Bioenergy without land conflicts

Bioenergy without land conflicts

The cultivation of manioc on abandoned mining land

The production of bioethanol on disused mining land makes a meaningful contribution to climate protection in Vietnam.

The production of bioethanol has been criticized for years. On the one hand, the production of biofuels results in land conflicts, especially when it comes to agricultural food production. On the other hand, biofuels are described as inefficient as they continue to feed technologies such as the combustion engine or oil/gas heating. This is particularly evident in the current debate on e-fuels.

Both of these criticisms are justified. The combustion engine has an expiration date, whether powered by biofuels or e-fuels. The inefficiency of these technologies compared to electrified drives and heat pumps, for example, makes it clear where the future lies.

The argument of land conflicts cannot be refuted either. In view of the number of 768 million undernourished people in the world (German Federal Statistical Office), it is clear that we will have to use agricultural land even more consistently in future to feed people with plants and not to grow biomass or concentrate feed for livestock farming.

However, there are exceptions where the production of biomass can make sense. This is the case on land that is not or cannot be used for conventional agricultural purposes. One example is our FABIKLI project – facade greening at Berlin schools. Together with the TU Berlin, we are planting energy crops on school facades in Berlin. The biomass obtained can be used for pellet heating systems, providing a_CO2-neutral source of energy. Other benefits include an increase in inner-city biodiversity, better air quality, building insulation and much more. With over 2000 hectares of windowless building facades within the Berlin S-Bahn ring, there is great potential for scaling.

Another example of the sensible production of biomass and the processing of this biomass to generate energy is our project study from Vietnam. Vietnam’s energy demand is steadily increasing due to economic growth and industrialization. The share of renewable energies is set to rise from 3.7 percent in 2020 to 10 percent in 2030. In order to achieve this goal, the Vietnamese government has prescribed the addition of bioethanol and the recultivation of abandoned mining areas. UfU benefits from this because in our CPEP project we work with mining companies that use cassava to recultivate their abandoned mining land in order to generate additional profits through its sale. The use of the resulting bioethanol leads to_{CO2 savings of} up to 50% compared to conventional fuels.

Due to past activities, abandoned mining areas are often contaminated with heavy metals and other toxic substances and are therefore unsuitable for food production. The cultivation of cassava therefore does not compete with food production and is a suitable recultivation measure. On the UfU test areas in Vietnam, cassava yields are in the good mid-range at 25 tons per hectare. The national average yields are between 13 and 35 tons. However, only 2 tons of ethanol per hectare could be produced, 1.5 tons less than the average. This indicates a low sugar content, which is due to the poorer soil quality.

The use of bioethanol from manioc, which is grown on abandoned mining land, can reduce_{CO2 emissions} by up to 50 percent compared to conventional fuels. This saving is also significantly higher compared to conventionally produced bioethanol. For example, large areas of rainforest are often cleared for conventional biofuel production, resulting in immense_{CO2 emissions}. However, the negative effects of land use change are avoided when using abandoned mining areas.

The cultivation of cassava on disused mining land for the production of bioethanol can be a sustainable way for Vietnam to meet its increasing energy needs and reduce_{CO2 emissions} at the same time. For this reason, the follow-up project will further analyze the cultivation and economic utilization of cassava in order to successfully scale up the production of bioethanol.

You can find out more about the opportunities and challenges of bioethanol production in Vietnam in our new UfU paper on our website.