Cenicafé generates electricity from coffee tree wood
It is the first time that the use of this coffee byproduct is researched to generate electricity, not only in Colombia, but in the world, hence the importance of this cutting-edge technological development.
The National Coffee Research Center (Cenicafé), the scientific research and technological development arm of the Colombian Coffee Growers Federation (FNC), advances in generation of electricity on a large scale from the coffee tree wood, an initiative that places Cenicafé at the forefront of sustainable, renewable and alternative energy.
The project, within the framework of the Energy and Climate Partnership of the Americas (ECPA) initiative, is developed by the team of Cenicafé’s Agricultural Engineering discipline, under the supervision of researcher Carlos Oliveros.
It is the first time that the coffee tree wood is used to generate electricity, not only in Colombia, but in the world, hence the importance of this development. On average, per every 1.25 kg of coffee tree wood chips it is possible to generate one electric kilowatt (1kWe).
The main innovation by Cenicafé lies in adapting existing technology, a gasifier of open patent, to use of coffee tree wood, something that had not been put into practice so far, because in Colombia the issue had only been worked at academic and research levels.
The correct operation of the equipment requires coffee tree wood chips of 10-40 mm long. Coffee tree wood is difficult to chip, mainly because it is hard and has many knots that produce chips whose size is different from that required for the equipment operation. With a blade chipping machine assembled in Colombia, a yield of 57% of chips was achieved. The coffee tree stems must be cut to 80 cm long. The chips must have a 10% to 15% water content.
The coffee tree wood is a lignocellulosic material that in the gasification process becomes combustible gas, containing 20% of carbon monoxide (CO), 20% of hydrogen (H2) and 3-4% of methane (CH4). “These gases are used to move an internal combustion engine that in turn moves an electric generator,” Oliveros explains.
In coffee-producing countries such as Colombia, coffee tree wood as waste is abundant, either from cuts or renovations, because between 80,000 and 90,000 coffee hectares are renovated per year, and every hectare on average yields about 17 tons of dry wood, which would work to produce 697.7 GWe every year.
“The wood is the result of the photosynthetic activity of the plant, which captures the CO2 from the atmosphere. As an additional advantage of biomass gasification, not all captured CO2 is returned to the atmosphere, but an important part (up to 50%) becomes carbon monoxide (CO), which is fuel that can be used to move an engine, generate electricity, or produce heat,” Oliveros explains.
This technology can be used on different scales and hence its potential is very large. “A power plant can generate from 10 kWe up to over 1 MWe, depending on the need of a given region. The required coffee tree wood will always be available in sufficient quantity, without incurring in large transportation costs,” he notes. The current cost of 1kWe produced with this equipment is 29 dollar cents, including the generator, the chipping machine and the labor.
With this technology it is possible to decentralize generation of electric power, sustainably benefiting communities that are not connected to the national power grid or lack a good service, besides replacing fossil fuels that produce greenhouse gases.
Origins of the project
The project began with the training of Oliveros at the US Agricultural Research Service in 2014. Then the US Department of Agriculture facilitated an equipment designed to generate electricity from biomass, manufactured by the American company All Power Labs.
The equipment converts wood pieces into fuel gas with low content of tars, which is used to operate an internal combustion engine and, through a generator, to produce up to 20 kWe.
The ECPA initiative seeks to replace fossil fuels, which produce greenhouse gas emissions, with gasified biomass, a very ecofriendly power alternative.
Recently, the US Ambassador to Colombia, Kevin Whitaker, visited the facilities of Cenicafé, in Chinchiná, Caldas, to learn about the progress of this project.