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August 2014 Policy Study, Number 14-3


Geothermal Energy: Important Potential in the U.S. and Iowa


Different Energy for Different Uses



An important part of the energy discussion, which gets confused in the global-warming debate, is that different sources of energy are appropriate for different needs.  Gasoline and diesel fuel, the niche sector of electric powered cars aside, are the most efficient, cost-effective way to power vehicles and other motorized equipment.  We also have a reliable, safe, and easily replicable delivery system.


Even before it becomes gasoline, oil is a critical input for making plastic and many other chemistry-driven products, all benefiting humankind.  For example, important health and safety products such as Plexiglas, artificial limbs, aspirin, and rubbing alcohol are oil based.  And recreational and convenience products such as scotch tape, soccer balls, guitar strings, pacifiers, fabric softener, hair color, lipstick, and shaving cream might not be “necessary” to our existence, but undeniably make the world a better and more comfortable place.  Steel is necessary for safe and secure factories, offices, and homes, yet we can’t produce steel without coal – another enemy of the environmentalists. 


A key consideration in the energy discussion must be the amount of power generated by the source.  This is often ignored.  Is a power source effective?  Does it produce more energy to do work than it consumes?  In order to be effective, an energy source must generate, and we must be able to capture and use, more power than is used in consuming it.  This is called “energy density” and “power density.”  As high school physics teaches, “energy” is the ability or capacity to do work, “power” is the rate of doing that work.[9]  In order to be economically useful, the energy and power produced by something needs to be high.  The energy produced by many historical sources (wood) and renewable sources (ethanol, wind, and solar) is generally very low.  It is not very dense or economically productive.


Unfortunately, most current renewable fuel sources have low energy and power numbers – hence the problems.  For example, the power density of wind is only about 1.2 watts per square meter (W/m2).[10]  The largest off-shore wind field, the London Array in the ocean south of England, only has a power density of about 2.5 W/m2.  Those wind turbines standing in the Iowa cornfields are not any better. 


Because current solar panel technology is very ineffective at converting sunlight into electricity, the power density of solar power is only about 5 W/m2.  Even in the desert, with sunlight shining all day, every day, energy from the sun originally has a power density of only about 200 W/m2.  The energy captured by solar panels is only a tenth of that, about 20 W/m2.  The power density of sun in Iowa is probably about 170 W/m2 at its June/July peak, which would result in a captured power density of about 5 W/m2 because of panel placement and continuity issues.[11]


Yet some activists (the Iowa Environmental Council) claim Iowa can be the next solar king, claiming that a solar array in Iowa can produce a “comparable amount of electricity as one located in Miami, Houston, (or) Atlanta.”[12]  The interesting thing to note about the photos in the Environmental Council’s booklet is that they show acres and acres of solar panels, taking up good Iowa farmland, which certainly can be used for more productive purposes.  At least farmers can still grow crops near the bottoms of wind towers. 


A similar problem exists in using those same crops to make bio-fuels such as ethanol – the power density is low (0.05 W/m2).  Some argue that converting grain food to animal food is an inefficient use of crops and a poor way to feed people.  Converting corn to ethanol is an even more inefficient use of the crops.[13]  Only government subsidies make it economically viable.


In contrast, the power density of natural gas is 28 W/m2 and that of modern gas and coal-fired power plants often near 1,000 W/m2.  Even a small propane-powered home generator has a power density of almost 1,000 W/m2.[14] 


These facts lead to the conclusion that we must bring the discussion of power density to the forefront of energy sector economics and planning.  If Iowans truly want to “go off the grid” while being energy efficient, they should invest in home generators and propane tanks.  They should not install solar panels or wind turbines.


At the very least, having home generators available as back-up systems during weather-caused power grid outages or system-demand peaks would ensure homes and businesses could still function.  Independent back-up systems are especially critical for the medical and water industries.  A 30-minute power outage costs a medium-sized industrial business about $15,700, while an eight-hour power loss can result in a loss of almost $100,000, according to Allianz Global, an international business risk insurer.[15]  Critically important to many industrial processes is water, and loss of power means no running water.



As recently as 2013, writers and scientists affiliated with The Oil Drum and similar websites claimed that oil supplies had “peaked” and would run out soon.[16]  These theories have been debunked and the proponents discredited as the reality is that “soon” in this case is another 400 years from now.  The “technically recoverable resources” of oil are over 2.5 trillion barrels and increasing on an almost daily basis.[17]  At the same time, we are becoming ever more efficient at processing and using that oil to do work.  Cars and semi-trucks are significantly more efficient than they were even 20 years ago.


Once you move from the transportation sector into power needed for electricity and heating and used in both industrial and residential applications, the energy can come from a wider variety of sources.  Yet power density is still a critical but overlooked factor.


Another important criterion is dealing in truth, not political “spin.” For example, the book Hard Facts – Dangerous Half-Truths and Total Nonsense notes that coal reserves in the United States alone are estimated to extend for another 485 years.[18]  The idea of “peak” oil and coal has been discredited, yet many in the public still believe we are running out of both resources. 


It is interesting to note that oil and coal are basically highly concentrated sunlight, created over millions of years by pressure on organic material.  The plant material is created from sunlight and CO2.  Coal is highly efficient at powering large industrial plants and providing consistent, reliable electricity to vast numbers of people.  Natural gas fits into that same category.  Yet they are denigrated by environmentalists, and California even prohibits electricity generated from coal from being sold in their state.


One reason wind and solar receive favorable press is that they are viewed as unending.  Except when the sun doesn’t shine or the wind doesn’t blow.  Then they are nothing.  And humans are unable to make either the sun shine or the wind blow. 


As a result, wind and solar power, the darlings of the “renewable energy” movement, are highly unreliable, very inefficient, and the energy they create is difficult to store and manage.  Neither solar nor wind power can be counted on to provide constant, reliable electricity, and especially in a crisis situation are irrelevant.  This is one reason their cost is so high.  There must be redundant backup systems to provide a consistent baseline energy load. 


The State of Iowa recently turned down a federal government funded grant to study and analyze solar energy implementation and use in Iowa because the grant required a positive, pro-active approach to the issue.  It was designed not to seriously consider both the positives and negatives, but only to promote the positives.  While the Legislature passed and the Governor signed pro-solar energy tax credits in 2014, upping the allowable credits to $4.5 million, those credits are intended to be used by those who have already decided, based on their own decision-making process, that solar works for them.  Solar is not right for every application.  The rejected grant did not allow for a negative conclusion.[19]  That is why it was turned down.  The state will now fund a serious look at the issue with our own tax dollars ($150,000), not unquestioning acceptance of the fallacy that solar energy is the solution to everything.


Hydro-electricity and nuclear energy are two renewable sources which are also unfashionable and disliked by the environmental movement, but they are significant current and future sources of electricity.  Like oil, natural gas, and coal, they are highly controllable and the energy they generate can be easily stored and managed.  Their power density is high and more consistent.  Significant advances are being made in both sectors, with modular turbines being designed for low-head, run-of-the river dam installation and several companies investing in designing small modular nuclear reactors.  Unfortunately, both hydro- and nuclear energy have a marketing and image problem and remain unfashionable with the environmentalists.


As Kathleen White wrote in the Austin American-Statesman last December: “Before the Industrial Revolution, all societies were dependent on the limited flow of solar energy captured in living plants for subsistence needs such as food, fuel, and shelter. Physical living conditions differed across societies and eras, but there was no sustained upward trend.”[20]  Learning to efficiently use fossil fuels changed that.


Geothermal energy is yet another category of renewables which receives little press, though it is quite useful in many applications.




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