Many of wind energy’s problems, such as its intermittent nature; its slaying birds, bats and other animals; its noise pollution; its degradation of vistas; and its higher costs compared to traditional technologies are well known. The latest study, however, shows that it also reduces the productivity of surrounding vegetation. The study finds that wind turbines elevated both day and night temperatures, which suppressed soil moisture and enhanced water stress, decreasing local vegetative growth and productivity. Further, wind requires 5 to 6 times more land than traditional technologies (coal, natural gas and nuclear) for the same amount of capacity and 12 times more when generating capability is also considered.
A number of recent studies discuss these issues and are highlighted below.
Study on Vegetation
Six Chinese scientists used remotely-sensed imaging data, including leaf area index (LAI), normalized difference vegetation index (NDVI), an enhanced vegetation index (EVI), gross primary production (GPP) and net primary production (NPP), coupled with other data (temperature, soil moisture, evapotranspiration, albedo and wind) over the period 2003 to 2014 to analyze the effects of a wind farm on summer vegetative growth in a region of northern China. A total of 1,747 wind turbines were constructed between 2005 and 2011 in the region with land cover consisting primarily of grassland and crops, accounting for 53.4 and 44.7 percent, respectively, of the total cover.[i]
The study found that wind turbines elevated day temperatures by 0.45 to 0.65°C and night temperatures by 0.15 to 0.18°C. The researchers found that the leaf area index decreased by 14.5 percent, the enhanced vegetation index decreased by 14.8 percent and the normalized difference vegetation index decreased by 8.9 percent over the study period. Summer gross primary production was inhibited by 8.9 percent and net primary production by 4.0 percent. The authors concluded that their research “provides significant observational evidence that wind farms can inhibit the growth and productivity of the underlying vegetation.”
Study on Land Use
The Strata group at Utah State University compared the land use of wind energy to traditional forms of generating electricity. They calculated the full-cycle land use required to generate 1 megawatt of electricity from each source of energy in 2015, including the land required to drill and mine for natural gas and coal, the processing and transportation requirements and the power plant footprint. They found that wind required 5 to 6 times as much land than coal, natural gas and nuclear power.
Specifically, the report found that coal, natural gas and nuclear power all have the smallest physical footprint of about 12 acres per megawatt. Solar and wind are much more land intensive using 43.5 and 70.6 acres per megawatt, respectively. Hydroelectricity generated by large dams had a significantly larger footprint–315.2 acres per megawatt.[ii] See chart below.
Taking capacity factors into consideration and using the above data on land usage, to replace the energy from all 274 gigawatts of coal-fired capacity that the United States currently has with wind power would require a land area consisting of almost the entire state of Washington—over 12 times the land area that the coal-fired units require.
Over Production or Power Shortages
As mentioned above, wind power is intermittent, producing power only when the wind is blowing, which has resulted in both overproduction and shortages of renewable energy. A study examined this issue using 5 years of data from the German electric sector.[iii]
The German electric fleet consists of about 50 gigawatts of wind turbines (onshore and offshore combined) and 40 gigawatts of photovoltaic solar. This renewable capacity represents about 65 percent of the renewable energy generated annually in Germany—the rest comes from hydroelectricity, biomass and geothermal. Because of the intermittency of wind and solar power, there are sometimes periods of overproduction and periods of shortages of renewable electricity. One such period of shortage was in the second half of January when most of the electricity was produced by conventional power sources—lignite, coal, natural gas, and nuclear.
A large fraction of the renewable power in Germany is exported. The exported electricity matches the annual production of photovoltaic solar energy or about two-thirds of the wind power production. (See chart below.) The export of excess energy is only a temporary solution to the over production of intermittent renewable energy if other European Union countries having similar weather patterns to Germany also construct wind and solar power.
Storage is another alternative, but it is not feasible with current battery technologies since they are not cost effective. If fossil and nuclear technologies are not acceptable as back-up due to Germany’s phasing out of nuclear power and its plan to decarbonize its electric sector, the only consideration left to a 100 percent renewable system is to adapt to the intermittency of wind and solar power and accept periods of darkness when the energy is not available.
The study indicates that we may “risk entering a new era where daily life could depend again on the variability of the weather, as it was centuries ago.”
Further, Germany has paid dearly for its renewable energy. As the graph below shows, Germany and Denmark have the largest amount of solar and wind power and the highest electricity prices in Europe, which are about three times higher than those in the United States.
Note: the graph is in Euro cents per kilowatt hour. 1 Euro equals about 1.20 U.S. dollars.
Wind power is not only bird-killing, noise-polluting, eyesore-causing, cost-prohibiting and vegetative-decreasing, but its intermittency leads to periods of overproduction or power shortages that necessitate reliance on traditional technologies as back-up or on costly storage technologies. In the case of Germany, where nuclear power is being phased out and fossil fuels are taboo because of plans to decarbonize, the only option may be to accept periods without electricity putting a civilized nation back centuries.
[i] CO2 Science, Another Reason to Reject Wind Farms, August 29, 2017, http://www.co2science.org/articles/V20/aug/a17.php
[ii] Watts Up With That?, The Footprint of Energy: Land Use of U.S. Electricity Production, August 9, 2017, https://wattsupwiththat.com/2017/08/09/the-footprint-of-energy-land-use-of-u-s-electricity-production/
[iii] Arguments-Revue, Hidden consequences of intermittent electricity production, http://revue-arguments.com/articles/index.php?id=76