Dr. Kate Shoulders, assistant professor in the Agriculture Education, Communications and Technology Department at the University of Arkansas at Fayetteville says not all forms of renewable energies are created equal.
One of Shoulders’ primary duties is to see which forms of renewable energy (solar, wind and hydro) work best in Arkansas. To accomplish that goal, she started the Solar Energy Analysis Station at the UA farm in Fayetteville. Shoulders uses the station to test practical ways renewable energy can be used in agriculture or a homestead.
Shoulders is quick to say that renewable energy is not necessarily the right fit for everyone, and some forms of renewable energy work better than others due to location, climate, economic feasiblity and other factors.
Wind is not a Good Option
While Arkansas is home to some companies that manufacture the gigantic wind turbines used for commercial wind power generation, Shoulders said wind is not a practical option in the Natural State.
There is a wind turbine set up at the analysis station in Fayetteville, but Shoulders said the primary reason it’s there is to show how “inefficient” wind-power is for Arkansas.
Shoulders said there are three primary reasons why wind power is not a very efficient option for renewable energy in Arkansas:
- First, turbine systems are designed primarily for constant West Coast winds that often blow close to the ground. In Arkansas, she said the turbine has to be elevated, which adds to the expense, and the wind is not very consistent here at all.
- Second, she said turbine systems have several moving parts, which require more maintenance and expense, especially over the long term.
- Third, Shoulders said there are some unexpected regulations that can influence where you can put wind turbines. For example, she said twind turbines have proven to be very detrimental to the bat population. As a result, the Environmental Protection Agency has placed restrictions on using wind turbines in the flight patterns of bats.
“Wind is not as useful for Arkansas as solar,” Shoulders said.
Solar is Best Option in Arkansas
Shoulders said they are using solar energy in both “on grid” and “off grid” applications at the university farm.
“On grid” refers to using a form of renewable energy as a secondary source of power in addition to the electricity provided by a public utility. “Off grid” refers to using renewable energy as the sole source of power for a structure.
In on-grid applications at the Energy Analysis Station in Fayetteville, Shoulders said they have a 1 kilowatt solar generator to support power for a shop/classroom at the university farm. That on-grid system also helps power a micro-invertor that measures how much energy each cell in a solar panel is producing over any five-minute time frame. Shoulders said that data allows them and the public to see how well the solar panels are working under varying conditions.
To demonstration an off-grid application for solar power, Shoulders said they set up set up two water troughs in the middle of a pasture equipped with a water pump that operates solely off a couple for solar panels connected to the pump. She noted that the system does not have a battery storage system – all the power to operate the water pump comes strictly from the solar panels themselves.
Shoulders said the intent of the solar-powered water trough demonstration is to show ranchers that they can deliver water to remote parts of their pasture without having to haul it. The pumps are using a 250-watt solar panel without any battery back-up. She said any time you can avoid having a battery back-up system, it makes the overall system much more cost efficient.
Shoulders said other practical off-grid applications for solar power without having to have a battery back-up system would include solar panels that could be used for portable charging stations for rechargeable tools at remote locations, solar water heaters, electronic gates and recreational uses for RVs, boats or camping.
She also noted that not all solar panels are created equal. While the price of the panels have come down in recent years, she said the power-generating silicon in some panels is superior to the silicon in others. Shoulders recommended checking out the efficiency of a panel before buying it.
Shoulders said the most efficient and affordable source of renewable energy is also the least available: micro-hydro.
She described the micro-hydro system as simply a miniature version of a hydro-electric power plant where a constant flow of water helps turn a generator that produces electricity.
Since that stream flows constantly, Shoulders said the hydro generator can produce power around the clock regardless of the weather conditions. That makes it much more efficient than solar or wind power because both of those can be affected by the elements.
She said micro-hydro systems can be produce electricity with as little as 100 gallons of water going over a five-foot dropoff or five gallons of water going over a 100-foot dropoff.
While it is the most efficient and affordable system, Shoulders said not everyone has a stream that meets the flow requirements. However, if a person does have a flowing stream on their property, it would be the best option for a renewable energy source.