Sunday, January 9, 2011
One of the dirty little secrets of “green” electric cars is that the batteries have consumed a lot of energy and created considerable greenhouse gases before they are even installed in the vehicle. The real environmental cost of batteries goes all of the way back to the mines, where diesel fuel is used in large quantities to extract ore. Fossil fuel is an ingredient in the plastic battery cases. Refining the ore into metals and useful compounds often is extremely energy intensive. It takes fossil fuel to ship the materials to the battery maker and still more energy to assemble them. Of course then they need to be shipped to distributors or to the vehicle manufacturers. More energy lost. The real energy costs should probably even include the energy budgets of all of the employees of all the companies involved insofar as those expenses are directly tied to the manufacturing process. (A miner’s gasoline costs getting to the mine, for example) Then there is the energy to move the electric vehicle’s extra battery weight, and eventually everything involved in the steps of removal and recycling. Then there is the fact that fossil fuel is burned by utilities to generate electricity to recharge the batteries, but let’s leave that one aside for the moment.
It is a reasonable to ask, “How much energy is actually saved over simply fueling vehicles with gasoline directly?” After all, gasoline has one thing going for it. The pipeline between the well and your car is very efficient. This is something to consider with other supposedly “green” products as well. Solar cells, for example, are notoriously energy intensive to make and, likewise, do not last forever. It’s like the oil used to make the fertilizer for the corn to make cleaner burning ethanol fuel. There is no such a thing as a “free lunch…”
I am certainly not saying that this stuff is a waste of time to pursue, but that it should be considered in the design considerations of nascent technologies like PRT. This applies to all design choices, not just whether to use batteries. In particular, I would point out that my call for a minimalist track profile is not purely for aesthetic reasons. We ought to be asking ourselves, “What is the greenest possible medium for moving from point A to point B within the urban/suburban environment?” This, as luck would have it, will also probably be the cheapest, and least objectionable to look at.
I submit that a power-carrying micro-monorail system is the greenest alternative, all things considered, unless we can invent a way to make ski lifts have branching routes and off-line stations. It should be as close to invisible as possible and use minimal materials. It should allow very flexible routing options including tight turns, steep slopes, etc. If it can’t be run somewhere, then people can’t use it. I further submit that it should be thick enough to be a “workhorse” that can take fast vehicles and span wide streets without shaking or sagging. Being too thin mandates closely spaced supports, which can also be a disadvantage. On balance, this trade-off puts me squarely in the Ed Anderson camp, size wise, of about a meter high and about two thirds of that in width. Long-time readers of this blog know how much I have agonized over these dimensions. One advantage to a self-leveling suspended vehicle, I would note, is that it can transition in elevation easily, so that the main routing need not be on the same level as the stations, enabling track that can be higher and more out-of-the-way, if that is what the community demands. We don’t want to cut trees to put PRT in.
PRT has been caught up in kind of a “Gee-wiz, I’m so futuristic!” mindset, even though there is nothing, in this age, futuristic about it. But it is still about being green. My last post was about how free-roaming robocars had co-opted the PRT moniker, and we’ve been having a lively debate on better names. I would just like to add this thought to that debate. If PRT is the physical equivalent of the internet, then the track is the equivalent of telephone wires or fiber optic lines. I say, “Let’s go broadband from the start!” Furthermore, let’s make that infrastructure as green as it can be. That means not being designed to be scrapped, but rather being modular, so it can be moved and reused rather than melted down; It should contain zero fodder for the landfill. PRT, of the powered rail variety, isn’t just another green transportation alternative. It is the ultimate green alternative, bar none. (I’m not counting open-air or human powered vehicles) So maybe it should be presented that way, by the infrastructure, and not the vehicles or the difficult-to-explain operational characteristics.
After all, if you are promoting “elevated microrail transit,” then the whole rest of the PRT paradigm becomes implied.
“Automated or involving lots and lots of drivers?” - Automated.
“Make everyone wait behind a stopped vehicle or have off-line stations?” - Off-line. You get the idea.
In the end, being green, being efficient, and being prosperous are all one-in-the-same. Battery powered electric vehicles, though not a complete red herring, do start with substantial energy deficits that should not be ignored, so environmentalists should be made aware of the fact that powered rails are a much more efficient option.
Elevated, line-powered, mini-monorail transit: To me, it’s a no-brainer. There should be non-profits promoting it, universities developing vehicles for it, the works. It’s where we need to go. Delay in doing so is simply squandering resources, including our land, our raw materials, our fuel, our time, (spent in traffic) our time (spent building and unbuilding stuff) our (still not totally carbonated) atmosphere, and of course, our money.
PS - If there’s anyone who can find a link to actual studies on the energy used in the life cycle of batteries I would be grateful if you would share… I have only found this paper, which is so outdated that it doesn’t even have figures for Lithium-based types. Finally, I would like to share this video, listed as “300 years of fossil fuels in 300 seconds”.