Dr. Neville Trotz served as Dean, Faculty of Natural Sciences at the University of Guyana and Director of the Institute of Applied Science and Technology at Turkeyen, Guyana, before becoming Science Adviser to the Commonwealth Secretary-General (1991-1997). Most recently he served as Science Adviser to the Caribbean Community Climate Change Centre, based in Belmopan, Belize.
Recently we have been regaled with a barrage of information on oil and gas and plans for onshore facilities to utilise Guyana’s natural gas resources and to inter alia generate 150 MW of electricity for local use. There has also been some focus on greening the energy sector through exploitation of renewable sources of energy, mainly hydro (Amaila Falls) and wind (Hope Beach). It is not clear which strategy for a greener Guyana is being followed at this point of time but both the Low Carbon Development Strategy (LCDS) and the Green State Development Strategy have the common objective of transformation of our energy sector as part of our overall effort to achieve a low carbon economy. As we shape the future architecture of the energy sector it would be advisable not to ignore some low hanging fruits for energy generation which provide a win-win scenario for Guyana if implemented. I refer to the mundane but well-established technology of waste to energy. Under this umbrella we have a range of wastes to utilise – domestic waste, waste from sawmills, waste from the rice industry and other agriculture wastes including from livestock. We have over the years utilised the waste from the sugar industry (bagasse) and this is still a possibility should Guyana continue to be a major sugar producer.
Management of our domestic waste has always been a challenge for Caribbean countries. The favoured method is landfills but these are often poorly designed and can lead to both air and aquifer pollution. For small island states there is also the challenge of available space. If properly designed, constructed and managed, landfills provide a source of methane which is then utilised for energy generation. This has to be accompanied by facilities for sorting the waste into organic and non-organic matter. I am not familiar with what obtains at the Haag Bosch landfill on the East Bank but there have been complaints from residents downwind from the facility about the odour that emanates from it. It would be useful to assess the potential for harvesting the gas that it generates for use in generating energy. If Guyana persists with landfills, arrangements should be in place to ensure that they are designed so that they can be utilised for energy generation.
There has been in operation mature technologies for the transformation of domestic waste to energy, usually through a combustion process. One might ask why this approach has not been adopted in the region. It certainly is not as a result of a lack of interest but rather due to the unavailability of plants that operate at a scale that matches the amount of locally available waste. The plants on the market are designed to handle volumes of waste generated by large metropolitan cities and the wastes generated in our countries over a year would be able to provide feedstock to keep such a plant operational for about a few weeks. As a result if a country needed to pursue this avenue they would have had to commission a plant of the required capacity at astronomical costs. Some Caribbean countries had considered pooling and transporting their wastes to a designated waste to energy facility. Apart from the logistical problems posed by collection and transport, there was the additional social issue about local scepticism of processing other people’s waste. Recently there have been some companies that are addressing this sizing issue and designing plants that can operate in small economies as well as to utilise a range of feedstock including in one instance hospital wastes. I expect that these will start appearing across the region in due course, mainly to address the need to effectively deal with the waste pollution issue.
What of energy generation using wastes from the sawmilling and rice industries? Again there are mature affordable off the shelf technologies. Under the auspices of the Institute of Applied Science and Technology (IAST) as far back as the 1980s, these technologies were successfully introduced and utilised in Guyana. For wood waste, IAST worked with the Willems Timber Company at their facility in Kaow Island on the Essequibo River. At that time Kaow Island was a vibrant sawmilling enterprise and all of the island’s power was produced through the use of highly expensive diesel generators. The Institute’s engineers worked with personnel to install a state-of-the-art generating facility that utilised the enormous amount of wood waste generated by the sawmill. This resulted in significant savings and aesthetically more pleasant surroundings due to the absence of piles of wood waste. Residents also had the benefit of free electricity for their living quarters. The installed capacity of the plant far exceeded the needs of the Kaow Island facility and with support from the Canadian International Development Agency (CIDA) we explored the feasibility of a power cable link between Kaow Island and Bartica so that the excess power could be utilised there to meet the needs in that community. Unfortunately, there was no follow up on this but the project fully demonstrated the feasibility of wood waste to energy technology which could be applied across the length and breadth of Guyana. It would be useful to assess the amount of waste being generated by the industry at this time and to use this as a basis for supporting the use of this resource.
Rice husks are a major waste generated by the rice industry and can be seen piled up, many times
smouldering and creating environmental challenges outside the multiple rice milling facilities. Husks have tremendous value on the global market and we need to treat it as a resource and not a bothersome waste. Again, in the eighties the IAST entered into an arrangement with the Kayman Sankar Company to implement a project that would illustrate the feasibility of utilising the rice husk for energy generation at its milling facilities on the Essequibo coast and at Blairmont. Through the partnership, waste to energy plants specifically designed to use rice-husk as feedstock were installed at both locations. Both facilities were operated by Kayman Sankar personnel and generated all of the energy required to operate the mills from the installed facilities. Energy costs compared to those arising from the use of diesel generators or taking energy from the grid plummeted as a result of this transformation. Private sector interest in the sawmilling and the rice industries was attracted because we were able to make a business case for the investment, showing that the savings that accrue would pay back for the investment in a short time.
