This is a list of four key technologies that could be developed to produce substantial energy savings for Minnesota. It is not a comprehensive list, but it is what I believe are the most important technologies. Investing in them today will make our future more secure, as our lives will be less dependant on the whims of the global energy market.
Minnesota’s energy usage in year 2000 in Billion BTUs (from various sources) was:
While the total BBTUs consumed has certainly risen, the relative percentages of the various uses is probably similar today. This data shows where we need to focus our attention, as well as how to evaluate proposed technologies. The four alternatives I propose are:
Distributed Electricity Grid Potential Savings: 60% of Electricity (18% of Total)
Electricity is generated centrally at an overall efficiency of about 40%, which is roughly the theoretical limit. The remainder of energy used is lost as heat, which creates “thermal pollution” around power plants. A distributed grid, where electricity is generated everywhere, would allow that heat to be captured and used for heating, hot water, and other household uses.
Small generating stations do exist, but a truly distributed grid requires the ability to send power back into the grid – a technology not possible with current transformer and metering systems. What needs to be developed are ways of making every energy consumer a potential producer. When this is done, the heat that is currently wasted can be put toward heating, reducing needs in that area.
Methane Production from Waste Potential Savings: 50% of Heat (20% of Total)
Household waste is largely food and cellulosic (paper) products, as nearly everything else is recycled. This is the kind of material that the bacteria that produce methane thrive on, if given the chance. Systems like this provide cooking fuel in Haiti and other nations.
Combining household sewage with grinders for larger paper materials would turn the excess of our nation into the raw material for in-home generation of fuel in digestion tanks. The outflow could proceed to the sewers for regular processing. Combining this with a Distributed Electricity Grid would produce a truly distributed energy network.
How much energy can be produced from such a system? Initial estimates based on experience suggest that about half of all heat requirements can be met, but the total is unclear. Refinement of a reasonable target would be the first priority of any research. What is clear is that the largest use of energy, home and business heating, is present at the same place as the greatest source of fuel we have, paper based waste.
Turbine Hybrid Automobiles Potential Savings: 75% of Transport (24% of Total)
Current fleet average over all cars and trucks is about 20 miles per gallon. Hybrids can easily reach 40 or even 60 miles per gallon using the same basic piston gasoline engine. They achieve this by using an electric motor to provide the power at variable speeds, thus allowing the engine to run at a more constant speed and producing only the power that is needed.
Such a system is ideal for a turbine engine, which was previously shown to be unworkable for transportation based on its inability to change speed easily. The advantages of a small turbine are many. For one, the efficiency of an piston engine is never more than about 12%, whereas a turbine can reasonably achieve 30% efficiency. Another advantage is greatly reduced weight. Lastly, they can burn a wider variety of fuels. Small turbines of 30kW (40hp) and 60kW (80hp) are currently produced by Capstone, and with modification can be made to run a hybrid automobile.
A Turbine Hybrid should be capable of 100 miles per gallon or more based solely on increased efficiency, but a conservative estimate of 80 miles per gallon is reasonable for a fleet average. In such a system, only one quarter of the fuel currently consumed would be necessary.
Renewable Fuels from Agriculture Potential Savings: 25% of Transport (8% of Total)
Our ability to grow enough fuel to meet our transportation needs is currently limited. Only through reducing our overall consumption can we begin to dream of weaning ourselves completely off of petroleum products.
A Turbine Hybrid, as described above, would give us the efficiency to make that final leap possible. In addition, their ability to use nearly any fuel gives us a chance to explore new ways of turning plant products into fuels. Ethanol production is inherently wasteful, as the plant fibers have to be converted into sugars and the sugars then fermented. The conversion to sugars consumes about one sixth of the total energy, and the yeast extract a tax of one third of the energy value in fermentation for their good work. After half of the energy is removed, the ethanol has to be distilled from the water it was made in, which is not a simple process.
Given a system that can burn a wider variety of fuels, such as the Turbine Hybrid, other approaches for breaking down the long chains of cellulose into something akin to diesel fuel can be implemented. Systems based on heat, microwaves, and chemical degradation have been shown to be at least partially effective. Combining this with native grasses such as Switchgrass, which produce more fiber than conventional crops, could produce our remaining transportation fuel needs from farmland.
These key technologies, together, have the potential to reduce our energy consumption from conventional sources by as much as 70% with no change in our lifestyle. In addition, they make it possible to be completely independent from oil and gas markets.
Some of them are relatively well known, and others need considerable work. I believe that they represent the most important areas of research for weaning ourselves off of volatile international markets for energy. These technologies may be more expensive, at least at the start, but as energy becomes more expensive there will undoubtedly be a need for alternatives.
I happen to think that what is presented here are the most important alternatives that will prepare us for a future that will someday include significantly higher costs for the energy we consume today.