Blessed with Sunshine
With the first week of May seeing 100 degree plus days of heat, it reminded me of how blessed we are to have sunshine. The sun is essential to crop production and the continuation of life on our planet. West Texans have grown use to seeing wind turbines circling the horizon, but agriculture also uses solar power.
The main use of electricity is for irrigation and in operations of livestock and dairy facilities. Lighting, ventilation, refrigeration, water/space heating, pumping water and fanning for aeration and crop drying are common electric uses. Solar energy can substitute for the more traditional energy sources such as gasoline, diesel and natural gas.
Two types of solar systems are solar electric converting solar energy to electric power and solar thermal using solar energy to heat water and air. Both convert sunlight into usable energy, and both have many applications in agricultural settings to aid farmers and ranchers in their daily operations.
Solar electric called photovoltaic or PV Systems generate electricity directly from sunlight and can be used to power anything from small electronics like calculators and road signs to homes and large commercial buildings. The primary agricultural applications for solar PV electricity have been for charging batteries for fence chargers, gate openers, building lighting and water pumping from remote wells, streams or lakes to provide water for livestock and small-scale irrigation. The introduction of solar PV came in the 1950’s through space applications and gained recognition in the 1970’s as a source of non-space applications in the energy crisis. For agriculture the sales and usage of standalone systems began in the 1980’s. It is becoming more common to see solar panels on roofs in Howard county. These panels are what most people envision when one mentions solar power. Many think of the large solar farms in our nation’s western states when they hear of solar power. These farms have produced renewable energy for many decades, but they also came with a negative effect. They took up a vast amount of land that was sacrificed for other uses. That is until a process called agrivoltaics was established.
Agrivoltaics is farming crops under solar panels. It can boost food production, save water and even improve the efficiency of electric production. The first agrivoltaics research site was at Biosphere 2 in Arizona. The study focused on chiltepin and jalapeno peppers and cherry tomatoes positioned under the PV array of panels. They found that the agrivoltaics system affected three factors in the plant growth and reproduction-air temperature, direct sunlight and atmospheric demand for water. The shade the panels provided resulted in cooler daytime temperatures and warmer nighttime temperatures compared to tradition open-sky planting. There was also lower vapor pressure or more moisture in the air and less transpiration water loss in the plants. Basically, the plant crops did better in the shade of the solar panels because they were spared from the direct sun.
It turned out that the plants grown under the panels also benefitted the solar panels. Solar panels are inherently sensitive to temperature so that as they warm their efficiency drops. Cultivating crops underneath the PV panels allowed researchers to reduce the temperature of the panels. Areas under the panels can even be reseeded to provide habitat and forage for pollinators, birds and other small species. Sheep are commonly used for grazing for vegetation control at solar facilities.
Solar thermal electric energy concentrates the light from the sun to create heat, and that heat is used to run a heat engine which turns a generator to make electricity. In agriculture, livestock, food processing, dairy operations require substantial amounts of heated water for sterilization, production and environmental control. Solar air heating is used to heat spaces in barns and for crop drying such as grain and peanuts. Heating water and cooling milk can account for up to 40% of energy used on a dairy farm. Aquaculture and breweries are two other industries that can use solar energy for hot water needs.
Whether local agriculture is using solar PV or solar thermal equipment, solar energy is another renewable energy resource to aid our farmers and ranchers. So next time you step out into our West Texas sunshine feel blessed for all the sun does for our benefit.