Farmers could become the “energy moguls of the 21st Century” if they move beyond ethanol to the large-scale development of wind and solar energy, which, like farming, requires “management of significant areas of land,” said CarbonFree, a Cambridge, UK, research company.
“For several decades, the energy market has been dominated by a handful of companies and closed to new entrants,” said CarbonFree. It claims, perhaps naively, “The fragmented nature of agricultural production will prevent farmers from dominating the global economy in the same way as oil producers do today.” Guess they never heard of Archer Daniels Midland Co., the largest ethanol producer, which plans to increase its production from 1.1 billion gal/year to 1.5 billion gal/year.
In recent years, wind power has been the fastest growing form of electricity generation in the US on a percentage basis. If renewable energy continues to grow at its current rate, CarbonFree predicted, “Farmers will occupy a strategic position within the energy market within 2 decades.” But instead of growing crops for conversion to ethanol, future energy farmers will supervise fields of wind turbines or photovoltaic devices.
“Although uneconomic today, solar energy farming will eventually benefit from advances in solar cell technology-in particular the ability to deposit photovoltaic materials on low-cost polymer-based substrates. In theory, installation of polymer-based photovoltaic material could be as straightforward as the deployment of the large amounts of polythene farmers use to speed up the growth of fruit and vegetables,” said CarbonFree in a February report.
Wind farms
“Wind farms” with dozens, even hundreds, of giant wind turbines already exist in many places around the globe. The European Union has pledged to increase installed wind capacity on the continent to 10 Gw by 2010.
But wind farms are really industrial installations of vast proportions with turbines as tall as a 30-floor building and whirling blades twice as long as a city bus. Critics claim they’re a source of noise pollution and work poorly-even dangerously-at low temperatures, flinging ice deposits like projectiles. Occasionally, blades shatter into shrapnel or come loose and go flying for great distances. The California Energy Commission reported an annual average kill of 200-300 redtail hawks, 40-60 golden eagles, and 7,000 other migrating birds at wind turbine sites in southern California.
Wind generators work best where the wind speed averages more than 12.5 mph. A near constant flow of nonturbulent wind is necessary year-round to avoid damage from sudden wind bursts.
Because wind speed is never constant, a wind generator’s annual energy production never lives up to its nameplate rating. Even a well-placed wind turbine might generate only 35% of its rated capacity. A 1,000 kw wind turbine would produce as much energy in a year as a 350 kw fuel-fired generator. And an alternative power system would still be necessary on the days when there was no wind.
Best sites
Some of the best sites for wind turbines are mountain ridges, mountain passes, and tops of cliff faces where changes in ground elevation create greater wind velocities. Seashores are good sites for turbines because the differences in heating and cooling of land and sea create convection winds day and night. Sea winds carry more energy than winds of the same speed in mountainous areas because the air at sea level is denser.
Unfortunately, those areas tend to be picturesque, and that has triggered much opposition to wind farms in otherwise ideal sites. Proponents claim offshore wind turbines are less of an eyesore and may even be invisible from shore since they don’t have to be as tall to catch the more potent offshore winds. However, offshore conditions are harsh, abrasive, and corrosive, and it is nearly impossible to repair a turbine in open waters. Moreover, water depth has to be less than 40 m with a flat seabed. Locations are restricted by shipping lanes, military zones, pipelines, helicopter flight paths, ferry routes, and fishing grounds. Long distances to grid connections and absence of port facilities can make offshore sites uneconomical.
Some have even suggested airborne wind turbines suspended from helium balloons tethered to earth. But imagine the bird-kill rate from such a machine, not to mention the hazard to aircraft.
While costs continue to drop, until wind power can compete without subsidy with fuel-powered generation, proponents are just tilting at windmills.✦