I was interested to read Dan Gray’s take on the Top Gear team’s enthusiastic reception of the hydrogen fuel-cell Honda Clarity — suggesting that such a response in such a mainstream channel was a “profound” moment.

My interpretation of Dan’s key point is that the Honda is “just like the car of today” and therefore would be more accepted by the average punter due to reduced barriers (at least perceived barriers) of filling up and the speed of refuelling.

I have to respectfully disagree with the notion that hydrogen fuel cell vehicles will create a significant impact in the mainstream market (at least in the short- to medium-term — e.g. 5–10 years), and would like to throw a few points forward as to why I think electric vehicles, using battery technology, is more likely to become the new standard for cars in that period.

• While most manufacturers have been working on hydrogen powered vehicles for some time, most have seemingly reduced their investment due to a number of critical issues (some of which I’ll expand on below).  On the flipside, most major manufacturers (Nissan, VW, Audi, GM to name just a few) have announced electric drive-train vehicles, or at least plug-in hybrids (in the case of Toyota and GM), as their preferred platform for alternative vehicle systems.  In the case of GM and Nissan, plans are to have production-ready vehicles as early as next year.  Honda is, I think, the only maker continuing to actively promote hydrogen fuel-cells as their platform of choice.
• The infrastructure for electric vehicles already exists to a degree that is suitable for most people’s driving patterns (< 50 miles per day) — and it’s sitting in every person’s garage.  Additional infrastructure for in-transit recharging is required, but not as critical, for these common trips.  That’s what allows Tesla and Nissan to launch electric vehicles within a 12 month time-frame, not 5 or 10 years.  Hydrogen vehicles will need significant investment in hydrogen fuel distribution before the first vehicle can roll off the line.  This is what really annoyed me about Top Gear’s coverage — it completely ignored the fact that hydrogen vehicles can’t operate in the same way as petrol-fueled vehicles until this infrastructure is in place, and it will be sporadic at best in the early stages of deployment, in which case it has exactly the same issues as they claimed for electric vehicles.
• Hydrogen fuel generation is an energy-intensive process, and my understanding is that it is far less efficient than battery technology in terms of energy conversion (i.e. while hydrogen has more energy per unit of storage, creating the fuel is less efficient than charging a battery).  For example, see the “Efficiency” section of this article for a summary — approx 22% efficiency for fuel cells vs. 85% for batteries.  Another paper (PDF 66 KB) from the European Fuel Cell Forum estimates the ratio as 22% vs. 66% respectively.  While I’ve read of some promising advances in using biological and chemical processes to generate hydrogen, these are still very experimental and are some years off production-ready.
• Battery-powered vehicles can take advantage of long-running trends in battery technology improvement that is shared across the consumer electronics, electrical-industrial production and other industries.  Portable hydrogen fuel-cells are (mostly) automotive industry specific, which has a big potential to impact economies of scale and innovation moving forward.
• Innovative concepts such as A Better Place are trialling alternative models to reduce the “recharge” time to an average of a a minute (technically this is not recharging — they switch over batteries that have been charged over a longer period).  While A Better Place relies on significant infrastructure investment, the experience will be closely equivalent to “refuelling”, overcoming the cognitive barriers that the Top Gear team claim hydrogen overcomes.  In other words, there’s more than one way to respond to the barriers to extending travel distance for battery-based vehicles.

Most importantly, though — electric vehicles and related technologies are available today and are viable given current infrastructure for a significant proportion of every-day use.  They are also a lot less expensive than hydrogen-based vehicles to produce, bringing them into range of conventional vehicles on a total cost of ownership basis, and even more so with government clean-vehicle subsidies (where available).  Economies of scale and technology improvements are likely to close the existing gap pretty rapidly.

As an aside, I think there are other significant issues with comparing the Tesla Roadster with the Clarity, especially in the context of a program like Top Gear.  For a start, the Tesla is a sports car, built on a Lotus rolling chassis modelled on the Elise, and the Top Gear team did give it a thrashing — I doubt expectations of performance would be so high for the Clarity.

As a counter-point to the finding that the battery lacked staying power, a Tesla Roadster here in Australia completed 500+ km (300 miles) on a single charge.  Additionally, the Tesla is the first vehicle from a new manufacturer that is deliberately provocative (thus the sports car styling and positioning that makes it much more expensive than comparable vehicles), and pioneered a new approach to battery technology that future electric vehicles are leveraging to achieve rapidly increasing ranges.

I think that a comparison between the Clarity the up-coming Tesla S will be a much fairer comparison, and the S will be taking advantage of newer battery technology and much learning by Tesla from the experience of developing, producing and rolling out the Roadster, so is likely to perform better on many levels.

One last gripe with the Top Gear comparison — Jeremy took great pleasure in dissing the Tesla for its likely reliance on coal-powered electricity, which of course also produces greenhouse gas emissions.  This is demonstrably misleading.  Based on the US energy mix an electric vehicle, even if powered by coal-generated electricity, an electric vehicle still achieves approx. 30% less emissions.  Buyers can choose GreenPower (offset) or have renewable capacity installed — in fact I believe that Tesla offer solar and renewable energy options as part of the purchase of the vehicle in the US — and given both the price premium and the nature of the market for such a vehicle, one would expect most owners would opt for a zero-emissions option.