Biomass
When you burn a log in your fireplace or in a campfire, you are using biomass energy. Because plants and trees depend on sunlight to grow, biomass energy is a form of stored solar energy. Although wood is the largest source of biomass energy, we also use corn, sugarcane wastes, and other farming byproducts.
There are three ways to use biomass. It can be burned to produce heat and electricity, changed to a gas-like fuel such as methane, or changed to a liquid fuel. Liquid fuels, also called biofuels, include two forms of alcohol: ethanol and methanol.
Diesel fuel can also be replaced by biodiesel made from vegetable oils. In the United States, this fuel is now being produced from soybean oil. However, any vegetable oil—corn, cottonseed, peanut, sunflower, or canola—could be used to produce biodiesel.
The most commonly used biofuel in the United States is ethanol, which is produced from corn and other grains. However, ethanol made from corn is currently more expensive than gasoline on a gallon-for-gallon basis. And even if we took all the corn that could possibly be grown in the United States and used it to produce ethanol, it would not make enough ethanol to power all our cars. So, it is very important for scientists to find less expensive ways to produce ethanol from other biomass crops.
Wind Energy
Did you know that wind is considered an indirect form of solar energy? This is because the wind is driven mainly by temperature differences on the surface of the earth that are caused by sunshine.
For centuries, the wind has been used to sail ships, grind grain, and pump water. Now, people use the wind to generate electricity. The windmills built a long time ago had many blades, but today's wind turbines usually have just two or three blades that turn when the wind blows. But the blades on wind turbines are much longer. In fact, wind turbine blades can be up to 82 feet long!
The blades drive a generator that produces electricity, much like steam turbines. The longer the blades and the faster the wind speed, the more electricity the turbine generates. Wind turbines are placed on towers because the wind blows harder and more steadily above the ground.
To produce the most electricity, wind turbines need to be located in areas where the wind blows at a constant speed, which it does not do in all parts of the world.
Large groups of wind turbines, called wind farms, are connected to electric utility power lines and provide electricity to many people. New turbine designs now take advantage of less windy areas by using better blades, more electronic controls, and other improvements. An advantage of wind turbines over some forms of renewable energy is that they can produce electricity whenever the wind blows (at night and also during the day). In theory, wind systems can produce electricity 24 hours every day, unlike solar power systems that can't make power at night. However, even in the windiest places, the wind does not blow all the time.
Wave Energy
Waves contain large amounts of energy. Wave energy is in effect a stored and concentrated form of solar energy, since the winds that produce waves are caused by temperature, as I said in the previous section. The strong winds blowing across the Atlantic Ocean create large waves, making the west coast of Europe ideally suited to wave energy schemes.
Wave energy research is still carried on and has benefited from funding provided by the European Commission.
Hydro-electric Energy
The water in rivers and streams can be captured and turned into hydropower, also called hydro-electric power. The most common form of hydropower uses dams on rivers to create large reservoirs of water.
Water released from the reservoirs flows through turbines, causing them to spin. The turbines are connected to generators that produce electricity.
Hydro-electric power plants in the United States generate enough electricity to power whole towns, cities, and even entire regions of the country. Hydropower currently is one of the largest sources of renewable power, generating about 10 percent of the United States' electricity.
Hydropower is also inexpensive, and like many other renewable energy sources, it does not produce air pollution.
However, the drawback to hydropower is that damming rivers can change the ecology of the region. For example, the water below the dam is often colder than what would normally flow down the river, so fish sometimes die. The water level of the river below the dam can be higher or lower than its natural state, which affects the plants that grow along the riverbanks.
Tidal Energy
There are a few places in the world where there is a large enough difference between the high and low tides of the ocean to generate electricity.
The gravity of the moon pulls on the earth and causes our tides to rise and fall as it travels in its orbit.
Water can be collected behind a dam at high tide, held for a few hours after the tide changes, and then released. As it surges down to the lower level, it turns turbines and generates electricity.
The first tidal power station began working in France in 1968. Some of the highest tides in the world are in the Bay of Fundy in Nova Scotia , where a large tidal power station is being built.
Geothermal Energy
We can also get energy directly from the heat in the earth. This is known as geothermal energy, from "geo" for earth and "thermal" for heat. Geothermal energy starts with hot, molten rock (called magma) miles below the earth's surface that heats a section of the earth's crust. The heat rising from the magma warms underground pools of water known as geothermal reservoirs. Sometimes the water can even boil to produce steam. If there is an opening through the rock to the surface, the hot underground water may seep out to form hot springs, or it may boil to form geysers.
