Last week, I asked the question of whether it mattered whether a ton of CO2 emitted today was any different than emitting a ton of CO2 into the atmosphere in 50 years. In thinking about the energy economics of light-rail, it seems to me that the green advocates have answered it in the negative.
Consider this: Light-rail proponents celebrate the seemingly enormous efficiencies light rail has over traveling by cars powered by internal combustion engines. For example light rail expends on average 3,465 BTU of energy per passenger mile as compared to a slightly larger 3,885 BTU per passenger mile average for all automobiles. However, despite the similar energy use on a per passenger mile basis (indeed, passenger cars using internal combustion engines are actually more energy efficient, and hybrid cars even moreso) advocates of light rail point to the CO2 emissions differences between light rail and automobiles. For example, light rail CO2 emissions per passenger mile are 0.36 pounds while average automobile emissions per passenger mile are 0.61 pounds of CO2.
However, the big ugly (not so) secret of light rail and many white elephant projects like it is that it requires a sh*tload of energy to produce the rail systems in the first place. And once you consider the full life-cycle of the production and maintenance of a light rail system as compared to cars and roads, it is a no contest win for the cars (even ignoring the other benefits of cars and roads, such as that quaint old idea of being able to go where you want when you want … how much is THAT worth and how much does THAT get included in the calculus of transportation economics?).
Building a light rail line requires a phenomenal amount of energy and releases a phenomenal amount of CO2 into the atmosphere. For example, while Portland’s North Interstate light rail line is expected to reduce energy use by about 23 billion BTU per year (remember, these are planners’ estimates, which given some other history are unlikely to materialize). However, to build the system requires the use of 3.9 trillion BTU of energy. Ignoring discounting, this means that it will take 172 years of operation in order for the light-rail system to recoup its construction energy usage. Light rail lines average less than 1/4 of that life span, so even using conservative estimates, we’d have to rebuild the thing 2 times over … in other words, the energy train is pulling away faster than the conservation train … we’ll never make up the savings. The same is true of CO2 emissions. In some future posts we’ll illustrate some of the data.
The point being is that these light rail lines, even if they were not white elephants and even if they did deliver the CO2 and energy savings as promised, are making the tradeoff I asked about earlier. They are “saying” in effect that it is OK to dump tons and tons more CO2 into the atmosphere today in order to recognize future CO2 reduction benefits. But isn’t this exactly what the “business as usual” crowd is advocating? Isn’t the idea that as we get richer and technology develops and energy sources naturally decarbonize, that we will be emitting more CO2 today fully knowing that the benefits will be received in the future? Is the record of economic history better than the record of the transportation planners at delivering such promised benefits? Indeed it is. So please remind me, what is the difference here? I have my own thoughts, I’d like to hear yours.