Public defence

2020-04-24, digitally via conference (Zoom), public link https://stockholmuniversity.zoom.us/j/268491560, Stockholm, 13:00 (English)

Opponent

Ny, Henrik, Ph.D.

Supervisor

Schlyter, Peter, Professor

Dissertation (pdf)

Klick here

Abstract

The developments towards a bio-based economy and a renewable energy-based power supply require thorough assessments of feedstocks and frameworks. In the past, political targets for increasing shares of renewable energies for combatting climate change have triggered direct land use changes (LUCs) and even indirect land use changes (iLUCs). As a consequence, residues from grassland and agriculture, which are not used for other purposes, got into the focus of renewable energy policies. Despite the technical feasibility, a general approach for assessing amounts of residues has been lacking, making planning processes for bioenergy highly customized. This study introduces a general, uniform modeling-approach based on Geographic Information Systems (GIS) and publicly available statistical and map data to locate potentials on a 1 km-grid throughout the European Union (EU). Sustainable potentials were calculated for five model regions in Northwest Europe considering input data such as animal livestock, regional (elevation-dependent) yield data, protection areas, and residue-to-crop ratios. Framing two scenarios, the model results were fed into a Decision Support Tool (DST) as a planning tool for bioenergy. Agricultural residues and surplus grass may provide significant potentials on regional levels, e.g. up to 52,236 TJ/ a from straw and 1,301 TJ/ a from root crop residues in Northrhine-Westphalia, or 9,141 TJ/ a from oil plant residues in Île de France, and 12,226 TJ of surplus grass in Rhineland-Palatinate.

At the same time, ground mounted PV-systems were installed on arable land formerly used for food or feed production. Hence, high quality soils were taken out of agricultural production. For addressing this type of conflict, Agrophotovoltaic (APV) systems combine agricultural biomass and solar power production on the same site and time for increasing area use efficiency. Even though APV might prove suitable in the technical sense, it might be rejected by society i.e. due to its landscape impact. The Responsible Research and Innovation (RRI)-concept was applied for APV by involving stakeholders already in the technology development process. In a series of workshops with citizens and experts, a comprehensive analysis of the driving and restraining forces for APV was done. A System Dynamics approach with Causal Loop Diagrams (CLD) visualizes and reveals the internal and external dynamics of the APV-technology. Stakeholders have pointed out the importance of defining a good framework for APV first, i.e. roof and industrial areas for PV system shall be exploited first. Any change in the set-up for the PV-system impacts the conditions for the agricultural cultivation conditions, i.e. the height and width of the mounting system influences the working conditions and distribution of water. The shading of the plants can increase the yields in dry and hot summers, while it may lead to yield reductions in other years. The acceptance level is driven by regional aspects such as tourism, local recreation and landscape impact. In this way, local knowledge from participatory studies is seen as prerequisite for a legitimate framework.