This is the second part in an interview with Michael Brylawski of the Rocky Mountain Institute where he talks about the history of the Hypercar and what this exciting concept is up to today. In the first part of the interview, Michael shared his personal background and involvement with the Hypercar concept with us. Also, if you haven't already, I recommend that you read the Hypercar history article first as background to this wide-ranging and insightful interview. With that bit of business out of the way, on to the interview...
ABG: It has been 15 years since the Hypercar concept was first envisaged. Have the concept or the materials that were expected to be used to make a Hypercar changed over time with the advent of new technologies?
MB: In summary, no. The Hypercar Concept is technology neutral. When Amory Lovins conceived of the Hypercar Concept in 1991, it was at its core an automotive design strategy that focused on platform physics and not on specific technologies.
How the Hypercar design strategy emerged is an interesting story. Amory was well known for the concept of "least cost/end use," specifically in the electric utilities sector. What "least cost/end use" means is that we need to first look at the end use of what we need energy for, and then find the least cost way to provide it. In the 1970s, when Amory wrote his landmark "Soft Energy Paths," the experts at the time were predicting the need for hundreds, if not thousands, of new power plants to fulfill the US' "insatiable need for power." This sounds familiar, no? Anyway, Amory pointed out that people don't have a need for power - people want hot showers and cold beer, not kilowatts. (How many people do you know say "wow, what I really need now is a few kilowatt-hours"?).
The cold beers discussion continues after the jump
Well, in providing cold beer and hot showers, there are numerous ways to provide those services. In the case of cold beer, we can burn huge amounts of coal at centralized powerplants (maybe at 30 percent efficiency at best), transmit them hundreds of miles over powerlines and through the grid, and deliver it to a house in an inefficient, cheap refrigerator-all with a net efficiency in the single digits. Alternatively, we can spend a bit more on a refrigerator (more efficient compressors, better insulation, etc.) that uses radically less power, but cools the beer the same. However, this reduced power requires less electricity to be provided to the house, through the inefficient grid, and from the coal burned at 30 percent efficiency at the powerplant. Thus, instead of compounding the inefficiency as we turn coal into electricity and so forth, saving the kilowatts at the house compounds the savings: if the ultimate efficiency is, say, 10 percent of turning coal into refrigeration for your beer, every unit of energy saved at the fridge saves ten times that in coal.
When you look at energy use from that perspective-very logical, but revolutionary in the 1970s - you find that the least cost use of providing services tends to be saving energy, not providing more. This has borne out over the last few decades (we are much more efficient per unit of GDP now than in the late 70s), and one thing RMI emphasizes, as we enter this debate again, is that efficiency can take us much farther in the future than building centralized powerplants.
For Hypercar, Amory applied the same "least cost/end use" thinking from the grid to the car in 1991. Instead of the conventional wisdom of making the car more efficient with a more advanced powertrain (the thinking in the automotive industry then...and now), what if we look at where the energy ultimately goes in the car? What is the "end use" of gasoline?
Well, for simplicity's sake, it turns out that the "end use" of energy gets split in three ways: a third heats the air through aerodynamic drag, a third heats the tires through rolling resistance loss, and a third goes to kinetic energy to propel the car which is ultimately lost in heating the brakes. So energy, which comes into the car as gasoline, gets put through an engine (maybe with around 20-25 percent ultimate tank-to-wheels efficiency), which then gets lost in aero drag, rolling resistance, and brake heat. The "less than 1 percent moves the driver" statement is born from this logic: if ultimately a third of 20 percent moves the car, and the driver (say an American of 200lb) is about around 5 percent of the average curb weight of 4000-lb, then you can see that our method of converting gasoline to mobility is highly unsatisfactory.
Instead, if we look at the platform physics of the car-how we reduce aerodynamic drag, rolling resistance, and braking loss (the latter two a function of mass) - then like the cold beer example we turn the compounding losses of the drivetrain in compounding savings. One unit of energy saved by making the car more aerodynamic saves around 8 units of gasoline (less in a hybrid or electric-drivetrain). And thus the Hypercar Concept focuses on reducing those three "end uses" of energy: aero drag, rolling resistance, and braking loss, and synergizes them with an advanced drivesystem, to create radical efficiency gains.