For thousands of years, people have been using hot springs for bathing and for cooking food. With today's technology, we do not have to wait for the hot water to come to the earth's surface. Instead, we can drill wells deep below the surface of the earth to tap into geothermal reservoirs. This is called direct use of geothermal energy, and it provides a steady stream of hot water that is pumped to the earth's surface so its heat can be used.
Geothermal energy also is used to produce electricity. Similar to solar thermal electricity, steam—either pulled directly from the geothermal reservoir or from water heated to make steam—is piped to the power plant. There, it rotates a turbine that generates electricity.
While geothermal energy is a good source of power, we could run out of it by drawing so much energy out of the reservoir that it is not able to replenish itself at the rate we're using it. In addition, water from geothermal reservoirs often contains minerals that are corrosive and polluting.
Non-renewable Energy
What is Non-renewable Energy?
Non-renewable energy sources come out of the ground as liquids, gases and solids. Right now, crude (petroleum) is the only naturally liquid commercial fossil fuel. and are normally gases, and is a solid. Coal, petroleum, natural gas, and propane are all considered fossil fuels because they formed from the buried remains of plants and animals that lived millions of years ago. ore, a solid, is mined and converted to a fuel. Uranium is not a fossil fuel. These energy sources are considered non-renewable because they can not be replenished in a short period of time. Renewable energy sources can be replenished naturally in a short period of time.
- Oil
- Natural Gas
- Coal
- Nuclear
Oil
Oil was formed from the remains of animals and plants that lived millions of years ago in a marine environment before the dinosaurs. Over the years, the remains were covered by layers of mud. Heat and pressure from these layers helped the remains turn into what we today call crude oil. The word "petroleum" means "rock oil" or "oil from the earth."
After crude oil is removed from the ground, it is sent to a by pipeline, ship or barge. At a , different parts of the crude oil are separated into useable .
One barrel of crude oil, when , produces 19.4 gallons of finished motor gasoline, as well as other petroleum products. Most of the petroleum products are used to produce energy. For instance, many people across the United States use to heat their homes and fuel their cars. Other products made from petroleum include: ink, crayons, bubble gum, dishwashing liquids, deodorant, eyeglasses, records, tires, ammonia, and heart valves.
Natural Gas
For many years, it was discarded as worthless. Even today, some countries still get rid of it by burning it in giant flares, so large they can be seen from the Space Shuttle. Yet, it is one of the most valuable fuels we have.
Natural gas is made up mainly of methane. Methane is highly flammable and burns almost completely. There is no ash and very little air pollution.
Natural gas provides one-fifth of all the energy used in the United States. It is especially important in homes, where it supplies nearly half of all the energy used for cooking, heating, and for fuelling other types of home appliances.
Because natural gas has no odour, gas companies add a chemical to it that smells a little like rotten eggs. The odour makes it easy to smell if there is a gas leak in your house.
Coal
Coal is our most abundant fossil fuel. But coal is not a perfect fuel.
Trapped inside coal are traces of impurities like sulphur and nitrogen. When coal burns, these impurities are released into the air. While floating in the air, these substances can combine with water vapour and form droplets that fall to earth as weak forms of sulphuric and nitric acid – scientists call it "acid rain."
There are also tiny specks of minerals – including common dirt – mixed in coal. These tiny particles don't burn and make up the ash left behind in a coal combustor. Some of the tiny particles also get caught up in the swirling combustion gases and, along with water vapour, form the smoke that comes out of a coal plant's smokestack.
Also coal, like all fossil fuels, is formed out of carbon. All living things - even people - are made up of carbon. But when coal burns, its carbon combines with oxygen in the air and forms carbon dioxide. Carbon dioxide is a colourless, odourless gas, but in the atmosphere, it is one of several gases that can trap the earth's heat.
Sounds like coal is a dirty fuel to burn. Many years ago, it was. But things have changed. Especially in the last 20 years, scientists have developed ways to capture the pollutants trapped in coal before the impurities can escape into the atmosphere. Today, we have technology that can filter out 99 percent of the tiny particles and remove more than 95 percent of the acid rain pollutants in coal.
Nuclear
Nuclear power plants provide about 17 percent of the world's electricity. Some countries depend more on nuclear power for electricity than others. In France, for instance, about 75 percent of the electricity is generated from nuclear power. In the United States, nuclear power supplies about 15 percent of the electricity overall, but some states get more power from nuclear plants than others. There are more than 400 nuclear power plants around the world.
Nuclear power stations, unlike coal, do not produce sulphur dioxide and carbon dioxide. However, radioactive waste is very dangerous for thousands of years and safe storage is expensive.
By
Chris Sampson