Flashcards in Electricity and Heating Deck (92)
what are fossil fuels
- Fossil fuels are formed of the remains of dead previously living organisms.
- Fossil fuels is the general term used to describe buried combustible geological deposits of organic material, formed from decaying plants or animals. These deposits have been converted to crude oil, coal, natural gas or other heavy oils, due to exposure to heat and pressure in the earth’s crust.
are fossil fuels renewable?
Fossil fuel is a non-renewable energy source. This means that the energy comes from sources which will run out/not be replenished in our lifetime.
fossil fuels and co2
The burning of fossil fuels by humans is the largest source of emissions of CO2, a greenhouse gas, contributing to the enhanced greenhouse effect.
types of fossil fuels
natural gas, oil and coal
- Oil is the world’s primary fuel source for transportation.
- A major source of greenhouse gas emissions.
- Heavier crude oils, particularly those extracted from tar sands and (through fracking) from shale, require the use of energy intensive methods that result in more emissions and environmental degradation compared to conventional oils.
- As conventional oil from underground runs out, more oil producers are turning to unconventional sources such as tar sands and shale.
- Primarily used to generate electricity.
coal and the environment
- The combustion of coal releases air pollutants such as acid rain inducing sulphur dioxide, nitrogen oxides and mercury.
- The mining process can also be very damaging to the environment, often resulting in destruction of vegetation and top soil. Rivers and streams can also be destroyed or contaminated by mine wastes.
natural gas use
- Commonly used for heat, cooking and electricity
natural gas and the environment
- Burns cleaner than coal and oil with almost zero sulphur dioxide emissions and far fewer nitrogen oxide and particulate emissions.
- Primarily composed of methane. Methane is a greenhouse gas 20 times as potent as CO2. Capturing and burning the gas to produce usable heat and power prevents methane from being released from landfill or feedlot into the atmosphere directly.
advantages of fossil fuels
- The energy produced by fossil fuels is greater than that produced by an equivalent amount from other energy sources.
- Coal is found in abundance. Used un most power plants because it reduces production costs to a great extent.
- Fossil fuels are easier to extract and process, therefore it is cheaper than non-conventional energy forms.
disadvantages of fossil fuels
- Although oil, natural gas and coal found in abundance in nature, the alarming rate at which they are being consumed has resulted in substantial depletion of their reservoirs. Besides, it is impossible to replenish the resources as it takes millions of years for hydrocarbon chains to form organic remains.
- Fossil fuels release greenhouse gases into the atmosphere including, methane, carbon dioxide etc. These gases are capable of damaging the ozone layer (enhanced greenhouse gas effect).
- Depletion of reservoirs has made the extraction of fossil fuels an expensive affair. This is likely to affect the fuel prices in the near future.
- Leakage of some fossil fuels such as natural gases and crude oil can lead to severe hazards. Hence transportation of these fuels is very risky and costs more, (think oil spills).
- Fossil Fuels have contributed in more than one way to global warming.
renewable energy definition
Renewable energy sources are constantly replenished, therefore will never run out.
why is the sun the ultimate energy source on earth
- Producers convert light energy from the sun into chemical energy in the form of glucose, using photosynthesis. Glucose provides energy in which all life depends on.
- When living organisms die they have the potential to become fossil fuels, this means that the sun was the original source of energy for all fossil fuels.
- The sun also has the power to generate electricity through the use solar panels, contributes to wind and hydro power and powers biomass/biofuels.
renewable energy sources include
- Wind Power.
- Solar Power.
- Geothermal Energy.
biomass electricity generation
- Bioenergy is derived from biomass to generate electricity and heat or to produce fuel for transport.
- Biomass is an organic matter made up of recently living plant and animal material. It contains stored energy from the sun.
- Biomass may be converted to biofuels or biogas or used directly in order to be burned as fuels.
- When biomass is burned it releases its chemical energy as heat.
biogas and ethanol
› Biogas formed from decomposed paper, food scraps and yard waste in landfills.
› Ethanol made from crops such as corn and sugar cane that are fermented to produce fuel. Biodiesel is produced from vegetable oils and animal fats.
advantages of biomass
- Biomass used as fuel reduces the need for fossil fuels to produce heat.
