Category Archives: Biomass Energy

Biomass Energy in Nigeria: An Overview

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biomass-sustainabilityOil and gas accounts for over 70% of energy consumed in Nigeria, according to the World Bank. Considering this dependency on fossil oil and possibility of it running out in the future, there should be an urgent intervention to look into other ways to generate energy in Nigeria. The world is moving away gradually from fossil oil and aligning towards sustainable energy resources to substitute conventional fuel, Nigeria should not be exempted from this movement. Biomass, a popular form of renewable energy, is considered as a credible and green alternative source of energy which many developed and developing countries have been maximizing to its potential.

Power generation and supply have been inadequate in Nigeria. This inadequacy of power limits human, commercial and industrial productivity and economic growth . What is the use of infrastructure without constant electricity? Even God created light first. Sustainable and constant supply of power should be one of the priority of government in nation development. Investing in biomass will cause an increase in the amount of power generated in Nigeria. Infact, biomass energy has the potential to resolve the energy crisis in the country in the not so distant future.

What is Biomass

The word biomass refers to organic matter (mainly plants) which acts as a source of sustainable and renewable energy. It is a renewable energy source because the plants can be replaced as oppose to the conventional fossil fuel which is not renewable. Biomass energy is a transferred energy from the sun; plants derives energy from the sun through photosynthesis which is further transferred through the food chain to animals’ bodies and their waste.

Biomass has the potential to provide an affordable and sustainable source of energy, while at the same time help in curbing the green house effect. In India the total biomass generation capacity is 8,700 MW according to U.S. of Commerce’s International Trade Administration, whereas the generating capacity in U.S. is 20,156  MW with 178 biomass power plants, according to Biomass Magazine.

Power Sector in Nigeria

Unfortunately, the total installed electricity capacity generated in Nigeria is 12,522MW, well below the current demand of 98,000MW . The actual output is about 3,800MW, resulting in a demand shortfall of 94,500MW throughout the country. As a result of this wide gap between demand and output, only 45% of Nigeria’s population has access to electricity. Renewable energy contributed 19% of total electricity generated in Nigeria out of which biomass contribution is infinitesimal.

Electricity generation for Nigeria’s grid is largely dominated by two sources; non-renewable thermal (natural gas and coal) and renewable (hydro). Nigeria depends on non-renewable energy despite its vast potential in renewable sources such as solar, wind, biomass and hydro. The total potential of these renewables is estimated at over 68,000MW, which is more than five times the current power output.

Biomass Resources in Nigeria

Biomass can come in different forms like wood and wood waste, agriculture produce and waste, solid waste.

Wood

Electricity can be generated with wood and wood product/waste(like sawdust) in modern day through cogeneration, gasification or pyrolysis.

Agriculture Residues

In Nigeria, agricultural residues are highly important sources of biomass fuels for both the domestic and industrial sectors. Availability of primary residues for energy application is usually low since collection is difficult and they have other uses as fertilizer, animal feed etc.

However secondary residues are usually available in relatively large quantities at the processing site and may be used as captive energy source for the same processing plant involving minimal transportation and handling cost.

Municipal Solid Waste

Back then in secondary school, I learnt that gas could be tapped from septic tank which could further be used for cooking.  Any organic waste (like animal waste, human waste) when decomposed by anaerobic microorganisms releases biogas which can be tapped and stored for either cooking or to generate electricity.

Biomass can be used to provide heat and electricity as well as biofuel and biogas for transport. There are enough biomass capacity to meet our demand for electricity and other purposes. From climatic point of view, there is a warm climate in Nigeria which is a good breeding ground for bacteria to grow and decompose the wastes. There are plant and animal growth all year round which in turn create waste and consequently produce biomass.

