Showing posts with label Prius. Show all posts
Showing posts with label Prius. Show all posts

Thursday, June 16, 2016

Could the Hydrogen Economy Run on Ethanol?

  • Plans for a fuel cell car running on ethanol look like a clever way to circumvent the obstacles faced by other fuel cell vehicles.
  • However, it is not clear that ethanol's perceived logistical benefits or emissions profile would give Nissan an edge in the competitive market for green cars.

Japan's Nissan Motor Co., