Different sources of energy: which one is less “bad”?

— Anh NGUYEN

I admit, it does feel a bit better when I switched from a conventional electricity contract to some “renewable” one. This is how you would probably feel if you sign a contract with Octopus Renewables or any other Renewable electricity provider. 

A brighter way, Octopus Renewables advertisement
A brighter future equals a green field and sunset, and a kid. Source
An advertisement from GRDF - a major French natural gaz provider - in a campaign to promote the usage of “green, local and renewable gas” from the peelings and leftovers of fruits & vegetables, and also, from the breaths of cows. “Choosing gas is also choosing future”. Source
An advertisement from GRDF – a major French natural gas provider – in a campaign to promote the usage of “green, local and renewable gas” from the peelings and leftovers of fruits & vegetables, and also, from the breaths of cows. “Choosing gas is also choosing future”. Source

The thing is, to an uninformed eye, we do feel hopeful when we see this – “at least they are trying to do something, we’ll make clean energy one day”. But hopes won’t work. Only informed actions will actually lead us to a less dirty future.

So let’s take a look at different energy sources, and examine the advantages and disadvantages of each of them. And let us all be reminded one more time – that any choice we make on our energy source will have an impact on the environment. There is no such thing as “green” or “clean” energy. There are just less-bad options. 

Something that does not have an impact does not exist.

Ecolo mon cul (Roughly translated to “Sustainable my ass”)

Coal – we used to be mad love

It was one of the major inventions of our times: burning coal to fuel our machines, back in the late 19th century. It changed the way humanity functions, produces and consumes. 

The famous history asides, in our modern days, coal is receiving bad reputation and there is a good reason why: the burning of coal accounts for 46% of CO2 emissions worldwide and 72% of total greenhouse gas (GHG) emissions from the electricity sector.

*An important side note on the difference between CO2 emissions & GHG emissions (so that stuff doesn’t all sound the same): GHG is “any gas in the atmosphere which absorbs and re-emits heat, and thereby keeps the planet’s atmosphere warmer than it otherwise would be”. The main GHGs in the Earth’s atmosphere are water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone. And CO2, well, it’s just one type of gas.

Global greenhouse gas emissions by gas - our world in data
Global GHG emissions by gas – CO2 takes up a large part of the total GHG emissions. Source

Most coal-fired power plants are found in Asia: China accounts for 51.7% of world coal consumption, followed by India (11.8%) and the United States (7, 2%). Yet, the biggest consumers per capita are Australia (80% of their electricity comes from coal), South Africa (70%) and Poland (74%). 

According to Geoscience Australia – a public sector geoscience organisation,  “Australia’s abundant and low-cost coal resources are used to generate 3/4 of domestic electricity and underpin some of the cheapest electricity in the world.”. That’s neat, we should favor local products, shouldn’t we?

It’s hard to skip on coal as our main energy fuel, as they are available in big quantities, distributed almost everywhere on the planet and can easily be transported. 

And we don’t just use it for electricity, even if it accounts for most burnt coal. Coal is the energy that fuels also the steel industry, cement manufacturing, food processing, paper manufacturing and alumina refineries etc.

More than one-third of global electricity comes from low-carbon sources, but a lot less of total energy does. Global energy vs. electricity breakdown
Important notions: “Energy” vs “Electricity”: fossil fuels (oil, coal, gas) are still the main sources of energy for our industries and machines. Source

Oil – who runs the world

Same as coal, oil is a major source of energy, which fuels land and air transport petrochemical industry (plastics, soaps and detergents, solvents, drugs, fertilizers, pesticides, explosives, synthetic fibers and rubbers, paints, epoxy resins, and flooring and insulating materials), electricity and heating.