In November 2016, The Ebonyi State Government  took over  the United Nations Industrial Development Organization (UNIDO) demonstration biomass gasifier power plant located at the UNIDO Mini -industrial cluster in Ekwashi Ngbo in Ohaukwu Local Government Area of the State. The power plant is to generate 5.5 Megawatt energy using rice husk and other available waste materials available. More of these type of power plants and commitment are needed to utilize the potential of biomass fully.

Why Biomass Energy?

Since biomass makes use of waste to supply energy, it helps in waste management. It also has the potential to supply more energy (10 times) than the one produced from sun and wind. Biomass will lead to increase in revenue generation and conserves our foreign exchange. Increase in energy generation will yield more productivity for industries and the rate at which they are shutting down due to the fact that they spend more on power will be reduced to minimal.

Many local factories/companies will spring up and foreign investors will be eager to invest in Nigeria with little concern about power. Establishment of biopower plants will surely create more jobs and indirectly reduce the number of people living in poverty which is increasing everyday at an alarming rate.

Africa’s most populous country needs more than 10 times its current electricity output to guarantee supply for its 198 million people – nearly half of whom have no access at all, according to power minister Babatunde Fashola. Biomass energy potential in Nigeria is promising –  with heavy investment, stake holder cooperation and development of indigenous technologies. The deployment of large-scale biomass energy systems will not only significantly increase Nigeria’s electricity capacity but also ease power shortages in the country.

Renewable Energy in Refugee Camps

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dabaab-refugee-campAccess to clean and affordable energy is a prerequisite for sustainable development of mankind, and refugees are no exception. Refugee camps across the world house more than 65 million people, and almost all refugee camps are plagued by fuel poverty. Needless to say, urgent measure are required to make camps livable and sustainable.

Rapid advancements in renewable energy technologies have made it possible to deploy such systems on various scales.  The scalability potential of renewable energy systems makes them well-suited for refugee camps, especially in conflict-afflicted areas of the Middle East, Asia and Africa.

Renewable energy in refugee camps can be made available in the form of solar energy, biomass energy and wind energy. Solar panels, solar cooking units, solar lanterns, biomass cookstoves and biogas plants are some of the popular renewable energy technologies that can improve living standards in refugee camps. It is important to focus on specific needs of refugees and customization of technology towards local conditions. For example, solar technologies are better understood than biogas systems in Jordan.

Solar Energy

Solar energy can provide long-term resilience to people living in refugee camps. With many camps effectively transformed into full-fledged towns and cities, it is essential to harness the power of sun to run these camps smoothly. Solar cookers, solar lanterns and solar water heaters are already being used in several refugee camps, and focus has now shifted to grid-connected solar power projects.

The 5MW Azraq solar project is the world’s first grid-connected renewable energy project to be established in a refugee camp. The project is being funded entirely by Ikea through the Brighter Lives for Refugees campaign. The program, now in its third year, seeks to improve the lives of refugees around the world by providing access to sustainable energy supplies.

Biomass Energy

Due to lack of land and resources, refugee camps puts tremendous pressure on natural vegetation, especially supply of fuel wood to camp-dwellers. Replacement of traditional stoves with efficient biomass-fired cook stoves can save as much as 80% of cooking fuel.

Instead of wood, it would be also be a good option to use agricultural wastes, like husk and straw. Another interesting proposition for refugee camps is to set up small-scale DIY biogas plants, based on human wastes and food residuals. The biogas produced can be used as a cooking medium as well as for power/heat generation.

Wind Energy

Small wind turbines can also play a key role in providing energy to dwellers of refugee camps. Such turbines are used for micro-generation and can provide power from 1kW to 300kW. Majority of small wind turbines are traditional horizontal axis wind turbines but vertical axis wind turbines are a growing type of wind turbine in the small wind market. Small wind turbines are usually mounted on a tower to raise them above any nearby obstacles, and can sited in refugee camps experiencing wind speeds of 4m/s or more.

