José Luis Márquez, Yaisema Fabelo and their son Yadir stand around a table holding fruits harvested from their Los Tres Hermanos agroecological farm, in Martí, a municipality in northwestern Cuba. The family of farmers values the final products of biogas technology, rich in nutrients suitable for fertilizing and restoring the soil. CREDIT: Jorge Luis Baños/IPS
By Luis Brizuela
MARTÍ, Cuba , Apr 20 2023 – The first five biomethane-fuelled buses in the Cuban municipality of Martí will not only be a milestone in the country but will also represent a solution to the serious problem of transportation, while reducing emissions of greenhouse gases and bolstering local development.
Yaisema Fabelo, a librarian at the local prep school, told IPS that “the buses will boost the quality of life of the residents” of the municipality located in the north of the western province of Matanzas, about 200 kilometers east of Havana.
Fabelo, who is also a farmer from the Los Tres Hermanos agroecological farm, stressed that using biogas on an industrial scale and on individual farms “to produce electricity, cook food and obtain biofertilizers for organic crops” will benefit the 22,000 inhabitants of the municipality and surrounding areas.
The Martí I and nearby Martí II covered lagoon biodigesters will produce around 1,800 and 3,600 cubic meters of biogas per day, respectively, when they come into operation. They will connect through two separate gas pipelines with a biomethane plant where the fuel will be obtained for a group of buses. CREDIT: Jorge Luis Baños/IPS
The project
Turning pig manure and crop waste into biomethane and biogas is the focus of the project “Global Action for Climate Change in Cuba: Municipality of Martí, towards a carbon-neutral sustainable development model.”
The project, carried out by the United Nations Development Program (UNDP) and the Ministry of Economy and Planning with 5.5 million dollars in financing disbursed by the European Union, began to be implemented in 2020 and is to be completed in 2024.“[We want] to demonstrate that the biodigesters are economically feasible for Cuba, that connected with large pig farms they can be used to generate electricity and contribute to the economy.” — Anober Aguilar
“The main problem that Martí has in the case of greenhouse gases is waste, responsible for 57 percent of our emissions,” explained Sobeida Reyes, director of territorial development for the town.
In an interview with IPS, the official pointed out that with the project and as part of the local development strategy, the aim is to gradually contribute to decarbonization with the use of renewable energy sources and incorporate biogas to biomethane conversion technology.
Biogas is composed mainly of methane and carbon dioxide, obtained in biodigesters from the decomposition of organic residues such as agricultural or livestock waste by bacteria, through anaerobic digestion, without oxygen.
Biomethane, also known as a renewable gas, is derived from a treatment process that removes carbon dioxide, moisture, ammonia, hydrogen sulfide, among other impurities from biogas, which brings its composition closer to that of fossil natural gas and favors its use to generate electricity and heat and to fuel vehicles.
The plan is to strengthen the public transport system through “16 buses powered by biomethane, the first five of which are to be tested in February 2024, after a bidding process outlined in the project that will facilitate their importation,” Reyes said.
“There is a commitment that these buses will be driven by women,” she added.
The future biomethane plant, which has already been awarded in tender, will provide, according to the plan, about 150 cubic meters per hour of gas suitable for bottling.
It will depend on the Martí I and Martí II covered lagoon biodigesters, which will be the largest in the country and will produce around 1,800 and 3,600 cubic meters of biogas per day, respectively, when they come into operation.
These, in turn, will each be fed by a pig breeding center belonging to the Matanzas Pork Company.
A third of the 14 kilometers of gas pipelines that will connect both biodigesters to the biomethane plant have already been put in place.
The generator is also being installed, while the lagoon is being filled with water to check its operation. The last thing needed is to put in place the membrane that will cover it.
This part is expected to be operational in February of next year, as well as the biomethane plant, so that the first five buses can then be tested, according to the established timeframe.
With the help of an electricity generator, the Martí I biodigester is to provide 100 kilowatts per hour, equivalent to the approximate consumption of 80 to 100 homes. The Martí II will provide even more.
A poster shows what the Martí I covered lagoon biodigester will look like. For Anober Aguilar, a specialist at the Indio Hatuey Pastures and Forages Experimental Station, responsible for the technological assembly, the construction of this type of biodigesters is economically feasible in Cuba. CREDIT: Jorge Luis Baños/IPS
Greater commitment to biogas
A potent greenhouse gas, methane has 80 times the climate-warming power of carbon dioxide, studies show.
