1. Renewable Energy Technologies
GCSE Construction & the Built Environment
Unit 2
Renewable Energy Technologies

2. Learning Outcomes
Demonstrate knowledge and understanding of the following renewable energy technologies and/or materials and identify their component parts.
Analyse and evaluate the advantages and disadvantages of these technologies and/or materials used as alternatives to fossil fuels. The following should be considered:
cost;
performance;
reliability.

3. Sustainability
The term sustainability was defined by Bruntland as:
"Development that meets the needs of the present without compromising the ability of future generations to meet their own needs."
Our Common Future know as the ‘Bruntland Report’, from the United Nations World Commission on Environment and Development (WCED) (1987)

4. Renewable Energy
Since the industrial revolution we have been dependant on fossil fuels such as oil, coal and gas to generate energy. Fossil fuels are non-renewable and therefore one day will run out. In addition, greenhouse gases are produced when burning these fossil fuels. Therefore relying solely on fossil fuels is unsustainable.
One way to reduce our dependency on fossil fuels to produce energy and reduce greenhouse gas emissions is to use renewable energy resources.
Renewable energy resources are sources of power that quickly replenish themselves and can be used again and again.

5. Renewable Energy technologies
Examples of renewable energy resources
Wind
Solar – power from the sun
Biomass – organic matter used as a fuel
Hydro – energy from moving water
Wave & Tidal – energy from wave and tidal movements

6. Renewable Energy technologies
Research and produce a list of renewable energy technologies from the following categories:
Wind,
Solar,
Biomass.

7. Examples of renewable energy technologies
Wind
Solar
Biomass
Wind turbine
Solar water heater
Solar photovoltaic cells
Air source heat pump
Ground source heat pump
Wood Chip Boiler
Wood Pellet Boiler
Anaerobic Digester

8. Renewable Energy technologies
Wind energy describes the process where electricity is generated by wind turbines. The turbines convert the kinetic energy in the wind into mechanical power.
There are two main types of wind turbine which are distinguished by the axis in which the rotor of the turbine rotates.
Vertical Axis Wind Turbines.
Horizontal Axis Wind Turbines.
The wind turbine blades which are connected to the rotor are turned by the wind and drive the main shaft, which spins the generator to generate electricity.

9. Wind Turbine
Activity
Research how the blades, rotor and components situated within the nacelle (gear box, generator and motor) work together to convert kinetic wind energy into electricity
Images by the author
Picture of a horizontal axis wind turbine

10. Renewable Energy technologies
Solar energy is the energy radiated from the sun. Solar energy can be used to generate electricity or heat water.
Two main types of solar collectors:
Solar Photovoltaic (PV) Panels produce electricity from the
Solar Water heaters

11. Solar Photovoltaic (PV)
PV panels generate electricity when sunlight hits the PV cell. The light excites the photons in the cell causing them to move, generating electricity.
The electricity flows to an inverter which converts the current from DC to AC so that it can be used in our buildings.
The main components which make up a solar PV system are:
PV panels (each panel is made up of a number of cells)
Inverter
Meter (to measure the amount of energy produced by the system)

12. Solar Photovoltaic (PV)
PV Panel installation
Images by the author
Inverter

13. Solar Water Heaters
Solar energy can be captured by solar water heaters to heat water
Two main types of solar water heaters are:
Evacuated tube
Flat plate
The heat energy is transferred from the external panel or tubes by air or fluid to an insulated hot water storage cylinder where water is heated and stored for use within the building.

14. Solar Collector Flat Plate Solar Heater Evacuated Tube
Title Solar glass tube hot water panel array on a roof
Item number: Collection:iStockRelease info:No release requiredAll of Thinkstock's images come with a royalty-free licence.
Flat-plate solar collector
Item number: Collection:iStockRelease info:No release requiredAll of Thinkstock's images come with a royalty-free licence.
Images © thinkstockphotos.co.uk

15. Diagram: Solar hot water system
Main Components:
Solar collector panel or tubes
Pump
Hot water cylinder
Pipework from collector to storage tank
Source:

16. Solar water heater Activity
In pairs research how both evacuated tube and flat plate solar water heaters work.
Summarise your answer in a short paragraph and sketch a diagram showing how the main components link together to provide hot water to the hot water storage tank

17. Renewable Energy technologies
Solar energy
The air, ground and water is heated by the sun. This energy can be captured by ground source and air source heat pumps.
A heat pump takes the heat from the air outside a building or in the ground (soil or water) and increases the heat to a higher and more useful temperature for use in our buildings.
The energy that heat pumps produce is classed as renewable because the air, ground and water is heated by the sun.

