Dear Reader,
This was one of the blog posts I wrote in my older blog makeachange17.wordpress.com (please feel free to browse it). Since Life Cycle Assessment played a big role so far in my life and has been a great interest, I am reposting this over here as my first post.
Hope you enjoy!
Recently, I have come across many of these YouTube videos which claim to “debunk” renewable energy. They say that renewable energy doesn’t really help in reducing emissions and help to reduce climate change impacts. When they explain why the manufacturing process of for example, solar panels, produce a lot of waste and use coal, it is easy to see why one can get easily carried away with these facts. A popular and recent example of such misinformation is present in the film “Planet of Humans”. These facts are true and the same goes for the production of wind turbines. While I agree that healthy scepticism is great to have, it is important to look at facts in context and look at the bigger picture. These videos overlook the big picture which can give a completely different message. So, how can we deconstruct these types of claims and come closer to the truth? Let me introduce you to life cycle assessment or LCA.
LCA is a method of calculating the environmental impact of an object or system by taking multiple stages of the life-cycle, usually from the raw material acquisition to the disposal phase. If all stages from raw material acquisition to the disposal phase are considered, it is called cradle-to-grave and if the stages stop at the factory stage, it is called cradle-to-gate. Take a cup as an example. It is made from plastic which originates from crude oil - this can be analogous to birth or the start of the cups’s life. Crude oil is distilled and the necessary fractions are used to make plastic pellets which are then moulded into cups - this is the factory phase. Then the cup ends up in your kitchen and you use it to drink beer at a party - this is the use phase. At the end of the night, you throw the plastic cup into the bin. If you’re lucky, this is taken to the recycling centre where it is melted and used to make other plastic materials, if not, it is burned- this is the end of life phase or EoL.
Crushed plastic pellets in a recycling centre in Kandy, Sri Lanka
Using LCA as a tool provides a wholesome picture of the environmental impact of an object or a system. It is important to look whether a study looks at cradle-to-gate emissions or the entire lifecycle emissions as it determines the results. Of course, it is the cradle-to-grave approach which paints the complete picture. Likewise, renewable energy like wind and solar power will produce electricity during its use phase. This electricity is produced without direct emissions of greenhouse gases or other pollutants and they replace a certain amount of fossil fuel electricity. Thus, renewable energy substitutes the need for this fossil fuel energy which would otherwise emit lots of harmful gases into the atmosphere.
As you can see, a system or object has many stages in its life, just like we humans have childhood, adolescence, adulthood and old age. At each stage, there are different emissions and thus, varying impacts on the environment. Therefore, a cherry picked argument like “oh making a solar panel produces a lot of CO2 so it’s bad” can’t be used. When we narrow down our focus too much, we lose sight of what reality is. While it is true that the production of solar panels and wind turbines use a lot of energy and produce many emissions, some of which are toxic, when you compare the overall life cycles of a solar panel/wind turbine with that of a coal fired power plant, the differences are much more clear (1). Take a look at the figure below (Li et al., 2019). There’s a lot of tall bars at the production stage for the wind turbine, just like many people claim. But there are tall bars for the coal power plant at the operations or use phase. And this use phase is usually 25-30 years long where CO2 and other gases are spewed into the atmosphere. Now, if you look closely, the graphs for the emissions of a coal power plant are given in kilotonnes while the emissions for the wind turbine are in tonnes, a whole 1000 times smaller.
But, this is how the picture really looks like.
In reality, the wind turbine may have the majority of its impacts in the production and construction phase however, in the complete picture, the coal power plants emissions, especially CO2, far outweigh that of a wind turbine.
The latest LCA standard provides a detailed view of the emissions across 18 different indicators (2) which can be clustered into impacts on human health, impacts on natural environments and impacts of depleting natural resources like metals, oil and minerals. The figure below shows you how the indicators line up. The left most column shows the 18 indicators, the middle column shows you the paths through which the indicators affect either human health, ecosystem health or resource availability. For example, if water use is affected by mining, it could lead to less water being available to grow crops which means less food and a negative impact on human health. The final column shows what is known as end-point indicators. Like the name suggests, this is where impacts are eventually being felt.
As an Energy Science student, LCA as a methodology fascinates me. Some of the results can be quite surprising and confrontational, such as a tote bag not always being the more environmentally friendly choice. LCA is a great tool to understand the impacts of a product's life cycle, but it's not with its own shortcomings as we'll learn in a future blog. Stay tuned until then!
LCA comparison of wind turbine and coal power plant https://sci-hub.se/10.1016/j.jclepro.2019.119192
2. The ReCiPe method with the 18 indicators https://www.rivm.nl/en/life-cycle-assessment-lca/recipe
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