty normal that sometimes needs to buy some electricity - the European grid as a whole relies on it's interconnection. However, now - Germany has a ton of spare energy and it's evidently selling to everyone, except France... and it's winter