Abstract
Concerns about climate change related to fossil fuel carbon dioxide emissions require the development of alternative energy resources. In most scenario studies on future energy supply, bio-energy is one of the dominant renewable alternatives foreseen. Apart from the use of residues and wastes, the cultivation of dedicated ‘energy crops’ will
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be necessary. Especially in densely populated regions such as the Netherlands, energy crop introduction is strongly hampered by lack of available land, related to the low valued added of energy crops compared to e.g. agriculture. A strategy that may help overcome these problems is multiple land use: combining the production of energy crops to other targets on the same tract of land. If a plot not only generates biomass, but also serves other functions such as nature management, more income may be generated, and overall land use efficiency may increase.
Central question in this thesis is whether, and to what extent, multiple land use can improve opportunities for energy crops in the Netherlands, in comparison with energy cropping as single land use. We specified this question into three criteria:
(1) multiple land use energy farming options should be biophysically feasible;
(2) such combinations should lead to lower biomass production prices compared to single land use;
(3) the combinations should open up an area for energy cropping significant to the national renewable energy targets.
The first research topic was to further identify and specify the concept of multiple land use, and develop an operationalisation procedure. Subsequently, specific options for combination of energy crop cultivation with another function were elaborated. In a relatively simple and qualitative way, we analysed four options with willow as an energy crop: combination with drinking water production (on two levels), with traditional willow coppice management, and with an ecological corridor function. We executed more detailed studies on two combination options: willow in hydrological buffer zones around nature reserves, and willow as a breeding bird habitat.
Most studied options of combining willow SRC with another function into a multiple land use type appeared to be biophysically feasible. The effect on financial competitiveness of introducing willow SRC in Multiple Land Use varies per combination: in some cases, like the option in groundwater protection areas, competitiveness remains unchanged, while in others, such as the buffer zones, a significant competitiveness increase can be obtained. However, the price reductions are not in the order of magnitude that the price of energy crops draws near to the current prices of biomass residues, the only resource currently applied for bioenergy. The total of land potentially suitable for the investigated options adds up to ca. 100,000 ha, while the area with improved financial competitiveness is ca 30,000 ha in total. Given the projections on required area for meeting the national renewable energy objective, MLU areas with improved financial competitiveness will only partly meet this area claim.
Therefore, multiple land use will enhance opportunities for energy crop introduction in the Netherlands, but it will not be the panacea for large-scale introduction of competitive energy farming. Potential areas remain limited, as well as financial benefits compared to single land use, and several implementation problems may hamper introduction in practice. This limited perspective on the short term may be altered by long-term developments, such as technical innovations, and developments in the EU Common Agricultural Policy and in the global climate policy.
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