Solar lights in Azraq Refugee Camp (Jordan)

Solar lights in Azraq Refugee Camp (Jordan)

Conclusions

Renewable energy systems have the potential to improve living standards in refugee camps and ease the sufferings of displaced and impoverished communities. Solar panels, biogas system, biomass stoves and micro wind turbines are some of the renewable energy systems that can be customized for refugee camps and transform them into a less harsh place for displaced people.

Is Green Car Fuel A Reality?

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drop-in-biofuelsVehicles remain a huge global pollutant, pumping out 28.85Tg of CO2 in Maharashtra alone, according to a study by the Indian Institute for Science in Bangalore. However, vehicles cannot be discarded, as they form the lifeblood of the country’s towns and cities. Between electric vehicles and hybrids, work is being done to help rectify the situation by making use of green car fuel and technological advancements.

Emissions continue to be a huge issue, and there are two main options for helping to rectify that. The first is electric, which is seeing widespread adoption; and the second, biomass fuel, for more traditional vehicles. Between the two, excellent progress is being made, but there’s much more to be done.

How electric is helping

Electric cars are favoured heavily by the national authorities. A recent Times of India report outlined how the government is aiming for an all-electric vehicle fleet by 2030 and is pushing this through with up to US$16m of electric vehicle grants this year. Green vehicles are obviously a great choice, improving in-city noise and air pollution whilst providing better vehicular safety to boot; a study by the USA’s MIT suggested that electric vehicles are all-around safer than combustion.

However, where EVs fall down to some extent is through the energy they use. As they are charged from the electricity grid, this means that the electricity is largely derived from fossil fuels – official statistics show that India is 44% powered by coal. Ultimately, however, this does mean that emissions are reduced. Fuel is only burned at one source, and oil refining isn’t done at all, which is another source of pollutants. However, as time goes on and the government’s energy policy changes, EVs will continue to be a great option.

The role of biofuels

Biofuels are seeing a huge growth in use – BP has reported that globally, ethanol production grew 3% in 2017. Biofuel is commonly a more favoured option by the big energy companies given the infrastructure often available already to them. While biofuel has been slow on the uptake in India, despite the massive potential available for production, there are now signs this is turning around with the construction of two US$790m biofuel facilities.

Biofuels are increasingly being used to power vehicles around the world

The big benefit of biofuel is that it will have a positive impact on combustion and electric vehicles. The Indian government has stated they intend to use biofuel alongside coal production, with as much as 10% of energy being created using biofuel. Therefore, despite not being emission-free, biofuel will provide a genuine green energy option to both types of eco-friendly vehicle.

Green car fuel is not entirely clean. The energy has to come from somewhere, and in India, this is usually from coal, gas, and oil. However, the increase in biofuel means that this energy will inevitably get cleaner, making green car fuel absolutely a reality.

Biomass Energy and Sustainability

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biomass-sustainabilityBiomass energy systems offer significant possibilities for reducing greenhouse gas emissions due to their immense potential to replace fossil fuels in energy production. Biomass reduces emissions and enhances carbon sequestration since short-rotation crops or forests established on abandoned agricultural land accumulate carbon in the soil. Biomass energy usually provides an irreversible mitigation effect by reducing carbon dioxide at source, but it may emit more carbon per unit of energy than fossil fuels unless biomass fuels are produced in a sustainable manner.

Biomass resources can play a major role in reducing the reliance on fossil fuels by making use of thermo-chemical conversion technologies. In addition, the increased utilization of biomass-based fuels will be instrumental in safeguarding the environment, generation of new job opportunities, sustainable development and health improvements in rural areas.

The development of efficient biomass handling technology, improvement of agro-forestry systems and establishment of small and large-scale biomass-based power plants can play a major role in sustainable development of rural as well as urban areas. Biomass energy could also aid in modernizing the agricultural economy and creating significant job opportunities.

