Renewable Energy technologies nearly always focus on new ways to develop electrical power. If you stop and think about it, wind, solar, wave, tidal, hydro and so on all produce electricity, and although of extreme relevance and importance to mitigate the effects of global warming and reduce greenhouse gases very little is being done to reduce emissions from the transport sector.
The only alternatives are electric transport (still utilizing electricity which is being produced from fossil fuels), hydrogen (not yet a viable and safe alternative) and ethanol fuel, which in some parts of the world has proven to be successful, however, it would mean a major change in engines and it would bring disadvantages to the sugar industry.
Fossil fuels are still therefore, a major part of our lives when it comes to transport; be it cars, buses, boats, planes or scooters and the Greenhouse Gas Emissions (GHG) that…
The methodology of composting can be categorized into three major segments—anaerobic composting, aerobic composting, and vermicomposting. In anaerobic composting, the organic matter is decomposed in the absence of air. Organic matter may be collected in pits and covered with a thick layer of soil and left undisturbed six to eight months. The compost so formed may not be completely converted and may include aggregated masses.
Aerobic compostingis the process by which organic wastes are converted into compost or manure in presence of air and can be of different types. The most common is the Heap Method, where organic matter needs to be divided into three different types and to be placed in a heap one over the other, covered by a thin layer of soil or dry leaves. This heap needs to be mixed every week, and it takes about three weeks for conversion to take place. The process is same in the Pit Method, but carried out specially constructed pits. Mixing has to be done every 15 days, and there is no fixed time in which the compost may be ready. Berkley Method uses a labor-intensive technique and has precise requirements of the material to be composted. Easily biodegradable materials, such as grass, vegetable matter, etc., are mixed with animal matter in the ratio of 2:1. Compost is usually ready in 15 days.
Vermicomposting involves use of earthworms as natural and versatile bioreactors for the process of conversion. It is carried out in specially designed pits where earthworm culture also needs to be done. Vermicomposting is a precision-based option and requires overseeing of work by an expert. It is also a more expensive option (O&M costs especially are high). However, unlike the above two options, it is a completely odorless process making it a preferred solution in residential areas. It also has an extremely high rate of conversion, so quality of the end product is very high with rich macro and micronutrients. The end product also has the advantage that it can be dried and stored safely for a longer period of time.
The Middle East and North Africa (MENA) region is highly susceptible to climate change, on account of its water scarcity, high dependence on climate-sensitive agriculture, concentration of population and economic activity in urban coastal zones, and the presence of conflict-affected areas. Moreover, the region is one of the biggest contributors to greenhouse gas emissions on account of its thriving oil and gas industry.
The world’s dependence on Middle East energy resources has caused the region to have some of the largest carbon footprints per capita worldwide. Not surprisingly, the carbon emissions from UAE are approximately 55 tons per capita, which is more than double the US per capita footprint of 22 tons per year. The MENA region is now gearing up to meet the challenge of global warming, as with the rapid growth of the carbon market. During the last few years, many MENA countries, like UAE, Qatar, Egypt and Saudi Arabia have unveiled multi-billion dollar investment plans in the cleantech sector to portray a ‘green’ image.
There is an urgent need to foster sustainable energy systems, diversify energy sources, and implement energy efficiency measures. The clean development mechanism (CDM), under the Kyoto Protocol, is one of the most important tools to support renewable energy and energy efficiency initiatives in the MENA countries. Some MENA countries have already launched ambitious sustainable energy programs while others are beginning to recognize the need to adopt improved standards of energy efficiency.
The UAE, cognizant of its role as a major contributor to climate change, has launched several ambitious governmental initiatives aimed at reducing emissions by approximately 40 percent. Masdar, a $15 billion future energy company, will leverage the funds to produce a clean energy portfolio, which will then invest in clean energy technology across the Middle East and North African region. Egypt is the regional CDM leader with twelve projects in the UNFCCC pipeline and many more in the conceptualization phase.
