It has been very windy over the holidays here in Denmark with too little snow to call it a white Christmas, and I was curious as to just how much energy all the wind turbines in the country had supplied. According to energinet.dk the electricity supplied by wind as I write this is 1,659 MW and the total consumption is 4,612 MW, so things have calmed down now.
This is how the energy flowed over the last 4 days:
Those dips and peaks are smoothed out by export to and import from Norway, Sweden and Germany (e.g. the cable to Norway has a maximum capacity of 1600 MW!). So geographically Denmark is in an ideal position. A lot of trade is going on, but on very windy days the owners of the wind turbines are actually not that happy, because they are often forced to sell very cheap, and prices can even go negative.
I think this goes to show that we are closing in on the model of society being powered by 100% renewables. The missing piece? Storage of course. Look at those dark green in the bottom of the above image. Those are conventional power plants, and they are still needed to stabilize frequency. A few are still burning coal, but many burn waste and biofuels. They will shrink even more when batteries (both stationary and in cars) are implemented into the system.
According to dkvind.dk there are 6,100 turbines installed in the country with a total capacity of 5,300 MW. About half of those are quite old and with less than 1 MW capacity, so as they are being replaced with new turbines, we could easily expect a total capacity around 10 GW within the next 20 years.
It is actually quite a feat to manage this kind of intermittent flow of energy, I mean, at one point in time wind accounts for 1,000 MW or less, and a few hours later it can rise to 5,000 MW, and I can sit here and not notice the tremendous shifts going on in the grid. In the summer solar tops at around 500 MW and it just flows steadily into the system as well.
Thanks to the decades of experience with wind power in the country, the management of energy has become very efficient. Denmark has one of the worlds most resilient power grids, despite depending so much on renewables. Solar and wind is winning, while oil and coal is losing. Fast. That’s the new reality.