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Renewable Energy

Unit of work for S3 technologies CDT experiences

Julian King

on 16 August 2012

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Transcript of Renewable Energy

Renewable Energy
And one more thing...
is here
Energy comes in different forms, it is all around us but can't be seen, the effects of energy however can be seen, heard and felt. We need energy to do work for us. We use a lot of energy so that our lives are both comfortable and enjoyable. Much of the energy we use comes from burning fossil fuels but some comes from renewable sources. Eventually fossil fuels will run out and so new technologies are being developed to provide safe, sustainable energy for our future. Energy is measured in joules.
In order to release the energy stored in fossil fuels we need to burn them. This produces heat that we can convert into kinetic energy. Unfortunately it also releases Carbon Dioxide, and other gasses that contribute to the greenhouse effect. If we want to slow down the rate at which our planet is heating up then we need to reduce the amount of fossil fuels we are burning.
What is Energy?
Fossil Fuels and the Environment
Renewable Energy Sources -
Sun Dependent
Kinetic energy is present in every object that has mass, when it is moving. A car traveling on a motorway has burned fuel to reach its desired speed. Take away its fuel source and the kinetic energy will enable the car to keep moving, we call this momentum, at least until wind resistance and friction brings the car to a halt.
Potential energy is present when any mass is lifted above the the ground or has the ability to fall or roll down a slope. It can also be stored in a spring or by compressing air. A parachutist will accelerate when he jumps from a plane because he has mass and the effect of gravity pulls him down.
Chemical energy can take the form of a combustible chemical, such as petrol or alcohol. It may also be a volatile chemical that gives out heat when mixed with another chemical (a catalyst).
Sound energy takes the form of a wave, and can be transmitted through air, water and rock. Although we can hear a range of sound frequencies most of the spectrum falls above and below what our ears can detect.
We see light everyday from the sun, which has traveled 93 million miles to get here. We can produce light by lighting fires, some insects even generate their own light by mixing chemicals in their bodies. We can now produce light using electricity by simply flicking a switch. Light is essential for life on earth because without it no plants would grow.
Heat is essential to all life on earth, mammals generate their own heat by converting fuel they eat. Reptiles rely on the sun to keep them warm. without heat we could not convert the energy from food and our muscles would not work.
Natural Gas
Electricity has only been harnessed by humans as recently as 200 years ago. 100 years ago most peoples homes had no electricity. Our dependance on a ready available supply means we need to burn millions of tons of coal every year.
Coal was formed millions of years ago by falling trees crushed by massive pressure and locked underground before they could rot. Coal is burned in power stations to release heat, which by turning water into steam can generate electricity by using its kinetic energy to turn turbines.
Oil was formed millions of years ago by the bodies of trillions of tiny sea creatures and plants falling to the bottom of the sea and being covered by sediment. Oil is used to produce petrol and diesel which we burn to power our cars. It is also used to produce plastic, widely used for industrial manufacturing of most products especially packaging.
Natural gas was formed millions of years ago in the same way as oil. Natural gas can be burned to release heat, when it is burned it releases harmful gases that contribute to global warming. Often it is just burned as a waste by-product of the oil fields as it is simply too difficult or expensive to get to shore.
Peat is formed when vegetation is compressed in a bog, because of the chemicals in the bog the vegetation can't rot. Peat must be dug from a peat bog and dried before it can be burned. As with all fossil fuels, burning peat releases carbon dioxide into the environment.
Not all of our energy comes from burning fossil fuels, some is produced using sources that will last for ever. The sun bathes the earth 24 hours a day in a constant stream of energy, and it is the heat from the sun that stops the earth from cooling into a lifeless frozen rock hurtling through space. The sun allows plants and trees to grow, it generates the weather that brings us rain and wind. Combined with the gravitational pull of the moon the sun even contributes to the tides of the sea.
Solar Power
Bio mass
Solar power has given birth to life on earth, without the sun there would be no life on earth. Just stand in the sun's light on a summer's day and you can feel the effect of the energy on your body. Solar power is now used to heat water, cook food, generate electricity in photovoltaic cells and of course grow every plant on earth that we eat or feed to our farm animals.