The MENA region is an attractive CDM destination as it is rich in renewable energy resources and has a robust oil and gas industry. Surprisingly, very few CDM projects are taking place in MENA countries with only 22 CDM projects have been registered to date. The region accounts for only 1.5 percent of global CDM projects and only two percent of emission reduction credits. The two main challenges facing many of these projects are: weak capacity in most MENA countries for identifying, developing and implementing carbon finance projects and securing underlying finance.
Currently, there are several CDM projects in progress in Egypt, Jordan, Bahrain, Morocco, Syria and Tunisia. Many companies and consulting firms have begun to explore this now fast-developing field. One of them, the UK-based EcoSecurities, opened a regional office in Dubai. The company has offices in Bahrain and Lebanon and is planning for branches in Saudi Arabia and Qatar as well as intermediates in Egypt and Libya next year. The Masdar Company of Abu Dhabi, meanwhile, is the first local company in the region to pursue a CDM project.
The Al-Shaheen project is the first of its kind in the region and third CDM project in the petroleum industry worldwide. The Al-Shaheen oilfield has flared the associated gas since the oilfield began operations in 1994. Prior to the project activity, the facilities used 125 tons per day (tpd) of associated gas for power and heat generation, and the remaining 4,100 tpd was flared. Under the current project, total gas production after the completion of the project activity is 5,000 tpd with 2,800-3,400 tpd to be exported to Qatar Petroleum (QP); 680 tpd for on-site consumption, and only 900 tpd still to be flared. The project activity will reduce GHG emissions by approximately 2.5 million tCO2 per year and approximately 17 million tCO2 during the initial seven-year crediting period.
Potential CDM projects that can be implemented in the region may come from varied areas like sustainable energy, energy efficiency, waste management, landfill gas capture, industrial processes, biogas technology and carbon flaring. For example, the energy efficiency CDM projects in the oil and gas industry, can save millions of dollars and reduce tons of CO2 emissions. In addition, renewable energy, particularly solar and wind, holds great potential for the region, similar to biomass in Asia.
The composting process is a complex interaction between the waste and the microorganisms within the waste. The microorganisms that carry out this process fall into three groups: bacteria, fungi, and actinomycetes.Actinomycetes are a form of fungi-like bacteria that break down organic matter. The first stage of the biological activity is the consumption of easily available sugars by bacteria, which causes a fast rise in temperature. The second stage involves bacteria and actinomycetes that cause cellulose breakdown. The last stage is concerned with the breakdown of the tougher lignins by fungi.
Central solutions are exemplified by low-cost composting without forced aeration, and technologically more advanced systems with forced aeration and temperature feedback. Central composting plants are capable of handling more than 100,000 tons of biodegradable waste per year, but typically the plant size is about 10,000 to 30,000 tons per year. Biodegradable wastes must be separated prior to composting: Only pure foodwaste, garden waste, wood chips, and to some extent paper are suitable for producing good-quality compost.
The composting plants consist of some or all of the following technical units: bag openers, magnetic and/or ballistic separators, screeners (sieves), shredders, mixing and homogenization equipment, turning equipment, irrigation systems, aeration systems, draining systems, bio-filters, scrubbers, control systems, and steering systems. The composting process occurs when biodegradable waste is piled together with a structure allowing for oxygen diffusion and with a dry matter content suiting microbial growth. The temperature of the biomass increases due to the microbial activity and the insulation properties of the piled material. The temperature often reaches 65 degrees C to 75 degrees C within a few days and then declines slowly. This high temperature hastens the elimination of pathogens and weed seeds.
Like any developing country, the Philippines is facing a formidable challenge of fostering sustainable energy options to support the energy requirements of its economic and social development goals with minimal adverse effects on the environment. In the Philippines, renewable energy sources contribute 43 percent to the country’s primary energy mix, one of the highest in Southeast Asia. The Philippines has an existing capacity of 5,500 MW of renewable energy power. Out of which, 61 percent is hydropower while 37 percent is geothermal power. Biomass energy application accounts for around 15 percent of the primary energy use in the country. The resources available in the Philippines can generate biomass projects with a potential capacity of around 200 MW.
