To my constant surprise and dislike, people continue to think of biofuels as a clean, renewable alternative for the future. People (and especially policy makers) need to rethink the idea of promoting biofuels to protect the climate, because it simply doesn’t work.
Unless you’re working in the energy department (or perhaps marketing), the odds are you’re not familiar with this concept, but it’s an easy one to grasp. EROEI stands for energy returned on energy invested – it’s a measure of how much energy you’re getting from something compared to how much energy you invest in it. If the EROEI is 1, then you get exactly as much energy as you put in, which makes it usefull. If it is 2, you get twice as much energy, and so on.
The EROEI for shale oil for exaple is 5, for natural gas it is 10, for wind 18, and for hydro 100. But what’s the EROEI for biodiesel? 1.3. That means that thinking only in terms of energy, you get 1.3 times more than what you put in; if you take into consideration the work put into it, the land which could be used for something else and the necessary infrastructure, you get to about 1 – which means that biodiesel is mostly useless; it doesn’t provide any additional energy into the equation (for a more detailed list on EROEI, check this wikipedia article).
Also, one of the main points behind people supporting biodiesel is carbon neutrality – the idea that the CO2 emitted while the biodiesel is used is balanced by the plants, as they grow (before becoming biodiesel). But in a new paper published online in the journal Climatic Change, John DeCicco takes on that widespread and fundamentally wrong idea.
Why is it fundamentally wrong? Because the argument is invalid: the plants used for biodiesel (usually corn, soybeans and sugarcane) are already pulling the CO2 out of the atmosphere – using them for fuel doesn’t provide any additional benefits!
“Plants used to make biofuels do not remove any additional carbon dioxide just because they are used to make fuel as opposed to, say, corn flakes,” DeCicco said.
DeCicco’s paper is unique because it strays from the traditional life-cycle-analysis approach that forms a basis for current environmental policies promoting biofuels, and instead, goes for a more scientific carbon cycle analysis based on biogeochemical fundamentals. His point was to show the conditions under which biofuels provide a climatic advantage. Gas emissions from biofuels are just 2% lower than those from gasoline, and about 1% higher than those from petroleum diesel.
“If there is any climate benefit to biofuels, it occurs only if harvesting the source crops causes a greater net removal of carbon dioxide from the air than would otherwise have occurred,” DeCicco said.
This is only the latest in a series of scientific papers which show that when you take into consideration all the global impacts, ethanol and biodiesel, which are currently regarded as the replacement for petroleum fuels, don’t reduce greenhouse gas emissions at all.
Enjoyed this article? Join 40,000+ subscribers to the ZME Science newsletter. Subscribe now!