Harvesting practices remove only a small portion of branches and tops leaving sufficient biomass to conserve organic matter and nutrients. Moreover, the ash obtained after combustion of biomass compensates for nutrient losses by fertilizing the soil periodically in natural forests as well as fields.

The impact of forest biomass utilization on the ecology and biodiversity has been found to be insignificant. Infact, forest residues are environmentally beneficial because of their potential to replace fossil fuels as an energy source.

A quick glance at popular biomass resources

A quick glance at popular biomass resources

Plantation of energy crops on abandoned agricultural land will lead to an increase in species diversity. The creation of structurally and species diverse forests helps in reducing the impacts of insects, diseases and weeds. Similarly the artificial creation of diversity is essential when genetically modified or genetically identical species are being planted.

Short-rotation crops give higher yields than forests so smaller tracts are needed to produce biomass which results in the reduction of area under intensive forest management. An intelligent approach in forest management will go a long way in the realization of sustainability goals.

Improvements in agricultural practices promises to increased biomass yields, reductions in cultivation costs, and improved environmental quality. Extensive research in the fields of plant genetics, analytical techniques, remote sensing and geographic information systems (GIS) will immensely help in increasing the energy potential of biomass feedstock.

A large amount of energy is expended in the cultivation and processing of crops like sugarcane, coconut, and rice which can met by utilizing energy-rich residues for electricity production. The integration of biomass-fueled gasifiers in coal-fired power stations would be advantageous in terms of improved flexibility in response to fluctuations in biomass availability and lower investment costs. The growth of the biomass energy industry can also be achieved by laying more stress on green power marketing.

Role of Biomass Energy in Rural Development

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biomass-balesBiomass energy systems not only offer significant possibilities for clean energy production and agricultural waste management but also foster sustainable development in rural areas. The increased utilization of biomass wastes will be instrumental in safeguarding the environment, generation of new job opportunities, sustainable development and health improvements in rural areas.

Biomass energy has the potential to modernize the agricultural economy and catalyze rural development. The development of efficient biomass handling technology, improvement of agro-forestry systems and establishment of small, medium and large-scale biomass-based power plants can play a major role in rural development.

Sustainable harvesting practices remove only a small portion of branches and tops leaving sufficient biomass to conserve organic matter and nutrients. Moreover, the ash obtained after combustion of biomass compensates for nutrient losses by fertilizing the soil periodically in natural forests as well as fields.

Planting of energy crops on abandoned agricultural lands will lead to an increase in species diversity. The creation of structurally and species diverse forests helps in reducing the impacts of insects, diseases and weeds. Similarly the artificial creation of diversity is essential when genetically modified or genetically identical species are being planted.

Improvements in agricultural practices promises to increased biomass yields, reductions in cultivation costs, and improved environmental quality. Extensive research in the fields of plant genetics, analytical techniques, remote sensing and geographic information systems (GIS) will immensely help in increasing the energy potential of biomass feedstock.

Rural areas are the preferred hunting ground for the development of biomass sector worldwide. By making use of various biological and thermal processes (anaerobic digestion, combustion, gasification, pyrolysis), agricultural wastes can be converted into biofuels, heat or electricity, and thus catalyzing sustainable development of rural areas economically, socially and environmentally.

Biomass energy can reduce 'fuel poverty' in remote and isolated communities

Biomass energy can reduce ‘fuel poverty’ in remote and isolated communities

A large amount of energy is utilized in the cultivation and processing of crops like sugarcane, wheat and rice which can met by utilizing energy-rich residues for electricity production. The integration of biomass-fueled gasifiers in coal-fired power stations would be advantageous in terms of improved flexibility in response to fluctuations in biomass availability and lower investment costs.

There are many areas in India where people still lack access to electricity and thus face enormous hardship in day-to-day lives. Biomass energy promises to reduce ‘fuel poverty’ commonly prevalent among remote and isolated communities.  Obviously, when a remote area is able to access reliable and cheap energy, it will lead to economic development and youth empowerment.

