During the last Christmas we have experienced windy weather in Poland. This caused not only a lot of property damage, but also had positive effects. It cleared the smog and allowed the Polish wind energy to beat several records.
According to an article on the website wysokieniecie.pl, based on data from PSE (Polish power grid operator), on December 23rd, Polish windmills worked at 90% of their capacity, generating electricity with a power of about 5.2 GW (while at that time the total power demand in the country reached 22 GW). On the first day of Christmas, December 25th, the production from wind turbines filled 40% of the total demand for electricity.
The chart below shows this situation in detail. Wind power production is marked in blue, while the red line is the total demand for electricity at a given moment in Poland. It can be seen that at times we were dealing with overproduction of energy on a national scale. It was successfully exported abroad.
Although on the one hand, we have cool records, on the other – we saw underlying problems resulting from large amounts of electricity produced in sources, that cannot change their output. Of course, you can limit the production of a wind farm, for example by turning some of the turbines off, but this does not benefit their owner. He would like to capitalize on the best possible, favorable weather conditions. It is also in the interest of the environment — when we don’t have to burn coal, let’s not do it.
It is also worth noting that we have quite unusual weather conditions at the moment. On one hand, a lot of wind, but on the other hand also high temperatures. In the winter traditionally in the country a lot of electricity is used by people for electric heating of houses and apartments, but due to the lack of frost during holidays (and less workload in industry, trade, and services) we were also dealing with an extremely low demand for electricity.
The problem in such situations is that in Poland there are almost no sources of electricity that could be turned off completely in such situations. There are also no sources that can be started immediately when the wind stops blowing, or when the speed exceeds the limits at which the wind turbines should be switched off for safety reasons. Pumped storage power plants can be stopped, but we only have a couple here. To some extent, it’s also possible (for some time, and even this not always) to limit the power of hydroelectric power plants. Coal-fueled power plants can naturally work with less power, but it is neither ecological nor profitable. The individual emissions of pollutants in relation to the electricity produced are greater than when they work with a near nominal capacity.
What is the answer? In the scale of the entire power system, it would be necessary to build a lot of small, flexible power plants that would be easy to start up, and easily adjust to the changing load. Ideally, these sources should be scattered around the country as much as possible to reduce losses on electricity transmission. Technically, it’s not difficult, just put a few GWs in the form of gas turbines or diesel generators (running on natural gas, or preferably biogas). The biogas plants are quite a nice solution in this respect, although for some reasons they are not optimal (to make biogas you need some heat, and it’s mostly supplied in a form of waste from this biogas engine).
We can also search for solutions to store the power for later, such as in the form of compressed air (it perfectly matches gas turbines, which also need compressed air for work). Surplus electricity can also be stored in homes, in batteries of electric cars, but these are still not popular enough on the Polish market. And I also do not think that consumers would want to use their batteries as a place to store electricity from the grid (which would also require their unloading at times appropriate not for the car’s owner).