The country has abundant supplies of biomass resources, offering much potential for clean energy generation. These include agricultural crop residues, forest residues, animal wastes, agro-industrial wastes, municipal solid wastes and aquatic biomass. The most common agricultural wastes are rice hull, bagasse, coconut shell/husk and coconut coir. The use of crop residues as biofuels is increasing in the Philippines as fossil fuel prices continue to rise. Rice hull is perhaps the most important, underdeveloped biomass resource that could be fully utilized in a sustainable manner.
The Philippines is mainly an agricultural country with a land area of 30 million hectares, 47 percent of which is agricultural. The total area devoted to agricultural crops is 13 million hectares distributed among food grains, food crops and non-food crops.Among the crops grown, rice, coconut and sugarcane are major contributors to biomass energy resources. The most common agricultural residues are rice husk, rice straw, coconut husk, coconut shell and bagasse. The country has good potential for biomass power plants as one-third of the country’s agricultural land produces rice, and consequently large volumes of rice straw and hulls are generated.
The term ‘Biofuel’ refers to liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. A variety of fuels can be produced from biomass resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The biomass resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues.
The agricultural resources include grains used for biofuels production, animal manures and residues, and crop residues derived primarily from corn and small grains (e.g., wheat straw). A variety of regionally significant crops, such as cotton, sugarcane, rice, and fruit and nut orchards can also be a source of crop residues. The forest resources include residues produced during the harvesting of forest products, fuelwood extracted from forestlands, residues generated at primary forest product processing mills, and forest resources that could become available through initiatives to reduce fire hazards and improve forest health. Municipal and urban wood residues are widely available and include a variety of materials — yard and tree trimmings, land-clearing wood residues, wooden pallets, organic wastes, packaging materials, and construction and demolition debris.
Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking. Biofuel industries are expanding in Europe, Asia and the Americas. Biofuels are generally considered as offering many priorities, including sustainability, reduction of greenhouse gas emissions, regional development, social structure and agriculture, and security of supply.
First-generation biofuels are made from sugar, starch, vegetable oil, or animal fats using conventional technology. The basic feedstocks for the production of first-generation biofuels come from agriculture and food processing. The most common first-generation biofuels are:
Biodiesel: extraction with or without esterification of vegetable oils from seeds of plants like soybean, oil palm, oilseed rape and sunflower or residues including animal fats derived from rendering applied as fuel in diesel engines
Bioethanol: fermentation of simple sugars from sugar crops like sugarcane or from starch crops like maize and wheat applied as fuel in petrol engines
Bio-oil: thermo-chemical conversion of biomass. A process still in the development phase
Biogas: anaerobic fermentation or organic waste, animal manures, crop residues an energy crops applied as fuel in engines suitable for compressed natural gas.
First-generation biofuels can be used in low-percentage blends with conventional fuels in most vehicles and can be distributed through existing infrastructure. Some diesel vehicles can run on 100 % biodiesel, and ‘flex-fuel’ vehicles are already available in many countries around the world.
Second-generation biofuels are derived from non-food feedstock including lignocellulosic biomass like crop residues or wood. Two transformative technologies are under development.
Biochemical: modification of the bio-ethanol fermentation process including a pre-treatment procedure
Thermochemical: modification of the bio-oil process to produce syngas and methanol, Fisher-Tropsch diesel or dimethyl ether (DME).
Advanced conversion technologies are needed for a second generation of biofuels. The second generation technologies use a wider range of biomass resources – agriculture, forestry and waste materials. One of the most promising second-generation biofuel technologies – ligno-cellulosic processing (e. g. from forest materials) – is already well advanced. Pilot plants have been established in the EU, in Denmark, Spain and Sweden.
