Using Energy in our Lives

1. Using Energy in our Lives Nonrenewable Energy Sources • We rely on non-renewable energy sources to meet most of our energy needs in our homes, businesses, and schools • For this reason, they are known as conventional sources or traditional sources of energy • Non-renewable energy sources cannot be easily made or renewed

2. Renewable Energy Sources • Someday, we will use up non-renewable energy sources • Because of this and because non-renewable energy harms the environment, more and more we are using renewable energy sources • Renewable energy sources can be easily made or renewed • Renewable energy sources are alternative sources because they are not based on burning fossil fuels or splitting atoms

3. Coal • Coal is the most plentiful fossil fuel found on Earth • There are four main categories of coal, depending on how much carbon it contains • The amount of carbon in coal determines how much energy it can produce • In Canada, coal is mostly found in the western provinces Categories of Coal

4. Coal is removed from the ground using either surface mining or underground mining • Coal buried less than 70 m underground is surface mined by removing topsoil and layers of rock to expose the large beds of coal • Underground mining removes coal buried deep underground • Once the coal is separated from rocks, dirt, and other unwanted materials, it is transported to electric utility companies and other industries • Power plants burn coal to make steam • The steam turns turbines or engines that generate electricity • About 20% of Canada’s electricity is fuelled by coal

5. Crude oil and natural gas • Crude oil comes out of the ground as a smelly, yellowish black liquid • Natural gas is normally a colourless, odorless gas • Crude oil and natural gas are fossil fuels that are drilled from underground areas called reservoirs or traps found either on land or offshore deep under the sea floor

6. After they are removed from the ground, crude oil and natural gas are transported to refineries • Crude oil and natural gas are made up of many different hydrocarbon molecules • A refinery is an industrial plant that heats oil and gas to sort, split, and reassemble the molecules so they can be made into different products

7. Crude oil can be made into diesel fuel, jet fuel, and gasoline • Processed natural gas mostly consists of methane, but fuels such as butane and propane are also made from natural gas • Natural gas is an energy source for electricity, steam heat production, industry, and domestic uses like furnace fuel.

8. Nuclear Power • Nuclear energy is the energy in the nucleus or central core of an atom • It can be released through nuclear fusion or nuclear fission • Energy is released during nuclear fusion when atoms combine to form larger atoms • Energy is released during nuclear fission when atoms are split apart to make smaller atoms • Nuclear power plants use nuclear fission to make electricity

9. Nuclear power plants primarily use uranium-235 (U-235) as fuel to make energy through fission • This is because the atoms in U-235 are easy to split apart • Uranium is a common metal that is found in most rocks • However, it is non-renewable, and U-235 is quite rare • It makes up only about 0.7% of the naturally occurring uranium on Earth

10. Nuclear power plants make electricity much like other power plants that burn coal or natural gas: • the fuel creates heat; • the heat creates steam; • the steam turns a turbine; • the turbine turns a generator, which is a machine that converts mechanical energy (motion) into electrical energy; • the generator makes electricity. • In nuclear power plants, reactors control the chain reaction described above • Nuclear reactors are the structures in which nuclear fission occurs

11. Renewable Energy Sources Hydroelectric Power • Hydroelectricity is electricity that is made from falling or flowing water • Hydroelectric power plants or hydropower plants use the force of moving water to turn turbines that drive generators to produce electricity • The best places to build these plants are along fast-moving rivers or streams, in mountainous areas, or in areas with consistent rainfall • Canada’s geography is well-suited for hydropower; as a result, it is the source for most of the electricity used by Canadians

12. Most hydropower plants use either the natural drop of a river, such as a waterfall, or a dam built across a river to create a driving force of water • The amount of water moving through the turbines (water flow) and the height from which the water falls from the upper reservoir in the dam or from the waterfall (called the head) determines the amount of electricity produced • The more flow and head, the more electricity is created

13. Solar power • Solar power refers to the methods that are used to harness the light and heat from the sun • They can be used to heat houses and water, and generate electricity • Solar power uses several different methods: • Photovoltaic (PV) cells (photo = light; voltaic = electricity) are grouped together in panels • They are made out of semi-conductive materials, such as silicon and glass • When light strikes the cells, an electric current is produced