Bio mass is a general term for all plant matter that we eat, feed to animals, burn directly in the form of wood or generate gas from as it rots in adapted land fill sites. Bio mass is considered green because although it releases carbon dioxide when it burns in order to grow in the first place it takes carbon dioxide out of the atmosphere. It puts back what it takes out unlike burning fossil fuels.
Hydro-electric utilizes the water table to generate electricity from the potential energy in rainwater. As rain falls on high mountains it is pulled by gravity down towards the sea, we simply block its path with a dam and drive turbines which in turn drive generators to produce electricity. Not all hydro-electric works on rain fall. Some stations pump water up the mountain at low demand times, using electricity from the national grid, so they can release it at peak demand periods later.
Man has been using the power of the wind to do work for hundreds of years. Windmills in Holland were used to pump water from low lying farmland, reclaiming millions of hectares, from the sea. We have used windmills to turn grindstones to grind wheat into flour long before electricity was invented. We now use windmills to harness the kinetic energy of the wind and convert it into electricity using generators. Not everyone is happy about this as they take ten years to become carbon neutral and they are a blot on the landscape.
Storms and wind out at sea ensure a supply of waves onto our shores. These waves of water contain a huge amount of kinetic energy. If we can find a mechanical way of absorbing some of this energy without excessive production, installation costs then this energy should last for ever. Unfortunately the size of waves varies, often too small to generate any electricity sometimes so powerful that most mechanical devices would be destroyed by their power.
Renewable Energy Sources -
Not Sun Dependent
Molten rocks and metals at the earths core continue to erupt huge amounts of heat energy up to the surface. We can see this geological activity at volcanoes where lava pours out. In areas of the world where this activity happens close to the surface, heat energy can be extracted by pumping water underground and allowing high pressure steam to return to the surface. This contains kinetic energy that can drive turbines which drive generators producing electricity.
The sun and moon combine gravitational pull to lift our ocean sea water by meters.As the moon revolves around the earth and as the earth revolves around the sun the gravitational pull changes, bringing very high and low tides on a monthly cycle. Rising and falling tides provide us with a regular supply of potential energy. We can predict not only the time of every tide but also the quantity of energy it contains, for the next one hundred years. Many devices have been build and tested from tidal barriers to underwater hydro propellers, all produce large amounts of electricity. The only downside is the availability of suitable coastal regions where these facilities can be installed.
Nuclear power is the term given to describe the production of electricity from the releasing of heat energy from radioactive plutonium, by controlling a nuclear fission reaction. Nuclear power stations do not produce carbon dioxide and therefore do not contribute to global warming, but there are concerns. The initial investment in the power station is very expensive and they need to be located in geologically safe regions. The waste product is highly radioactive and will remain so for thousands of years. Accidents do happen and if a station goes into meltdown radioactive waste spews into the earths atmosphere contaminating farmland, homes and the environment.
Task 003 - Energy consumption diary
What impact do your daily energy needs have on society and the environment? Keep a record of what energy requirements you have for a 24 hour period, from the fridge cooling your food, to the washing machine cleaning your clothes. The record could be in the form of a video diary, graph, table or mind-map. Make sure to record which of the energy types you are using and for an additional challenge report how you could reduce your carbon footprint.
Task 004 - Consume less Energy
This task is a group activity. In your discussion groups you need to analyze what human energy consumption requirements could be made more efficient. Create a mind map that shows all of the main energy needs of society and decide on three ways of reducing our energy consumption.
Heat Energy
Heat energy is contained in every material that is above ambient temperature, or where any material is heated above the temperature of its surroundings. It takes energy to raise the water in a kettle to boiling point, we can calculate how much energy by using this simple formula:
Specific heat
Delta, the change
(in temperature)
Energy heat
Potential Energy
Potential energy is a measure of the energy used to raise a mass a given height. The effort required is calculated by multiplying the mass of an object in kg by the force of gravity which is a constant of value 9.81! Here's an example. If a 5kg mass is sitting on a table it exerts a force (in Newtons) of 5 x 9.81 = 49.05 Newtons.
