Sustainable Transportation D. Erb
Summary of Dave Erb's Presentation on Sustainable Transportation (April 11, 2011)
Our present transportation system is unsustainable: it is too dependent on petroleum, and it releases too many emissions (both noxious and greenhouse). Any truly sustainable system must reduce noxious emissions while utilizing energy sources which are renewable within human time scales. Greenhouse gas emissions are closely correlated to hydrocarbon fuel consumption, and are usually (though not always) reduced when efficiency is improved. Hybrid vehicles are marketed on the basis of their efficiency (high miles per gallon), but they exist primarily as a means of balancing low emissions with high efficiency.
There are many ways to achieve a sustainable transportation system, but they're not all created equal. To gain the most access with the least economic, social, and political cost, we need to take four simultaneous steps. In order of effectiveness, these are:
1. Reduce vehicle miles traveled (VMT) -
As a society, Americans rely far too heavily on motor vehicles for access to our lives' activities. Reducing our per capita VMT is the easiest, most effective, least costly step we can take towards sustainability. Taken with sufficient forethought and intention, this step will significantly improve our quality of life, at virtually zero cost.
2. Use vehicles more productively -
We need to do a much better job of matching our tools to the tasks we perform with them. When we put vehicle capacity on the road, we need to fill it, either by choosing smaller vehicles to carry the same loads, or by consolidating loads to more fully utilize the same vehicles. Simply taking the easiest, most accessible forms of steps 1 and 2 could reduce American transportation energy usage by 80%.
3. Electrify the vehicle fleet -
Improved technology can provide further conservation beyond steps 1 and 2, though usually at increased cost. As fuel becomes more costly and less available, many of these improvements will arrive through market mechanisms. It is important to stimulate powertrain electrification through active consumer demand and governmental action. However, step 3 is nowhere near as effective or easy as steps 1 and 2. At its logical end, electrification can cut vehicular energy consumption by roughly 50%, and emissions somewhat more. Combined, steps 1-3 could thus take us 90% of the way to sustainability.
4. Shift to renewable energy sources -
Steps 1-3 represent conservation. In addition to conservation, true sustainability requires a shift to renewable energy sources. Small scale, grid-tied, photovoltaic (PV) generation, widely replicated and broadly distributed, is the most effective way to provide this energy. We have a moral imperative to focus our financial and political resources on PV, primarily because most other renewable options place mobility in competition with food, water, and habitat. PV's small scale also enables us to act as individuals, without requiring any additional permission or action from governments, utilities, and other such ponderous entities.
For people who are really serious about the topic, Dave is doing a workshop on Sat, 21 May at the American Solar Energy Society's National Solar Conference in Raleigh. Details at http://www.nationalsolarconference.org/solar2011/public/enter.aspx(click "Program" then "Workshops"). Dave also invites people to contact him directly.
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