[merpnderp]

But how much of this was overlapping power production with baseline fossil fuel production? Wind power often doesn't displace fossil fuels, it coincides with it, since wind is less predictable and coal plants take hours to ramp up/down.

If 39% of Danes' electricity completely displaced the same amount of fossil fuels, my jaw would hit the floor.

[kaybe]

The charts I linked below [1] have a comparison for 2013-2014 for Germany (eg page 8). I assume the situation in Denmark might be similar.

There is also this statement:

" Wind power achieved a new record of 29.7 GW in peak power production at Friday, 12th of December 2014. The daily wind energy production was 562 GWh. Both figures represent new records. The last records of 5th of December 2013 with a maximum power of 26.3 GW and a daily energy of 485 GWh have been exceeded by 13% resp. 16%. Photovoltaic power reached a maximum of 4.9 GW at the same day. The maximum total power from solar and wind was about 34 GW, which is well below the maximum of 14.4.2014 when a total production of 38.8 GW was reached.

In order to provide sufficient space for the wind power in the grid, nuclear power plants have reduced their base load generation by about 10%, lignite plants by about 30%."

[1] http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files...

[mrweasel]

A few years ago I worked on software that manages selling electrical power from small decentralized power plants. When the wind isn't blowing the missing power can be supplied by electricity generated by plants that are built for generating heat. These are typically 2MW plants that can ramp up in 20 minutes or so, and they are scattered through out Denmark. These are all a mix of biomass, gas, oil or goal, or even garbage incinerators. The smallest one I saw was a large commercial greenhouse, with a 0.7MW generator. You bundle all the small plants up into 10MW packages and sell their potential output via www.nordpoolspot.com.

There's also a plan that involve simply pay large power consumers to halt production do compensate for missing electricity in the grid.

The Danish power grid is also closely linked to the those of Norway, Sweden and Germany, allowing export of cheap wind power, when there's a surplus and import of nuclear, hydro, coal and gas when there's no wind.

You're right in as so fare that wind power isn't magical, there needs to be a backup when the wind isn't blowing.

[jacquesm]

As long as the windpower installed reduces the need for baseline to be produced the efficiency can get pretty good indeed. No matter how high it goes this will not result in all baseline power generation being halted simply because it takes time to bring those plants online (shutting them down can go quite fast but ramping them back up takes time). Also, because of the inherent instability of renewables you always want to have a certain percentage of the current requirement available as non-renewable just in case.

[toomuchtodo]

Not sure if its the same for the Danes, but in the US coal is being displaced by natural gas, which can be throttled quickly for grid demand response (and is cleaner, and releases drastically less CO2 per unit of power generated, and can be moved across the country quicker via pipeline vs trains).

[crdoconnor]

The cleanliness of natural gas is significantly overstated. Fracking is a dirty business.