Are biofuels environmentally friendly

Biofuels are said to harm the environment

Benjamin Hammer: If you ask politicians what recipes they have in the fight against climate change, the word "biofuels" is often used. Fuel made from renewable raw materials such as soy, rapeseed or sugar, that sounds good at first, especially climate-neutral. But it's not that simple, say some researchers, and for years there has been a debate in science about how useful biofuels are. Today the debate should get a new lease of life. "Biofuel harms the climate", reports the "FAZ" today, referring to an internal investigation by the European Commission. - I am now on the phone with Nils Rettenmaier, he is doing research at the Institute for Energy and Environmental Research in Heidelberg. Have a nice day, Mr. Rettenmaier.

Nils Rettenmaier: Yes, good afternoon.

Hammer: Mr. Rettenmaier, the study has not yet been published, so let's talk about the subject in general. How can it even be that biofuels harm the climate?

Rettenmaier: The climate impact of biofuels can be determined with so-called greenhouse gas balances, in which all greenhouse gas emissions are recorded along the entire life cycle. First of all, there is the CO2 uptake by the plant, then the processing, the cultivation of the plants, which also use fertilizers and diesel fuel, and finally, of course, the combustion in the car, where the same CO2 molecule that was previously absorbed by the plant and was released back into the atmosphere. Of course, one must not forget that a whole range of inputs, energy and auxiliary materials, were used in between, which in turn are also associated with CO2 emissions. Nonetheless, if you look at the balance sheet at the end, biofuels first save greenhouse gases compared to fossil fuels. However, the balance can still be negative if so-called land use changes are involved, i.e. if rainforests are cleared for the cultivation of biofuels, for the cultivation of energy crops, for example, because this causes very large CO2 emissions that are later no longer due to the biofuel can be saved.

Hammer: The EU Commission probably speaks of these effects in the report, writing that some biofuels are even more harmful to the climate than fuels made from petroleum. There palm oil, soy and rapeseed are mentioned. The Federal Association of the German Bioethanol Industry, which criticizes the EU's investigations very sharply, says the EU is making false statements. Where is there perhaps a solution to this dispute, whether it is good or bad for the environment?

Rettenmaier: It amazes me that the bioethanol industry in particular is so strongly criticized because the biofuels that are used in the direction of gasoline, i.e. bioethanol, have so far been in a significantly better position than biodiesel fuels on all balance sheets. The dispute that has been going on since 2008 since Timothy Searchinger published his article. The point is to quantify those land use changes that I just mentioned. A distinction is made between direct and indirect land use changes. Direct land use changes come about when, for example, a new plantation for palm oil is built on the former rainforest floor and this rainforest is released into the atmosphere as CO2 emissions. The bigger problem, however, are the so-called indirect land use changes, when, for example, sugar cane is grown on a former cattle pasture in Brazil, i.e. there is no direct conversion of the rainforest, but the cattle farmer has to avoid it, he is displaced, and that is how it can be that at the end of the chain rainforest will be felled again, and it is precisely these indirect land use changes that are currently the subject of discussion and the EU Commission has long wanted to position itself on how it wants to deal with the problem. It is scientifically highly controversial, all scientists say yes, there is this effect, but the extent of the effect, the studies diverge very widely. This is because the greenhouse gas emissions have to be linked to econometric models, and there has not yet been a consensus in the scientific community. I dare to doubt whether this exists. I suspect that if the Commission succeeds in finding a solution, it will then be a question of, for example, politically established values, which are then always open to attack.

Hammer: Nils Rettenmaier from the Institute for Energy and Environmental Research in Heidelberg - thank you very much. So the discussion will continue and we will continue to accompany it.

Statements by our interlocutors reflect their own views. Deutschlandradio does not adopt the statements of its interlocutors in interviews and discussions as its own.