Oil is widely used because of its high energy density and efficiency, and the fact that it can be easily transported. If only it did not emit that much GHG, during both the production process and usage…

Global carbon emissions from burning coal, oil, natural gas, and cement production since the start of the industrial revolution. 
Global CO2-emissions from burning coal, oil, natural gas, and cement. Oil is only second to coal. Source
GHG emissions at each stage of oil’s life
GHG emissions at each stage of oil’s life. It’s very GHG emissions intense. Source

Apart from its heavy-carbon nature, the other disadvantages of the good old oil that we have grown addicted to can include declining reserves, source of conflict and increasingly high operating cost

It is known that the US, China, Japan are in the lead when it comes to the total consumption of oil, respectively. But if we count consumption by 1000 habitants in 2012, the list of the biggest consumers are Singapore (202 barrels/day), Kuwait (139 barrels/day) and Luxembourg (119 barrels/day) – in comparison to France (28 barrels/day) or the US (61 barrels/day). This can be explained by the fact that these countries have very high living standards with lots of travelling.

Natural gas – it must be better, there is the word “natural” in it?

Natural gas is also one of human’s main sources of energy, used 39% for electricity, 29% for industry and 27% for electricity and heating. For the advantages, natural gas is available in large quantities and is exploitable without complex transformation. Its downsides, however, are quite a few: heavy-carbon source (both during production to usage process), can be dangerous by its explosive nature, difficult to transport (e.g using gas pipeline or liquefied form)

A truck of Super U in France run by natural gas
I look greener, do I? The ad says “less CO2, fewer decibels – with natural gas, this truck is good to all.” Source

The biggest consumers by quantity are the US, Russia and China, but in terms of consumption per capita, Trinidad & Tobago, Qatar, Bahrain are ahead of the world, with respectively 17500, 16300 and 10000 m3/year – in comparison with Belgium (1500 m3/year) or Japan (1013 m3/year).

Trinidad and Tobago houses one of the largest natural gas processing facilities in the Western Hemisphere, as 100% of their electricity coming from natural gas. Qatar, meanwhile, contains 14% of all known natural-gas reserves, only third behind Russia and Iran. And for Bahrain, the country is a minor producer of natural gas but consumes all of its gas output. It’s home-grown fuel, of course, we’ll use it! 

Nuclear power – a dilemma

We fear it but we are secretly in love – it is such a dilemma. Nuclear power plants produce no GHG emissions during operation, but radioactive waste, some of which can remain radioactive for several days or hundred of thousands of years.

The top 3 countries that produce the most nuclear electricity are the U.S., followed by France and China, with respectively 95, 56 and 49 reactors. And the top 3 countries with the biggest share of nuclear power electricity are France (70,6%), Slovakia (53,9%) and Ukraine (53,9%). 

If you want to delve more into nuclear power, its pros and cons – I invite you to read this article written by Jean-Marc Jancovici, French engineering energy and climate expert, which debunks some stereotypes around nuclear power, from radioactive waste and the risk of accidents, as well as the costly installation of a nuclear power plant. 

The problem with nuclear power can lie in the rebound effect. If electricity is relatively cheap and produced with low-carbon sources in comparison to other fossil-based ones, we tend to use more of it instead of reducing our consumption. 

Hydropower – old but still gold?

Hydropower might look so innocent. After all, humans had been yielding the power of water to run their machines since ancient times.

Watermill of Braine-le-Château, Belgium, dated back to the 12th century
Watermill of Braine-le-Château, Belgium, dated back to the 12th century. Source

Hydropower is indeed a renewable source of energy, dependent on precipitation and rainfall which is non-exhausted. Hydropower plant does not emit GHG during operation. 

Hydropower is also the only modular electricity source – thanks to the possibility of storage by reservoirs, electricity can be quickly mobilized to respond to high consumption calls. They can produce at full capacity in 3 minutes, while it will take 11 hours for a thermal power plant and 40 hours for a nuclear reactor to reach the same level of production. 

But they sure come with a price – as seen in the movie Frozen 2 or in other important reports, dams can alter or disrupt the course of rivers, which eventually will lead to habitat degradation, blockage of migration of fish, mortality of fish, lower rates of dissolved oxygen downstream.

