I come across many people making the point that if we went to wind and solar, we would still have to keep coal plants online in times of no wind or sun. Denmark uses a lot of wind from off-shore turbines. Do they have gas-fired plants on standby? It is my understanding that coal plants have to keep running, it isn’t easy to just flip the switch to on, whereas gas cogen turbines are a bit more flexible.
Despite global advertising campaigns to the contrary, most of Denmark’s electrical energy does not come from wind. Oil and gas provide most of their energy, with coal on the decline but still in widespread use. Wind only supplies about 20 percent.
If they have a shortage of wind/solar electricity and no coal plants running to make up the difference, perhaps they could simply buy the electricity from a neighbouring country.
Exactly. The European power grid is pretty well integrated, and to address this very issue, including the construction of off-shore wind turbines and tidal power stations, a new power grid under the north sea has been proposed to balance the load and store power in Norwegian hydroelectric reservoirs.
The story goes that there’s big subsidies involved. Our government is under obligation to buy the windmill-owners electricity at a (high) fixed rate, even though it’s often produced at times when there’s low demand on the grid.
The government have to sell it at a loss, often to hydro-electric power-plants in our nordic neighbouring countries. They can store it by using it to pump water up into their reservoirs. When demands pick up, they open up the sluices and sell the power at a premium. If there were no such customers nearby, it would be even more expensive to the tax-payers.
Mind you I haven’t looked that deeply into this business, and I’ve mainly read it about in the same newspaper (Weekendavisen) which is one of the most respected in Denmark, but on certain issues is quite biased.
I don’t believe there are any hydro-electric plants in Norway capable of pumping water into their reservoirs. It’s possible Norwegian power companies buy cheap, subsidised energy and leave water in their reservoirs for sale at a more profitable time, but your source, or memory, or both don’t seem reliable enough that I’d bet on it being so without more evidence.
This site says that “water is conserved” in both Norway and Sweden when they get high levels of wind power output from Denmark.
I don’t know if that means that the Swedish and Norwegian hydroelectric power stations actually pump water into their reservoirs when they have extra energy available, or whether, as you suggest, they just temporarily use less water for hydroelectric power generation.
The reservoirs are typically mountain lakes, with an elevation above the power station ranging from around 100m to 1000m. Building a pumping system to move water back into the reservoirs would be insanely expensive, and would only be useful if Danish wind power production was larger than the off hour power consumption of all of Denmark, Norway and Sweden.
I find it highly unlikely even a plan for such systems excist in the Scandinavian electricity production business.
It is a common enough technique called “pumped storage”. There is at least one plant in Sweden and stacks more all over the world. It is cost effective when your main generating plant are base load suppliers that like to run steadily and can’t be switched on an off quickly. If your coal and nuclear plant are up and running the power has to go somewhere when the factories are quiet - you can’t just turn them off for the night - so you might as well use the power to pump water. Then, when everybody finishes their favourite soap and they all get up and turn on the kettle, the water can be released bringing extra capacity onto the grid in minutes.
It is probably because Norway gets a massive proportion of its electricty from hydro resources - which can be run up quickly - that it does not seem to have any pumped storage.
Apparently Norwegian electricity production is more complex than I thought and includes pump stations moving water all over the place, mostly feeding water from surrounding lakes into main reservoirs, but also including pumping water into the reservoir during summer and using it during winter.
Please ignore everything I’ve said so far, and enjoy this list which includes several pumping stations in Norway: Pumped storage hydroelectricity.