BloomEnergy has been running the media circuit recently with their announcement of a hydrocarbon based fuel cell for electrical power generation. They were on 60 minutes this past weekend, Good Morning America this morning and will probably be on 20/20 later this week. The hype surrounding the box is huge and almost buried in the hype is the fact that it runs off of hydrocarbon based fuel. Thus it may not be a long term solution, but as it “burns” more cleanly and more efficiently than other hydrocarbon based energy systems it promises to be an excellent intermediate step. The stories to date discuss having one for your home allowing you to go off the grid (though you’ll still need a steady supply of a fuel source). But since the fuel source is a hydrocarbon, I say “screw that, I want one for my car“.
The blog/news site Good.is is running a series of articles on transportation. Recently they posted an infographic showing where the energy in your car is wasted. I was planning on running a similar article, but they beat me to the punch. Notice the large amount of loss coming from the engine. This, while true, is a bit misleading as the efficiency of an internal combustion engine (ICE) varies with RPM. Also the drive train losses vary depending on the type of drive train. All Wheel Drive is probably much more wasteful than the 5.6% shown below. So GOOD.IS’s infographic is nice, but it doesn’t quite give you enough information to make a decision.
I’m focusing on the engine and drive train losses because these are the things you can control when you decide on the type of car you want to buy. It would be great to see this same sort of infographic reproduced for several different types of cars. First up would be a hybrid like a Prius. This is sometimes called a Parallel-Hybrid because both the electric motor and the ICE can simultaneously supply power to the drive train. Of course, if you do that you incur some fraction of the engine losses and the drive train losses just to have the ICE hooked up in parallel.
What’s surprising is that the series hybrid is as efficient (if not more so) than a parallel hybrid. In a series hybrid there’s an ICE, but it powers a generator that is connected to electric motors that run the car. Part of the reason why this type achieves its efficiency is that it can run the ICE at the optimal RPM all the time and because it can dispense with much of the drive train that accompanies an ICE when it is connected to the wheels (there’s no gear box for example).
A fuel cell car would just replace the ICE and Generator in the above picture and provide power that way. Up until the BloomBox started getting attention the primary type of Fuel Cell that was being considered was a hydrogen fuel cell. It’s clean, producing only H2O as a waste product and relatively cool, but getting the hydrogen fuel is a big problem. Bloom’s fuel cell in contrast can run off of hydrocarbons which have a ready-made infrastructure, but they do run hot, about 2x hotter than a normal ICE. So it’s not clear if it’s feasible, but it would be way cool to have one.
I like Good.is’s website. They do good stuff. But this article set me back a bit. All it says is “Urmmmm, cars baaaaad”, they don’t give me enough information to decide what’s better or even… ahem good. Hopefully they’ll address this in the remaining 6 parts.
* Water vapor is a green house gas so if all the cars on the road today were magically converted into hydrogen fuel cell cars, the amount of water vapor in the atmosphere would increase significantly. Whether that’s significant in comparison to natural evaporation from lakes and oceans and how potent water vapor is as a green house gas may be the subject of a future article.