The top 3 countries with the biggest share of hydropower electricity are Norway (99% coming from hydropower), Ecuador (65%) and Venezuela (64%). Spoiler alert: they have big rivers and steep valleys.

Wind power – an eyesore, but does it really work?

Being another renewable source of electricity, wind power parks do not emit GHG during operation. Yet there are quite a few downsides:

  • A wind turbine only operates at full power on average a quarter of the time. Due to low-energy density, it must take at least 10 ha to install an interesting park.
  • An intermittent source of energy where the production is very dependent on weather, with no possible storage solution
  • A short lifespan (20 years on average): this means that we have to remake new wind turbines, which will require rare metals and other resources often
  • Visual & sound pollution
  • Dangerous to birds and bird migrations: 573,000 birds and 888,000 bats were killed each year at U.S. wind farms in 2012
Bird Mortality caused by Wind Turbines
An escape game for birds & bats. Source

China is leading in terms of total production quantity (28,4%), followed by the US (21,2%) and Germany (8,8%).

The top 3 countries with the biggest share of wind power electricity are Denmark (50% of their electricity comes from wind power), Lithuania (38%) and Ireland (32%). The Top-10 does consist of only European Union member states, probably thanks to the 2009 Renewable Energy Directive

Solar power – here comes the sun, do do do

The most hyped renewable source – solar panels, which do not emit GHG during operations. The three countries with the biggest share of solar power electricity are Italy (biggest, but only accounts for 8,5%), Greece (7,5%) and Germany (7%). Spoiler alert: Italy and Greece receive a lot more solar irradiation per square meter than the rest of Europe.

To me, the most interesting aspect of this electricity source lies in its decentralized model, in which everyone can produce their own electricity based on their demand and their availability of space to install solar panels. 

An off-grid house with installed solar panels
An off-grid house with installed solar panels. Here’s an interesting article on The Conversation on how to start living off-grid. Source

On an industrial level, solar power is not really an interesting alternative because large-scale production will require huge areas in a very sunny climate. It has a relatively short average life (25 years) & the panels are still a nuisance to recycle.

And even though it does not emit GHG during operation, the production phase is very polluting in comparison to other energy sources: it requires corrosive chemicals such as sodium hydroxide and hydrofluoric acid and emits toxic wastewater. There is not yet a possibility for storage either, and it’s impossible to “control” the production based on demand.

Energy density VS Carbon intensity

We cannot compare different energy sources without comparing their energy density and carbon intensity.

Regarding energy density, if we take our unit volume as lighting a bulb of 100-watt for a year, 24 hours a day, here are the densities of the above-discussed energies:

How much energy does it take to light a bulb of 100-watt for a year, 24 hours a day using different energy sources such as coal, oil, gas, nuclear, wind, hydro, solar panels
Made this illustration based on this infographic and this article.

Gotta love nuclear, don’t we? Make me think of vibranium from Black Panther.  

log scales not enough paper for uranium
Illustration found on Reddit. Source

Carbon intensity, meanwhile, is defined as “the emission rate of a given pollutant relative to the intensity of a specific activity”, a.k.a one of the major criteria in deciding roughly if one source is “green” and the other is “dirty”.

 

Average emissions over the full lifecycle of different electricity generation technologies including nuclear solar and wind
Average life-cycle CO2-equivalent emissions for different electricity generators. Tidal power is not mentioned here, as the technology is being developed. Source

Nuclear & wind are almost at the same level of carbon intensity, while in the case of solar power, it depends on different types of installations. It’s very interesting to see that solar power has about the same level of CO2 intensity as geothermal – which is also another renewable source of energy yet a lot less popular. Biomass is also renewable (trees are renewable), yet its carbon intensity is five times more than solar power and 20 times more than wind power.

I didn’t mention biomass, methanation of CO2, pyro-gasification, or solar thermal, but will address these less-known energy sources in another article dedicated to them. 


If you want to read further on this topic:

Less waste, less energy: better ways to heat places in a temperate climate

Build our houses the way we build LEGOS?

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