Biomass Energy in China

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biomass-chinaBiomass energy in China has been developing at a rapid pace. The installed biomass power generation capacity in China increased sharply from 1.4 GW in 2006 to 14.88 GW in 2017. While the energy share of biomass remains relatively low compared to other sources of renewable energy, China plans to increase the proportion of biomass energy up to 15 percent and total installed capacity of biomass power generation to 30 GW by 2030.

In terms of impact, the theoretical biomass energy resource in China is about 5 billion tons coal equivalent, which equals 4 times of all energy consumption. As per conservative estimates, currently China is only using 5 percent of its total biomass potential.

According to IRENA, the majority of biomass capacity is in Eastern China, with the coastal province of Shandong accounting for 14 percent of the total alone. While the direct burning of mass for heat remains the primary use of biomass in China, in 2009, composition of China’s biomass power generation consisted in 62 percent of straw direct-fired power generation and 29 percent of waste incineration, with a mix of other feedstock accounting for the remaining 9 percent.

Biomass Resources in China

Major biomass resources in China include waste from agriculture, forestry, industries, animal manure and sewage, and municipal solid waste. While the largest contributing sources are estimated to be residues from annual crop production like wheat straw, much of the straw and stalk are presently used for cooking and heating in rural households at low efficiencies. Therefore, agricultural residues, forestry residues, and garden waste were found to be the most cited resources with big potential for energy production in China.

Agricultural residues are derived from agriculture harvesting such as maize, rice and cotton stalks, wheat straw and husks, and are most available in Central and northeastern China where most of the large stalk and straw potential is located. Because straw and stalks are produced as by-products of food production systems, they are perceived to be sustainable sources of biomass for energy that do not threaten food security.

Furthermore, it is estimated that China produces around 700 Mt of straw per year, 37 percent of which is corn straw, 28 percent rice, 20 percent wheat and 15 percent from various other crops. Around 50 percent of this straw is used for fertilizers, for which 350 Mt of straw is available for energy production per year.

Biomass resources are underutilized across China

Biomass resources are underutilized across China

Forestry residues are mostly available in the southern and central parts of China. While a few projects that use forestry wastes like tree bark and wood processing wastes are under way, one of the most cited resources with analyzed potential is garden waste. According to research, energy production from garden waste biomass accounted for 20.7 percent of China’s urban residential electricity consumption, or 12.6 percent of China’s transport gasoline demand in 2008.

Future Perspectives

The Chinese government believes that biomass feedstock should neither compete with edible food crops nor cause carbon debt or negative environmental impacts. As biomass takes on an increasing significant role in the China’s national energy-mix, future research specific to technology assessment, in addition to data collection and supply chain management of potential resources is necessary to continue to understand how biomass can become a game-changer in China’s energy future.

References

IRENA, 2014. Renewable Energy Prospects: China, REmap 2030 analysis. IRENA, Abu Dhabi. www.irena.org/remap

National Academy of Engineering and NRC, 2007: Energy Futures and Urban Air Pollution: Challenges for China and the United States.

Xingang, Z., Zhongfu, T., Pingkuo, L, 2013. Development goal of 30 GW for China’s biomass power generation: Will it be achieved? Renewable and Sustainable Energy Reviews, Volume 25, September 2013, 310–317.

Xingang, Z., Jieyu, W., Xiaomeng, L., Tiantian, F., Pingkuo, L, 2012. Focus on situation and policies for biomass power generation in China. Renewable and Sustainable Energy Reviews, Volume 16, Issue 6, August 2012, 3722–3729.

Li, J., Jinming, B. MOA/DOE Project Expert Team, 1998. Assessment of Biomass Resource Availability in China. China Environmental Science Press, Beijing, China.

Klimowicz, G., 2014. “China’s big plans for biomass,” Eco-Business, Global Biomass Series, accessed on Apr 6, 2015.

