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Biomass

A profitable Energy Resource

Presented by: Akash Kewal Ram

(AREVA T&D Pakistan Pvt. Ltd.)

23rd multi-topic International Symposium 2008

March 29, 2008

IEEEP, Karachi Centre

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Contents

What is biomass?? The difference b/w biomass & fossil fuel How biomass works Biomass helps in reducing global warming A neutral source of energy Source of biomass Some of the most efficient residues Various processes to obtain energy Ways to produce transportation biofuels Generating energy from biomass Efficiency of biomass Advantages & Disadvantages

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A renewable energy par excellence, is the oldest sources, of power used by humans.

Is still the basic energy source for some 1.6 billion humans who do not have access to electricity.

Biomass include: dead trees, tree branches, yard clippings, left-over crops, wood chips, bark & sawdust from lumber mills, grasses and manure.

can be used to produce electricity, heat or fuel for transportation.

has a calorific value, roughly equivalent to one-third of that of fossil fuels.

Biomass is relatively evenly distributed over the surface of the globe

Biomass:

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Renewable over much shorter periods, ranging from a few decades for forestry biomass to a few months for energy crops.

When burned, the chemical energy in biomass is released as heat

Each MW of power produced by a biomass power plant means a reduction in CO2 emission of around 3000 to 5000 metric tons.

can be converted to other usable forms of energy like methane gas or transportation fuels like ethanol and biodiesel.

Biomass fuels provide about 3 percent of the energy used in the United States.

Biomass:……………..cont

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millions of families cook, heat and light their homes by burning biomass materials.

The use of biomass in distributed generation is considered one of the best ways to meet targets for renewable energy without compromising supply reliability.

Biomass:……………..cont

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Biomass is carbon based and is composed of a mixture of organic molecules containing hydrogen, usually including atoms of oxygen, often nitrogen and also small quantities of other atoms, including alkali, alkaline earth and heavy metals. 

These metals are often found in functional molecules such as the porphyries which include chlorophyll which contains magnesium.

Chemical Composition:

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The vital difference between biomass and fossil fuels is one of time scale.

Biomass takes carbon out of the atmosphere while it is growing, and returns it as it is burned. 

biomass maintains a closed carbon cycle with no net increase in atmospheric CO2 levels.

The difference b/w biomass & fossil fuel

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Virgin wood, from forestry, arboricultural activities or from wood processing

Energy crops: high yield crops grown specifically for energy applications

Agricultural residues: residues from agriculture harvesting or processing

Food waste, from food and drink manufacture, preparation and processing, and post-consumer waste

Industrial waste and co-products from manufacturing and industrial processes.

Categories of biomass materials

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Biomass is fed into a furnace where it is burned. The heat is used to boil water in the boiler, and the energy in the steam is used to turn turbines and generators.

Biomass can also be tapped right at the landfill with burning waster products. When garbage decomposes, it gives off methane gas. Pipelines are put into the landfills and the methane gas can be collected. It is then used in power plants to make electricity.

Also used to produce ethanol, a liquid alcohol fuel. Ethanol can be used in special types of cars that are made for using alcohol fuel instead of gasoline.

The alcohol can also be combined with gasoline. This reduces our dependence on oil

How biomass works:

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Sources of biomass:

Wood chips / waste Nut shells Sewage sludge Olive pips Bone meal Leather waste Animal litter Coal Tyres Sugar Cane Bagasse Oil sludge/waste Energy crops Oil seed rape husks Rice and Corn husks Packaging Waste Chicken Waste, etc.

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Some of the most efficient residues

1. BAGASSE: bagasse, the sugarcane fiber that remains after the juice

has been extracted in sugar factories and distilleries, is the king of biomass.

Bagasse leads wood as the preferred biofuel for generating electricity.

Each year approximately 1.2 billion metric tons of sugarcane are harvested worldwide, yielding around 350 million metric tons of bagasse.

If existing installations were modernized, bagasse could produce much more electrical power, estimated at around 50,000 MW for power plants operating primarily on this fuel.

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Some of the most efficient residues

2. RICE HUSKS OR CHAFF: The grain of the rice is separated from its envelope or

husk before it is consumed.

Rice husks represent approximately 20% o the weight of the rice.

Other than its utilization as a biofuel, there is no other process for eliminating this waste, which accumulates in heaps around rice mills.

World produces around 600 million metric tons of rice per year, approximately 120 million metric tons of rice chaff is left unused annually.

the total approx. 15000 MW of electricity could be generated from above qty.

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Some of the most efficient residues

3. WOOD: wood has traditionally been the major source of primary

energy used by humans.

today, the source of wood based biofuel is the waste produced by forestry operations (twigs, bark, sawdust, etc.)

Wood is one of the biomass which has largest caloric value.

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S.no Description Kcal/kg kWh/kg

1 Bagasse 2,272 2.64

2 Rice husk 3,150 3.66

3 Sunflower husk 4,155 4.83

4 Cotton stalk 3,900 4.53

5 Can trash 2,880 3.35

6 Wood chips 4,490 5.22

7 Palm shell 4,390 5.10

8 Chilly stalk 3,850 4.48

Comparison of kcal/kg & kWh/gm of some of the residues

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Biomass contains stored energy from the sun. Plants absorb the sun's energy in a process called photosynthesis. The chemical energy in plants gets passed on to animals and people that eat them.

