Biomass, Tides, and Fuel Cells By Justin Whitney, Jack Muldoon, and Pat Kane A Block Alternative Energy Sources #2

Biomass What is it? Biomass is organic matter used as fuel. Generally, dead trees, fallen tree branches, bark, and yard clippings are used. Biomass fuels are renewable resources, as long as plants are not used up faster than they can grow.

Biomass (cont.) How do you get energy from it? To get energy from biomass, you burn it. This releases a gas that is used for energy. In biomass power plants, the biomass is burned and the heat given off is used to boil water. The energy in the steam is used to turn turbines and generators.

Biomass (cont.) Wood Wood fuel is a biomass fuel that is used to power electricity generating power plants and to heat homes. Wood fuel is the world’s most important form of non- fossil energy. It is used by many poor people in rural areas who depend on wood fires for heat and cooking.

Biomass (cont.) Charcoal Charcoal is made from wood. It is produced by burning wood in a limited supply of air to make it lighter. It is very important among the urban poor and is a major energy source in Latin America. It is a major component in producing electricity as well.

Wood and Charcoal CharcoalWood

Biomass (cont.) Methane Methane is the main component of natural gas. It is the most abundant organic compound on the earth. Methane is piped to people’s homes where it’s used for cooking and heating. It makes an attractive fuel. Hard to ship because it is a gas in normal conditions.

Biomass (cont.) Ethanol Ethanol is a type of alcohol produced by the fermentation and distillation of grains, sugarcane, and sugar beets. Ethanol can be used as fuel for cars in place of gasoline. Most cars can run on a combination of gas and ethanol called gasohol. Ethanol produces less carbon monoxide and nitrogen oxides then gas. However, it is more expensive.

Methane and Ethanol Ethanol Methane

Methane and Ethanol

Biomass (cont.) Where is it being used? Biomass is used all across the world, especially in less developed areas. It is mostly used in Asia, Africa, and South America. Poor, rural areas also depend greatly on biomass.

Biomass (cont.) AdvantagesDisadvantages Biomass fuels are renewable resources. They are readily available to many people. Made from animal waste and plant matter, materials that otherwise would not be used. Forcing a widespread removal of trees and plants. More plants are being burned than being grown. Land used for energy producing crops can’t be used for food crops. Farmland is decreasing.

Biomass (cont.)

Tides How can you get energy from tides? You can get energy from the falling and rising of the tides. The tides move through turbines which are housed in tidal barrages. Tidal barrages are huge dams built across the water. It works like hydro-electricity except for the fact that the dams are much bigger.

Tides (cont.) Where is it being used? La Rance, in Brittney, France was the first active tidal barrage in the world, in It still remains to be the biggest in the world. Other places large tidal barrages are being used are, the Bay of Fundy in Canada, and Kislaya Guba in Russia. Smaller forms of tidal energy are used all over the world.

Tides (cont.) AdvantagesDisadvantages Once you’ve built it, tidal power is free. It produces no green house gases or other waste. It needs no fuel. Produces electricity reliably. Not expensive to maintain. Tides are predictable. A barrage can be very expensive to build. Barrages can change the environment for many miles upstream and downstream. It only provides power for around 10 hours each day, when the tide is changing. There are few suitable sites for tidal barrages.

Tides (cont.)

Fuel Cells What are they? A fuel cell is a device that generates electricity by converting the chemical energy of a fuel and an oxidant to electric energy. The most common fuel used is hydrogen, and oxygen is very important as well. It was invented by William Robert Grove.

Fuel Cells (cont.) How do they work? First, hydrogen atoms are channeled into the anode, and oxygen from the air is pumped into the cathode. The anode and cathode are storage compartments in the fuel cell that hold their respective gases. Second, the hydrogen then flows through until it hits the proton exchange membrane. This is where the hydrogen is broken apart into protons and electrons. Third, the protons are allowed to pass through into the cathode while electrons must travel along an external circuit creating an electrical current. Fourth, at the cathode the electrons and protons combine with oxygen to form water which flows out of the cell.

Fuel Cells (cont.) Where is it being used? Fuel cells are being used a lot today in cars. They are also being used by NASA to power space stations. They are similar to batteries in cars, besides the fact that they need a constant fuel and oxygen source, but they can produce a lot more energy which is why car companies are now using fuel cells.

Fuel Cells (cont.) AdvantagesDisadvantages Fuel cells can be used to produce power for an electric motor as well as directly producing electricity in place of a generator. They produce no greenhouse gases or other air pollutants. Readily available Much more efficient compared to gas engines. (60% to 20%) Completely silent Flexible and portable Renewable resource Hydrogen is difficult to contain, so storage and distribution poses as a problem. Safety of hydrogen will always be a concern. Since water is always around fuel cells, it cannot operate very well in cold weather. Presently, the cost of fuel cells is not competitive.

Fuel Cells (cont.)