Beef cattle in a corral.
Credit: Germán Miranda/IPS
Releasing Clean Energy from Manure
By Marcela Valente - IPS/IFEJ
Manure, Argentina's leading source of climate-changing emissions is beginning to be used as raw material for clean energy.
BUENOS AIRES, Aug 31 (Tierramérica).- With enormous potential for biogas production, Argentina is gearing up for this clean energy alternative that has already had good results on some ranches that transform manure into energy.
Biogas is a fuel that is generated from the biodegradation of organic material in an airless environment. But to achieve sustained development of this source it will be necessary to break through some bottlenecks, according to experts consulted for this report.
"Biogas is in full upswing. We completed a study of potential and an expansion plan, and we are trying to push pilot projects and concrete applications in agro-industry," Jorge Hilbert, head of the National Bioenergy Program of the National Agricultural Technology Institute (INTA), told this reporter.
To promote this type of energy, INTA this year published the Biogas Production Manual and the Atlas of Potential Biogas Production in Argentina. It is receiving cooperation from Germany, where this technology, subsidized by the government, is used in turbines that generate electricity equivalent to three nuclear power plants.
In Argentina, 86 percent of energy comes from the burning of fossil fuels (mostly petroleum and natural gas), six percent from hydroelectric dams, and 1.6 percent from nuclear. The rest comes from firewood, pulp, coal and alternative sources.
Meanwhile, farming activity is the main source of greenhouse-effect gases that contribute to climate change, accounting for 29 percent of Argentina's total emissions, according to the last official measurements.
Those emissions, principally methane gas - whose greenhouse effect is much stronger than carbon dioxide - could be avoided by turning the organic material that produces it into biogas, which burns even cleaner than natural gas.
Hilbert maintains that in Argentina there is great potential for biogas. "What is lacking is investment," which is not related to technology but rather to the shortage of financing in general for the agricultural sector, he said.
Eduardo Gropelli, head of non-conventional energy at the chemical engineering department of the National University of the Coast (Litoral), said in an interview for this report that from the technological perspective, "the solution has been developed, it's available and has great potential."
"If production is blocked, it's due to lack of financing," he said.
"The companies with the financial capacity have access to the technology and are advancing," said Gropelli, for example at primary production ranches and in the agro-food industrial sector.
One of the companies that has achieved transformation of its own waste into energy is Cabañas Argentinas del Sol, a pig farm with 10,000 head on 22 hectares in Marcos Paz, 50 kilometers west of Buenos Aires, and only three km from the city limits.
"We were concerned about the methane pollution from the manure, as well as the stench and the flies," said agricultural engineer Hugo García, owner of the company. After trying some homemade approaches, he traveled to Brazil, where he saw a "biodigester" in operation - and bought one.
To obtain biogas, the biological degradation of the organic material - the manure - must be the result of anaerobic bacteria, microorganisms that live and reproduce without oxygen. This controlled process can capture a biological fuel rich in methane that when burned releases much less carbon dioxide than a coal or oil fueled power plant.
Even better, biogas production is an efficient solution for handling animal waste.
The manure from livestock on dairy farms, feedlots, meat-packing plants and other sites, like García's farm, can be turned into the raw material for fuel, as can waste from the production of cane alcohol, processed fruits and vegetables, and even sawdust.
To obtain biologically-based methane, in addition to the fermentable raw material, a biodigester is needed. It is a hermetic reactor where the fuel is generated and collected to then be used to generate heat for ovens and water heaters, or to fuel an electric turbine.
After he purchased his first biodigester in Brazil, García added a second, and then a third larger one, with a capacity for 2,250 cubic meters of manure. The system for transporting the animal waste to the reactor and the pipeline for carrying the gas are simple and economical, he says.
With biogas, the entrepreneur replaced the tanks of natural gas he used to buy in order to heat some of his barns, and to process the soybeans used for feeding the pigs.
Each of these steps, which used to require fossil fuels, now are run on biogas. "The pigs, with their waste, provide their own caloric energy," he summarized. Furthermore, as a byproduct, the liquid from the manure is used for a fertilizer with a high concentration of nutrients to grow the soybeans that feed the animals.
The savings total about 5,200 dollars per month, just on the gas bill. "In two years we paid off the biodigester," said the farmer.
According to Gropelli, the biggest developments in biogas are being seen in agro-industrial companies, like big breweries, and factories that make gelatin, yeast and other foods.
He also underscored the cases of pig farms, feedlots and dairies where large volumes of manure accumulate and an environmental solution is needed for its disposal. "In less than four years the investment can be paid off," he said.
However, there is another less developed area that would require a cultural shift: urban solid waste. In this sphere, there are experiences in small towns. In the eastern province of Santa Fe, the town of Emilia, with 1,000 residents, has its own organic waste recycling plant.
Other towns of 3,000 to 7,000 people have been put to the test. "In this case, the Achilles heel is in separating the organic from the inorganic waste. People are used to throwing out the garbage and aren't aware of the environmental responsibility. What is needed is a cultural change, which takes time," said Gropelli.