P3 Energy resources Flashcards
What is a renewable resource?
A renewable energy resource is one that is being (or can be) replenished as it is used.
Renewable resources are replenished either by:
human action, e.g trees cut down for bio-fuel are replaced by planting new trees
natural processes, e.g water let through a dam for
hydroelectricity is replaced through the
water cycle
What is a non renewable energy resource?
A non-renewable energy resource is one with a
finite amount. It will eventually run out when all reserves have been used up. (e.g fossil fuels)
Biofuels:
Biofuels are fuels made from plant materials. These include biodiesel, made from plant oils, and bioethanol, made by fermenting sugar and wheat. They are renewable but carbon neutral as burning them still giving off carbon dioxide which gets reabsorbed when growing these plants.
Nuclear Power:
The fuel is usually uranium and in the nuclear stores. The uranium nucleus is unstable and can split in to two. As there is many Uranium atoms it can become very hot and a liquid called a coolant is pumped through the core and transfers this energy to the heat exchanger which turns water to steam and drives a generator. There is nuclear waste that needs to be stored into the earth but there is no emissions but this fuel is non renewable. The power output is very high.
Fossil fuel powered power plant:
The fuels burn providing heat energy that transfers to the water and turn it to steam which turn a turbine which powers generators converting the energy from thermal to electrical.
Fuels could be crude oil, coal or natural gas.
It is non renewable but can be used in transport and heating as well. It releases greenhouse gases however.It is readily available at the moment and it is easy to use.
Wind turbine:
The turbine consists of a generator in a
nacelle at the top of a high tower. The wind turns the blades of the turbine and these, in turn, spin the
generator. It is renewable , cheap to run and doesn’t produce greenhouse gases however they are unreliable as they are based on wind strength and ugly and have a low power outage.
Water based power sources:
Tide, Hydroelectricity and Wave
Tidal:
The Moon’s gravitational pull lifts the level of the seas twice a day and this is the force that gives us
tidal power.
At high tide, the sea is trapped behind a
barrage/dam.
The water is allowed to run out through pipes that lead back to the sea.
As the water runs through the pipes it spins turbines that are linked to generators.
It is renewable but its power outage is variable but can be very high.
Hydroelectric:
Water is held behind a
dam in a lake or reservoir high up a mountain.
Rivers or rainfall fills the reservoir.
When energy is needed, the water is allowed to run down through pipes to another lake lower down the mountain.
As the water runs through the pipes it spins turbines that are linked to generators.
The water can be pumped back up during the night when electricity is cheaper.
It is renewable and no emissions are produced and reliable and can be switched on when needed.
However dams damage habitats and are visual pollution. The plants that die from creating this can rot and give off methane.
Wave: A floating generator that moves up and down due to the movement of the waves and need to withstand storms. A cable delivers the electricity to the grid. The outage is low but is renewable you can connect many.
Solar panels:
Solar power comes from the Sun so it is a renewable energy source.
We can use the energy from the sun to provide heat directly. We can also use solar panels made up of solar cells to turn sunlight into sustainable electricity.
Solar electricity panels
Electricity is generated from energy from the Sun by solar panels. These are made up from individual solar cells (also called photovoltaic cells).
Light from the sun passes through the glass cover of a solar cell.
The sunlight hits layers of semiconductors, giving extra energy to electrons in the semiconductors.
This energy builds up negative and positive charges in the different layers.
The opposite charges cause an electrical current to flow through metal wires.
This electricity can then be used locally or transported through the National Grid to homes and workplaces.
Solar thermal panels
As well as being used to generate electricity, solar energy can be used to directly provide heat to our homes. One common usage is to provide hot water rather than relying on a gas-powered boiler.
Solar thermal panels absorb energy from the sun. This heats up a fluid that is piped through them. The fluid then transports this heat to a water tank.
To develop a sustainable future you need to think about meeting today’s needs and protecting the environment and resources for the future.
Solar energy is a renewable source. As long as the Sun lights the Earth, we will always have solar energy…
Solar power is sustainable because it releases no greenhouse gases or pollution,
The negative impact of solar power is down to the impact of their manufacture and transport. Large amounts of energy and water are needed to manufacture solar cells and the chemicals used can cause pollution.
Solar cells include rare metals and extracting these causes damage to local environments.
