Unit 2 ~ Renewable Energy Air, Earth, Fire and Water ~ An Introduction to Environmental Science Unit 2 ~ Renewable Energy

Introduction to Renewable Energy As fossil fuels are being used up it is urgent that we find something to replace them to satisfy our energy needs. Renewable energy is the way forward. By using different types of renewable energy in different areas we could provide for all of our future energy needs.

Unit 2 ~ Renewable Energy Energy Energy cannot be created or destroyed; it can only change from one form to another. There are many different forms of energy such as: Kinetic, Potential, Nuclear, Chemical, Electrical, Magnetic, Heat, Sound

Unit 2 ~ Renewable Energy Renewable Versus Non- Renewable Energy A renewable source of energy is one which is derived from resources which are replaced or regenerated e.g. biomass, water or wind. A non-renewable source of energy is one which will become depleted in time e.g. fossil fuels

Unit 2 ~ Renewable Energy Renewable Versus Non- Renewable Energy We usually burn fossil fuels in order to convert their chemical energy to heat, light and other forms of energy. Renewable sources of energy include hydroelectricity, wind energy, tidal energy, solar energy, and biomass.

Unit 2 ~ Renewable Energy Hydroelectricity Hydroelectricity involves building a dam across a river to form a lake. Water flowing through the dam turns a generator to produce electricity.

Unit 2 ~ Renewable Energy Hydropower

Unit 2 ~ Renewable Energy Hydropower in Ireland ~ Ardnacrusha Co. Clare

Unit 2 ~ Renewable Energy Wind power and wind farms Wind energy involves the wind turning large wind turbines, which generate electricity.

Unit 2 ~ Renewable Energy Wind Power

Unit 2 ~ Renewable Energy Wind power in Ireland Arklow West of Ireland wind farm (photo:GE Energy)

Unit 2 ~ Renewable Energy Tidal power Tidal energy involves building a dam across an estuary to form a lake. This lake fills and empties as the tide rises and falls. The water flowing through the dam generates electricity. Another way uses under- water turbines. home.clara.net/darvill/altenerg/tidal.htm

Unit 2 ~ Renewable Energy Harnessing the tide Tidal power plant St. Malo/Bretagne

Unit 2 ~ Renewable Energy Solar energy There are several ways to harness the sun’s energy. It can be trapped by solar panels and used to heat water. The sun can be focused onto a boiler and used to generate steam to produce electricity. The light energy can be converted into electricity using solar cells (photovoltaic cells).

Unit 2 ~ Renewable Energy Many ways to harness the sun

Unit 2 ~ Renewable Energy The biomass solution Biomass is plant matter and can be used as several ways. Sugar cane or sugar beet or whey bcan be fermented to make bio-alcohol which can be used instead of petrol. Biodiesel is made from vegetable oils, like rapeseed oil, which can be used in unmodified diesel engines. Fast growing crops like elephant grass or willow can be used as solid fuel for boilers.

Unit 2 ~ Renewable Energy Biomass Systems

Unit 2 ~ Renewable Energy Biomass in Ireland Elephant grass Rapeseed

Unit 2 ~ Renewable Energy From Carbery to cars Whey → Bioethanol → E85

Unit 2 ~ Renewable Energy Energy from the Sun The sun’s energy can be harnessed in 2 main ways: Solar panels that heat up in the suns light to produce electricity Solar cells that use light to produce electricity.

Unit 2 ~ Renewable Energy Harnessing Light Energy Visible light is only part of the electromagnetic spectrum. Radiation from the sun is not monochromatic - it is made up of a range of different wavelengths, and therefore energies. Light can be separated into different wavelengths, and we can see them in the form of a rainbow.

Unit 2 ~ Renewable Energy Trapping sunlight in silicon Silicon can only trap a certain wavelength of light and turn it into electricity. Sunlight has a wide range of wavelengths – some are absorbed and the others pass straight through.

Unit 2 ~ Renewable Energy Harnessing Light Energy Only a certain amount of energy, measured in electron volts (eV) and defined by our cell material (about 1.1 eV for crystalline silicon), is required to knock an electron loose. We call this the band gap energy of a material. The devices are known as solar cells or photovoltaic cells.

Unit 2 ~ Renewable Energy Solar Cells Solar cells are known as photovoltaic or photoelectric cells. They convert light directly into electricity Solar energy is free - it needs no fuel and produces no waste or pollution. Photovoltaic (PV) cells are made of special materials called semiconductors such as silicon.

Unit 2 ~ Renewable Energy How do photovoltaic cells work? Semiconductors are materials which have a conductivity between conductors (generally metals) and non- conductors or insulators (such as most ceramics). Semiconductors can be pure elements, such as silicon or germanium, or compounds such as gallium arsenide or cadmium selenide. In a process called doping, small amounts of impurities are added to the pure semiconductors causing large changes in the conductivity of the material. When light strikes the cell, a certain portion of it is absorbed within the semiconductor material.

Unit 2 ~ Renewable Energy How do photovoltaic cells work? This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the Photovoltaic cell, we can draw that current off to use externally.

Unit 2 ~ Renewable Energy How solar cells work

Unit 2 ~ Renewable Energy Solar Energy Systems (1)

Unit 2 ~ Renewable Energy Solar Energy Systems (2)

Unit 2 ~ Renewable Energy Solar Panels to produce hot water

Unit 2 ~ Renewable Energy Renewable Energy Sources in Ireland Activity: What area in Ireland would be the best for different types of renewable energy sources?

Unit 2 ~ Renewable Energy Renewable Energy Sources in Ireland Can you think of Irish examples of renewable energy? Wind Power Hydropower Biomass Solar Panels Solar Cells

Unit 2 ~ Renewable Energy Renewable energy in Ireland Ireland is producing more and more of its energy from renewable resources. How does Ireland compare with other countries in Europe?

Unit 2 ~ Renewable Energy Worldwatch Guide of Renewable Energy Usage and Targets for the Future

Unit 2 ~ Renewable Energy Biodiesel in Ireland

Unit 2 ~ Renewable Energy Some Irish wind farms

Unit 2 ~ Renewable Energy Conclusion – a lot done, much more to do! In 1990 renewable energy was 1.9% of Ireland’s primary energy supply – by 2006 it had reached 4.5% (wind 2.7%, hydro 1.2%) In 2006 we produced 1,622 GWh from wind, with 782 MW installed capacity Landfill gas contributed 108 GWh in 2006 and hydropower 724 GWh