“…Power densities of efficient petroleum and coal sources vary from around 1000-10,000 We/m 2 , while renewables generally range from highs for hydroelectricity of around 0.5-200 We/m 2 , to lower power densities for solar and wind around 0.5-10 and less than 1 We/m 2 for biomass and biofuels (Smil 2015;Capellán-Pérez, de Castro, and Arto 2017). These systems may additionally require new transmissions and inputs of raw materials, including fossil fuels systems during transition, collectively extending spatial demands (Heinberg and Fridley 2016;Capellán-Pérez, de Castro, and Arto 2017;Huber and McCarthy 2017). While only a small fraction of total available planetary surface area (Jacobson and Delucchi 2011), in relative terms these new energy infrastructures may require areas 1 to 3 orders of magnitude larger than existing systems worldwide (Smil 2015), exceeding available land area for many highly industrialized regions (Capellán-Pérez, de Castro, and Arto 2017).…”