Research Your Intensity: Why Carbon Intensity of Your Electricity is Important

The carbon intensity of your electricity determines if an electric car is a good investment

To live a really good low carbon life you’ll need plenty of low carbon electricity.  But how carbon intensive your electricity is at the moment dictates the benefits of things like going solar or getting an electric car.

Two step shrink plan: decarbonize your electricity and then electrify everything

If you only have a high-quality, climate-friendly lifestyle, then you’ll need plenty of low-carbon electricity. Today I’m going to talk about the carbon intensity of your electricity and why understanding it is important when you come to make decisions about reducing your carbon footprint. If you were looking for a simple two-step strategy to tackle your carbon footprint, it would be to decarbonize your electricity supply and then to electrify everything you possibly can.

Coal is worst, followed by oil and gas

Although this would still leave you with some significant emissions from food and products, it’s going to get you a very, very long way. The carbon intensity of electricity generation varies dramatically by technology. Coal is the most carbon intensity form of electricity generation followed by oil and then natural gas. Each of these fossil fuels are considerably more carbon intensive than any of the low carbon alternatives such as solar, nuclear, wind, and hydro. When we consume grid electricity we need to account for the direct combustion emissions that occur at the plant, indirect emissions from fuel production, and also grid losses.

Countries have very different fuel mix

We can see that this intensity varies enormously between countries based on the variation in their fuel mix. Just like the attractiveness of solar as an investment varies around the world, so does it benefit in terms of cutting carbon if we compare the carbon intensity of solar electricity to the average grid intensity. We can see that there is enormous variation between countries in coal dominated countries like India, Australia and China, solar has enormous potential to cut emissions by displacing grid electricity.

Solar can still make an impact in the US but less so in France, Brazil

In countries with a broader generation mix like Germany, Japan, the U.S. and the UK, solar still has considerable potential to cut emissions. Whereas if you live in a place like France, Brazil or a hydro area like Canada, solar’s potential to cut emissions is much lower.

Consider where you live before buying an electric car

If we’re trying to reduce emissions from cars, electric cars are not always the best option. The emissions from electric cars are determined by the type of electricity the cars use. If the electricity comes from coal, the emissions from the electric car are similar to a gasoline car that gets 30 miles per gallon. If the electricity comes from natural gas, the electric car is slightly better than the best hybrid car. If the electricity comes from a low-carbon source, the electric car has half the emissions of the best gasoline hybrid.

Coal-powered electricity in an electric car offers little benefit

If we look at the emissions of an electric vehicle powered by grid electricity, we once again see enormous variation even after you account for the considerable manufacturing footprint of the electric car. Vehicle emissions can be five times greater in parts of the world with coal than they are in places where hydro dominates. When you convert these figures to admission equivalent fuel economies, it ranges from 20 miles per gallon in India up over 200 miles per gallon in a place like Paraguay or Iceland. Local electricity also has the potential to decarbonize how we heat our buildings and how we power our industry.

Consider displacing natural gas and use an electricity driven heat pump

When we look at the carbon intensity of a unit of heat provided by different heating systems, we can see that coal is the most carbon intensive, followed by oil and then natural gas. When we compare this to what we get from electric heaters using grid electricity, we can see that only very low carbon electricity has much promise if we want to displace something like natural gas. So, in terms of both carbon and in terms of if you’re going to go the low-carbon heating route using electricity, it’s probably a good idea to think about using heat pumps.

Grid carbon intensity varies greatly from city to city

So there are great technology options for people considering low carbon heating with electricity throughout this video. I’ve been using average grid intensities which, I think, is the best place to start and understand this issue. But there is some more complexity. Some countries have separate grid regions, so you need to think of those as having different intensities. In the US, for example, the carbon intensity in cold-dominated Colorado is over 3 times greater than hydro-heavy upstate New York.

Also, depending on costs and resources, carbon grid electricity can fluctuate over the year or even over a period of 24 hours, as we see in this picture from the UK. This is a pretty easy subject to overthink but at the end of the day, it’s really very simple. If we want to live high quality lives, improve energy access and not toast the planet, then we need massive quantities of low-carbon electricity. Catching tomorrow for day 19, or we’re looking at solar power.

Lindsay Wilson
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I founded Shrink That Footprint in November 2012, after a long period of research. For many years I have calculated, studied and worked with carbon footprints, and Shrink That Footprint is that interest come to life.

I have an Economics degree from UCL, have previously worked as an energy efficiency analyst at BNEF and continue to work as a strategy consultant at Maneas.  I have consulted to numerous clients in energy and finance, as well as the World Economic Forum.

When I’m not crunching carbon footprints you’ll often find me helping my two year old son tend to the tomatoes, salad and peppers growing in our upcycled greenhouse.

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