Shi, Y., Ge, Y., Chang, J., Shao, H., and Tang, Y., 2013. Garden waste biomass for renewable and sustainable energy production in China: Potential, challenges and development. Renewable and Sustainable Energy Reviews 22 (2013) 432–437

Xu, J. and Yuan, Z, 2015. “An overview of the biomass energy policy in China,” BESustainable, May 21, 2015.

Summary of Biomass Combustion Technologies

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Direct combustion is the best established and most commonly used technology for converting biomass to heat. During combustion, biomass fuel is burnt in excess air to produce heat. The first stage of combustion involves the evolution of combustible vapours from the biomass, which burn as flames. The residual material, in the form of charcoal, is burnt in a forced air supply to give more heat. The hot combustion gases are sometimes used directly for product drying, but more usually they are passed through a heat exchanger to produce hot air, hot water or steam.

The combustion efficiency depends primarily on good contact between the oxygen in the air and the biomass fuel. The main products of efficient biomass combustion are carbon dioxide and water vapor, however tars, smoke and alkaline ash particles are also emitted. Minimization of these emissions and accommodation of their possible effects are important concerns in the design of environmentally acceptable biomass combustion systems.

Biomass combustion systems, based on a range of furnace designs, can be very efficient at producing hot gases, hot air, hot water or steam, typically recovering 65-90% of the energy contained in the fuel. Lower efficiencies are generally associated with wetter fuels. To cope with a diversity of fuel characteristics and combustion requirements, a number of designs of combustion furnaces or combustors are routinely utilized around the world

Underfeed Stokers

Biomass is fed into the combustion zone from underneath a firing grate. These stoker designs are only suitable for small scale systems up to a nominal boiler capacity of 6 MWth and for biomass fuels with low ash content, such as wood chips and sawdust. High ash content fuels such as bark, straw and cereals need more efficient ash removal systems. Sintered or molten ash particles covering the upper surface of the fuel bed can cause problems in underfeed stokers due to unstable combustion conditions when the fuel and the air are breaking through the ash covered surface.

Grate Stokers

The most common type of biomass boiler is based on a grate to support a bed of fuel and to mix a controlled amount of combustion air, which often enters from beneath the grate. Biomass fuel is added at one end of the grate and is burned in a fuel bed which moves progressively down the grate, either via gravity or with mechanical assistance, to an ash removal system at the other end. In more sophisticated designs this allows the overall combustion process to be separated into its three main activities:

  • Initial fuel drying
  • Ignition and combustion of volatile constituents
  • Burning out of the char.

Grate stokers are well proven and reliable and can tolerate wide variations in fuel quality (i.e. variations in moisture content and particle size) as well as fuels with high ash content. They are also controllable and efficient.

Fluidized Bed Boilers

The basis for a fluidized bed combustion system is a bed of an inert mineral such as sand or limestone through which air is blown from below. The air is pumped through the bed in sufficient volume and at a high enough pressure to entrain the small particles of the bed material so that they behave much like a fluid.

The combustion chamber of a fluidized bed plant is shaped so that above a certain height the air velocity drops below that necessary to entrain the particles. This helps retain the bulk of the entrained bed material towards the bottom of the chamber. Once the bed becomes hot, combustible material introduced into it will burn, generating heat as in a more conventional furnace. The proportion of combustible material such as biomass within the bed is normally only around 5%. The primary driving force for development of fluidized bed combustion is reduced SO2 and NOx emissions from coal combustion.

Bubbling fluidized bed (BFB) combustors are of interest for plants with a nominal boiler capacity greater than 10 MWth. Circulating fluidized bed (CFB) combustors are more suitable for plants larger than 30 MWth. The minimum plant size below which CFB and BFB technologies are not economically competitive is considered to be around 5-10 MWe.

