Monday, April 4, 2011
Waste Not, Want Not
One section of the class needs to cover very basic engineering and technological issues associated with the developed on a national energy policy. Start with the attached diagram - - the inputs and outputs of the current energy system in the United States. Focus on moving the discussion and context from barrels to BTUs - - what you need to get to work is a certain number of BTUs. What you need in the winter to heat your house are BTUs - - in the age of cheap energy you really didn't care where they came from.
In the case of the United States, it is not just BTUs - - it is BTUs with 12 zeros (the annual values in the graphic are quadrillion -- for 2009 the estimated U.S, energy use in 2009 was 94.6 Quads). Looking at the big picture - - of the 94.6 Quads in 2009, 39.97 Quads was actually utilized; the remaining 54.64 Quads are lost - - inefficiencies and losses. Most of the loss is heat - - basic thermodynamics and when energy was cheap, no one really cared that much about thermo.
Look at transportation - - when we talk about cutting foreign oil imports by one-third, this is the part of the graphic that is impacted the most by this policy direction. When the average driver completes their journey to work or the mall - - they need to remember that for every BTU that went into the tank, 0.75 BTU is wasted via mechanical inefficiencies and heat loss. Many investors are beginning to get this point - - rising oil prices provide an opportunity for reinventing the internal combustion engine. Bill Gates and Khosla Ventures are just two such investors - - companies like EcoMotors, Achates Power, and Pinnacle Engines are working on our next generation engines. All three companies are developing variations on an opposed piston engine, a technology used in airplanes and ships in the mid-20th century, but long considered expensive and unworkable for automobiles. Opposed piston engines eliminate the cylinder head, which serves as the combustion chamber for a conventional engine. Instead, two pistons face each other and the space between them forms the combustion chamber where fuel is ignited. Discarding the heavy cylinder head allows opposed engines to be lighter and cheaper to make. Typically, two-thirds of the energy generated by a conventional engine is wasted as heat; an opposed piston design is able to tap more energy to propel a vehicle.
Next have the class turn to electricity generation. For every BTU that pulls into the loading lock of the local power plant that powere your new big screen television, on average approximately 0.68 BTU are rejected, namely with mechanical inefficiencies and heat loss. Combined-cycle generation, where some of the waste heat is capture and utilized, would help the situation, especially as we attempt to utilized more electric vehicles. I would point out to the future presidents that electric motors are 90% efficient - - but we are only 30% efficient at getting the electricity to the car.
The last activity for the class should be a field trip to see corn being grown. When you think of an acre of corn, don't think in terms of barrels of ethanol. Always think in terms of BTUs per acre - - do the same with wind and solar farms. In the case of corn and ethanol, remind the class that there are 116,000 BTUs in a gallon of gasoline versus 76,000 BTUs in a gallon of ethanol. This has significant policy ramifications - - along with the fact the average grocery store is 25% corn and you might be looking at 1,000 gallons of water per gallon of ethanol. Utilizing high BTU energy resources to grow, process, and distribute lower BTU fuels has long-term policy ramifications.