Every day, people get up, go to school or work, walk, read, and do many other things. Where do we get the energy? The answer lies in what we eat, drink, and breathe; our fuel is food, water, and air. But what about non-living things? What powers a car? What makes water boil? Where does your computer get its energy from?
"I put gasoline in the car, cook over a gas stove, and plug in the computer," you reply. Your answer sums up the main energy sources that power non-living things: oil, gas, and electricity. Oil and gas have two energy uses; the first is to fuel cars, buses, trains, and planes, and the second is to generate electricity. Coal, nuclear power, and hydropower (energy from flowing water) are also used to make electricity.
People in most developed countries use oil for 50% of their energy. Problems arise, however, when we rely so heavily on oil for our energy needs. First of all, there is a limited supply of oil. Oil industry experts estimate that current oil reserves will last for only forty more years. This means that by 2045, there will be no more oil to make gasoline or electricity.
Currently, most of the world's available oil is consumed only by developed countries. Nearly a third of the world's population of 6.1 billion people has no electricity, and another third has only limited access to electricity. Twenty percent of the world's population consumes seventy percent of the world's energy resources. What will happen when developing countries get access to electricity and oil? There simply won't be enough.
Another problem is the location of our energy. As recently as a couple of centuries ago, virtually everyone used fuel that they could find close to home. In the modern world, energy sources are often long distances away from the end user. For example, many countries have no oil reserves and import all of their oil. When oil is transported over long distances, there is the risk of oil spills, which can cause irreversible damage to the natural environment. Conflicts, or even wars, can erupt over the control of oil fields and oil pipelines.
The most serious problem with burning oil for energy is global warming. The earth’s atmosphere is getting hotter because there is too much carbon dioxide (CO2) in the air. Burning fuels like gasoline (to drive cars) and coal (to produce electricity) releases large amounts of CO2 into the air. Scientists predict that global warming may cause sea levels to rise, animals to become extinct, and extreme weather, everything from severe droughts to hurricanes.
The good news is that we don't have to use oil, gas, and coal to produce energy. There are other energy sources that won't run out, don't require transportation across the globe, and don't release CO2. The best thing about energy from these alternative energy sources, also called "renewable energy," is that it is unlimited─it comes from water, wind, and the sun.
Wind power is not new; boats and ships have been using it for thousands of years to travel across the globe. Windmills in Europe have used wind for centuries to pump water, grind grain, and saw wood. In modern times, machines called wind turbines, with blades from one meter to one hundred meters long, turn wind into electricity. Scientists believe that if collections of these turbines were installed in wind farms in the world’s windiest places, there would be enough energy to satisfy global demand.
Solar power is energy from the sun. Energy from the sun can be used in two ways: to make electricity and to heat water. Solar cells are thin pieces of silicon that produce electricity when exposed to sunlight. You may have used a solar-powered calculator or flashlight. Solar cells can also power lights in a home. A solar-powered car has even been built! In Australia, a solar boat was showcased at the 2000 Olympic Games in Sydney. The Solar Sailor is powered by solar panels, and its movable, wing-like solar panels also function as sails. The sun's energy can also heat water efficiently and cheaply. Water is passed through solar collectors that concentrate the sun's rays and heat the water; the hot water is then stored in a tank and can be used for bathing or washing dishes.
Other kinds of renewable energy are also under development. One of these comes from biomass, which means organic matter. Wood has been used for thousands of years to create energy, but scientists have discovered that other kinds of organic matter can also be used to create fuel, like certain grasses, trees, plants, or even animal dung. Biomass can be treated and made into fuel, or it can produce electricity as it decomposes.
Another renewable energy source is geothermal energy, energy that comes from inside the earth. For example, steam from geysers and water from hot springs can be used to generate electricity. At geothermal power plants in California, geysers produce steam, which turns electric turbines. Some of these power generators have been operating for over forty years.
Hydrogen is a source of clean energy that is very attractive because it is the most abundant element in the universe. A fuel cell combines hydrogen and oxygen to produce electricity and heat─and the only by-product is pure water! Hydrogen fuel cells have the potential to replace the engines in vehicles and provide power for cars and buses. Many portable devices could also be powered by these fuel cells, such as laptop computers and cell phones.
A final type of alternative energy source under development is compressed air. Compressed air is the energy source for the "air car," which uses no gasoline. Instead, a tank full of compressed air powers the engine. The tank needs to be refilled at an "air" station. An air car factory has already been established in France, and production will begin soon.
So, if energy from oil, coal, and gas causes problems like pollution and global warming, to name only a few, why don't we switch to renewable energy immediately? Why doesn't every house have solar-heated hot water? Why aren't our computers powered by wind turbines? Why doesn’t everyone drive an air car?
There are a number of reasons. First, renewable energy is currently more expensive than traditional fuels. Second, decades of access to cheap oil have made consumers lazy and apathetic about energy. "There's enough oil now, who cares about the future?" and "As long as my city isn't polluted, it's okay," are common attitudes. Third, at present, the disadvantages of oil are still not grave enough to force citizens or governments to react. Pollution is an ever-increasing problem, but its effects are gradual, and the most severe effects of global warming may not be seen for another fifty years. Finally, companies and governments in the world's most industrialized nations currently earn large profits from the oil, coal, and gas industries. It is not in their interest to switch to renewable energy sources unless the public demands it.
The good news, however, is that many people around the world are changing their habits. For example, some schools, community groups, and small businesses are using wind turbines and solar panels as their sources of electricity. Governments are slowly changing regulations to make it easier for builders to construct homes that rely on renewable energy. The earth has taken good care of us─it gives us clean air, water, and food to eat. By switching to renewable sources of energy, we can start to take care of the earth.