The Price of Energy Consumption - The Renaissance of Renewable Energy - page 191

medium-level land impacts. The vast network of pipelines and refineries, the extraction of
tar sands in Alberta, the reservoir of the Three Gorges Dam, and the vast arrays of solar PV
panels needed to generate electricity on an industrial scale are among the manifestations of
theseimpacts.Windpoweralsohasaconsiderablelandimpactbecauseturbinesareusually
placed a few hundred metres apart to avoid mutual interference. However, this is mitigated
by the fact that wind farms can coexist with either cropland or pastoral farming. 3
Thethird,highest-impactcategoryisreservedforbiofuels.Becauseofthelowefficiency
of photosynthesis ( Section 1.2 ) , a large area of land is required to produce biomass fuels,
whether in the form of timber for direct combustion or an energy crop for alcoholic
fermentation. 4 Sugarcane ethanol is the most efficient of the biofuel crops, yet to meet
global primary production we would need the entire land area currently used by humans,
and using biofuels derived from soy we would need the entire land surface of the Earth
(see Figure 6.3 ) . Biofuels will eventually occupy an important niche in the energy mix,
but physical limits will prevent them from becoming a globally dominant energy solution
(Andrews et al. 2011 ) .
Figure 6.3. Land requirements by energy resource type to meet 10 percent and 100
percent of 2010 global energy demand, based on current conversion technologies. Data
are compared with current human land use. This shows that biofuels are by far the most
land-intensive of all energy sources. Source: Andrews et al. ( 2011 ) (modified).
Air Impacts
When wood, coal, or oil is burned, the most evident manifestation is the smoke. It
comprises tiny particles that can penetrate the lungs, enter the bloodstream, causing heart
disease, lung cancer, asthma and respiratory infections. 5 More than 2 million people die
every year from inhaling particles floating in indoor and outdoor air (WHO 2011 ). In both
developed and developing countries, the biggest contributors to air pollution are exhaust
fumes from transport and industries, combustion of wood for cooking and heating, and
conventional fossil fuel-based power plants. In developing countries, traditional burning
of solid fuels (e.g., cooking or space heating with wood or coal) exposes many people
to indoor smoke fumes. In addition to particles, carbon dioxide, sulphur dioxide, nitrogen
oxides, metals, and various kinds of dust are released by the combustion of wood, coal,
or oil. Each has different impacts on human health, ecosystems and climate. The burning