Image Credit: Chris LeBoutillier
It is widely accepted that fossil fuels are one of the factors that are contributing to climate change. Around the world people are looking for alternatives to the fossil fuels that we currently use.
Fossil fuels are any type of fuels which contain hydrocarbons. These are formed naturally in the Earth's crust from the remains of dead plants and animals over millions of years. These materials are extracted and burned as a fuel whether in power stations or domestically in our homes.
The main fossil fuels are coal, crude oil and natural gas.
Oil, gas and coal are all burnt in power stations to produce the electricity which heats and lights our houses, to runs our TVs and computers and charges our phones.
When these fossil fuels are burnt in a power station, the heat is used to turn water into steam, and this steam drives huge turbines. The turning of these turbines creates the electricity that ends up in our homes. This is referred to as a Steam Electric Power Plant.
Gas is also transmitted directly into homes where it is used for heating in gas-fired boilers and gas fires as well as for cooking.
The other main use for fossil fuels is for transportation, where they are used in the form of petrol and aviation fuel. In a car, petrol is burnt to create a hot gas which moves the pistons in the car’s engine. In a modern jet aircraft the fuel is again burnt to create hot gas which as it expands is forced out of the back of the engine, creating thrust which pushes the aircraft forward.
Burning these hydrocarbon-containing materials creates carbon dioxide, which then contributes to climate change by raising temperatures worldwide. So why is this a problem?
That is a bigger topic than can be covered here, but in short, higher temperatures around the world cause melting of the ice caps which raises water levels, affects the habitats of plants and wildlife, causes greater extremes of temperature and greater occurrences of flooding, heat waves, wildfires and drought.
There are a number of ways to produce power which do not involve burning fossil fuels, and they are improving all the time.
So here is a summary of the alternatives to fossil fuels that are currently used around the world.
Image Credit: American Public Power Association
Man has harnessed the power of water for centuries, for example in a simple water mill, where water turns a wheel to grind grains. Today hydrolectric power is the most widely used way of generating power without using fossil fuels.
The most commonly used type of hydroelectric power stations work on a similar principle. Water is used to turn a turbine, and so like a conventional or nuclear power station it generates electricity.
The main argument against hydroelectric power stations is that they take up a large amount of land, and building them can mean clearing and flooding large areas which requires people and animals to be displaced. Vast areas of biologically diverse land may be lost.
The ecosystems of the waterways around the hydroelectric power station can also be disrupted, affecting fish and river dwelling animals and plant.
Image Credit: American Public Power Association
Wind power is created by using a turbine which is moved by the power of the wind which produces an electric current. This is then usually fed directly into the national electricity transmission network.
A large number of wind turbines are needed to produce the amount of electricity that most western countries need, and many people object to the location of wind farms in the sort of wide open spaces that are needed. Wind farms can be built onshore or offshore.
The main downside is that they only produce electricity when the wind blows, so it needs to be used in conjunction with other energy sources.
Image Credit: American Public Power Association
Energy from the sun can be harvested using solar panels which can be placed on roofs or may be installed in areas of open land. Solar panels can even be used on a small scale to power individual road signs, garden lighting and pocket calculators.
Photovoltaic cells convert the sun’s energy to a current and then like wind power, the current can be fed into the national grid. The current can also be stored in a solar battery. This is more common where small domestic solar panels are used.
The biggest drawback of solar power is that you need a climate with a lot of sunshine to use it effectively. However the efficiency of solar panels is improving all the time, making it possible to use them more widely in countries with a more varied climate such as the UK.
Biomass refers to any plant-based material which is used as fuel to produce heat or electricity. For example, wood and wood residues, energy crops and waste from industry, farms and households.
So while this could refer to someone who chops down a tree to put on a domestic fire, more commonly it means using the by-products of the wood processing industry and agricultural residue which are transformed into a useful product.
The biomass may be dried and compressed into a briquette for domestic heating and cooking. It can also be heated to extract types of gas which can be used for heating and of oil which can be used in the plastics industry. In the future it is possible that biomass could be used as a substitute for petroleum.
Biofuel is an alternative to the petrol that we put in our vehicles and the aviation fuel used by aircraft. It may be an alternative that is produced from plants grown specifically to produce fuel, or as a by-product of bio waste.
The two most common biofuels are Bioethanol which is made from sugar, and Biodiesel which is made from oils or fats. At present only a tiny percentage of vehicles are run on biofuels.
Image Credit: Lukáš Lehotský
Currently the second most widely used type of non-fossil fuel is Nuclear Energy. In a nuclear power station, nuclear fission (often called “splitting the atom”) of uranium and plutonium is used to create a huge amount of energy in the form of heat. Just like in a conventional fossil fuel powered steam electric power plant, this energy heats up water and produces steam which drives turbines.
However nuclear power has always controversial, as the nuclear materials can be highly dangerous, and high profile nuclear power plant accidents have made some people antipathetic to nuclear power.
Many countries which wish to become more self-sufficient in energy production rather than importing oil and gas are now reconsidering nuclear power.
Hydrogen gas is an alternative to transportation fuel has had some degree as success; however the draw backs are that firstly since hydrogen is not naturally occurring it has to be manufactured. Secondly it is very difficult to store successfully in the sort of quantities required for cars.
Hydrogen is also highly flammable as the early hydrogen-filled airships such as the Hindenburg demonstrated. However as it contains no carbon it is still being developed and tested as a low carbon fuel alternative.
Biogas is the term for a mixture of gases, mainly consisting of methane, carbon dioxide and hydrogen sulphide. It is produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It may be harvested from landfill or produced industrially in an anaerobic digester.
Biogas can be compressed and used as a transportation fuel in a similar way to hydrogen gas and it can also be used create heat and electricity in power stations.
Image Credit: Evan Demicoli
Waste to energy plants burn domestic solid waste to produce heat in steam electric power plants. This has the advantage of reducing the amount of material that goes to landfill, but can be unpopular with local communities if the stored waste smells.
Sweden has been the most enthusiastic adopter of this type of power, with 99% of household waste being either recycled or burnt in a waste-to-energy plant. Indeed it is so successful that that Sweden imports waste from several European countries.
Wave power is a way of harnessing the energy of the sea. The movement of the sea’s wind waves can be collected by a Wave Energy Converter device.
There are currently no commercial wave power units in use, in spite of there being many experimental plants tested.
Tidal power or tidal energy is the term for converting energy from tides into useful forms of power, mainly electricity.
Like wave power it uses energy from the movement of water, but uses energy from tidal wave movement rather than from the waves created by wind. Like Wave Power there is no commercial use of Tidal Energy at present.
There are many alternatives to fossil fuels that are used around the world, from small scale hydroelectric schemes to a heavy reliance on nuclear power.
All of these types of power generation give us hope that the world will be able to reduce its reliance on fossil fuels. Hopefully we can replace them with clean, safe fuels that do not emit carbon into the atmosphere, contributing to pollution and climate change.
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