Sustainable energy is the provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs.
A broader interpretation may allow inclusion of fossil fuels and nuclear fission as transitional sources while technology develops, as long as new sources are developed for future generations to use. A narrower interpretation includes only energy sources which are not expected to be depleted in a time frame relevant to the human race.
pSustainable energy sources are most often regarded as including all renewable sources, such as biofuels, solar power, wind power, wave power, geothermal power and tidal power.
It usually also includes technologies that improve energy efficiency. Conventional nuclear power and fusion power may be included, but they are controversial politically due to concerns about waste disposal and the risks of disaster due to accident, terrorism, or natural disaster.
Primary energy sources are substances or processes with concentrations of energy at a high enough potential to be feasibly encouraged to convert to lower energy forms under human control for human benefit.
Except for nuclear fuels, tidal energy and geothermal energy, all terrestrial energy sources are from current solar insulation or from fossil remains of plant and animal life that relied directly and indirectly upon sunlight, respectively.
And ultimately, solar energy itself is the result of the Sun's nuclear fusion. Geothermal power from hot, hardened rock above the magma of the earth's core is the result of the accumulation of radioactive materials during the formation of Earth which was the byproduct of a previous supernova event.
Bioenergy technologies use renewable biomass resources to produce an array of energy related products including electricity, liquid, solid, and gaseous fuels, heat, chemicals, and other materials.
Bioenergy ranks second (to hydropower) in renewable U.S. primary energy production and accounts for three percent of the primary energy production in the United States.
Hydroelectric Power
uses the force of moving water to produce electricity.
Currently supplies 15% of world’s electricity.
Hydropower is one of the main suppliers of electricity in the world.
Hydropower produces essentially no carbon dioxide or other harmful emissions.
hydropower is far less expensive to generate once the plants are in place.
hydroelectric dams have an ability to handle seasonal high peak loads.
TIDAL POWER
- As water flows from a higher level to a lower level, it can be used to spin an electricity - generating turbine.
- can only generate when the tide is flowing in or out - only for 10 hours each day.
-Only around 20 sites in the world have been identified as possible tidal power stations.
-The largest tidal power station in the worldis in the Rance estuary in northern France. It was built in 1966.
GeothermalPower
Source of volcanoes.
Hot rocks underground heat water to produce steam.
We drill holes down to the hot region, steam comes up, is purified and used to drive turbines, which drive electric generators.
The first geothermal power station was built at Landrello, in Italy
SOLAR ENERGY
Daily energy from the sun is six hundred times greater than energy produced each day by all other energy sources combined.
Passive Heating - Sun’s energy is converted directly to heat and used at collection site.
South-Facing Windows.
Active Heating - Sun’s energy converted into heat, but transported elsewhere to be used.
Domestic Water Heating
Electrical Generation - Solar energy is transformed into electrical energy.
Photovoltaic Science
BIOENERGY
Energy from organic material
plant material and animal waste
There are a wide variety of biomass energy resources, including tree and grass crops and forestry, agricultural, and urban wastes.
Releasing chemical energy stored in biomass.
Burned directly for heat.
Burned to produce electricity.
Converted to alcohol or used to generate methane.
Costs depends on type of technology used, size of the power plant, and the cost of biomass supply.
WIND ENERGY
-During the day, the air above the land heats up more quickly thanthe air over water.
-The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating winds.
-At night, the winds are reversed because the air cools more rapidly over land than over water.
COAL
Coal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons.
The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the earth was partly covered with swampy forests.
For millions of years, a layer of dead plants at the bottom of the swamps was covered by layers of water and dirt, trapping the energy of the dead plants.
The heat and pressure from the top layers helped the plant remains turn into what we today call coal.
TyPES OF COAL
Coal is classified into 4 types depending on the amount of carbon, oxygen and hydrogen. The higher the carbon content, the more energy the coal contains.
Lignite- the lowest rank of coal with the lowest energy content. Lignite coal deposits tend to be relatively young coal deposits that were not subjected to extreme heat or pressure.
Subbituminous - a higher heating value than lignite. Subbituminous coal typically contains 35-45 percent carbon, compared to 25-35 percent for lignite
Bituminous coal - has two to three times the heating value of lignite. Bituminous coal was formed under high heat and pressure.
Anthracite - has a heating value slightly lower than bituminous coal
ADVANTAGE OF COAL
One of the most abundant energy sources
Versatile; can be burned directly, transformed into liquid, gas, or feedstock
Inexpensive compared to other energy sources
Reduces dependence on foreign oil
Can lower overall amount of greenhouse gases
Leading source of electricity today
By-product of burning (ash) can be used for concrete and roadways
DISADVANTAGES OF COAL
Source of pollution: emits waste, SO2 , Nitrogen Oxide
Coal mining mars the landscape
Liquification, gasification require large amounts of water
Physical transport is difficult and technology to process to liquid or gas is not fully developed
Solid is more difficult to burn than liquid or gases
High water content reduces heating value
Dirty industry—leads to health problems
Dirty coal creates more pollution and emissions
OIL
Crude oil is a smelly, yellow-to-black liquid and is usually found in underground areas.
Oil was formed from the remains of animals and plants that lived millions of years ago in a marine (water) environment before the dinosaurs.
Over the years, the remains were covered by layers of mud.
ADVANTAGES OF OIL
Oil is one of the most abundant energy resources
Liquid form of oil makes it easy to transport and use
Oil has high heating value
Relatively inexpensive and no new technology needed to use
DISADVANTAGES OF OIL
Oil burning leads to carbon emissions and Oil drilling endangers the environment and ecosystesm
Oil recovery processes not efficient enough—technology needs to be developed to provide better yields
Oil transportation (by ship) can lead to spills, causing environmental and ecological damage
NUCLEAR POWER
Nuclear power is generated from the splitting of uranium atoms.
In a nuclear reactor uranium fuel is assembled in such a way that a controlled fission chain reaction (neutrons are released, producing fission in other atoms) can be achieved.
This reaction creates heat which is used to boil water, thereby creating steam that drives turbine generators and produces electricity.
ADVANTAGES OF NUCLEAR POWER
Clear power with no atmospheric emissions
Useful source of energy
Low cost power for today’s consumption
Viable form of energy in countries that do not have access to other forms of fuel
DISADVANTAGES OF NUCLEAR POWER
Potential of high risk disaster.
Waste produced with nowhere to put it
Earthquakes can cause damage and leaks at plants.
Contamination of the environment.
Useful lifetime of a nuclear power plant
