How Does Biomass Energy Work|Biomass Energy Pros And Cons.

Significance of awareness about how does biomass energy work and biomass energy pros and cons among the people around the world has greatly enhanced in the context of growing perception about global warming and other associated problems of using fossil fuels. With rising energy demand and growing consciousness that the power sector is one of the major contributors to Green House Gas (GHG) emissions, promotion of use of low cost clean and environment friendly energy from biomass has acquired special importance. The South Asian countries like India, Pakistan and Sri Lanka, have already started giving special emphasis for use of relatively environment friendly energy from biomass fuel available from local sources. In this context the National Action Plan on Climate Change of the Government of India is a welcome move, which aims at achieving 15% of the total grid purchase to come from renewable clean energy sources (excluding hydro power with storage capacity in excess of daily peaking capacity) in the next 10 years.

Spreading the knowledge about biomass energy advantages and disadvantages among the rural masses would greatly help the developing countries in their endeavor to promote use of low cost clean energy from biomass fuel, by improving access to minimum electricity in remote rural areas where grid expansion is not economically viable. The biomass in the rural areas can offer technologies matching with the above requirements at a competitive cost. Regulatory instruments like preferential pricing and renewable energy trading certificates are also expected to help this cause for increasing use of relatively clean energy from biomass fuel.

Let me now discuss various biomass energy pros and cons and other related facts along with simplified explanation of 'how does biomass energy work', for better appreciation of this low cost renewable source of energy.

What is Biomass?

Biomass is a natural substance (organic matter) produced by plants both terrestrial and aquatic and its derivatives, which stores solar energy by the process of photosynthesis in the presence of sunlight. As plant life renews and adds to itself over a relatively short period of time, biomass is considered a low cost renewable source of clean energy. Biomass fuel had been a major source of energy prior to the discovery of fossil fuels like coal and petroleum. Even though its role is presently diminished in the developed countries, it is still widely used in rural communities of the developing countries for their energy needs in terms of cooking and limited industrial use. Energy from biomass has become one of the most commonly used alternative energy in the last two decades, second only to hydro power in the generation of electricity.

Biomass Classifications

Biomass can be classified into two broad types - Solid biomass and Powdery biomass.

Solid biomass: Are any type of branches, non-forestry weeds like stems of ipomoea, lantana etc and agricultural residues like coconut shell, cotton stock, mustard stalk, con cob etc;

Powdery biomass: Is available either naturally in a powdered form or may be crushed into a powder like sawdust, agricultural residues like rice husk, groundnut shell, coffee husk, sugarcane trash, or dry leaves and grass;

How does Biomass energy work?

To describe 'how does biomass energy work' the process of Photosynthesis needs to be explained. Through this process solar energy is captured by the chlorophyll in the plant, which is a green pigment found in almost all plants, by converting carbon dioxide from the air and ground water into carbohydrates, a compound composed of carbon, hydrogen and oxygen. When burnt, these carbohydrates release the energy they captured from the sun and re-convert them into carbon dioxide and water. Thus, biomass functions as a natural storage system of solar energy like batteries. As long as biomass is produced with minimal long-term effect on the resources including land’s capacity to re-grow biomass plants, this natural storage system would continue to be the source of energy for an indefinite period. Worldwide photosynthetic activity on plants is estimated to store more than 15 times, as much energy as is annually consumed by all the nations in the world!

Biomass Gasification process

The most common method to capture energy from biomass has been to burn it to produce heat. Burning biomass in conventional boilers has many ecological advantages over burning fossil fuels. Advancement in recent years has shown that a process called "gasification" is more efficient and cleaner way to produce combustible gases, which reduces emissions of various particulates from biomass combustion. Biomass gasification means incomplete combustion of biomass resulting in production of combustible gases the mixture of which is called pyrolysis gas that can be used to run internal combustion engines. In this technology, biomass fuel is burnt in a device called ‘Gasifier’ in a partial supply of oxygen to generate clean combustible pyrolysis gas.

This gas is fed into a modified diesel engine which runs on a mixture of gas and diesel, resulting in a saving up to 80% of the diesel consumption. The engine is connected to a generator that produces electricity. The waste heat from the engine can be used for drying, heating or boiling water, or for running air-conditioning or cold storage plants.

Major disadvantages

Going into biomass energy advantages and disadvantages there are few drawbacks of energy from biomass. But we need to look into the issue in totality to see if biomass can be a good alternative fuel to fossil fuels like coal or oil. The biggest disadvantages of biomass are that it releases carbon during burning process and biomass for energy has environmental risks that need to be moderated. If not managed carefully, production of biomass can be at unsustainable rates, ecosystems can be damaged, large amounts of water can be consumed, and net greenhouse emissions may occur

Experts believe that there is a large variety of biomass resources that can be harvested sustain ably and with negligible harm. Putting into practice proper policy is essential for securing the benefits of biomass and avoiding the associated risks.

Conclusion.

To promote beneficial use of biomass energy will require policy to guide industries to harvest the right kinds of biomass resources and for use of appropriate biomass conversion technologies and applications. This will create public confidence that biomass can be a sustainable and useful climate solution. Despite the fact that a number of environmental groups are opposed to the large-scale use of forest biomass in energy production in the light of the pressing need to reduce carbon emissions, it would be evident from the description under ‘how does biomass energy work’ given above that biomass is one of the few potential replacements of fossil fuels in the near future as a natural source of energy for an indefinite period. Biomass fuel has been utilized so widely, that it accounts for almost 15% of the world's total energy supply and as much as 35% of rural supply in developing countries, mostly for cooking and heating purposes.

Discussion on biomass energy pros and cons also calls for mentioning that at the existing cost of biomass fuel and normal financing conditions as applied to renewable energy power projects, the cost of energy generation from biomass gasification based power plants using diesel engines running in a dual fuel mode is always lower than that from normal diesel engines running on pure diesel oil. In an industrial plant where an existing diesel set is re-modeled for use with a biomass gasification plant the pay back period in a typical case, can be as low as 1 to 3 years.