As such, any materials or technologies that improve the platform physics, and economically improve powertrain performance, work with the Hypercar Concept. In some sense it is a "technology neutral" architecture, although as you point out we do feel that some technologies show exceptional promise, like carbon-fiber composites. But even with composites, we are open to light metals such as aluminum or lightweight steel as described in the WTOE report. There has been a lot of promising research into lightweight steels, for instance the Ultra Light Steel Auto Body concept that showcased over 40 percent mass reduction for a full passenger car; however, we've yet to see these meaningfully put into a car platform to achieve strong weight savings in the real world.
The same "technology neutral" logic applies to powertrain, as we'll get to later; there are many promising configurations, although we still feel that hybridizing of some sort (whether it be a plug-in, series, parallel, or with fuel cell) is an essential part of the concept.
ABG: What do you see as the most appropriate propulsion technology for use in a Hypercar today - hydrogen combustion hybrid, hydrogen fuel cell hybrid, other fuel cell hybrid, petrol-electric or diesel-electric hybrid, or plug-in electric?
MB: An excellent question. Again as a technology neutral concept, in a Hypercar many different propulsion technologies could work. The key insight is that by using Hypercar's design philosophy - make the platform efficient first, then add the powertrain - many of these propulsion technologies would work better, and could be commercialized a lot faster, than with a conventional vehicle.
Take fuel cells. Current fuel cell prototype vehicles (e.g., Ford's Explorer fuel cell SUV, GM's Equinox) are modifications of heavy SUVs. While they provide better conventional packaging solutions for adding the stack and tanks, and represent real-world production platforms, the problem with this approach is that the weight and inefficiency of the platform requires large fuel cell stacks and super-high pressure (10k psi) tanks. As fuel cell stacks and storage roughly scale in cost with their size, larger stacks and tanks mean bigger costs-and more time needed in the lab to get per kilowatt (kW) or kilowatt hour costs down to make the vehicles "marketable."
On the other hand, the Revolution concept vehicle we did at Hypercar, Inc. required only a 35-kW fuel cell stack-about half to a third the size of the stacks put in most concept fuel cell vehicles today. With this stack, we had excellent acceleration and hill-climbing performance due to the Revolution's low curb mass and good aerodynamics. The use of composites and integrated design made the vehicle (minus the powertrain) cost competitive with a steel vehicle at similar (mid-50,000 per year) production volumes, thus enabling higher tolerances for stack and tank cost. As a result, the Revolution's efficient platform could have accelerated the implementation of fuel cells as it enabled fuel cells to economically get implemented onto vehicles sooner, and once implemented would then accelerate the technology down its experience curve.
This same logic applies to any hybrid or electric-dominated propulsion system. Minimize tractive load, and you minimize the size of your power electronics, your energy storage, and your conversion device-whether it be fuel cell, internal combustion engine, etc. To paraphrase that old ad, "at (Hypercar), we don't make the propulsion system...we make it work better."
That said, if these vehicles hit the road today, it's likely that a variety of propulsion technologies would be employed, based on the market requirements and fueling infrastructure of the application. I think right now "conventional" hybrids like that of the Prius or Honda's system can provide a ton of benefits, and their potential can be increased if they were put on more efficient platforms. The Prius is not bad, especially for aero, but for a small four-seater it weighs close to 3000 lbs. Shave off a third of this weight, and you've got a truly revolutionary vehicle. So in the short term I like conventional hybrids.
In the mid-term, plug-in hybrids show a lot of promise, particularly when considering what is called "vehicle to grid" (V2G) potential. Amory has talked about this for over a decade, and now the industry is taking this concept seriously. Plug-ins may not just draw power from the grid at night, but could help utilities (and ultimately renewables) in balancing electric loads, essentially becoming mobile energy storage devices. Plug-ins could provide ultimately a cheap electricity storage and transfer device for variable sources such as wind and solar. On this potential synergy with renewable sources alone, plug-ins are something to seriously look at. The key consideration in terms of the Hypercar concept is to carefully balance your stack storage capacity, as batteries are ultimately very heavy. You don't want to pessimize your system due to an unnecessarily large battery pack.
In the long term, I know fuel cells are becoming 'out of vogue' these days, but their potential remains high. The same barriers remain - fueling infrastructure, stack performance in the automotive environment, and cost in particular - but some automakers, in particular GM and Honda, are going full-force in their development and are making good progress. Ultimately, I see fuel cells as part of an automotive future, faster if the automakers get smart and focus on putting them in efficient platforms.