Willow trees grow quickly. Within a few years they can produce biomass which can be converted into energy. This is a profitable business and it may contribute to an environmentally and carbon friendly energy production, especially if you simultaneously reuse and recirculate essential resources and fertilise with eg. sewage sludge from wastewater treatment or with gasified material from biogas plants.
This is common knowledge and several countries, such as Sweden, have come far with this type of energy production. However, there are actually some unknown factors connected with willow cultivation that scientists in the Biosystems Division at Risø DTU wish to study more closely.
"When you grow fast-growing willow trees, there will be emission of greenhouse gases, but simultaneously the strong root system of the willow trees will bind carbon in the soil. So the project is initially seeking to measure this balance, "says Professor Per Ambus.
Analysis of resource consumption
The project also includes an assessment of the overall resource consumption in connection with willow cultivation. The assessment looks at the consumption of material (eg. machines and fertiliser) and of fossil fuel, but also at inputs from nature (eg. rain and soil) as well as from society in terms of work and services. To be able to compare all types of used resources, all inputs are converted into the solar energy that has been used to create the resource. This analysis is called eMergy assessment.
The Biosystems Division hopes to attract partners and external funding to expand the research on willows and other fast-growing plant species that are suitable for biomass production.