Energy Challenges: Why There Isn’t an Easy Solution
Increasing Energy Efficiency
Meeting energy demand over the next century will require not just producing more, but also using what we do produce more efficiently while supplying consumers with affordable energy to allow them to maintain a comfortable standard of living. New technologies and new cultural habits will be needed. Electricity generated on the wind-swept prairies of Texas and sun-laden deserts of Arizona must be carried efficiently to houses and businesses in New York and Chicago. Doing so remains difficult, since a large portion of useable electricity is lost to heat as it travels long distances through wires and cables. The red-hot wires you see heating your toast in the morning have been designed specifically to use the resistive heat generated by the movement of electrons. But, if the objective is to move electricity over large distances efficiently, this loss of energy is undesirable. By improving efficiency, less total energy will be needed to power everything we use. Accordingly, scientists and engineers are working to streamline the electricity grid, modernizing transmission cables with new materials that allow electrons to move more easily, producing less waste.
Another energy-saving efficiency can be found in hybrid cars. These cars capture a portion of the energy traditionally wasted as heat from friction between the tires and brakes. When you rub your hands together really fast, the heat you feel is created by friction. This same effect occurs when the brakes on your car slow the rotating wheels—the energy used to move the wheel is converted into heat. In hybrid cars, this contact recycles some of that wasted energy into electricity that can then offset some of the gasoline used in the car’s engine.
Becoming more energy efficient will also require us to change how our buildings are made, how we heat our homes, and how we light our classrooms. For example, when coal is burned in a power plant, the energy released is used to superheat water, just as you would boil a pot of water on your stove. The process creates very hot and high-pressure steam that then pushes a propeller. The spinning motion of this propeller turns a large magnet that generates an electrical current that is then transmitted to your home. But that steam at the power plant is still very hot after it has been used to create electricity. Rather than letting this heat escape as wasted energy, it is possible to send the steam out to homes and buildings to provide warmth on cold winter days. This process, called “combined heat and power,” will require us to rethink the ways in which we live and work, making our cities and buildings more connected.
Energy efficiency is also being explored in other areas as well. If you have ever been in a car on a sunny day without the air-conditioning on, you know it can become very hot and uncomfortable. By redesigning our homes and buildings, this energy from the sun could be captured to heat rooms or the water we use in our showers and kitchens. We can use less energy by making even the simplest things more efficient—from our light bulbs to our cars, from our home air conditioners to our computers. Engineers will continue to be on the forefront of such innovation, helping to reduce our reliance on fossil fuels and impact on the environment.