Tim O’Connor of EDF writes about the benefits of transportation diversification at EDF’s California Dream 2.0. I think that fuel diversity is a useful objective, but achieving that will be difficult due to the network externalities inherent in transportation technologies. Gasoline and diesel vehicles became dominant because having single-fuel refueling networks is more cost effective for both vendors and customers, and reduce the search costs for drivers to find those stations. Think of how many fueling stations someone might have to pass to reach their particular energy source. Investing in a particular fuel requires a certain level of revenue. Note how many local gas stations have closed because they didn’t have enough sales.

For a more recent example, we can look at cell phone operating systems. Initially each manufacturer had their own system, but now virtually all phones are driven by two systems, Android and iOS, while Windows 8 keeps trying to make inroads.

We need to be very aware of the fueling network economics when pushing for new transportation energy sources. Investing in a system is as much a set of business decisions as a policy decision. One approach might be to focus on using particular fuels in a narrow set of sectors and discourage broad sector-wide use. Another might be to use a geographic focus and to set up means of interconnecting across those geographies.