What is Biomass?

Biomass is any organic matter—wood, crops, seaweed, animal wastes—

that can be used as an energy source. Biomass is probably our oldest

source of energy after the sun. For thousands of years, people have

burned wood to heat their homes and cook their food.

Biomass gets its energy from the sun. All organic matter contains

stored energy from the sun. During a process called photosynthesis,

sunlight gives plants the energy they need to convert water and carbon

dioxide into oxygen and sugars. These sugars, called carbohydrates,

supply plants and the animals that eat plants with energy. Foods rich in

carbohydrates are a good source of energy for the human body!

Biomass is a renewable energy source because its supplies are not

limited. We can always grow trees and crops, and waste will always exist.










Types of Biomass

We use four types of biomass today—wood and agricultural products,

solid waste, landfill gas and biogas, and alcohol fuels.


1. Wood and Agricultural Products

Most biomass used today is home grown energy. Wood—logs, chips,

bark, and sawdust—accounts for about 49 percent of biomass energy.

But any organic matter can produce biomass energy. Other biomass

sources include agricultural waste products like fruit pits and corncobs.

Wood and wood waste, along with agricultural waste, are used to

generate electricity. Much of the electricity is used by the industries

making the waste; it is not distributed by utilities, it is cogenerated. Paper

mills and saw mills use much of their waste products to generate steam

and electricity for their use. However, since they use so much energy,

they need to buy additional electricity from utilities.

Increasingly, timber companies and companies involved with wood

products are seeing the benefits of using their lumber scrap and sawdust

for power generation. This saves disposal costs and, in some areas, may

reduce the companies’ utility bills. In fact, the pulp and paper industries

rely on biomass to meet half of their energy needs. Other industries

that use biomass include lumber producers, furniture manufacturers,

agricultural businesses like nut and rice growers, and liquor producers.

2. Solid Waste

Burning trash turns waste into a usable form of energy. One ton (2,000

pounds) of garbage contains about as much heat energy as 500 pounds

of coal. Garbage is not all biomass; perhaps half of its energy content

comes from plastics, which are made from petroleum and natural gas.

Power plants that burn garbage for energy are called waste-to-energy

plants. These plants generate electricity much as coal-fired plants do,

except that combustible garbage—not coal—is the fuel used to fire

their boilers. Making electricity from garbage costs more than making

it from coal and other energy sources. The main advantage of burning

solid waste is that it reduces the amount of garbage dumped in landfills

by 60 to 90 percent, which in turn reduces the cost of landfill disposal. It

also makes use of the energy in the garbage, rather than burying it in a

landfill, where it remains unused.


3 Landfill Gas

Bacteria and fungi are not picky eaters. They eat dead plants and

animals, causing them to rot or decay. A fungus on a rotting log is

converting cellulose to sugars to feed itself. Although this process is

slowed in a landfill, a substance called methane gas is still produced as

the waste decays.

New regulations require landfills to collect methane gas for safety and

environmental reasons. Methane gas is colorless and odorless, but it

is not harmless. The gas can cause fires or explosions if it seeps into

nearby homes and is ignited. Landfills can collect the methane gas,

purify it, and use it as fuel.

Methane, the main ingredient in natural gas, is a good energy

source. Most gas furnaces and stoves use methane supplied by

utility companies. In 2003, East Kentucky Power Cooperative began

recovering methane from three landfills. The utility now uses the gas

at five landfills to generate 16 megawatts of electricity—enough to

power 7,500 to 8,000 homes.

Today, a small portion of landfill gas is used to provide energy. Most

is burned off at the landfill. With today’s low natural gas prices, this

higher-priced biogas is rarely economical to collect. Methane,

however, is a more powerful greenhouse gas than carbon dioxide. It is

better to burn landfill methane and change it into carbon dioxide than

release it into the atmosphere.

Methane can also be produced using energy from agricultural and

human wastes. Biogas digesters are airtight containers or pits lined

with steel or bricks. Waste put into the containers is fermented without

oxygen to produce a methane-rich gas. This gas can be used to

produce electricity, or for cooking and lighting. It is a safe and clean-

burning gas, producing little carbon monoxide and no smoke.

Biogas digesters are inexpensive to build and maintain. They can be

built as family-sized or community-sized units. They need moderate

temperatures and moisture for the fermentation process to occur.

For developing countries, biogas digesters may be one of the best

answers to many of their energy needs. They can help reverse the

rampant deforestation caused by wood-burning, and can reduce air

pollution, fertilize over-used fields, and produce clean, safe energy for

rural communities.


Use of Biomass

Until the mid-1800s, wood gave Americans 90 percent of the energy

used in the country. Today, biomass provides about 4.1 percent of the

total energy we consume. Biomass has largely been replaced by coal,

natural gas, and petroleum.

Almost half of the biomass used today comes from burning wood and

wood scraps such as saw dust. More than one-third is from biofuels,

principally ethanol, that are used as a gasoline additive. The rest comes

from crops, garbage, and landfill gas.

Industry is the biggest user of biomass. Over 51 percent of biomass is

used by industry. Electric utilities use 11 percent of biomass for power

generation. Biomass produces 0.7 percent of the electricity we use.

Transportation is the next biggest user of biomass; almost 24 percent

of biomass is used by the transportation sector to produce ethanol and


The residential sector uses 11 percent of the biomass supply. About

one-tenth of American homes burn wood for heating, but few use

wood as the only source of heat. Most of these homes burn wood in

fireplaces and wood stoves for additional heat.


Using Biomass Energy

Usually we burn wood and use its energy for heating. Burning,

however, is not the only way to convert biomass energy into a

usable energy source. There are four ways:

Fermentation: There are several types of processes that can

produce an alcohol (ethanol) from various plants, especially

corn. The two most commonly used processes involve using

yeast to ferment the starch in the plant to produce ethanol. One

of the newest processes involves using enzymes to break down

the cellulose in the plant fibers, allowing more ethanol to be

made from each plant, because all of the plant tissue is utilized,

not just the starch.

Burning: We can burn biomass in waste-to-energy plants to

produce steam for making electricity, or we can burn it to

provide heat for industries and homes.

Bacterial Decay: Bacteria feed on dead plants and animals,

producing methane. Methane is produced whenever organic

material decays. Methane is the main ingredient in natural gas,

the gas sold by natural gas utilities. Many landfills are recovering

and using the methane gas produced by the garbage.

Conversion: Biomass can be converted into gas or liquid fuels

by using chemicals or heat. In India, cow manure is converted

to methane gas to produce electricity. Methane gas can also be

converted to methanol, a liquid form of methane.


Biomass and the Environment

Environmentally, biomass has some advantages over fossil fuels such

as coal and petroleum. Biomass contains little sulfur and nitrogen, so

it does not produce the pollutants that can cause acid rain. Growing

plants for use as biomass fuels may also help keep carbon dioxide levels

balanced. Plants remove carbon dioxide—one of the greenhouse

gases—from the atmosphere when they grow.


About Pontianak Biomass

we make a renewable energy in West Borneo.

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