How green is green electricity?
- May 12
- 5 min read
Written by Michael Harries
President of the North West Environment Centre (NWEC)
Tasmania is regarded as one of the very few countries, or in our case states, that generates 100% of its electricity through renewables.
Not quite true as we have a gas fired power station but let’s park that problem for now. To achieve 100% renewables all but one of Tasmania’s great rivers and several smaller rivers had to be dammed. Add to that many hundreds of kilometers of high transmission lines gouged and still being gouged through native forests and farmland to connect wind turbines to the grid and you’ll find that generating electricity in Tasmania competes with forestry on the environmental destruction scorecard.
But right now, as governments everywhere say they are transitioning away from fossil fuels, we have become rather smug and we are even giving the other states a helping hand. Plans are ahead to turn Tasmania into a giant battery. When the mainland has too much electricity, they will store it here in the form of hydro and we will send it back as electricity when demand there is very high.
Throughout the whole world the debate about electricity supply has become a fight between ‘dirty power’ generated by fossil fuels and ‘green power’ generated from renewables. Every world government other than the current USA regime has a program of transitioning away from fossil fuels and for some countries nuclear is a third player. Nuclear sits in the middle. Some argue the numbers add up, others argue otherwise. Decommissioning nuclear is colossal in comparison to any other generator technology. Greenhouse emissions of an electricity generator have become the measure of good and bad or if you prefer green and dirty power. If only it were that simple we in Tasmania would be in line for a trophy or two.
Every time we use electricity whether that is from the solar panel on our roof or a coal burning power station somewhere, there will be a carbon footprint. If all you are measuring is the quantity of carbon emitted in the time it takes to boil your kettle then clearly your solar panels, wind generator or hydro dam generator will win hands down. In fact in real time, none of those would emit one molecule of CO2 to produce the electricity needed to boil your kettle. Sadly this simple analysis so often used to push renewables.
The correct measure of greenhouse emissions is it to include mining and conversion, manufacturing and transport, building and installation, service and maintenance and sending electricity to the point of use. We also need to factor in decommissioning and recycling at end of life. It’s a cradle to grave calculation and we could be measuring many other environmental and social costs as well but in this exercise we are only calculating greenhouse emissions.
Seen this way, all electricity has a carbon footprint. It doesn’t mean all electricity is bad but it does mean we need to get away from dirty or green and think about emissions as being on a continuum. As we will see, what matters most is not the technology but the emissions in total. We know the carbon footprint of producing a cubic meter of concrete. We have similar emissions data on producing a ton of copper, a wind generator sail, a turbine, a cooling tower, a kilogram of pure Uranium yellowcake and so on and so on. We also know quite precisely what fuel is burnt to produce electricity and therefore can closely calculate the ongoing emissions of those generators.
Then there’s decommissioning. All infrastructure as a whole has a life expectancy which is quite accurately estimated. One of Australia’s first big wind farms in Victoria is soon to be decommissioned. Their business model says service costs of the generators will soon be so high it is better business to decommission and (maybe) install new ones.
Having now calculated, as well as one can, cradle to grave emissions, we need to calculate how much electricity will be produced by any one generator in its lifetime. The maths is straight forward. Add together the total of the emissions I have described above for each generator and divide this by how much electricity has been generated in the lifetime of that generator be it a solar panel or a nuclear power plant.
The figure you end up with is called the LCHGEE ‘Life Cycle Greenhouse Gas Emissions’. and is expressed in the CO2 equivalent emitted for each kilowatt hour of electricity generated.
The figures in the table at the end of this article are from the International Panel On Climate Change. They gather a huge amount of data so the calculations are reliable. The large differences between the minimum and maximum range reflect the many variables in engineering, regulation, recycling and local environment but the median comparison between technologies is consistent.
What does this all mean? The first thing is it tells us what we already know. Generators powered by fossil fuels emit more CO2 per kW hour than renewables. In fact Coal emits twenty times that of rooftop solar. It follows that every time we displace coal or gas with some form of renewable or nuclear there will be a significant decrease in greenhouse emissions but only from the power station being displaced. What if that station was still needed due to new demand or a new coal or gas or even nuclear power station is built elsewhere? And this is exactly what is happening across the world.
Renewables not only have their own greenhouse footprint but for all the billions of dollars poured into them, they cannot even get close to keeping up with the persistent growth in demand for electricity which itself is being spurned on by electrification of transport, machinery that until now has run on oil, and then there’s the massive increase in data centre and AI use. A study in the U.K found an additional six nuclear power stations would be needed just to charge E.Vs if the country replaced all combustion cars with EVs.
And yet from China to the U.K and everywhere in between, governments, corporations developing renewables and many environmental advocates are seriously telling us we are moving to net zero carbon emissions. Plug your bath, turn the taps on and try to stop it overflowing using only a teaspoon. You won’t win that way but turn the taps off and you’ll finally get there.
Take a look at the graph below. It seems pretty impressive doesn’t it. It is typical of the graphs produced by those companies behind renewables and governments wanting to sell their ‘green’ credentials. Then have a look at the second graph. You don’t have to look long to see that since 1980 total electricity generation has doubled and both renewables and fossil fuels have increased generation by about 12.5 Petawatt hrs each.
And remember; emissions come from generation by both fossil fuels and renewables. True meaning needs context. There is only one answer. Turn the taps off.
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