Let’s focus on energy production. Fossil fuels – oil, gas, coal – currently represent 82% of the global energy mix, with high consequences in terms of greenhouse gas emissions. The current aim to limit carbon emissions on a global scale means reducing the energy production from fossil fuels and developing low-carbon energy sources. Yet, decarbonizing the energy mix poses this often-forgotten challenge: developing new energy production systems will require more lands, which may further exacerbate the competition over land use. The graph represents the land-use efficiency of different energy sources considered from two approaches.
First, the land intensity measured in terms of direct footprint represents the surface strictly required to produce one unit of energy, including areas taken by machinery, pipelines, reservoirs and access roads. Alternatively, the landscape-level impact includes additional regulatory or technical space requirements that some technologies need. For example, the direct footprint of wind energy (1 m²/MWh) counts the turbine area and access roads, whereas its total landscape impact (127 m²/MWh) additionally considers the required areas between turbines. Oil and gas technologies are also submitted to similar constraints with a necessary spacing between wells.
Natural gas, coal and fossil oil have low land footprints (landscape-level impact inferior to 10 m²/MWh), which means the area required to produce 1MWh of energy is relatively minor. The most reduced footprint comes from nuclear energy (0.1 m²/MWh), counting areas dedicated to waste storage. Renewables generally have greater land impacts than extractive energy. The land intensity from non-biomass renewables is between 5 m²/MWh and 20 m²/MWh – apart from wind energy, up to 130 m²/MWh. Biomass (excluding biofuels from residues) is the least land-use efficient source of energy and requires from 200 m²/MWh to 1,000 m²/MWh. In other words, land requirements to produce one unit of energy from solar photovoltaic and wind are 25 and 200 times higher respectively than from underground coal. For biomass this number reaches 1300.
Land-use efficiency (m²/MWh) in energy systems
Note: Energy sources without spacing requirement have the same value for direct and landscape-level impacts
Large areas will be required for energy expansion, even more if new energy developments focus on renewables. At a time when the competition for land use is already major and only expected to increase, ensuring all the needs of the population, energy supply included, whilst decarbonizing the energy mix will indeed prove challenging. A possible adaptation would be to co-locate some land uses: for instance, more biofuels could be produced from agricultural residues and wastes, urban areas can be optimized to host a part of the energy production – solar panels on rooftops, mini-eoliennes – and the spacing between eoliennes or oil and gas wells could be used to grow some crops. The question remains on whether nuclear, which have low greenhouse gas emissions in addition to limited land use impact, is also an acceptable solution.
Claire Hugo, Analyst – Source: IPBES, UNCCD, Trainor et al. (2016)