What can we learn about decarbonization from past experiences?

I have been developing this website for almost two years. It started out with my own curiosity of the state of decarbonization around the world. I wanted to know how much of our electricity comes from low-carbon sources, what it looks like in different countries and how it has and continues to develop over time. Apart from satisfying my own curiosity, this website aims to make decarbonization and electricity data more accessible to a broad public. I hope that this can contribute to a more rational and humble discussion of future energy policy.

There are a lot of claims being thrown around in the energy policy debate, often with a lot of certainty and lack of nuance. When I hear a call to build a certain amount of a certain energy source in a certain time span, or to go from a certain percentage of low-carbon electricity to a higher one within a certain number of years, or that all we need to reach a certain goal is political will – my first question is, has anybody else achieved this? Our planet is run by around 200 different governments, all with different energy policies, and this is in many ways a great asset. It means that rather than betting our energy and climate future on one single policy prescription, we can experiment with different strategies and learn from each others experiences.

This article is an attempt to answer some of the most important questions when it comes to decarbonization efforts, by pointing to our past and present achievements. I aim to clarify the distinction between what we know is possible, because it has already been achieved – and what we don’t know, because it hasn’t yet been done.

Of course, the fact that something hasn’t already been done doesn’t mean that it can’t be done. What it does mean is that we don’t know that it can be done. It may definitely be worth trying out. I am not advocating one approach over another. I am advocating humility. There’s definitely a role for advocacy of specific technologies or policies. But the rest of us should remain skeptical. Even if we believe there’s a 90% chance of success of our favorite approach, the risk of climate change demands that we also consider the 10% chance of failure.

Without further ado, let’s jump into the questions.

Can 100% of an electricity grid run on renewable energy?

Yes. Five countries already get 100% of their electricity from renewable energy sources.

Ethiopia, Iceland, Bhutan, Paraguay and Albania all get 100% of their electricity from renewable energy sources. All of them get most of their electricity from hydropower.

Can 100% of an electricity grid run on wind and solar energy?

We don’t know. The closest we have come is 49%.

In 2020, Denmark got 45.4% of its electricity from wind energy and another 3.4% from solar. While wind power has expanded at a fast rate in Denmark in the last two decades, in 2020 it did not continue to grow.

Going from 0 to 50% of wind and solar may be easier than going from 50 to 100%. The reason is that wind and solar energy are intermittent – when the sun doesn’t shine and the wind doesn’t blow, other energy sources are needed as backup. Denmark has solved this problem so far by relying on fossil fuels (18%) as well as imported electricity (19%). Getting rid of fossil fuels altogether may be done by increasing the amount of imported electricity – effectively making Denmark part of a larger grid which itself faces the same challenges of running purely on wind and solar. The other solution is an expansion of energy storage.

The problem is that Denmark at this moment has virtually no energy storage capacity. There are two other countries that do – Portugal has storage which could last around 9 hours given average electricity consumption, and Lithuania’s could last around 8 hours. This is probably not enough to support a grid running 100% on wind and solar. But it’s a significant base to build on.

Of the two, Portugal has the most wind and solar – generating a total of 26% of its electricity. The growth rate in Portugal is slower than it has been in Denmark. The share of electricity that came from low-carbon sources in 2020 was in fact lower than it was in 2014.

Can 100% of an electricity grid run on nuclear energy?

Probably. The record is 87%.

France got 67% of its electricity from nuclear energy in 2020. The highest share it ever got from nuclear was 79%, back in 2006. Lithuania holds the world record – in 1993 it got 87% of its electricity from nuclear power. There’s no reason I know of why you couldn’t go from 79% or 87% to 100%, or beyond (excess electricity could be used for exports, and to enable further electrification of the economy).

Do you have to choose either nuclear or renewables?

No. Three countries already get 90% or more of their electricity from a combination of nuclear energy and renewables.

Switzerland (99% low-carbon electricity) and Sweden (98%) both get around a third of their electricity from nuclear and most of the remainder from renewables. France also gets its electricity from such a combination, but nuclear makes up a much larger share (67%).

Can a major economy rely on low-carbon electricity?

Yes. The worlds seventh largest economy already does this.

France is the seventh largest economy in the world (ranked by nominal GDP). Its electricity is 91% based on low-carbon sources. Other significant economies worth mentioning are Canada and Brazil (both 83% low-carbon electricity).

Can a modern economy function without fossil fuels?

We don’t know. This has not been done.

Electricity only makes up one part of our total energy consumption. In fact, most energy that we use is in the form of fossil fuels used directly in industry, agriculture, transport, heating and so on. Moving to a low-carbon economy requires that we not only achieve 100% low-carbon electricity, but also that we electrify these other sectors.

Globally, only 17% of the energy we use comes in the form of electricity. But some countries are more electrified than others. The countries that get the highest share of their energy from electricity are Norway (49%), Paraguay (47%), Tajikistan (46%) and Bhutan (43%). It just so happens that these four countries also get 93-100% of their electricity from low-carbon sources. So all in all they get close to 50% of their total energy from low-carbon sources. Pretty impressive. But still far from reaching the goal of powering 100% of an economy without fossil fuels.

Can you decarbonize electricity generation by reducing demand?

Yes. One country has done this.

In 1987, 39% of electricity in North Korea came from low-carbon sources (all of it from hydropower). This was very close to the world average at the time (36%). In 2019, 87% of electricity in North Korea came from low-carbon sources – a whopping decarbonization success. How did it do it? Hydropower generation did not in fact expand at all during the time period. Instead, they reduced overall electricity generation – from 35 TWh in 1989 to 16 TWh in 2019.

Of the other 26 countries that currently get 80% or more of their electricity from low-carbon sources, none of them achieved their success by reducing demand. All of them got there by investing in low-carbon electricity generation.

It’s also important to note that only 9% of North Korea’s total energy supply is electrified. While North Korea does show that it’s possible to decarbonize your electricity grid by reducing demand, it does not show that you can decarbonize the energy supply as a whole without investing in low-carbon energy sources. To get to 100% low-carbon energy without expanding low-carbon sources, North Korea would have to both electrify everything and reduce overall energy consumption by around 90%.