Land Use Requirements for Maximum Clean Energy Requirements
Discussion
Robert Pollin:
"Vettese provides virtually no evidence to support his claims on the land-use requirements for renewables. In fact, his claims cannot be supported, as a review of the relevant evidence makes amply clear. A critical contribution here is Mara Prentiss’s Energy Revolution, which offers a rigorous account. Focusing on the us economy to illustrate the main issues, Prentiss shows that, relying on existing solar technologies, the us could meet its entire energy consumption needs through solar energy alone, while utilizing just 0.8 per cent of the total us land area. If we allow that energy-efficient investment, as described above, can cut us per capita energy consumption by roughly 50 per cent over twenty years, this would then mean that solar energy could supply 100 per cent of us energy demand through utilizing 0.4 per cent of the country’s total landmass. Moreover, with the us as a high-efficiency economy, more than half of the necessary surface area could be provided through locating solar panels on rooftops and parking lots throughout the country.footnote16 If this is taken into account, solar-energy sources using existing technologies could supply 100 per cent of us energy demand while consuming somewhere between 0.1 and 0.2 per cent of additional us land area.
Wind power does require more land. Prentiss estimates that wind power could provide 100 per cent of existing us energy demand through using 15 per cent of the country’s land area. Again, assuming investment in energy efficiency lowers per capita energy consumption by half, then only 7.5 per cent of total us land area would be needed to produce 100 per cent of energy demand through wind power. Further, wind turbines can be placed on land currently used for agriculture with only minor losses of agricultural productivity. The turbines would need to be located on about 17 per cent of the existing farmland to generate 100 per cent of us energy supply with high efficiency. Farmers should welcome this dual use of their land, since it provides them with a major additional income source. At present, the states of Iowa, Kansas, Oklahoma and South Dakota generate more than 30 per cent of their electricity supply through wind turbines.
Of course, neither solar nor wind power need to be the sole energy source, in the us or elsewhere. The most effective renewable-energy infrastructure would combine solar and wind, along with geothermal, hydro and clean bioenergy as supplemental sources. Overall land-use requirements can be minimized through an integrated renewable-energy infrastructure. For example: roughly half of all us energy supply could be provided by solar panels on rooftops and parking lots, another 40 per cent by wind turbines mounted on about 7 per cent of us farmland and the remaining 10 per cent by geothermal, hydro and low-emissions bioenergy. This is without including contributions from solar farms in desert areas, solar panels mounted on highways or offshore wind projects, among other supplemental renewable energy sources. Moreover, it is through combining these sources that we can effectively address some of the real challenges in building a renewable-energy infrastructure: intermittency, transmission and storage. Intermittency refers to the fact that the sun does not shine and the wind does not blow 24 hours a day. Moreover, on average, different geographical areas receive different levels of sunshine and wind. As such, the solar and wind power that are generated in the sunnier and windier areas of the us—such as Southern California, Florida and the Midwest farm belt—will need to be stored and transmitted at reasonable cost to the less sunny and windy areas. Investments in advancing storage and transmission technologies therefore need to be included in the overall clean-energy investment programme at roughly 1.5 per cent of annual gdp.
It is true that conditions in the United States are more favourable than those in some other countries. Germany and the uk, the two countries cited by Vettese, have population densities seven or eight times greater than the us and receive less sunlight over the course of a year. As such, these countries, operating at high efficiency levels, would need to use about 3 per cent of their total land area to generate 100 per cent of their energy demand through domestically produced solar energy. Wind power would require a significant share of their land area. But here again, farmlands could be converted to dual use with only minor reductions in productivity. The uk and Germany could also supplement their solar and wind supply with domestically produced geothermal, hydro and clean bioenergy. Using cost-effective storage and transmission technologies, they could also import energy generated by solar and wind power in other countries, just as, in the United States, wind power generated in Iowa could be transmitted to New York City. Any such import requirements are likely to be modest. Both the uk and Germany are already net energy importers in any case. With respect to population density and the availability of sunlight to harvest, and factoring in likely global energy consumption levels over the next forty years, average requirements for renewables are much closer to those in the us than to Germany and the uk. Overall then, the work by Prentiss and others demonstrates that, in fact, requirements for land use present no constraint on developing a global clean-energy infrastructure." (https://newleftreview.org/issues/II112/articles/robert-pollin-de-growth-vs-a-green-new-deal)
The Vettese Counter-Argument
Robert Pollin:
"In the last number of nlr, Troy Vettese argued that it would be unrealistic to expect that a global renewable-energy infrastructure could be the foundation for a viable climate-stabilization project because, at present consumption levels, it would take up enormous amounts of the earth’s land surface. Vettese writes: ‘A fully renewable system will probably occupy a hundred times more land than a fossil-fuel powered one. In the case of the us, between 25 and 50 per cent of its territory, and in cloudy, densely populated countries such as the uk and Germany, all of the national territory might have to be covered in wind turbines, solar panels and biofuel crops to maintain current levels of energy production.’" (https://newleftreview.org/issues/II112/articles/robert-pollin-de-growth-vs-a-green-new-deal)