Biomass Electricity Generation Jessica Hatfield
Gasification of biomass or coal is a relatively old technology which has a very interesting history. In Western European cities, town gas was produced by the gasification of coal before natural gas became widely available. By 1850, large parts of London were lit by gasifier-produced gas lights. However, with the increasing availability of other energy sources and electrification, the technology soon lost its importance. In the early years of the 20th century, gasifier systems to power stationary engines and trucks were demonstrated but did not gain general acceptance. The technology reappeared only after petroleum fuels became scarce during World War II. Almost one million gasifier powered vehicles were in use during that time. Yet, with increasing availability of diesel and gasoline, this technology was again abandoned. Interest in Gasification Technology again resurfaced during the energy crisis of the 1970s and 1980s. By the 1980s about fifteen (15) manufacturers were offering wood and charcoal power gasifiers. Brazil, China, India, Indonesia, the Philippines and Thailand had gasifier programmes based on locally developed technologies. Scandinavia also embraced biomass gasification using residues of the wood, pulp and paper industry. Worldwide, the development and construction of new small and medium-size gasification plants has once more gained momentum during the last decade parallel to the discussions on climate change, solid waste management and reducing our carbon footprint. Many plants have been installed in India and South-East Asia. In Germany, the guaranteed high feed-in tariffs triggered the installation of about 50 gasifier power plants. In Guyana, there is an abundance of biomass suitable for gasification to create electricity in the form of rice husks and coconut husks. A greater incentive towards this direction is the improper disposal of coconut waste as reported by National Agricultural and Research Extension Institute (NAREI) in the local press (discarded dried husk and green shells) is a growing challenge in Guyana. In both the rural communities and built areas, improperly disposed shells are associated with environmental problems such as clogged waterways and breeding grounds for mosquitoes and vermin. It is now feasible that electricity could be generated from the coconut husks using the latest pyrolis gasification technology. 1
Energypedia
Electricity can be generated from the rice and coconut husks. In the case of rice husk, the heat generated from the gas turbines can be recovered and used as the source of energy for drying the paddy or parboiling the rice. Its high levels of efficiency and energy conversion create a consistent source of electricity production without generating any carbon emissions from the process. Carbon is stored in the waste product (ash), which is less than 2% of the total volume of biomass processed. 42 GREEN GUYANA - ADVANCING SUSTAINABLE DEVELOPMENT
The type of gasifier suitable for this process is known as an Imbert (or Throated) Fixed-Bed Downdraft Gasifier. The key advantage of such gasifiers is their ability to inherently produce gas with low tar and particulates making it wellsuited for power-generation. The gas derived from the rice husks is fed into the gas engines that drive the powergenerators. There are many major rice mills in Guyana and these are considered suitable for the construction of gasification power plants. The introduction of this technology would see the removal of thousands of tons of waste rice husks from the countryside and resolve the environment challenges currently being experienced by rice mills. Rice husk gasification process will generate clean sustainable electricity, rice husk ash and a reduction in carbon emissions. Rice husk ash contains 85% to 90% amorphous silica and is in great demand by the cement industry. The particle size of cement is 35 microns and there may be formation of void in the concrete mixes. This reduces the strength and quality of the concrete. The rice husk ash derived from gasification has a very small particle size of 25 microns which when added to the cement mix fills the interstices in between the cement and the aggregate. This creates a superior high strength cement or concrete which is used in the making of bridges, marine construction and building power plants. Rice Husk Ash is also sold as an insulator in the steel making process. It is useful to note that the rice husk gasification process saves 1 litre of oil for every 6kg rice husk utilised. The coconut husks and rice husks resource have the distinct advantage of being a renewable and relatively clean fuel. Benefits from its use, therefore, includes not only the displacement of fossil fuels but also the preservation of our environment. Guyana’s growing coconut industry also has great potential for the generation of renewable energy using its waste materials currently discarded. Recent strides in pyrolysis gasification means that waste to energy projects are now on the table nor only for agricultural waste but with waste from landfill and other sites being converted into energy. 2
A critical look at rice husk gasification in Cambodia: Technology and sustainability Hong Nam Nguyen, Minh Ha-Duong, Laurent van de Steene 2015.
Jessica Hatfield is a successful entrepreneur. She cofounded Clenergen Corporation to provide large scale sustainable energy crops for biomass electricity generation Jessica worked in Africa in the mining industry looking at land remediation using energy crops. In 2006 she was elected into the United Nations Environment Programme Who’s Who of Women and the Environment. Jessica has been working in the coconut and rice industry developing biomass gasification systems with the rice millers and coconut producers in Guyana. She was also active in developing with scientific partners a range of polyploid energy crop alternatives which produce maximum yields per acre for fuelling biomass gasification power stations. One of her heartfelt meme is: “The true meaning of life is to plant trees, under whose shade you do not expect to sit.”