14. Active solar energy uses collectors, such as mirrors and metal plates, to capture solar energy to heat air or water • Active solar energy is often used for space heating or water heating • Passive solar energy uses basic building materials like windows and insulation to control the amount of solar energy that is absorbed or lost in a building

15. Concentrating solar power uses mirrors arranged in towers, troughs, or dishes to concentrate solar energy to drive generators or engines to generate electricity

16. Wind power • Wind power uses the kinetic energy or motion found in moving air • It is mainly used to generate electricity, or mechanical power to grind grain or pump water • Turbines are used to capture the power of the wind • Large turbines are often grouped together in wind farms that provide power to an electrical grid that services homes and businesses • Wind turns the turbines’ blades, which spin a shaft that connects to an electric generator that makes electricity • Wind turbines come in different sizes but can be grouped into two types

17. Horizontal-axis turbines look like windmills that stand 20 storeys tall, with three blades that can measure longer than a football field • Most of the wind turbines used today are of this type

18. Vertical-axis turbines have two blades that go from top to bottom • They look like large egg beaters

19. Tidal Power • A tide is the alternate rising and falling of the ocean on a shore or coastline caused by the gravitational pull of the moon and sun and the rotation of Earth • Tides can also be used to generate electricity. • The most common form of tidal power involves building a large dam called a barrage across a river or outcropping of land • The barrage funnels water into a generating plant and through a large turbine as it flows in and out with the tide • The Annapolis Tidal Power Plant in Annapolis Royal, Nova Scotia, is one of only three tidal power plants in the world

20. Instead of barrages, tidal turbines can also be used to generate electricity • Tidal turbines take advantage of natural tidal flows • They can be anchored to the ocean floor or floated offshore • Nova Scotia is also experimenting with this new form of tidal technology

21. Geothermal power • Geothermal energy is heat that is generated within Earth’s core • Temperatures hotter than the sun’s surface are produced inside Earth because of the slow decay of radioactive particles • Large areas of geothermal energy called geothermal reservoirs are found mostly deep underground

22. In Canada, geothermal energy occurs at fairly low temperatures • Right now its primary use in Canada is to heat and cool homes and office buildings • Heat pumps extract near-surface geothermal energy from buried pipes to provide heat or air conditioning to buildings

23. More than 100 buildings in Toronto’s downtown core are air conditioned using a geothermal heat pump system that draws 4 °C water from Lake Ontario at a depth of 83 m

24. Biomass energy • Biomass is organic plant material and animal waste • Biomass contains stored energy from the sun • Plants absorb the sun’s energy through photosynthesis and this chemical energy is passed on to the animals and people that eat them • Examples of biomass include: • wood, and wood products like bark and sawdust; • agricultural crop left-overs; • animal manure and food processing wastes; • organic portions of municipal solid waste.

25. There are three main ways to convert biomass into energy: • Biomass can be burned to create heat; this can be used to create steam to drive turbines that generate electricity or heat homes and industries • Biomass can be heated (not burned) to break it down into gases, liquids, and solids; these can be processed to make fuels, such as methane • Biomass can be fermented or broken down by micro-organisms like yeasts and bacteria to create biofuelssuch as ethanol; biofuels are mainly used in vehicles, but can be used to power engines and fuel cells

26. Hydrogen fuel cells • The hydrogen fuel cell is a relatively new energy source • It can be thought of as a cross between an electrochemical cell, or regular battery, and a generator • Electrochemical cells convert chemical energy into electrical energy stored in positive and negative charges • However, unlike regular batteries, fuel cells do not wear out over time • Hydrogen and oxygen power fuel cells to make electricity • The only by-product is water • The hydrogen and oxygen are provided from external sources, so as long as they are supplied to the cell, it will produce electricity

27. Hydrogen fuel cells can be used: • to power electric cars; • to provide emergency power in remote places or at hospitals; • as portable sources of energy for laptop computers and cell phones • Fuel cells are also used to power NASA space shuttle electrical systems