More solar farms or more bioenergy crops? Mapping and assessing potential land-use conflicts among renewable energy technologies in eastern Ontario, Canada

Renewable energy systems are land intensive at local scales. Appropriate siting can help to mitigate the extent to which RE implementation compromises existing land-based economies and ecosystem services. As such, an integrated approach to land-use and energy planning, or land-energy planning, can help to ensure that RE technologies can be intensively implemented while minimizing negative impacts. Requisite to the development of such plans is (a) estimating total land availability on which technologies capable of supporting RE production functions after considering various socio-political, economic and ecological constraints; (b) identifying potential sources of conflict among multiple RE options; and (c) assessing the trade-offs associated with allocating this land toward one energy system and not another. The purpose of this paper is to address these issues at a regional-scale in the context of intensifying solar and bioenergy production. A methodology is developed from which to (a) locate land that is most likely to support both dedicated bioenergy feedstock and solar photovoltaic (PV) production in an area; (b) identify the point at which mutual land must be used in order to achieve their market potential; and (c) estimate and evaluate trade-offs associated with choosing one system over another at mutual land, in this case total potential electricity production and energy density (MWh/ha), in the context of regional energy needs and existing renewable electricity assets. Mutual land is located through GIS-based land-suitability modeling and map overlay techniques. Comparisons of production potential and land-use efficiency are made for a range of fixed-axis solar PV technologies against two short rotation woody coppice systems (poplar; willow) and two perennial grass systems (switch grass; miscanthus). Rooftop space is found to be sufficient to provide the land area required for solar PV to meet mid-day regional electricity requirements. If all mutual land in the region were allocated toward dedicated bioenergy crops instead of solar PV systems, (a) a 100 per cent renewable electricity system is within the limits of technical feasibility, even in the absence of large-scale storage systems; and/or (b) bioelectricity systems could provide back-up electricity for rooftop solar PV systems. The policy implications of these findings are discussed.