Solar Power at Night?
The nights are long an cold in northern latitudes. How does solar perform in the northern states in the US?
Using the National Renewable Energy Laboratory Solar Integration Dataset [1], its possible to see how the power collected through the year varies. The chart below show the output from an 84 MW solar plant in South East Michigan near Detroit and Toledo.
Plotting the power output over the year versus time of data show two of the problems facing ground solar in northern latitudes.
First, the seasonal variation causes the hours of production to vary - shorter in winter and longer in summer. This significantly reduced production through winter.
Second, the clouds cause days of almost zero production. This shows up as streaks across the graph. This leads to unplanned short falls through the year.
Of course the large black areas are night time when no power is produced.
These issues make firming up the grid more challenging the higher the latitude. Compared to the south western US, the seasonal variations are much higher due to the change in the length of the day. Additionally, the clouds from temperature climates increase daily variations in power production.
Generating solar power at night and on cloudy days is a way to fix this. 😉
