The search for energy alternatives continues with innovative options such as biogas and earth energy.
The big three alternative energy sources are just the beginning, says Rick Atkins, AgTech Centre Manager and Branch Head of Engineering for Alberta Agriculture, Food and Rural Development (AAFRD). Researchers are examining several new sources of energy that will further expand the toolbox for building a sustainable agricultural industry. "At the AgTech Centre, we try to find new ways to make agriculture more efficient and clean in its energy use," says Atkins. "With continued research and development in this area, the real societal, environmental and economic benefits of new energy sources will become more viable."
Biogas
One option researchers are exploring is biogas, a fuel produced by the anaerobic digestion of organic material such as manure. This innovative energy can be used for heat or electricity.
"Biogas can be produced on site with a digester," says Brian Sexton, of AAFRD. "Basically, manure is fed into the digester, where it is heated and kept for several days under anaerobic conditions (no oxygen). Because of our climate, heat usually has to be added for this process to take place. Anaerobic bacteria thrive in these conditions and break down the manure to produce methane or biogas. This biogas can be used to run a boiler for heat or to power a generator for electricity."
Effluent from this process has little odour, and contains fewer weed seeds and pathogens than raw manure, which is a benefit in cropping. "Digestion converts the nutrients found in the manure to a form that is more readily available to crops," says Sexton.
However, anaerobic digestion probably isn’t for every operation. "The process works best with liquid manure systems," he says. "As well, biogas production requires a large capital investment, specialized training and weekly upkeep. Proper handling is required, as biogas is explosive. As a result, only a larger dairy, 300 head or over, and swine production operations with over 2,000 animals, could see this as a viable alternative."
To make biogas cost effective, the gas must be used as it is produced, explains Sexton. Matching the energy to heat and electricity demands of an operation, plus being able to sell the excess energy, is the only way to make biogas cost effective. "This is difficult because the energy demands of an operation can vary widely depending on the season. Combination operations, such as a hog operation and greenhouse operation, can make better use of the energy produced."
"Currently there are about 25 systems operating in the U.S. Pilot projects have been conducted in Canada over the years but the economics have not been viable. However, significant advances in anaerobic digestion technology have made today’s systems more feasible. As a result, a number of systems are being built in Western Canada."
Earth energy
A more widely available energy source is earth heating and cooling systems. Earth energy systems use temperatures found in the earth or groundwater to heat or cool air and water for buildings.
"For instance, a heat pump can extract heat from the ground to heat a building," explains Sherry Perih, with the AAFRD Engineering Branch. "Reversing the pump in the summer can provide air conditioning by moving hot air out of a building and down into the ground."
Operating costs of an earth energy system are much lower than the costs of operating a combustion furnace with an air conditioning unit, she says. But the cost to install an earth energy system can be higher than the cost of installing a combustion system. "On average though, an earth energy system can save two thirds of the cost of heating and cooling with electricity."
The initial setup costs are a drawback, but the payback could more than make up those costs, she says. Supplemental heating or cooling may be required if the earth system cannot provide the necessary load. For example, a heating/cooling system for a 1200-sq. ft. area can have a capital cost of $10,000. Payback period for this example would be five to 12 years, depending on energy prices.
"This is a readily available technology, and one that could provide many benefits, including the reduction of greenhouse gas emissions," she adds.
Fuel for thought
More energy alternatives are coming online all the time, with varying degrees of practicality for current agricultural operations, says Atkins.
"Farmers are adopting and will continue to adopt economically viable and environmentally sustainable options that fit their operations," he says. "With continued research and development to fine-tune the applications for farmers, this trend is likely to grow in the future."
For producers, the bottom line will be more options for a new century of sustainable production.
More information
AgTech Centre and AAFRD Engineering Branch are committed to the development of information for producers and industry. For more information on alternative energy sources, contact the AgTech Centre directly. |