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Thursday, September 3, 2015
- The Cuban government is making another effort to boost generation of electricity from sugarcane biomass to meet the high electricity demand of the sugar industry itself, and gradually increase its contribution to the national grid.
“Five tons of bagasse (stalk residue) are equivalent to approximately one ton of fuel oil. We are sitting on a goldmine here,” Paulino López, head of the Sugar Ministry’s energy development programme, told IPS.
Bárbara Hernández, head of the Ministry’s Energy Management Department, said that for the time being the exploitation of that “goldmine” is based on the industrial and agricultural infrastructure that is already available, as plans to produce electricity above and beyond the needs of the industry require investments that have not yet been made.
“For now, we’re managing with what we have,” she said. Sugar mills that remain active after the 2002 restructuring have geared up for co-generation of electricity, for their own needs and for those of nearby communities.
Longer term plans are to generate surplus electricity and sell it to the national grid, but officials declined to say how much capital would be needed for this.
According to the Economic Commission for Latin America and the Caribbean (ECLAC), the potential for local production of electricity based on bagasse and recoverable sugarcane residues could be optimised by using high-pressure, high-temperature boilers connected to extraction-condensing turbogenerators.
Hernández emphasised that the plans for improving energy efficiency in the sugar industry have been a part of the national development programme for that purpose since 2005. The national programme is based primarily on electricity savings, and includes an increase in the use of renewable energy sources.
Cuba continues to depend mainly on oil for electricity generation. But sugarcane biomass is its principal and oldest source of clean energy, along with hydroelectric power.
In 2005, the sugar industry accounted for 4.5 percent of total electricity generation, Hernández said. This was achieved by 56 mills which processed some 12 million tons of sugarcane.
Research studies quoted by Hernández predict that during the present sugar harvest, up to 36.5 kilowatt-hours per ton of sugarcane could theoretically be generated, according to potential biomass amounts and industrial efficiency.
“In 2007 we are aiming for 40 sugar mills to be self-sufficient in electricity, out of the 50 that will operate during the harvest (which began in January), and for the sector to contribute 21.5 percent of the electricity it generates to the national grid,” the official explained.
The cost per kilowatt is four times less than that of electricity obtained from fossil fuels, and biomass is non-polluting, because according to experts it does not increase the amount of carbon dioxide in the atmosphere.
Owing to the fall in sugar production last decade, the industry’s share of the country’s total electricity generation fell from 10 to 5.6 percent between 1990 and 2002.
In 2002 the sector underwent restructuring, with the closure of 71 sugar mills and a reduction in the area planted in sugarcane. The aim was to increase efficiency in the face of ever lower prices on the international market.
The price of sugar began to improve in late 2005, reaching 17 cents (of a dollar) a pound in April 2006. It currently stands at around 10 cents a pound. Given the rallying in prices, the Cuban government decided to invest in the reactivation of the industry and to increase sugarcane planting.
In this new climate, the Heriberto Duquesne molasses manufacturing company located in Remedios, in the province of Villa Clara, 268 kilometres from Havana, started a project in 2006 to produce alcohol from sugarcane juice, using adapted Brazilian technology.
Among other advantages of this system which, it is hoped, will spread to other distilleries in the country, is that it spares more bagasse for electricity generation and it is 40 percent less polluting than making alcohol from molasses, said engineer Eloy Pérez, a member of the group that designed the project.
This is the first time the process has been tried, and it is part of the Cuban programme to modernise 11 out of the 17 existing distilleries and build seven new ones, in order to increase production to between 300,000 and 500,000 litres of ethanol a day.
So far in Cuba, alcohol has been manufactured only from molasses, a byproduct of sugar refining, and has been used almost entirely for making rum. But the goal of the development plan is to produce alcohol as fuel.
“There are three main products in this flexible industrialisation strategy: high quality sugar, alcohols, and electrical energy,” the company’s directors explained to IPS.
The Duquesne distillery has a production capacity of 50,000 litres of ethanol a day. “The idea is to diversify, so as not to depend on a single product,” Pérez said.
The pride and joy of this agroindustrial complex is that all the sugar it produces is refined in a nearby mill which is self-sufficient in electricity, generated from bagasse and cane straw.
“It’s the only refinery in the country at present that is self-sufficient in electricity and doesn’t consume oil,” the directors said.
The sugar mill generates three megawatts of electricity, to be boosted to 4.5 megawatts next year. According to the officials, it supplies the mill, the distillery, the refinery and about 2,000 people in the “batey”, as the small community of workers’ housing in a sugar factory is called in Cuba.