18. Heat Pumps
A ground source or air source heat pump uses the components listed below to take heat energy from either the ground or air and increases the heat to a higher and more useful temperature for use in the home to provide space heating and/or hot water.
Heat pump components
heat exchanger (evaporator)
compressor
condenser
expansion valve
Images by the author
Air source heat pump

19. Available: http://www.gov.scot/Publications/2009/03/20155542/5
Outline of a working ground source heat pump system, CES library
Source: Community Renewable Energy Toolkit - Section 3: Technologies. Published March 2009
Available:

20. Biomass
Biomass fuels come in many different forms, for example as solids such as wood chips or wood pellets, as liquids such as biodiesel or bioethanol and as gases such as biogas.
Biomass, which is material from living things, can be considered a renewable energy source if plants are replanted.
Wood chips or wood pellets are the most popular biomass fuels used to provide energy to our buildings

21. Biomass – Comparing wood chips & wood pellets
Produced by the shredding of trees such as willow into chips ranging in size of mm
High moisture content
Require drying either by storage in a dry area or by using heat produced by biomass boilers in large stores to reduce moisture content to less than 25%
The required time and energy for drying can add to the preparation costs of the wood chip
Wood chips are best suited to burning in larger scale boilers, for example those at hospital, leisure centres and district heating plants
Images by the author

22. Biomass – Comparing wood chips & wood pellets
Produced by mechanically compacting sawdust
Sawdust is extruded through a stainless steel former and the heat produced by the friction causes the lignin in the timber to melt and fuse the sawdust together.
Moisture content of approximately 10%.
Advantage of being a standard size 6 or 8 mm in diameter and usually mm long
Higher energy density than wood chips
Their regular size allows boiler manufacturers to produce automated systems for feeding the pellets into small scale boilers suitable for domestic use
Images by the author

23. Biomass
Biomass chips or pellets are burnt in a boiler to create heat energy. The heat is then used to heat water for use within the building and/or for space heating. Water is heated by the boiler and then pumped around the building via radiators or underfloor pipes to heat the space.
Thermostats within each room or building zone are used to turn on and off the radiators or underfloor heating to ensure that the building is heated to the desired temperature.
Images by the author

24. Benefits of renewable energy
Potentially infinite energy supply
Free energy
Environmental benefits
Energy generated on site which provides security of supply
Reduced greenhouse gas emissions

25. Benefits of renewable energy
Activity:
The cost, performance and reliability of renewable energy technologies and/or materials should be considered as you work in small group to analyse and evaluate the advantages and disadvantages of:
Heat pumps (ground source and air source);
Wind turbines;
Photovoltaic cells;
Solar water heaters; and
Biomass – Wood chip and wood pellet
Add your findings to the summary table shown on the next slide and give feedback to the class.

26. Heat pumps (ground source and air source)
Cost  
Performance  
Reliability  
Heat pumps (ground source and air source)
Higher installation and capital cost compared to non-renewable systems such as oil or gas boiler
Low maintenance
Wind Turbines
Must be placed in suitable location 
Only work when wind speed meets the turbine cut in speed
Solar PV 
Free energy from sun 
20 year life span 
Requires very little maintenance   
Solar water heater 
Requires daylight 
Most efficient in summer months 
Biomass 
Wood chip  & Wood pellet
Capital cost to install boiler and storage of chip/pellets as required 
Fuel cost - Need to purchase chips/pellets or produce your own 
Boiler requires servicing 
Moisture content of fuel source will impact on boiler efficiency  
Works constantly provided there is a fuel source 

27. Renewable Energy Technology – Component Parts
Activity:
From the knowledge gained from the presentation and using other resources such as the CCEA FactFiles, research and list the main component parts which make up the renewable energy technologies listed below:
Heat pump (ground source and air source);
Wind turbine
Solar photovoltaic (PV) cell
Solar water heaters (Evacuated tube and flat plate)
Biomass (Wood pellet or wood chip boiler)