BERLIN: Replacing diesel fuel with vegetable oils, such as rapeseed oil, or fermented products (beet, sugar, wheat) is an innovative method that has been popular for several years now.
It is increasingly being tested around the world as a way of reducing CO2 emissions. But German researchers are now calling into question the supposedly miraculous aspect of these fossil fuel alternatives.
Conducted by the Potsdam Institute for Climate Impact Research and published in the journal Nature of Climate Change, a new study points to a major problem: if fossil fuels are completely replaced by biofuels, the effect could prove counterproductive and even increase CO2 emissions.
The large-scale production of biofuels could, in fact, require the use of land for greater agricultural production.
"If cultivation for bioenergy grasses is not strictly limited to marginal or abandoned land, food production could shift, and agricultural land use expand into natural land. This would cause substantial carbon dioxide emissions due to forest clearing in regions with weak or no land regulation," the study's lead author, Leon Merfort, explains.
To reach these conclusions, the scientists based their research on several hypothetical scenarios relating to land use and the quantity of biofuels required to meet global energy demand.
"We find that without additional land-use regulation, land clearing related to the production of modern biofuels results in CO2 emission factors -- averaged over a 30-year period -- that are higher than those from burning fossil diesel," study co-author Florian Humpenöder says in a statement. Moreover, the researchers state that "only reducing the demand for bioenergy will not solve this problem."
In this context, the solution to limiting the potentially harmful and counterproductive impact of biofuels could therefore be to establish international agreements aimed at optimal protection of forests and other natural lands by introducing carbon pricing.
"The state of current global land regulation is inadequate to control land-use-change emissions from modern biofuels," Leon Merfort explains.
In his view, pricing all land-use-change emissions (with only 20% of the CO2 price in the energy system) would be more effective than a protection system covering 90% of all forests worldwide.
"Our results show that bioenergy can be produced with limited emissions under effective land-use regulations.
Yet, if the regulatory gap remains wide open, bioenergy will not be part of the solution to mitigate climate change, but part of the problem," concludes co-author Nico Bauer.
