Energy With Benefits
- Apr 10, 2014 3:00 am GMT
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The world needs a new energy system that will bolster the environment rather than making it uninhabitable to most living things.
Before designing and building such a system, it behooves us to consider what is wrong with what we have and how we can improve on that.
If it weren’t for climate change there would be no need to immediately consider a new energy system because existing fuels are sufficient to last through this century, at a minimum.
Climate change, which is inexorably turning our planet into a hostile environment, is primarily, about 57 percent, the consequence of burning fossil fuels from which we derive close to 85 percent of the energy we consume. We burn these fuels to produce a gas that will expand and drive a piston, turn a turbine or produce thrust that will drive an aircraft or some other means of transportation forward.
It is self-evident therefore the new energy system will have to be carbon free, yet be able to drive a piston or a turbine and produce thrust.
In nearly all cases we have to cool the gas used in a thermal cycle so that it can be condensed and reused and/or cool the fuel burning engine so that it does not overheat.
In most cases the coolant used for this purpose is water, which is becoming scarce in many regions due to climate change.
Furthermore warming water and reduced river flows caused by climate change have led to reduced production, or temporary shutdowns, of many thermoelectric power plants in recent times.
According to the Virginia Water Resources Research Center, an average of 95 liters of water is required to produce 1 kilowatt-hour of electricity.
Then there are the vast quantities of water being used to develop unconventional fossil fuel resources such as Alberta’s oil sands, which consume between .8 and 2.4 barrels of fresh water for every barrel of oil produced, depending on whether the oil is derived in situ or the bitumen is mined. And fracking’s water use is set to bring drillers into conflict with cities and farmers.
Thermal processes are also inherently wasteful. Per the following diagram for a reciprocating engine, only about a third of the heat produced from burning the fuel is converted to work, which is about the same return derived from thermal electric power plants whether they are fueled by gas, coal, oil, nuclear or fusion energy.
When transmission and other constraints are factored in, the U.S. economy converted only 14 percent of the total energy consumed in 2010 into useful work according to John Laitner of the American Council for an Energy-Efficient Economy.
As he points out, “One can easily imagine that waste of this magnitude creates an array of costs that can easily weaken the nation’s economic and social well being.”
Besides thermal waste, nuclear and coal generated power have well documented waste issues and the conveyance of fossil fuels to the end user and electricity to the consumer are problematic as well. As are the production of offshore oil and gas and nuclear power.
So what are we left with, bearing in mind decarbonisation requires the replacement of 85 percent of the world’s current energy supply? Plus the World Energy Congress forecasts the demand for primary energy will increase between 27 and 61 percent by 2050.
Solar and wind are the obvious choices but they are intermittent which is why electricity storage systems are in vogue. They are required to bridge the gap when the primary source is unavailable.
Like carbon capture and sequestration, electricity storage, is a redundant, unnecessary, expense. The oceans are already storing more energy than we can consume and this is the principal manifestation of, as well as the greatest concern with climate change as this heat is causing sea level rise and tropical storms.
Only one thing has demonstrably reduced atmospheric warming in recent times and that is the movement of heat into the deep ocean, which also reins in tropical storms and sea level rise.
If we could produce the energy we need by following this example we would kill two birds with one stone.
Most of the best places for producing this power are a significant distance from shore so to get the power to where it is need it has to be converted to the energy carrier hydrogen, which is another way of desalinating sea water.
When this hydrogen is converted back to energy on shore in either a fuel cell or a combustion engine, water, which Matthew Simmons pointed out, is even more priceless than oil, with out it we cannot create modern energy and there is nothing to eat, is reconstituted.
For the Asian market, hydrogen produced with OTEC would also be the nearest available energy resource.
In a stationary fuel cell water exhausted from the energy production process can be captured and put to direct use.
Hydrogen is also the thrust producer in many rocket engines.
So make that, three birds with one stone.
No, make that four because instead of creating waste heat such a system converts existing heat to productive energy.
Add another because no radioactive waste or ash is produced.
Add another because this would be base load energy and hydrogen is available on demand so there is no need to build excess capacity to handle only peak loads.
Add another because a hydrogen transportation accident would produce little environmental damage.
Add another because a production accident, particularly if the systems working fluid is carbon dioxide, would also produce little damage.
So that’s pretty much makes a whole flock of problems solved with one energy system that can produce as much as we currently derive from fossil fuels.
So what is the holdup to the resolution of our energy/environment conundrum, besides the obvious resistance from entrenched interests?
The one most often proffered is cost, which according to Luis Vega in his 2010 paper Economics of Ocean Thermal Energy Conversion (OTEC): An Update would be less than 0.18 $/kWh.
As Lindsay Wilson of Shrink That Footprint shows in the following graph that is about the median of average national electricity prices and less than half that of Denmark which is primarily dependant on wind.
So again, what is the hold up? There is so much to gain and in the alternaive everything to lose.