How can we ever get off our addiction to oil? Driving in the manner we are so dependent on for shopping, work, or vacation must require an immense amount of energy that surely the sun or wind can never supplant? Or, can it? Typical public image commercials from the conventional energy suppliers (take your pick) would have you believe that solar energy, energy conservation and energy efficiency efforts are “nice”, but will never really amount to anything.
Transportation is one of the most exciting areas that will propel renewable energy usage in one of the most monumental, economical, cost saving shifts of technology ever experienced in the history of the world. Yes, transportation does require a lot of energy, but so do other things we like or need to do.
The figure below from our Appliance Design and ASHRAE Journal articles shows the reduction of energy requirements for a typical family of four if they shift to the new heat pump water heater (HPWH) and ventless heat pump clothes dryer (HPCD) technologies. A HPWH reduces water heating energy by 2000kWh per year, while a HPCD reduces estimated household annual energy by another 1000kWh. So, a simple shift of water heating and clothes drying technologies can save 3000kWh per year….what can we do with that?
In the very near future, the Chevy Volt and Nissan Leaf, two types of electric vehicles, will be released to the market. For those of you wanting something a bit spiffier, check out the Tesla Roadster….zero to 60mph in less than 4 seconds. The new generation of electric vehicles are not puffed up golf carts. They are the best performing vehicles (full torque to the wheels at zero RPM) we have ever seen. Combined with continuing advances in battery technologies, one can get up to 250 miles per charge. And as battery pack charging infrastructure develops, as it had to for gas stations, long distance driving will be accommodated by a fast robotic exchange of battery packs or quick charge technologies…much faster and safer than today’s pumping gas (Did you realize that with an average of 12,000 miles of driving per year, and an average of 25mpg, you spend almost 10 hours per year pumping 500 gallons of gas and inhaling noxious fumes?).
The new generation of electric vehicles will drive about 4 miles per kWh of energy. This is about the amount of energy that a hair dryer would use in 45 minutes. From our discussion above that a simple change to a heat pump water heater and a heat pump clothes dryer, we have “saved” enough energy to drive 12,000 miles in an electric vehicle! That is amazing!! But the good news does not stop there. We need to figure out how much it costs per mile relative to the cost per mile for a gasoline or diesel powered vehicle. Our solar energy feature shows the cost of solar energy to be about 12.5 cents per kWh. With an electric vehicle driving 4 miles per kWh, we can calculate the driving cost for an electric vehicle to be 3.1 cents per mile. Let’s assume gas engine technology improves the average gas mileage of cars to 50mpg (about double where we are currently, but definitely achievable). Assuming a gas cost of $3/gallon (we are currently paying $3.20 per gallon in our area), we find a cost of 6 cents per mile. Can that be correct? A solar energy powered vehicle will be half the cost per mile as a gasoline engine car? Knowing that most people are not getting an average of 50 mpg, the margin is quite a bit more.
Ok, so maybe solar PV systems can provide the energy at a very low cost for meeting our transportation needs. It would seem like an immense area would be required for the solar panels? This is even better news. The portion of the Equinox House solar PV system devoted to electric vehicle transportation only requires 150 square feet of area. Yes, the area required for a lot of driving requires an area that is less than the roof of a car port. Maybe a house in Seattle requires 200 square feet and a house in Phoenix requires 100 square feet, but in either case, anywhere in the US will find that solar powered vehicles will have lower energy cost per mile than any combustion engine vehicle.
Of course the cost of the vehicle comes into the equation, however this is not as straightforward as economist would have you believe. People buy cars based on the image they would like to project and their bank account. No one (ok there are a few of you….most likely engineers like us) has ever bought a car based on a life cycle cost analysis, savings-to-investment ratio analysis, discounted payback analysis, or other similar economic metric to buy a car. It is a marketing issue. Electric vehicles will initially have the appearance of being expensive relative to their combustion engine counterparts, however, that will not continue. As in computers, flat screen TVs, cell phones and other technologies, the price will drop as development costs are recouped and production volumes increase. Electric vehicles are much simpler (translate into meaning lower cost) than combustion engine vehicles. An electric motor has one moving part….the rotor (well, ok, two bearings to hold the rotor), compared to the hundreds of parts in a combustion engine. There are no oil changes, spark plugs, timing gears, valve trains, oil pumps, oxygen sensors, or several other pieces found in a combustion engine. And, because an electric vehicle uses the motor to stop, brake changes will be unneeded. When everyone is sitting at a stoplight or stuck in traffic, there will be no noise (ok, probably some boom boxes somewhere), no wasted energy, and no pollution generation.
The bottom line is that Equinox House has installed sufficient solar PV capacity to give us 2000kWh of electric vehicle transportation per year, enough for our estimated 8000 miles of driving around our town. This will be at a cost that is less than half of the cost to drive a gasoline vehicle, and it only required only 150 square feet of solar panel area. So, solar and renewable energy technologies are very “nice” as the conventional energy resource companies say.
Professor Jacobi, Mechanical Science and Engineering Dept faculty member at the University of Illinois, driving his “Pi” mobile for the last time. New electric vehicle technology will reduce the cost of transportation, providing a surplus of combustion engine vehicles for county fair demo derbies.
