Innovation seeks to tap into wasted opportunities

America produces a lot of waste; take a drive to your local landfill to get a visual of just how much.  It is not only in the consumer goods sector where copious amounts of waste is produced in the form of packaging and poor design, but also in our energy sector.  A large amount of energy is wasted or simply not harnessed, but a new way of thinking and innovative design seeks to tap into these sources to generate electricity and essentially cut down on the world’s dependence upon fossil fuels.

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Several methods  can help us tap into some of the wasted opportunities going on all around us; the methodss discussed here include HRSG, cogeneration, geothermal energy, OTEC, solar roads, kinetic road ramps, and turning MSW into ethanol.

A heat recovery steam generator, or HRSG, “is a heat exchanger that recovers heat from a hot gas stream. It produces steam that can be used in a process or used to drive a steam turbine”.  Waste heat can be collected anywhere fossil fuels are burned or where electricity is generated.  The larger commercial applications seek to install HRSG systems at power plants to generate additional energy.  Combining a gas turbine system with a steam turbine system can recover the heat generated from the burning gas that would otherwise go to waste.  

Generally speaking, conventional power plants produce electricity and treat the heat generated as a byproduct; cogeneration facilities seek to maximize efficiency by capitalizing on all aspects of the energy generated.  Beside using the heat generated to operate steam turbines to create additional energy, the heat can be used “for domestic or industrial heating purposes or as a hot water heating system with temperatures ranging from approximately 80 to 130 °C”.

Geothermal facilities use this same concept to generate electricity except that they use the heat from the earth’s core to heat water into superheated dry steam that is then pumped through a steam turbine to generate electricity.  Heat from the earth’s core is accessed through drilling to certain depths where magma chambers are relatively close to the earth’s surface; most of these areas in this country are in the western U.S.  

After the steam is sent through the turbine system, the spent steam is run through a condenser where any contaminants, like hydrogen, nitrogen, CO2, mercury, or radon, that are gained through the process are sent through scrubbers where the non-combustible materials are cleaned.  The water is then run through cooling towers where a large percentage of it is injected back into the system.  Currently, the nitrogen is captured and used for making fertilizers; in the future, the hydrogen may be captured and stored for fuel cells. Geothermal energy facilities can operate 24/7 and are essentially a clean and free energy source.

"I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait 'til oil and coal run out before we tackle that,” Thomas Edison said in 1931.  Had geothermal energy or ocean thermal energy conversion (OTEC) been around in Edison’s time, he might very well have advocated those sorts of technology also.

The National Renewable Energy Laboratory (NREL) defines OTEC as “an energy technology that converts solar radiation to electric power. OTEC systems use the ocean's natural thermal gradient (the fact that the ocean's layers of water have different temperatures) to drive a power-producing cycle. As long as the temperature between the warm surface water and the cold deep water differs by about 20°C, an OTEC system can produce a significant amount of power”.  This is truly a clean and renewable source of power.  

The oceans act like a heat sponge, soaking up radiant heat as the sun shines down on them.  The cooler, lower layers of ocean water stay cool while the upper layers heat up; this temperature gradient creates conditions where heat energy can be transferred into work energy.  America’s Gulf of Mexico and the waters surrounding Florida show the necessary temperature gradients for OTEC development at 1000m depths.

America has access to roughly 1,000,000 sq. mi. of ocean suitable for OTEC development.  According to NREL, if we were to tap into the heat absorbed from the sun by the ocean in this one million square mile section and convert one-tenth of one percent of the radiant heat into electrical energy, we could meet 100% of the electricity needs for the United States on any given day.

Heat that is generated on America’s roadways and parking lots is another source of energy that is not being harnessed and essentially being wasted.  Researchers at Worcester Polytechnic Institutes “are developing a solar collector that could turn roads and parking lots into ubiquitous and inexpensive sources of electricity”. A company by the name of Solar Roadways is currently working on a 45-mile solar road prototype between Coeur D’Alene and Sandpoint, Idaho.  Right now, the cost of creating such a roadway is off-the-charts at roughly 200 times the cost of an asphalt road per square foot, though.

If turning our roads into solar panels turns out to be too expensive of a venture to undertake right now, then perhaps inserting copper pipes into the asphalt and using the system to create hot water that can be used for heating in homes and businesses is more practical.  If all else fails, then a fresh coat of solar power paint can turn our buildings and parking lots into energy collectors.

Tapping into the unharnessed energy in America’s roadways is not limited to solar energy; the number of cars and trucks passing over our streets could also provide enough electricity to power specific devices such as stoplights, streetlights, and rest stops.  The Electro-Kinetic Road Ramp, a design by Highway Energy Systems, uses the mechanical energy of our transportation industry to compress a system of hydraulics that in turn spins a highly efficient flywheel.  The energy from the flywheel can be used to power traffic lights on the spot or it can be stored in batteries.

Tapping into our wasted resources does not stop there, though.  A look at our landfills reveals...

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Read the full article at:

http://www.examiner.com/x-2903-Energy-Examiner
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