That site also shows our carbon budget. This is how much CO2 that can be emitted into the atmosphere and still give us a chance of remaining under 20 C warming. As of late March 2022 this budget is a little under 1,060 billion tonnes. Other estimates concur with this figure.
So, how much carbon do we emit each year? Although emissions dropped in 2020 by about 5% (because of covid) we are now back to emitting as much as we did pre-covid – roughly 36 billion tonnes per year.2
If you do the arithmetic and divide the carbon budget by how much we emit annually then we have only a few months past 29 years before we reach 20 C (and that assumes that we do not increase the amount we emit – a depressingly unlikely possibility.) However, let us err on the conservative side and say we have 30 years. That is, sometime in 2052!
What is to be done? Can ‘renewable’ energy save us?
Do The Maths
Let’s do a little bit more mathematics. (Apologies to those who do not like maths. Hopefully, the following calculations are not too difficult to follow.)
First, some background and provisos.
Often the ‘renewable’ options (e.g. solar, wind, hydro, geothermal etc) are termed renewable energy. This is a misnomer. Solar, wind, and hydro are used to generate electricity, which is one aspect of energy. Thus, the term should more correctly be renewable electricity. Other aspects of energy use include transportation, industrial use, manufacturing, and agriculture.
In 2020 ‘renewables’ made up 5.7% of the global total energy mix, with hydro contributing a further 6.9%.3 Of the global total energy consumption, approximately 20% of it is in the form of electricity. ‘Renewables’ contributed slightly less than 30% of electricity production in 2020.4
This suggests that, all else being equal, if ‘renewables’ were able to contribute 100% to global electricity production, then ‘renewables’ could expand by 333% (100/30 x 100.)
Thus, with the above background and the numbers, let us do a mathematical thought experiment. What if we switched entirely to ‘renewable’ electricity today (yes, today, not in five years time, not even in one years time, but now!)
If we did that, we could increase the contribution of ‘renewables’ to the energy mix from 5.7% to around 19% (5.7 x 3.33. From 30% of electricity production to 100%.) This is an increase of 13.3% on the present contribution.
But, before we do the calculation, there is one further consideration to take into account. ‘Renewable’ does not mean carbon-free. All ‘renewables’ have a carbon emission component when their full life-cycle is considered. This is less than that for fossil fuels, but not insignificant.
Each type of ‘renewable’ has different carbon emissions, as does each different fossil fuel. ‘Renewables’ emit between 3 – 10% carbon equivalent of that emitted by fossil fuels. For the sake of simplicity, let us assume a figure of 5%.
Theoretically, this represents a decrease in the amount of CO2 equivalent from 36 billion tonnes per year to 32.8 billion tonnes (36 x (100 – 0.133) x 1.05)
Now, let’s see what that does to our carbon budget. The arithmetic is straight forward. It is 1,060 ÷ 32.8 = 32.3 years.
What About EVs
Some readers may object that I have not taken into account the contribution of EVs (electric vehicles) in the coming years.
A similar thought/mathematical experiment can be done regarding EVs.
Beginning again with some background and provisos. Transportation contributes approximately 20% of global carbon emissions. Private cars, light trucks, and motorcycles make about 29% of all transport (other sectors include heavy trucks, shipping, and aviation.)
At present, only cars, light trucks, and motorcycles can effectively use an electricity source for motive power.
Presently the carbon emission efficiency of EVs versus conventional (fossil fuel) vehicles is only about 25%.5 In other words, over their life-time an EV can be expected to contribute around three-quarters as much carbon equivalent to the atmosphere as does a conventional vehicle. This is mainly because of the extra carbon emissions involved in manufacturing.
Now, suppose that all (yes, every single one) private cars, light trucks, and motorcycles were converted to EVs today. This would represent a contribution of 1.5% reduction in carbon emissions (0.29 x 0.25 x 0.2.)
How much does this represent? Just 0.54 billion tonnes.
Let’s now plug this into our calculations above. Instead of 1,060 ÷ 32.8 we now have the equation 1,060 ÷ (32.8 – 0.54) = 32.8 years.
Just three years! That’s all – three years we gain by switching to 100% ‘renewables.’
And that’s if: 1. We do it now (not possible) and 2. We do not increase the amount of carbon we pour into the atmosphere from other sources (unlikely).
OK, the mathematics may be imprecise, yet the results from the calculations are within the bounds of possibility. If anything, we are likely to gain less than three years, because of the two ‘ifs’ above.
One Final Rider
It will be noted that I have used the term ‘renewables’ rather than simply renewables. This is deliberate. I use the term ‘renewables’ to indicate that they are not renewable. To build, manufacture, transport, and decommission solar, wind, vehicles, batteries and the other components of these technologies uses finite resources. Plus, I have not even mentioned the environmental and social costs and damages that ‘renewables’ bring.
The question then is: If we had it, what would/could/should we do with the extra three years?
We could spend the three years devising different questions. We could spend the three years thinking (as Einstein suggested) differently. We could use a different thinking than the (mechanistic, technologically-driven) thinking we have used to get us to this predicament.
How about instead of waiting for that three years, we transform our thinking radically, and start asking questions related to how can we decrease our dependence upon electricity, how can we reduce our use of vehicles?
How can we de-grow?
1. Mercator Research Institute on Global Commons and Climate Change. https://www.mcc-berlin.net/en/research/co2-budget.html accessed 28 March 2022.
2. https://www.statista.com/statistics/276629/global-co2-emissions/ accessed 28 March 2022
3. Statistical Review of World Energy 2021 p12
4. www.ourworldindata.org Accessed 29 March 2022.5. In a study undertaken by Massachusetts Institute of Technology (MIT) Energy Initiative in November 2019 it is expected that this efficiency could rise to about 75%. However, the authors of that study do not expect this technology to be complete until about 2050.
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