Scientists argue that proper management of methane resulting from the decomposition of agricultural waste and livestock manure helps to mitigate water and soil pollution and to combat climate change.
Its extraction and energy use, especially in rural and semi-urban settings, can be a cost-effective solution to reduce the consumption of electricity based on fossil sources. In Cuba there are an estimated 5,000 small-scale (up to 24 cubic meters per day) biodigesters.
In this country of 11.1 million inhabitants, a significant percentage of the 3.9 million households use electricity as the main source of energy for cooking and heating water for bathing.
Renewable energy sources account for only five percent of the national energy mix.
In the case of biogas, “the main obstacle to its expansion is the availability of manure, as there is a low number of pigs and cattle, due to problems with feed and animal nutrition,” Anober Aguilar, an expert with the Indio Hatuey Pasture and Forage Experimental Station, located in Perico, another municipality of Matanzas, told IPS.
This scientific research center for technological management and innovation in the field of livestock production is in charge of the technological assembly of the biodigesters of the covered lagoon in Martí.
In the context of an economic crisis that has lasted for three decades, exacerbated by the tightening of the U.S, embargo, the COVID pandemic, and failed or delayed economic reforms, Cuba has limited imports of animal feed due to the shortage of foreign currency.
Furthermore, insufficient harvests do not guarantee abundant raw material to produce feed, while the scarcity of construction materials and their high cost make it impossible for many farmers to undertake the construction of a biodigester.
Conservative estimates by experts suggest that there is potential to expand the network of biodigesters on the island to up to 20,000 units, at least small-scale ones.
“If we look at the cost of the investment in the short term, it is more feasible to focus on wind or solar energy, because setting up a biodigester requires more financing, more time and specialized personnel,” explained Aguilar.
But seen at a distance of 10 to 15 years, “the investment evens out, because the potential of photovoltaic cells declines, repairs are made difficult by the rapid changes in technology, or the blades of the windmills deteriorate, in addition to the fact that both are more vulnerable to tropical cyclones,” the expert said.
“As long as they have raw material, biodigesters produce 24 hours a day,” he added.
He specified that one of the objectives of the project is “to demonstrate that the biodigesters are economically feasible for Cuba, that connected with large pig farms they can be used to generate electricity and contribute to the economy.”
Ministerial Order 395 of April 2021, of the Ministry of Energy and Mines, stipulated that each of the 168 Cuban municipalities must have a development program and strategy regarding biogas, and coordinate their management and implementation with those of their respective province.
Electrical technician Reinaldo Álvarez shows the electric generator located in the Martí I covered lagoon biodigester, in northwestern Cuba, which will provide about 100 kilowatt hours, equivalent to the electricity consumption of 80 to 100 homes. The nearby Martí II biodigester will produce even more. CREDIT: Jorge Luis Baños/IPS
Promoting agroecology
Martí’s development strategy includes projects to prepare preserves, spices and dehydrated foods with the help of the sun, a biomass gasifier for drying rice and generating electricity, the production of cooking oil, thermal baths, exploiting natural asphalt deposits, and social works, among others.
Reyes reported that 28 farms in the municipality have biodigesters, and that in 12 of them, as part of the project, “a module was delivered that includes a refrigerator, a stove, a rice cooker and a lamp, which use biogas.”
Another urgent objective is to foment agroecology and move towards local self-sufficiency in food, including animal feed.
“In the current harvest we had a yield per hectare of 19 tons of organic potatoes. As with the other crops, we only used biological products, of which more than 80 percent were produced by us,” farmer José Luis Márquez explained to IPS.
The 13-hectare Los Tres Hermanos agroecological teaching farm, dedicated to growing a variety of crops and small livestock using sustainable techniques, was granted in usufruct by the government, forms part of the Ciro Redondo credit and services cooperative, and has been managed by Márquez since 2018, together with his wife Yaisema Fabelo and their son Yadir.
A nationally manufactured PVC (polyvinyl chloride) tubular biodigester is also installed on the farm, with a volume of forty cubic meters.
“Due to the pandemic and the shortage of manure, it is not producing. We want to once again encourage pig and rabbit farming, recycle solid waste and convert it into organic fertilizer for crops and household chores,” said Márquez.
Biogas technology provides biol and biosol, liquid effluent and sludge, respectively, rich in nutrients to fertilize and restore the soil.
The farm is visited by students from different levels of education, up to prep school, who through workshops given by Márquez and Fabelo, learn about good agroecological practices “and the positive impact on the economy, people’s health and the environment,” Fabelo said.