Most modern solar panels are expected to last about 40 - 50 years. Recycling them will help make them more sustainable.
Advantages
One of the biggest benefits of solar energy is that it is renewable. It needs no extra fuel other than the light from the sun.
Solar panels are very versatile in their variety of sizes and uses. If you are installing them, the trick is to find the best location. You can use a light sensor to find out which spots get the best amount of light.
There are no fuel costs and no harmful polluting gases are produced.
Solar cells can provide electricity in remote locations where there is no mains electricity.
Solar thermal panels can be used to heat spaces and water directly.
Disadvantages
Due to our seasonal sunshine, solar power generates more electricity in summer with longer periods of daylight but long winters and cloudy skies reduce its efficiency.
Scotland’s variable sunshine means our renewable energy is more reliably generated through wind and hydroelectric power.
Solar panels don’t work at night. This is often when people are using the most energy in their homes.
Solar panels cannot store energy, so batteries or capacitors are needed to do this.
Making solar cells requires rare metals as well as lots of energy and water.
Geothermal energy:
Hot rocks heat water and drive a turbine which makes a generator convert to electricity. The store is thermal. It is needed to be placed in geologically active areas and it can even be used for heating. It is renewable and no emissions are produced.
How are these resources compared?
Power stations that use fossil fuels or nuclear fuel are very reliable sources of energy. These two types of station provide much of the country’s electricity. They operate almost continuously. When additional power is needed, gas power stations are usually used because they will come on very quickly and start generating electricity almost immediately.
The fuel for nuclear power stations is relatively cheap, but the power stations themselves are expensive to build. It is also very expensive to dismantle, or decommission, old nuclear power stations at the end of their useful life and the highly radioactive waste needs to be stored for millions of years before the natural activity will reduce to a safe level.
Water power, eg tidal and
hydroelectricity, is reliable and predictable because of the Moon causing the tides and rainfall filling reservoirs. They can also be used to supply additional demand. But many of the renewable sources are unreliable, including wind and solar energy, and cannot respond to increased demand - sunny and windy weather cannot be guaranteed.
Renewable resources have no fuel costs, but the equipment used is expensive to build.
What are energy needs:
Energy needs
Nearly everything requires
energy and a way to use energy is by transferring it from one energy store to another.
Systems that can store large amounts of energy are called
energy resources. The major energy resources available to produce electricity are fossil fuels,
nuclear fuel, bio-fuel, wind,
hydroelectricity, geothermal, tidal, water waves and the Sun. Ultimately, all the energy on Earth originally comes from the Sun but has been stored as different energy resources.
Energy is needed in:
homes - for cooking, heating and running appliances
public services, eg schools and hospitals - running machinery and warming rooms
factories and farms - operating heavy-duty machines and production chains
transport - buses, trains, cars and boats all need a fuel source and some trains and trams connect to an electricity supply
However, producing and distributing electricity can cause damage to the environment. Releasing energy from some stores causes pollution and harmful waste products. Burning fossil fuels releases carbon dioxide, adding to the greenhouse effect, and sulphur dioxide which causes acid rain.
What explains the patterns of energy consumptions?
During the Industrial Revolution, advances in automation and transport caused a significant increase in the amount of fossil fuels extracted and burnt.
In the 20th century, electricity became a convenient way of distributing energy. Most of the electricity generated globally is still produced by fossil fuels. This is partly due to:
the high power output fossil fuels give compared to other energy resources, like wind and water waves
the existing
infrastructure for extracting, transporting and processing fossil fuels - this makes fossil fuels cheaper than setting up new alternatives
The recognised impact on the environment of burning fossil fuels has caused science and society to develop the use of renewable energy resources and make machines more efficient.
In some developed countries, nuclear power stations are a growing form of electricity generation. Nuclear fuel can release large amounts of energy compared to fossil fuels and does not emit carbon dioxide. However, the radioactive waste that is produced is difficult to store and dispose of.
Other factors that could influence governments’ decisions about the use of energy resources are political and economic pressures. For example, countries where the economy is heavily based on extracting and exporting oil, have a strong interest in fossil fuels to be largely used in electricity generation. In order to compete with more developed countries, growing countries like China need a large power output to keep growing their industry. This means they are likely to continue using fossil fuels and developing the use of nuclear power, alongside increasing supply from renewable sources of energy.
