No. 257, Dec.18-24, 2003

SECCIÓN EN ESPAÑOL

ENVIRONMENT





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Biogas - using organic waste to
generate renewable fuel

 



Biogas - using organic waste to generate
renewable fuel

By Patricia Grogg

Pinar del Rio, Cuba, Dec. 12 (IPS) — In the industrial kitchen of the Marién N’Gouabi Farm Institute in the Cuban province of Pinar del Río, no one is bleary-eyed from wood smoke or feels stifled by the heat anymore. “Our working conditions have been humanized,” says Ciro Emilio Ortega, standing in front of a huge boiler where lunch is stewing.

The change was brought about by a biogas plant installed on the grounds of the Institute, where more than 700 students are being trained as veterinary and agronomy technicians. The plant uses the manure from three cattle farms.

“We used to cook with firewood, in the middle of the smoke and the heat. Now we work in much more comfortable conditions,” says Ortega, the current head of the kitchen team that is working hard to prepare lunch for the Institute’s students and staff.

The flames from the two-burner stove are as strong as those on any conventional stove, but this one is not fired by fuel that pollutes the environment.

The savings are also considerable, says Oscar Castro, assistant director of finance at the Institute, which is located in Pinar del Río, just over 170 kilometers west of Havana.

According to his estimates, the biogas stove and a second one that consumes another waste product, sawdust, save the Institute the monthly expense of using 200 liters of gasoline to fuel the vehicles that hauled in the firewood.

Castro mentions the environmental benefits among the main advantages of the biogas plant.

Biogas is obtained from the process of anaerobic digestion of organic matter like manure or vegetable waste by bacteria in warm, wet, and airless conditions. The inexpensive and renewable fuel can be used in motor vehicles or combined with natural gas to fuel the lighting system, and serves for industrial and household uses as well.

Besides taking advantage of waste that pollutes the environment, the process of producing biogas generates what Castro described as an “excellent” fertilizer, which can also be used as food for fish or fowl.

“The waste (produced by the biogas generation process) is used as fertilizer on the land that is cultivated by the students to practice what they are learning, and to supply the Institute. Chemical fertilizers aren’t used here,” says Castro.

The Institute’s biogas plant is the only one of its kind in Pinar del Río, but not in Cuba, engineer José Antonio Guardado told Tierramérica.

He said there were more than 100 small and medium-scale installations that use biogas, especially for cooking fuel. Many of them make use of manure from cattle and hog farms.

A plant that operates in the Las Tecas motel in Villa Clara, 300 kilometers from Havana, produces nearly 300 cubic meters of gas a day, enough to run the motel’s kitchen and barbecue.

“The investment involved in the most expensive and complicated plants of this kind is recuperated in around three years. Las Tecas recovered its investment in half that time,” says Guardado, in charge of the development of this source of energy in the non-governmental organization Cubasolar.

The cost of installing a small plant is 1,000 dollars. “But this one won’t cost us more than 800 dollars,” he says.

Cubasolar (Cuban Society for the Promotion of Renewable Energy Sources and Respect for the Environment) emerged in 1994.

According to the government, Cuba has the potential to produce more than 150,000 tons of fuel per year, from some 78 million cubic meters of biodegradable waste.

“As a sugar-producing country, we also have several installations in which we use cachaza (the residue left after filtering the pressed cane juice) which has a range of uses, including the generation of biogas,” says Guardado.

He explains that experts in Cuba are working on developing technologies that use organic material in “urban gardens,” the number of which has significantly increased in the past 10 years.

“We already have a small prototype of a biodigester (a sealed, airless container in which organic waste matter is fermented to produce gas) which uses vegetable waste in urban settings. Projects are also being carried out in city dumps,” he says.

He points out that the basic underlying principle of the projects is to ensure that they are cost-effective, environmentally friendly, and useful to society.