How important is the global growth of solar energy?

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RenewEconomy is a renowned Australian website that focuses on green energy. They published last week an article by Andrew Blakers based on the claim that “new solar capacity is being installed faster than anything else in history.”

This received some criticism online (“misinformation!”), on the grounds that:

(i) this is electricity only, not total energy; And

(ii) nature doesn't care how quickly something is installed, only about emissions.

We were instructed to look at this graph from Our World in Data:

It is true that solar energy still accounts for a small share (2%) of the energy supply, and emissions from no fossil fuel have peaked, not even coal.

But the topic at hand is changeand for that we have to look a little closer.

The transition to low emissions is based on two important things:

(i) decarbonisation of electricity; And

(ii) convert all other energy use into electricity (“electrify everything”).

You could add more items, such as using less energy in the first place, but that wouldn't prevent the need for (i) and (ii).

Andrew Blakers is Emeritus Professor of Renewable Energy at the Australian National University and is known for his work on the 100% renewable energy future and his contribution to the development of solar energy technology. I would be surprised if he had messed something up.

At first glance, the claim is easy to miss: 360 GW (gigawatts) of solar PV were installed in 2023 (the IEA says even more, 510 GW), and the fastest period of coal installation I can find is 75 GW per year , in the mid-2000s.

But it is more educational to look at electricity generation, rather than just installed capacity. Solar energy has a particularly low capacity factor: it generates less when it is cloudy, and not at all at night. There is also a risk of it going unused if too much is generated at once.

To see this I performed the following steps:

1. I downloaded global electricity generation data from ember.org.
2. Because generation fluctuates widely from year to year, I smoothed the data to reveal the underlying trend.
3. I have calculated the generational change from year to year.

Steps 1 and 2 provide the following results for the 6 main electricity sources:

Solar energy is the smallest of the six, and fossil resources are still growing.

Step 3 produces the following results for the growth rate of each electricity source:

Coal's growth rate peaked at 300 TWh (terawatt hours) per year in 2005 (the rise of China). It then declined until 2019 before accelerating again. Part of this is compensated by a slowdown in gas production. Still, the combined slowdown in coal and gas growth stopped in 2020, which is alarming.

Solar added almost 300 TWh in 2023, more than any other source, almost matching coal's old record. Actually, Ember's data for 2023 is preliminary; If the IEA estimate is correct, the increase could amount to 400 TWh.

My conclusion is that the original headline (“solar is being installed faster than any history of technology”) may be a bit breathless and lacking context, but the underlying trend is clear and the results are significant. 2023 was truly off the charts, and there is more to come. Solar energy generation is increasing as quickly as any form of electricity ever has. This has happened despite the fact that many regions impose no restrictions on fossil fuels at all, and the global average carbon price is only $5 per tonne.

Just imagine what we could do if we Real tried.

By means of Robert McLachlan, Massey University, New Zealand