Estimating the potential of roadside vegetation for bioenergy production

摘要

The Netherlands, like other European Union countries, is under intense pressure to increase its national share of energy from renewable sources in accordance with 2020 Kyoto Protocol obligations. Bioenergy in this context is especially interesting because it can replace liquid fuels so much in demand for transportation. In Europe, due to high population density, and intensive use of limited land resources, sources of biomass are quite limited. This study examines the potential of road verge for biomass production. In this case there is no conflict with agricultural production - "food for fuel" conflict - and very little problems with natural conservation, since we are focusing on already disturbed and heavily used and polluted areas. The road verge is also easily accessible and in most cases already has to be maintained and cultivated. We use GIS (Geographical information system) to identify the total area of land along the roads in the Netherlands that can potentially be used for bioenergy purposes. We then consider the opportunities and constraints of cultivating various types of biomass, mainly focusing on grasses and willow, short rotation coppice, as biomass sources on the road verge. Based on that, we distinguish between areas that are unavailable due to safety requirements, areas that are conditionally available provided that current regulations are revised and areas that are already unconditionally available. We assess the entire production chain in terms of Energy Return on Energy Invested (EROEI), and consider various combinations of grass and willow operations for bioenergy production. Looking at several roads in Eastern Overijssel, we have estimated that there is approximately 4.24-4.68 ha/km of road verge conditionally available along highways, A-roads, and some 0.80-2.67 ha/km available along local roads, N-roads. However, only 1.02-1.62 ha/km and 0.37-0.80 ha/km of A and N roads respectively are available unconditionally. The EROEI for some scenarios of both grass-based and willow-based production were quite high, 15-42, making such use of road verge quite promising. (C) 2015 Elsevier Ltd. All rights reserved.