Chapter 1 Why is energy a hot issue To understand why energy is important think about what you do in a single day You wake up to the sound of an alarm clock switch on the light and have a hot shower Maybe you walk to school drive or catch a bus If the weather is cold your school will be heated When you come home you might heat up a snack in the microwave and watch TV All these things use energy Why do we need energy Like other living things humans need energy to survive We get our energy from the plants and animals we eat It enables us to think grow jump run and dance We have learned to harness energy from the sun to make things work for us With energy we make electricity and can heat or cool our homes Energy allows cars buses trucks trains and planes to move and with it we can make all kinds of things from sunglasses and sneakers to cell phones and computers Where does our energy come from Did you know that the gas in your car comes from the decay of plants and animals that lived millions of years ago long before dinosaurs roamed the earth Gas is derived from fossil fuels which took a long time to form The Bund shown here lit up at night is one of the most famous streets in Shanghai China As the world’s cities grow and energy demands increase the way we produce distribute and use energy is damaging the environment
Oil and gas were created from the remains of tiny marine animals buried at the bottom of the ocean Long after the prehistoric seas vanished these animal remains were compressed by heat and pressure Oil was formed first but in deeper and hotter areas the cooking process continued until natural gas was formed The same process also created coal from the remains of trees and ferns Why is energy a hot issue World energy consumption by source Biomass 3 Nuclear 4 Hydropower 7 Geothermal wind solar 1 Others 1 Oil 32 Gas 23 Coal 29 Source BP Statistical Review of World Energy June 2013 Renewables 2014 Global Status Report 2014 Most of our energy comes from oil coal and natural gas which will run out someday Only 8 percent of our energy comes from renewable resources Why do we need to change our energy use Today fossil fuels provide 87 percent of our energy Until recently they were the cheapest source of energy Oil powers 90 percent of the world’s transportation and coal is the most popular fuel for generating electricity Natural gas is used mainly for heating But there are two huge problems with using fossil fuels First they are nonrenewable because they take millions of years to form and can only be used once If we keep using them as we are now nearly all of the existing reserves will be gone by the end of the twenty-second century Second when we burn fossil fuels we produce polluting gases that contribute to warming the earth’s temperature This is why we need to find alternatives FOCUS And then there was light Lhaba a 33-year-old farmer used to light her stone house in the remote village of Zem in Tibet with candles and lights made from butter oil In June 2006 a new solar power plant started to supply her house and the homes of 44 other families Lhaba now has electric lights a television and a machine to make butter tea With 3,000 hours of sun per year Tibet has the highest potential for solar power in the world after the Sahara desert Access to energy will help improve the villagers standards of living 7
Are We Running Out of Energy Going nuclear Some countries rely partly on nuclear power another nonrenewable source of energy Nuclear power is generated through nuclear fission a process that involves splitting tiny particles called atoms Every object in the universe is made up of atoms By splitting the bonds that hold atoms together an enormous amount of heat can be released This energy can be harnessed to generate electricity Currently about 4 percent of the world’s energy comes from nuclear power The fuel most widely used for this process is uranium which is extracted from the earth Many people are against nuclear power because its production creates highly toxic waste that takes more than 20,000 years to decay Using renewables Only 8 percent of our energy comes from renewables in other words sources that can be replaced Day after day the sun shines the wind blows water flows and trees grow These are all potential sources of energy Many of them have been used on a small scale for hundreds of years We have learned to design buildings that capture the heat of the sun and over the centuries we have used the power of the wind to mill flour and transport goods and people Wood is still used in many countries for Expert View Many experts agree that energy supplies are limited so we must look for alternative sources of energy in the future There is about 40 years worth of oil reserves at the current production rates For gas we know of 70 years worth of reserves For coal there is at least 160 years with estimates up to 1,000 years because no one has gone seriously exploring for coal Iain Conn director of British Petroleum speaking in 2006 heating and cooking But the use of renewable energy on a large scale costs more than burning fossil fuels which means that so far it has not been a favored option In places such as China Canada Brazil and the United States hydropower is an important source of renewable energy These countries have high mountains and fast-flowing rivers so they have the right geography for harnessing the power of falling and moving water To generate hydropower a river is dammed to form a reservoir The dam regulates the flow of water A large area needs to be flooded to create a reservoir and villages are sometimes relocated in the process 8
Why is energy a hot issue The Three Gorges Dam on the Yangtze River in China is the world’s largest hydroelectric power station More than 1 million people had to be relocated so that the reservoir could be built Who owns the energy resources Ownership of energy resources depends mostly on luck Reserves of fossil fuels are spread unevenly around the world More than one-quarter of the world’s coal reserves are found in the United States while almost half the world’s oil is in the Middle East The main reserves of uranium for nuclear power are in Australia Canada and Kazakhstan If a country has plentiful resources it is in a strong position because it can produce goods run a transportation system and supply the energy people need 9