The story about the rice husk does not end there. After combustion in the waste to energy facility, the residue left is an ash referred to as Rice Husk Ash (RHA). It is highly abrasive and at that time the Institute promoted it as a good base for use in locally manufactured scouring powder – a kind of local Vim. At IAST we also carried out research in the laboratory and our preliminary work indicated that it could be used as an extender for Portland cement, thus lowering the price of cement blocks ( less use of expensive Portland cement per block). Indeed mixing at a certain level did not compromise the strength of the blocks. Subsequent research in the Faculty of Technology at the University of Guyana led to a publication in 1990 by A.A. Boateng and D, Skeete in the Journal of Cement and Concrete Research, on the “Incineration of rice hull for use as a cementitious material: the Guyana experience.” They studied the potential of Rice Husk Ash derived from the incineration of rice husks as an extender to imported Portland cement and found that the rice husk ash produced from the incineration of rice husks is amorphous and highly reactive when mixed with lime and water. The study concluded that use of the rice husks generated in the rice industry could support a rural building industry through blending of the ash with Portland cement, thus significantly reducing the costs of building.
Fast forward to an article appearing on April 06, 2017 in the Dublin Business Wire, Research and Markets which reported the following : “The global Rice Husk Ash market is projected to reach USD 2.54 billion by 2021, at a compound annual growth rate (CAGR) of 5.4% from 2016 to 2021. Low manufacturing and raw material cost and use of RHA to produce high purity silica are the key factors driving the growth of the market. The increasing use of RHA instead of silica fume and fly ash in the cement and construction industry, and the high demand of RHA in the Asia-Pacific and Middle East & Africa regions are some of the key opportunities for the RHA industry. By application, the silica segment of the RHA market is projected to grow at the highest CAGR from 2016 to 2021. RHA has attracted the industry players as it is not only low cost but also the only known renewable source for producing silica. The use of RHA also helps the industry players in gaining carbon credits due to its renewable nature.”
Rice Husk Ash was also projected to continue its dominance during the forecast period, owing to increasing use in various applications, such as building & construction, steel industry, and ceramics & refractory, among others.
With the continued expansion of the local rice industry and the implementation of Guyana’s Low Carbon Development Strategy, the industry will find itself in a win-win situation by utilising the husks for energy generation and utilising the ash as a cement extender in the building industry or preferably utilising it as the raw material to produce pure silicon for the solar energy industry. With regards to the latter, Guyana’s silica sand is the raw material for the production of the silica used for the manufacture of photovoltaic cells for the solar energy industry. The process for transformation however is highly energy intensive and intricate. However Guyana’s vast deposits of silica leached over time is the ideal raw material for the production of the pure silica required by the solar energy industry. This coupled with the cheaper production from available RHA can for the basis of a thriving industry in Guyana. The rehabilitation of Tumatumari could be tied in with an industrial complex that draws on our sand and other clay resources.
Other opportunities exist in the sugar industry through use of bagasse, a technology we are familiar with. One approach to sugar is to regard it primarily as an industry generating energy, through cogeneration utilising the bagasse and treating sugar as a by product. Agronomic research has produced high fibre planting material that meets the specifications for this type of approach. As Guyana proceeds to consolidate its agricultural sector there would be many opportunities to generate energy from agricultural waste. IAST successfully implemented a national biogas programme. This involved the use of animal waste (livestock, pigs) to generate biogas which was used for heating, lighting and refrigeration. The project developed and employed digesters for domestic and institutional use. Over a four year period about ninety eight digesters were built and deployed in many communities across Guyana. The recent disclosure that a large scale dairy farm is being considered as part of a project to provide dairy products for Guyana opens the door for consideration of the installation of an industrial sized biogas plant utilising all of the animal waste that would be available. This would provide the energy required for their processing activities. Incidentally the slurry recovered after the fermentation cycle is completed is an excellent bio fertiliser which can be utilised as part of our thrust for sustainable and low emission agriculture.
All of these activities taken together are implementable and can make a significant contribution to our quest of weaning Guyana off of a fossil fuel based energy sector while at the same time contributing to the profitability in the rice and timber industries, providing new opportunities for industrial production from the Rice Husk Ash in the rice industry, and assisting with the management of the environmental challenges posed by waste to our health and well-being. All of these actions can and should be financed using local capital and not through the usual high cost international financing mechanisms. In our haste to address the energy issue locally let us not forget these low hanging fruit that can, with the right policy environment and a progressive private sector, redound to the benefit of all Guyanese and to the achievement of a climate resilient and low carbon development pathway for Guyana.