In order to lift the 5kg mass we need to apply a vertical force of at least 49.05N, if we lift the mass to a height of 3 metres it's potential energy will have increased by
147 joules, here is the formula.
Kinetic Energy
Every object that has mass and is moving contains kinetic energy. You can feel the effects of kinetic energy when wind blows the sail of your yacht or you hit a baseball hard with a bat. When calculating the kinetic energy contained in a object we need to know the mass of the object and it's velocity (speed measured in metres per second)
Not all energy on earth comes directly from the sun. When the earth was formed 4.5 billion years ago it was a burning mass of rock, it cooled on the outside but due to extreme forces and the component elements in the core the center of the earth still remains a red hot mass of iron and rock, too hot to be a solid but under so much pressure it remains one. Tap into this heat and you have free, non-polluting energy. The sun and moons gravitational force lifts the planets seas in a wave around the planet, this causes our tides and again its free, non-polluting energy. Some elements on earth are radioactive, if we release this energy we call in nuclear, not free as you use plutonium, and nuclear energy produces radioactive waste that can harm the environment.
Energy Potential
Energy Kinetic
Task 005 - Solar Car
Solar cars are the future. When fossil fuels run out and we need all of the farmland to grow crops for eating we will need to run our cars on electricity that is produced in an environmentally sensitive way. Today in pairs you are going to charge and race cars that are powered by nothing more that light. This experience is to construct a systems diagram of components that make the car move. On squares of paper write out the names of every component with a description of what it does. Then connect these blocks with arrows that show how each is intrinsically linked.
Task 006 - Potential Energy Car
Another car building exercise; this week you are going to build potential energy racers that store energy in an elastic band. The car that wins will be the car that travels the greatest distance.
Task 007 - Systems approach
We are going to look at machines as a system that have an input and an output. This can be a transfer of energy. A petrol engine uses chemical energy as it's input fuel to produce kinetic energy that drive it's wheels, the output.
List the missing energy types on the worksheet
Task 008 - Geothermal Power Station
Let us look at the inputs and outputs of a geothermal power station. We will use the systems approach to analyze the energy transfer within the plant. Use the worksheet below and fill in the inputs and outputs. You will then need to write or draw a storyboard (use comic life) of how cold water turns on the lights in our homes.
Task 009 - Hydroelectric Power Station
Having completed a systems approach energy transfer diagram for a geothermal power station, you need to complete an analysis of a hydroelectric power station. You will need to show all of the energy transfer from the sun evaporating sea water all the way through to how the electrical energy can drive an electric car fast up to the top of a hill. Use comic life to do this.
Task 010 - Energy Production
Its time to design our own power stations. If we use the systems approach we can design a power station that is environmentally friendly and provides bountiful free energy. You will produce a poster that explains the energy source of your power plant and how the energy is transferred, stored and finally converted into useable energy for people to buy. Your plant doesn't need to produce electrical energy, it could produce chemical, heat, biomass, or even potential energy. This task will form part of your S3 folio and is a required element.
Task 011 - Potential Energy Questions
We can store energy in its potential form. All we need to do is lift a known mass, in Kg, a specific height, in metres, and we can retrieve this energy by letting the mass fall due to gravity at a later date. Peak demand hydroelectric plants do this by pumping water to a reservoir on top of a mountain during low electrical demand times, and then release this water to drive turbines when demand for electricity is high. Use the formula to answer the following questions:-
Work Done
Task 012 - Work done question
Task 013 - Power Questions
Task 014 - Heat Energy Questions
Task 001 - Calculating Effort
In order to move objects we need to apply some effort, this is a quantity of force and is measured in Newtons. We can calculate the effort needed to move objects along a table by measuring the quantity of Newtons using a simple Newton meter. Try calculating how many Newtons it takes to move a 1Kg mass along the table: is the force different if you try to move it along the floor? Finally make a simple KNEX buggy and now calculate how much force is required. If it now requires less force, you have made a machine that makes life easier or more efficient, and welcome to engineering. In order to achieve this experience you need to write up what you did and what your findings were. This can go into your prezi.
