Coal Cascade Utilization
Bioenergy is a versatile energy source. In contrast to other forms of renewable energy, biomass can be supplied in solid, liquid and gaseous forms. Moreover, bioenergy can be used in the form of heat, electricity and transportation fuels. Biomass was the earliest form of energy used when humans first burned wood for heating and cooking. Today, the unsustainable use of fossil fuels has forced countries all over the world to boost the use of modern bioenergy in their energy mix.
Globally, bioenergy accounted for 14% of final energy consumption in 2012 with roughly 2.6 billion people still depending on traditional biomass for their energy needs. To meet future energy and climate goals, bioenergy will play a significant role—from liquid biofuels to biomass for heating and electricity as well as upcoming technologies like torrefaction, advanced biofuels and others.
Significant technological innovations are taking place in the field of liquid biofuels. USA and Brazil lead in the production of bioethanol and biodiesel – which are blended with gasoline and diesel in transportation sector. Both countries have made strides in the development of advanced biofuels, primarily obtained from cellulosic plant material, with the construction and operation of four new commercial plants in the US and one in Brazil. One of the key markets for liquid biofuels is the aviation sector where advanced biofuels are the only renewable option to replace jet fuel. China recently flew its first flight powered by a 50 – 50 blend of aviation fuel and bio-jet fuel. Commercial airlines have flown transatlantic from the US to Europe on aviation biofuels as well as from Europe to Brazil with many regional and national flights having taken place around the world.
The use of biomass for electricity is significant in Europe and the Americas. Cogeneration plants (producing heat and electricity) in particular have led to increasing efficiency and exploitation of locally available biomass in many developed countries. In developing countries where a significant proportion of the population lacks electricity access (India, China, Sub-Saharan Africa, etc.), modern biomass is seeing greater uptake astechnologiesfor biogas and biomass-powered off-grid systems become more competitive. Already cogeneration from sugarcane bagasse is occurring in Mauritius, Kenya and Ethiopia; there is also potential in other African cane-growing countries.
Important policy developments in the use of biomass for heating are popping up around the world, such as the introduction of the Renewable Heat Incentive scheme in UK. Since the launch of this scheme, biomass installations have accounted for more than 80% of all new renewable heat installationsin the UK. However, there is a lack of policy incentives for biomass heat in developing countries like Thailand, Malaysia, and Indonesia even though a significant amount of biomass is produced and used within the industries as heat, such as waste from palm oil processors in Malaysia and from sugar mills in Indonesia.
The most significant use of biomass, however, is in its traditional form for cooking and heating. Traditional biomass includes the use of fuelwood, charcoal, animal dung and agricultural residues in stoves with low efficiency. The mostly informal use of such biomass has led to lack of accurate data on the actual use of traditional biomass, especially in developing countries in Africa and Asia. Estimates suggest that traditional biomass makes up 9–10% of the global energy consumption. However, with rapid urbanisation, depletion of forestry biomass due to inefficient use, and increasing demand for energy access, communities are replacing traditional biomass with other forms of energy including biogas, (Liquefied Petroleum Gas (LPG), solar etc.
An important source of biomass is agricultural residues and wastes. A facility in Edmonton, Canada is using municipal solid waste to produce biofuels and chemicals. In Europe, Denmark is a world leader in the use of straw to produce heat and electricity. In India, the use of rice husk to produce gas and electricity has served more than 150 000 people in rural areas.
One of the rapidly advancing bioenergy sectors is the pellets market. Europe is the largest consumer of pellets, which are predominantly imported from the USA. Recent technological improvements in this sector include the development of steam exploded or black pellets. Another notable development is the increased use ofsmall-scale biogas digesters in China. This hasseen an upswing lately due to support from the Chinese government.
A key aspect of global bioenergy development is sustainability. As bioenergy is inherently produced from organic materials, particularly food crops and waste, a balance must be struck between demand for food, fibre, feed and energy. Additionally, environmental and social aspects of sustainability must be ensured, providing bioenergy with the opportunity to lead globally on improving food security, creating more and better jobs as well as protecting environmental resources.
Certification schemes for bioenergy and biomaterials in general have been developed by organisations such as the multi-stakeholder platform Roundtable on Sustainable Biomaterials to help monitor and improve practices related to their production so opportunities are optimized and potentially negative impacts are mitigated. The Global Bioenergy Partnership, hosted by the FAO, works with governments to monitor bioenergy and to develop appropriate policies through their sustainability indicators. World Bioenergy Association developed an industry driven sustainability criteria for biomass for energy and is awaiting field trials for developing the sustainability scheme.