Green Muscatine was first developed to give customers an opportunity to support renewable energy. Through that program, three solar arrays were constructed in front of MP&W's Administrative Office Center along with one wind turbine. At this time, while we'll continue to operate our solar panels, we're retiring the option for customers to participate in the Green Muscatine program.
To learn about a new way to have a direct impact on renewable sources of energy, click here.
MP&W's Renewable Energy Interests
Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.
Many people are familiar with so-called photovoltaic cells, or solar panels, found on things like spacecraft, rooftops, and handheld calculators. The cells are made of semiconductor materials like those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity.
On a much larger scale, solar thermal power plants employ various techniques to concentrate the sun's energy as a heat source. The heat is then used to boil water to drive a steam turbine that generates electricity in much the same fashion as coal and nuclear power plants, supplying electricity for thousands of people.
In one technique, long troughs of U-shaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses moveable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator.
Other solar technologies are passive. For example, big windows placed on the sunny side of a building allow sunlight to heat-absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water.
Source: National Geographic
Wind Energy and Wind Turbine Farms
Like old fashioned windmills, today’s wind machines (also called wind turbines) use blades to collect the wind’s kinetic energy. The wind flows over the blades creating lift, like the effect on airplane wings, which causes them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.
With the new wind machines, there is still the problem of what to do when the wind isn't blowing. At those times, other types of power plants must be used to make electricity.
In 2013, wind turbines in the United States generated about 4% of total U.S. electricity generation. Although this is a small share of the country's total electricity production, it was equal to the electricity use of about 15 million households in 2012.
The amount of electricity generated from wind has grown significantly in recent years. Electricity generation from wind in the United States increased from about 6 billion kilowatthours (kWh) in 2000, to about 168 billion kWh in 2013. In fact, in 2008, 2009, and 2012, wind was the fastest growing source of electricity production in the United States.
Source: Energy Information Administration
A geothermal heating and cooling system works on the simple fact that the earth below the frost line (In Iowa around 4 feet down) is a constant temperature of around 50 degrees year round. Using the principles of refrigeration, heat can be taken from the ground and transferred through a heat pump to the air in your home during the winter. In the summer, the process is reversed and the heat in your home is transferred to the ground to cool your home.
Main elements of a geothermal system include:
- Buried loops of plastic piping (either horizontal or vertical) call the ground loop
- A biodegradable liquid antifreeze
- A pump to circulate the antifreeze through the ground loop
- A heat pump
The ground loops are buried in the ground and are connected to the circulating pump inside your home. The pump circulates the water-biodegradable antifreeze through the buried ground loops and the liquid mixture absorbs heat from the ground as it circulates through the loop. The heat pump takes the heat from the liquid and transfers it to the air in your home. The cooling process works in reverse; the heat in your home is transferred through the heat pump into the liquid which is then absorbed back into the earth.
Types of Systems
Vertical loops use a bore hole about 4 inches in diameter bored near your home. The depth of the boring(s) depends on the specific needs of your home and what your contractor may encounter during boring. A U-shaped loop of plastic pipe is inserted into the bore hole, followed by sealing with a special grout mixture.
Learn More about Vertical loops.
There are a multitude of techniques for placing the loops in the ground ranging from digging a trench about three feet wide and eight feet deep and placing the piping “slinky-style” in the bottom of the trench and covering with soil to using special horizontal boring techniques.
Learn More about Horizontal loops.
Iowa Geothermal Association