Task 002 - Calculating Work
Work is a measurement of effort (in Newtons) multiplied by distance (in Meters). The unit of work is the Watt. If it takes an effort of 200 Newtons to push a broken down car, we can only calculate the work you are going to do, to move it, if we first know how far it needs to be pushed. Makes sense that someone who pushes a broken down car for 2 km will do twice the work of someone who pushes the car only 1km.
Efficiency is a measure of the amount of energy comes out of a system, compared to how much energy went in. It is therefor a ratio that can be turned into a percentage by multiplying by 100. We will look at different ways of making systems more efficient later but for now lets work out the efficiency percentages of the following systems.
Task 015 - Environmental Concerns
These videos show the environmental impact our desire for cheap energy is having on the planet. The citizens of planet Earth are now consuming more energy than at any point in history. This consumption will continue to rise as the global population increases. Fossil fuels will run out, its just a matter of time. Nuclear power is carbon neutral but it's waste remains radioactive for thousands of years. Governments around the world are looking towards emerging technologies to find a solution. This means investment now in science and technology so the engineers of tomorrow have resources at their disposal.
Task 016 - Efficiency
No system can be 100% efficient, whenever we transfer energy from one form to another we lose some of the energy due to friction, insulation, resistance or other ways. Reducing the loss makes any system more energy efficient. An average family car will typically use one gallon of fuel to travel an average of 50 miles, just think how much we could save if we could make it go 100 miles! Efficiency is a ratio calculated by dividing Energy out by Energy in, try these following questions.
Task 017 Application of Technology Project
Task 018 - Project feedback form
This project is broken down into five areas, each must be completed in order to achieve this compulsory experience. You are going to analyze the design and function of a wind farm. The wind farm will be on remote land on a hill overlooking a small town. The town is 30 miles from a large city. You can choose how you present your findings but you should consider a selection of approaches that might include, posters, systems diagrams, videos, story boards, computer modeling, rendered illustrations, questionnaires, results tables, interviews, data collection from field or desk and a detailed evaluation. The five areas to include in your project are:
Analysis of project
Selection of Resources
Block Diagram Solution
Environmental Concerns
You need to complete the project evaluation form, you can find this in the experiences table of the school website on the Renewable energy project page.
Task 019 - Word-bank
Task 020 - Presentation
Working in small groups you need to present your work to the rest of the group. Your findings from this project need to be concise and you will need evidence to support any argument for or against renewable energy production. The presentation will be filmed and you will be expected to use ICT in some way.
The following words have been used in this project and you must demonstrate your understanding of them in context. One way of doing this is to write out their meanings, another would be to discuss them each on a camstudio video that you make, this video could form part of the final project presentation.
Solar energy
Wind energy
Fossil fuels
It takes energy to raise the temperature of any mass. The amount of energy is dependent on the specific heat capacity of the material (the amount of energy to raise 1g of the material by 1 degree centigrade) and the mass of the material. Try these questions below.
Power is the rate at which energy is transferred, used or transformed. It is therefore the quantity of energy (joules) divided by the time taken to transfer it (in seconds). The unit of power is the Watt. Electrical power is also measured in Watts however the formula for electrical power is electrical current (Amps) multiplied by the voltage supply. The power rating of a domestic light-bulb is measured in Watts, although low power consumption light-bulbs are given an equivalent value as they now consume dramatically less power to produce the same amount of light, they are more efficient. To complete this experience complete the worksheet below:
This experience is essentially an essay writing experience, however it will involve a discussion with your friends and teacher. We all have concerns about our local and global environments. Some of these may only concern a small number of people, however some concerns affect everyone. Whether you are worried about speeding cars in built up areas or litter being dropped in the street, or you worry about air pollution from industry that causes lung disorders or radioactive contamination that causes cancer. The only way we can ensure our local and global environments are safe for future generations is by acting today. Engage in a discussion and list ten environmental concerns, put them in order of priority and justify why you consider each important. Finally write a letter to your MP, or produce a flyleaf to raise awareness of a specific local issue. If you don't act to protect your environment who will?
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