- Resource is always available as it is produced as a renewable source.
- Fuel can be produced from agricultural waste. A secondary product that will add value to the crop.
- Growing biomass crops produce oxygen and use carbon dioxide.
- Reduces landfill, makes more space.
- Less money spent on foreign oils.
- The Carbon dioxide produced from burning, is used by the other plant crops.
disadvantages of biomass
- Agricultural waste is not available if the basic crop is no longer grown.
- Additional work is needed in harvesting methods.
- Research needed to reduce costs of production of biomass-based fuels.
- Land used for energy crops maybe needed for other purposes such as farming, conservation, housing or agriculture.
- Biomass from animal waste is limited.
biofuel electricity generation
- Liquid fuels derived from other materials such as waste plant and animal matter.
- Two main types of biofuels in Australia is bioethanol and biodiesel.
- Biodiesel has the potential to reduce emissions by 85% compared to ordinary diesel.
- Ethanol can reduce emissions by 50%.
biofuels in the future
- In future, use plants containing tougher materials such as cellulose. This would be more efficient than biofuels as it contains more energy and releases less carbon dioxide. Cellulose is found in grass and saplings.
advantages of biofuels
- Easy to source. Biofuels are made from many different sources such as manure and waste from crops, which have very little other purpose.
- Cost Benefit. Biofuels are cleaner, which means they produce fewer emissions. This keeps engine running for longer, requires less maintenance and brings down pollution overall.
- Made from renewable resources. Crops can be replanted again.
- Reduces greenhouse gas emissions.
- Lowers dependence on foreign oil. Locally grown crops reduce nation’s dependence on fossil fuels.
disadvantages to biofuels
- High cost of production. Expensive to produce in current market.
- Uses Fertilisers. Biofuels produced from crops rely on fertilisers to grow better. Fertiliser run off can have harmful effects on the surrounding environments (eutrophication).
- Crops used for consumption reduces, as crops used for fuel take up space.
hydropower electricity generation
- Hydropower uses the force/energy of moving water to generate power, known as hydroelectricity.
- Hydropower is generated when falling water on turbine blades rotates a shaft and drives an electrical generator, converting the motion into electrical energy.
advantages of hydropower
- Fuelled by water, a clean fuel source. Water does not pollute the air.
- Hydropower relies on the water cycle, driven by the sun and is thus a renewable power source.
- Engineers can control the flow of water through the turbines to produce electricity on demand.
- Can provide water supply and flood control.
disadvantages of hydropower
- Can cause low dissolved oxygen levels in water, which results in added infrastructure to aerate the water, increasing cost.
- Dams installed to generate hydropower affect fish’s ability to travel upstream.
- Hydropower plants can be impacted by drought. If water is not available the power plant cannot produce electricity.
- Compete with other uses for the land. Land could alternatively be used for humans and flora and fauna (natural habitats).
wind power electricity generation
- Wind power is generated by converting the kinetic energy in the atmosphere into useable electricity with wind turbines.
- Wind is generated by complex mechanisms involving the rotation of the earth, the heat of the sun, the cooling effect of the oceans and polar ice caps, temperature gradients between land and sea and the physical effects of mountains and other obstacles.
- Wind turbines convert the force of wind into a rotational force, which is used to propel an electric generate to create electricity.
wind power advantages
- Australia has some of the world’s best wind resources. Wind is the fastest growing renewable energy source for electricity generation in Australia.
- Wind is a clean fuel source. It does not pollute the air, as it does not produce atmospheric emissions.
- Wind is a sustainable source of energy, as it is considered a form of solar energy (wind is caused by heating of the sun).
- Wind power is cost effective, it is one of the lowest-prices renewable energy technologies available today.
wind power disadvantages
- Good wind sites are often located in remote areas, far from cities where the electricity is needed. This requires transmission lines to be built to bring the electricity from the wind farm to the city.
- Wind resource development may not be considered a profitable use of land. Other uses for wind farms may be more profitable.
- Turbines may cause sound/aesthetic pollution.
- Turbines may damage local wildlife (bird killed by flying into rotors).