“Green Power” is a term used to describe environmentally friendly methods of creating usable power, usually electricity.
Traditional Energy Source
All methods of producing usable energy have some impact on our environment, but the traditional methods of energy production, the burning of fossil fuels (coal and petroleum) and nuclear, have far more negative impacts than most. Fossil fuels release carbon, nitrogen, and sulphur compounds into our atmosphere that cause climate changes potentially detrimental to human habitation. The two most serious threats are global warming and acid rain.
Nuclear energy has its own set of problems. The first concern is the safety of nuclear plants. Power plants by necessity must be located reasonably close to the region they serve. In most cases, this means a highly populated area. To have highly radioactive material so close to populated areas is a safety concern; additionally, the fuel rods must be transported to and from the power plant through these populated areas. The second concern is the disposal of the spent fuel rods. These rods remain extremely hazardous for thousands of years, and we have yet to determine a fool proof method for their disposal. These first two concerns lead to a third – cost. Regulations due to safety concerns make the building of new nuclear plants cost prohibitive.
Renewable energy technologies are Green Power sources. Renewable energy is any source of energy that is constantly being replaced, or at least, a source of energy that will not be depleted in any reasonable time frame. By convention, renewable energy sources are also environmentally friendly; it is Green Power. For example, solar energy is a renewable energy, but in a few billion years the sun will consume all of its fuel. However, for all practical purposes, the energy supply from the sun will always be available to us.
The major types of renewable energy are: wind, photovoltaic (solar), solar thermal, geothermal, oceanic, biomass, and hydroelectric.
Hydroelectric power is the kind of green power produced by Bowersock Mills and Power Company. It produces no toxic emissions, nor does it contribute to global warming or acid rain. In fact, by using hydropower instead of fossil fuels, Bowersock substantially reduces the amount of pollutants in our air.
The pool above the Bowersock dam provides the City of Lawrence with a reliable source of drinking water, even during periods of drought. The area around the Bowersock dam has also become a favorite hunting and nesting area for our national symbol, the bald eagle, during the winter months. This is green power at its best! If your house was powered by hydro power rather than coal you would prevent 7.2 tons of carbon dioxide from entering the atmosphere each year. How “green” is Bowersock? While there is some debate over the environmental impacts of hydroelectric power, Bowersock has been designated as a “low-impact” hydropower facility. This means that in comparison to other hydroelectric power plants, Bowersock’s environmental impacts are limited. Read more about Bowersock’s LIHI certification.
Why do we need green power?
It’s the economy! Modern economies are built on energy. The strongest economies are the ones that produce the most goods and services for the lowest cost. These are also the economies that are the most mechanized and technically advanced and, therefore, the ones that use the most energy!
If we are to continue to expand our economy and improve our standard of living, increased energy supplies will be necessary. If we rely on the traditional sources of energy (fossil fuels), we will continue to pollute the air we breathe and endanger our environment. In addition, there is only a finite reserve of oil, gas, and coal. In fact, our supplies of oil are anticipated to last only for 100 more years. The only logical alternative to fossil fuels is green power. Currently, Bowersock Mills and Power is the largest (and oldest) producer of green power in Kansas. You can buy Bowersock’s green attributes by buying Zephyr Energy.
Hydropower is the most developed of all renewable energy technologies. Ten-percent of our nation’s (20% of the world’s) electricity demand is supplied by hydropower. That is enough electricity to supply 28 million households, or the equivalent of one-half billion barrels of oil. If this power was produced by coal-fired generating stations, 7.7 million tons of particulates and 296 million tons of carbon dioxide would be added to the atmosphere annually. Yet hydropower is being generated at only 3% of our nation’s 80,000 dams. The Federal Energy Regulatory Commission (FERC) estimates that hydropower generation could be more than doubled by modifying existing dams. Worldwide, hydropower supplies 24% of electricity demand, enough for about one billion people. The Grand Coulee Dam (on the right) on the Columbia River in Washington is the largest hydroelectric facility in the United States (Photo courtsey of the US Bureau of Reclamation).
Simply stated, hydroelectric plants convert the energy in moving water(kinetic) into electrical energy. The energy in the water spins a turbine and the turbine then turns a generator which produces electricity. A simple diagram of the overall process is found on the Tennessee Valley Authority’s website. You can take a virtual step-by-step tour through a hydroelectric project on the Foundation for Water and Education website.
The amount of energy produced depends on the volume and speed of water flowing and the vertical distance between the turbines and the water surface (head). These two factors determine whether a dam can be an economical source of power. Of these, the most limiting is water flow. The stream to be dammed must have an average annual water flow sufficient to support hydropower. This restricts large hydro projects in arid and semi-arid regions and is the reason one does not find large hydro projects in Kansas.
There are three basic types of hydropower generation plants: low-head, medium- head, and high-head development. Low-head (<30 meters) development or run-of-the-river plants tap the energy in streams and rivers. These plants sometimes use small reservoirs retaining up to a week’s water supply, but low speed turbines are used which are designed to handle large volumes of water at low pressure, so often, no reservoir is needed. Run-of-river plants are small units and subject to large fluctuations in output due to variable rainfall. Bowersock is a 2.5 MW run-of-the-river facility on the Kaw (Kansas) River in Lawrence.
Medium-head (30 meters – 300 meters) development storage plants consist of a large dam in a mountainous area which creates a huge reservoir. The Grand Coulee Dam on the Columbia River in Washington (108 meters high, 1270 meters wide, 9450 MW) and the Hoover Dam on the Colorado River in Arizona/Nevada (220 meters high, 380 meters wide, 2000 MW) are good examples. These dams are true engineering marvels. In fact, the American Society of Civil Engineers has designated Hoover Dam as one of the seven civil engineering wonders of the modern world, but the massive lakes created by these dams are a graphic example of our ability to manipulate the environment – for better or worse. Dams are also used for flood control, irrigation, recreation, and often are the main source of potable water for many communities. Hydroelectric development is also possible in areas such as Niagara Falls where natural elevation changes can be used.
Another type of medium-head facility is a pumped storage plant. Most generators can also be used as motors, and, in a pumped storage plant, power is generated by water flowing from the reservoir through the dam when it is needed; when excess power is available, the turbine generators are used as motors to pump water back into the reservoir. This arrangement may seem odd, but it makes economic sense. For example, suppose that a particular area whose electricity demand varies from 100 MW to 150 MW. It is less expensive to install 125 MW of base-power (coal, nuclear) and a peak-power plant (hydro) which can deliver or absorb 25 MW than it is to install 100 MW of base power and 50 MW of peak power.
In the final type of hydropower facility, high-head developments, there must be an elevation difference of at least 300 meters between the turbines and the water surface. Generating stations of this type are found in the Alps and other mountainous areas, and high-speed turbines are used.