It may seem contradictory but the faster we build renewables the worse we make the carbon dioxide concentrations. How can this possibly be? The math is quite simple. Life Cycle Analysis studies have concluded that it takes 3.3 years of average solar PV production to offset the amount of CO2 that was required to build the PV. So if you are building solar PV at a rate faster than (1/(3.3 years + supply chain and construction time))*100, you will continuously make CO2 concentrations worse. The table below shows the CO2 concentration from PV manufacture (expressed in GW) for PV growth rates of 100%, 50% and 25% per year. I used the following assumptions:
- Started with 10 GW of solar.
- 3.3 years carbon payback period for solar PV
- 1 year added for supply chain and construction until the PV is producing carbon free electricity.
- Did not redistribute energy use from another part of the economy. (no reduction in living standards of the population)
The implications of this simple analysis are stark. We simply waited too long. Accelerating the transition to try and catch up, will make matters worse. Yes we have to eventually get there, but with all the talk about tipping points, there could be a real possibility that moving too fast could send us over the edge. There are 3 solutions to this dilemma.
- Take energy away from other things and use it to build solar PV (reduce the standard of living for everyone).
- Focus on carbon free generation with a much faster energy payback period.
a. Nuclear has a 6 week energy payback period compared to solar’s 3.3 years.
b. Carbon capture and sequestration. 7 month carbon payback period. - Only build solar where it makes sense. (like the Sahara).
The final word. Even if countries meet their stated commitments at COP28, it will not be sufficient to meet the 1.5 degree goal. Climate change and all its implications are here. Time to start dealing with it and adapt.