Nine Ways to Generate Electricity from Renewable Sources
Over 86 percent of the energy consumed in the United States comes from petroleum, natural gas, or coal. Unfortunately, our dependence on these nonrenewable resources could someday lead us straight to our demise. Without change, society as whole would be immobilized. But why wait for the inevitable when we can enact change now? Here are 9 sources of renewable energy that could potentially change how we power our future.
Currently, hydroelectric power plants provide only about five percent of the energy used in the United States. This type of power is more than a few centuries old as it has been used to power grain mills and other farm machinery. Unlike the water wheels of the past, modern hydroelectric power plants start with water stored in a reservoir behind a dam. The dam operators release water in a controlled manner through a spillway and over a turbine to generate electricity.
However, these types of power plants are not the panacea for our energy needs. In general, these structures have a relatively short lifespan and are prone to catastrophic failures. Another downside to hydroelectric power plants is their sometimes negative impacts on the environment. For example, in some areas whole populations of salmon have become eradicated because of their inability to swim upstream due to the presence of a dam. Downstream sediment transport is also blocked. This causes a severe reduction of nutrients in the water as well as excessive downstream river erosion. And finally, another problem with dams is finding an appropriate location to build them. There must be enough depth and space behind the dam to create a man-made lake, without destroying cities and natural life.
Geothermal energy works similar to a large heat exchanger. Deep in the earth's crust, heat from magma chambers and volcanic activity can be utilized to generate steam which can turn turbines. Alternatively, natural steam rising from crustal vents in the ground can be captured and directed into a power generation facility. The hot water vapor is directed towards turbines, which generate the electric power.
Geothermal power plants can also have very a short lifespan. Sometimes, the hot spots near the earth's surface can become inactive or run out of steam. The best geothermic sites have a magma chamber neither too shallow nor too deep from the surface. Ideally, a good geothermal site would also need to have natural channels or inlets, to constantly supply the hot magma with water.
One study indicated that if all the winds of North and South Dakota could be harness, it would provide 80% of the electrical energy used in the United States. Similar to hydroelectric power, wind power has been used for centuries. In the days of the old, it was used to turn grain mills or pump water. Nowadays these devices are very simplified. Basically, wind flows over a huge propeller that turns a turbine and generates electricity. Wind power stations provide a good amount of power in relation to the cost it requires to build them. They are inexpensive to build and are generally safe to use.
However, this technology does have a few downsides. Wind power farms usually create a lot of noise pollution. They could pose a problem if built near homes or in cities. Spinning propellers also pose a signicant problem to our bird populations. Additional, wind power is not completely reliable nor is it very efficient compared to other sources of energy. Despite these challenges, wind power is one of the most promising sources of alternative energy that scientists are considering today.
To harness the power of the tides you have to construct a dam or gate structure near the mouth of an ocean bay that has a large tidal range. The in and out flow of the oceans water is then used to move paddles which turn turbines to generate electricity.
Although this is a really great idea, it is not very practical. Most of the world’s coast does not have a tidal rise and fall large enough to create any usable amount of power. Current research suggests that the range must be at least 25 feet or more for sufficient power to be generated. It is also very hard to find suitable locations to build this kind of power plant.
Ocean Current Energy
Harnessing the power of the currents of the ocean is not a new idea. In the vast oceans of earth, there are currents that constantly travel the globe. The currents churn the sea in a never-ending underwater ‘river.’ This untapped source of energy may provide the electricity of the future. The concept is simple. A stationary set of turbines would rest in the ocean and would be turned by the natural movement of the water. This power generation facility essentially acts like a wind power plant except that it is constructed underwater. Challenges with this proposition include find a suitable location with enough water movement, constructing a machine that can survive the ocean, and preventing environmental damage.
Oceanic Thermal Energy
Between the Tropic of Cancer and the Tropic of Capricorn exists a portion of the ocean that experiences significant thermal stratification. These relatively shallow layers of water with varying temperatures have the potential to create electricity. To harness this energy, you would need to use a heat exchanging device to turn a turbine. However, in the case liquid ammonia would need to be piped through the system instead of water because of its low boiling point. Cold water from the lower layers of the ocean would be pumped into the system to cause the ammonia to condense. Then when it warms up in the hot layer of the ocean, it would turn back into a gas creating enough pressure to rotate a turbine.
Although a unique idea, current research shows that it is not likely to be very efficient. In addition to this, it would be difficult to transmit or store the energy generated from this to use where it is needed. Even so, this idea is not completely of off the table.
About seven percent of the energy consumed in the United States comes form nuclear energy. In this type of power plant, radioactive materials release energy by a process of nuclear fission. This energy is used to heat water that turn turbines to create electricity.
While this type of power plant can generate immense amounts of energy, many significant challenges and roadblocks exist for nuclear energy. These power plants are also very expensive to build and require a feasible way to dispose of the toxic waste. The perceived fear of terrorism and nuclear disasters is another roadblock for these clean and efficient power plants.
More recently though, there has been extensive research into the viability of Thorium as a greener and safer alternative to traditional uranium nuclear power plants. Thorium is much easier to find in nature and produces less waste. The process by which energy is extracted from this material is also different from that traditional uranium reactors. Expect to see more about this form of nuclear fuel in the future.
Have you ever thought about harnessing the immense energy located in lightning? The concept is simple. Large tesla-coil like devices would sit atop mountains and beckon the lightning to strike them. Lightning would strike metal rod in the device and electricity would be directed to large capacitors for storage. Then, the stored energy could be released slowly as it's needed to power homes and businesses. However this power source is not without its problems either. Energy from lightning is not very reliable and would never become a main source of power. Lightning and the high voltages associated with it are also very dangerous.
In consideration for the future, we as a race will find it necessary to reduce our dependence on non-renewable resources such as petroleum. As with anything else in this world, nothing comes without a downside. For petroleum it was obvious. The future lies not with just one type of power plant, but with a variety of renewable energy sources, including some lesser known sources of energy such as biomass, used wisely in conjunction with the smart use and transmission of the electricity they generate.