Third-generation biofuels may include production of bio-based hydrogen for use in fuel cell vehicles, e.g. Algae fuel, also called oilgae. Algae are low-input, high-yield feedstocks to produce biofuels.
Combined Heat and Power (CHP) is the simultaneous generation of multiple forms of useful energy (usually mechanical and thermal) in a single, integrated system. In conventional electricity generation systems, about 35% of the energy potential contained in the fuel is converted on average into electricity, whilst the rest is lost as waste heat. CHP systems use both electricity and heat and therefore can achieve an efficiency of up to 90%.
CHP systems consist of a number of individual components—prime mover (heat engine), generator, heat recovery, and electrical interconnection—configured into an integrated whole. Prime movers for CHP units include reciprocating engines, combustion or gas turbines, steam turbines, microturbines, and fuel cells.
A typical CHP system provides:
Distributed generation of electrical and/or mechanical power.
Waste-heat recovery for heating, cooling, or process applications.
Seamless system integration for a variety of technologies, thermal applications, and fuel types.
The success of any biomass-fuelled CHP project is heavily dependent on the availability of a suitable biomass feedstock freely available in urban and rural areas.
Rural Resources
Urban Resources
Forest residues
Urban wood waste
Wood wastes
Municipal solid wastes
Crop residues
Agro-industrial wastes
Energy crops
Food processing residues
Animal manure
Sewage
Technology Options
Reciprocating or internal combustion engines (ICEs) are among the most widely used prime movers to power small electricity generators. Advantages include large variations in the size range available, fast start-up, good efficiencies under partial load efficiency, reliability, and long life.
Steam turbines are the most commonly employed prime movers for large power outputs. Steam at lower pressure is extracted from the steam turbine and used directly or is converted to other forms of thermal energy. System efficiencies can vary between 15 and 35% depending on the steam parameters.
Co-firing of biomass with coal and other fossil fuels can provide a short-term, low-risk, low-cost option for producing renewable energy while simultaneously reducing the use of fossil fuels. Biomass can typically provide between 3 and 15 percent of the input energy into the power plant. Most forms of biomass are suitable for co-firing.
Steam engines are also proven technology but suited mainly for constant speed operation in industrial environments. Steam engines are available in different sizes ranging from a few kW to more than 1 MWe.
A gas turbine system requires landfill gas, biogas, or a biomass gasifier to produce the gas for the turbine. This biogas must be carefully filtered of particulate matter to avoid damaging the blades of the gas turbine.
Stirling engines utilize any source of heat provided that it is of sufficiently high temperature. A wide variety of heat sources can be used but the Stirling engine is particularly well-suited to biomass fuels. Stirling engines are available in the 0.5 to 150 kWe range and a number of companies are working on its further development.
A micro-turbine recovers part of the exhaust heat for preheating the combustion air and hence increases overall efficiency to around 20-30%. Several competing manufacturers are developing units in the 25-250kWe range. Advantages of micro-turbines include compact and light weight design, a fairly wide size range due to modularity, and low noise levels.
Fuel cells are electrochemical devices in which hydrogen-rich fuel produces heat and power. Hydrogen can be produced from a wide range of renewable and non-renewable sources. A future high temperature fuel cell burning biomass might be able to achieve greater than 50% efficiency.
Conclusions
CHP technologies are well suited for Clean Development Mechanism (CDM) and sustainable development projects, because they are, in general, socio-economically attractive and technologically mature and reliable. In developing countries, cogeneration can easily be integrated in many industries, especially agriculture and food-processing, taking advantage of the biomass residues of the production process. This has the dual benefits of lowering fuel costs and solving waste disposal issues.
The only alternatives are electric transport (still utilizing electricity which is being produced from fossil fuels), hydrogen (not yet a viable and safe alternative) and ethanol fuel, which in some parts of the world has proven to be successful, however, it would mean a major change in engines and it would bring disadvantages to the sugar industry.
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