Or we can say: Plants use and store carbon dioxide (CO2) when they grow. CO2 stored in the plant is released when the plant material is burned or decays. By replanting the crops, the new plants can use the CO2 produced by the burned plants. So using biomass and replanting helps close the carbon dioxide cycle.

It is also a renewable energy because plants to make biomass can be grown over and over

A neutral source of energy

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Biofuels for transportation

Green fuels produced from organic material can be used, either totally or partially, in the place of petroleum-based fuels.

Burning biofuels in vehicles lowers the greenhouse emission (GCG) produced by road transportation, which generates 24% of all planetary CO2 emissions.

biofuels lowers the demand for oil, and energy costs in consequences.

Biofuels open up a avenue for using agricultural products, helping to regulate market prices, for primary agricultural commodities, and also create jobs in rural areas.

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Ways to produce transportation biofuels

[1] Ethanol (bioethanol) is extracted by distilling plants which a high sugar content (sugar beet, sugarcane) or high starch content (wheat, potatoes, corn, etc.). ethyl alcohol is obtained by fermentation of the sugar or starch.

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Ways to produce transportation biofuels

[2] Easters are produced by the reaction of methanol or ethanol with vegetable oils (sunflower, soyabean, etc.) and are added to diesel fuel.

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Generating energy from biomass

• Generating energy from biomass is also called as conversion of biomass.

Various processes are employed to obtain energy from biomass. Three of them are:

1. COMBUSTION: biomass is used as fuel to heat water to obtain high-

pressure steam. The steam is fed to a turbine linked to an alternator, which produces electricity.

The low-pressure stream given off by the turbine may be used to supply heat to district heating networks as well as in various industrial processes: sugarcane distillation, paper-making, esterification, etc.

when waste energy is also made use of in a power plant, this is called cogeneration.

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Generating energy from biomass

2.  Gasification (Anaerobic digestion): Gasification is a partial oxidation process

whereby a carbon source such as coal, natural gas or biomass, is broken down into carbon monoxide (CO) and hydrogen (H2), plus carbon dioxide (CO2) and possibly hydrocarbon molecules such as methane (CH4).

Applications: Heating water in central heating, district heating

or process heating applications Steam for electricity generation or motive force  As part of systems producing electricity or motive

force  Transport using an internal combustion engine.

Types of gasification: Low temperature & high temperature gasification

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Generating energy from biomass

3.  Pyrolysis : Pyrolysis is the precursor to gasification, and

takes place as part of both gasification and combustion.  It consists of thermal decomposition in the absence of oxygen. It is essentially based on a long established process, being the basis of charcoal burning.

Applications: Biomass energy densification for transport or

storage Co-firing for heat or power Feedstock for gasification.

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Generating energy from biomass

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Generating energy from biomass

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Biomass a Profitable Energy

The wide use of biomass may significantly contribute to developing rural areas, as opposed to urban areas, because it will create sustainable activities that make use of unexplored agricultural resources and also provide access to electricity in isolated areas where the power supply is not always reliable.

Producing energy using biomass also allows for diversifying sources of income in the agricultural sector, where competition is fierce.

The traditional income generated by the production of electrical power will contribute to ensuring greater economic stability for agricultural producers.

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BIOMASS A PROFITABLE ENERGY……..cont.

1. In industrialized countries When biomass materials are not the byproducts of an

existing industry (bagassse produced by sugar factories, sawdust by forestry operations), using them as biofuel results in an increase in prices;

the cost of collecting the dead wood and branches from felled trees in forests and transforming then into wood pellets is Euro 40 to Euro 50 per metric ton, whereas the cost of sawmill waste is Euro 20 / metric ton.

In these countries, subsides are needed to make biomass a competitive energy. However, in contrast to other sources, biomass has a low environmental and social impact, which lower its cost over the long term.

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BIOMASS A PROFITABLE ENERGY……..cont.

2. In developing countries Biomass power plant investment and operating costs

are lower in developing countries.

In Thailand, the installation of a 15 MW capacity power plant costs around Euro 1250 / kW, in comparison to Euro 2500 / kW in Europe.

Biomass is more profitable energy because power plants in developing countries benefit from carbon credits.

It is a viable solution for electrifying rural areas that are not effectively connected to power grid.

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Efficiency of biomass

The electrical efficiency rating of transforming biomass into electrical energy is around 30% for 10 to 20 MW capacity plants.

This efficiency rating is representative of the latest technologies for solid biofuels used in plants of this size.

In comparison, top-ranked plants producing 500 MW and more with combined cycle gas turbines can only attain an electrical efficiency rating of 57%.

Regarding fossil fuels, the efficiency rating of the biggest coal-fired plants, with an output close to 1000 MW, does not exceed 45%.

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Advantages & Disadvantages:

1. Advantages: Theoretically inexhaustible fuel source. there is minimal environmental impact Alcohols and other fuels produced by biomass are

efficient, viable, and relatively clean-burning Available throughout the world

2. Disadvantages: Could contribute a great deal to global warming and

particulate pollution if directly burned Still an expensive source, both in terms of producing

the biomass and converting it to alcohols On a small scale there is most likely a net loss of

energy--energy must be put in to grow the plant mass

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Biomass power plant at Satyamaharshi (India)

>> Power Plant (Built by AREVA)

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