Last year global renewable electricity – i.e. hydro, wind and solar – consumption grew by 193.7 TWh. This represented 55% of the total growth in global electricity consumption.
And China, where renewable electricity consumption grew by 174.9 TWh, made up a large part of the increase. A renewables revolution is clearly unfolding. Or maybe not.
Careful readers will have noted the word order in my first sentence – hydro, wind and solar. If you follow debates on energy closely you will regularly be astonished by how often commentators act as if wind and solar dominate renewable energy. The fact that bioenergy has grown by more in this century than wind and solar combined is not something you will ever be told.
The same is true for hydro-electricity. A representative image of renewables in China is not this:
China gets five times more electricity from its hydroelectric plants than from wind and solar combined. Total hydroelectricity supply in 2014 was 1064.3 TWh, while wind was 158.4 TWh and solar was 29.1 TWh.
Most of these hydroelectric plants have been built this century. Total hydroelectric generation in 2000 was 222.4 TWh, one fifth of what it is today.
Last year China’s hydroelectric output increased by 144 TWh, but wind and solar increased by 30.8 TWh. Put together this made up roughly three quarters of the rise in China’s electricity generation.
So are renewables or, more accurately big hydro, taking over electricity generation?
First, growth in China’s electricity generation is slowing because its economy is having problems. In the decade before last year China’s electricity generation increased by an average of 350 TWh each year. If China’s economy returns to the growth levels the Communist Party believes is necessary to stop the risks of another Tiananmen, we aren’t likely to see such low growth continuing.
Second, hydroelectric output was artificially high due to the weather.
Hydroelectric dams operate on a simple principle. Flowing water is converted into electricity. More flowing water equals more power. So, roughly speaking, if it is wetter dams will produce more electricity.
And this is what happened in China last year. Official data shows that the capacity factors of China’s hydroelectric dams increased by 8.7% last year. In other words, had the climatic conditions been the same as in 2013, China’s hydroelectric output would only have grown by 48 TWh, and not 144 TWh.
The increase in China’s total renewable electricity generation was therefore double what it would have been had it not been for the wetter conditions.
So, not only does hydroelectricity dominate Chinese renewables, but we have to be incredibly careful interpreting year to year changes in production caused by rain conditions.
The same holds at the global level. If China’s hydroelectric output had stayed still last year, global hydroelectric output would have actually fallen by 67 TWh last year. Again, this was due to climatic conditions, not a decrease in hydroelectric capacity.
This fall in non-China hydroelectricity was greater than the increase in global generation from either wind or solar. Clearly lumping hydro, wind, and solar generation into one figure can lead to erroneous conclusions.
Note on data
Generation data taken from the latest BP Statistical Review of World Energy.