Biomass Resources from Sugar Industry

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Sugarcane is one of the most promising agricultural sources of biomass energy in the world. It is the most appropriate agricultural energy crop in most sugarcane producing countries due to its resistance to cyclonic winds, drought, pests and diseases, and its geographically widespread cultivation. Due to its high energy-to-volume ratio, it is considered one of nature’s most effective storage devices for solar energy and the most economically significant energy crop. The climatic and physiological factors that limit its cultivation to tropical and sub-tropical regions have resulted in its concentration in developing countries, and this, in turn, gives these countries a particular role in the world’s transition to sustainable use of natural resources.

According to the International Sugar Organization (ISO), Sugarcane is a highly efficient converter of solar energy, and has the highest energy-to-volume ratio among energy crops. Indeed, it gives the highest annual yield of biomass of all species. Roughly, 1 ton of Sugarcane biomass-based on Bagasse, foliage and ethanol output – has an energy content equivalent to one barrel of crude oil.   Sugarcane produces mainly two types of biomass, Cane Trash and Bagasse. Cane Trash is the field residue remaining after harvesting the Cane stalk and Bagasse is the milling by-product which remains after extracting sugar from the stalk. The potential energy value of these residues has traditionally been ignored by policy-makers and masses in developing countries. However, with rising fossil fuel prices and dwindling firewood supplies, this material is increasingly viewed as a valuable renewable energy resource.

Sugar mills have been using Bagasse to generate steam and electricity for internal plant requirements while Cane Trash remains underutilized to a great extent. Cane Trash and Bagasse are produced during the harvesting and milling process of Sugarcane which normally lasts 6 to 7 months.

Around the world, a portion of the Cane Trash is collected for sale to feed mills, while freshly cut green tops are sometimes collected for farm animals. In most cases, however, the residues are burned or left in the fields to decompose. Cane Trash, consisting of Sugarcane tops and leaves can potentially be converted into around 1kWh/kg, but is mostly burned in the field due to its bulkiness and its related high cost for collection/transportation.

On the other hand, Bagasse has been traditionally used as a fuel in the Sugar mill itself, to produce steam for the process and electricity for its own use. In general, for every ton of Sugarcane processed in the mill, around 190 kg Bagasse is produced. Low pressure boilers and low efficiency steam turbines are commonly used in developing countries. It would be a good business proposition to upgrade the present cogeneration systems to highly efficient, high pressure systems with higher capacities to ensure utilization of surplus Bagasse.

Importance of Biomass Energy

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Biomass energy has rapidly become a vital part of the global renewable energy mix and account for an ever-growing share of electric capacity added worldwide. Renewable energy supplies around one-fifth of the final energy consumption worldwide, counting traditional biomass, large hydropower, and “new” renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels).

Traditional biomass, primarily for cooking and heating, represents about 13 percent and is growing slowly or even declining in some regions as biomass is used more efficiently or replaced by more modern energy forms. Some of the recent predictions suggest that biomass energy is likely to make up one third of the total world energy mix by 2050. Infact, biofuel provides around 3% of the world’s fuel for transport.

Biomass energy resources are readily available in rural and urban areas of all countries. Biomass-based industries can foster rural development, provide employment opportunities and promote biomass re-growth through sustainable land management practices.

The negative aspects of traditional biomass utilization in developing countries can be mitigated by promotion of modern waste-to-energy technologies which provide solid, liquid and gaseous fuels as well as electricity. Biomass wastes encompass a wide array of materials derived from agricultural, agro-industrial, and timber residues, as well as municipal and industrial wastes.

The most common technique for producing both heat and electrical energy from biomass wastes is direct combustion. Thermal efficiencies as high as 80 – 90% can be achieved by advanced gasification technology with greatly reduced atmospheric emissions.

Combined heat and power (CHP) systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity. Biochemical processes, like anaerobic digestion and sanitary landfills, can also produce clean energy in the form of biogas and producer gas which can be converted to power and heat using a gas engine.

Advantages of Biomass Energy

Bioenergy systems offer significant possibilities for reducing greenhouse gas emissions due to their immense potential to replace fossil fuels in energy production. Biomass reduces emissions and enhances carbon sequestration since short-rotation crops or forests established on abandoned agricultural land accumulate carbon in the soil.

Bioenergy usually provides an irreversible mitigation effect by reducing carbon dioxide at source, but it may emit more carbon per unit of energy than fossil fuels unless biomass fuels are produced unsustainably.

Biomass can play a major role in reducing the reliance on fossil fuels by making use of thermochemical conversion technologies. In addition, the increased utilization of biomass-based fuels will be instrumental in safeguarding the environment, generation of new job opportunities, sustainable development and health improvements in rural areas.

The development of efficient biomass handling technology, improvement of agro-forestry systems and establishment of small and large-scale biomass-based power plants can play a major role in rural development. Biomass energy could also aid in modernizing the agricultural economy.

Consistent and reliable supply of biomass is crucial for any biomass project

When compared with wind and solar energy, biomass power plants are able to provide crucial, reliable baseload generation. Biomass plants provide fuel diversity, which protects communities from volatile fossil fuels. Since biomass energy uses domestically-produced fuels, biomass power greatly reduces our dependence on foreign energy sources and increases national energy security.

A large amount of energy is expended in the cultivation and processing of crops like sugarcane, coconut, and rice which can met by utilizing energy-rich residues for electricity production.

The integration of biomass-fueled gasifiers in coal-fired power stations would be advantageous in terms of improved flexibility in response to fluctuations in biomass availability and lower investment costs. The growth of the bioenergy industry can also be achieved by laying more stress on green power marketing.

Use of Palm Kernel Shells in Circulating Fluidized Bed Power Plants

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Palm kernel shells are widely used in fluidized bed combustion-based power plants in Japan and South Korea. The key advantages of fluidized bed combustion (FBC) technology are higher fuel flexibility, high efficiency and relatively low combustion temperature. FBC technology, which can either be bubbling fluidized bed (BFB) or circulating fluidized bed (CFB), is suitable for plant capacities above 20 MW. Palm kernel shells (PKS) is more suitable for CFB-based power plant because its size is less than 4 cm.

With relatively low operating temperature of around 650 – 900 oC, the ash problem can be minimized. Certain biomass fuels have high ash levels and ash-forming materials that can potentially damage these generating units. In addition, the fuel cleanliness factor is also important as certain impurities, such as metals, can block the air pores on the perforated plate of FBC unit. It is to be noted that air, especially oxygen, is essential for the biomass combustion process and for keeping the fuel bed in fluidized condition.

The requirements for clean fuel must be met by the provider or seller of the biomass fuel. Usually the purchasers require an acceptable amount of impurities (contaminants) of less than 1%. Cleaning of PKS is done by sifting (screening) which may either be manual or mechanical.

In addition to PKS, biomass pellets from agricultural wastes or agro-industrial wastes, such as EFB pellets which have a high ash content and low melting point, can also be used in CFB-based power plants. More specifically, CFBs are more efficient and emit less flue gas than BFBs.

The disadvantages of CFB power plant is the high concentration of the flue gas which demands high degree of efficiency of the dust precipitator and the boiler cleaning system. In addition, the bed material is lost alongwith ash and has to be replenished regularly.

A large-scale biomass power plant in Japan

The commonly used bed materials are silica sand and dolomite. To reduce operating costs, bed material is usually reused after separation of ash. The technique is that the ash mixture is separated from a large size material with fine particles and silica sand in a water classifier. Next the fine material is returned to the bed.

Currently power plants in Japan that have an efficiency of more than 41% are only based on ultra supercritical pulverized coal. Modification of power plants can also be done to improve the efficiency, which require more investments. The existing CFB power plants are driving up the need to use more and more PKS in Japan for biomass power generation without significant plant modifications.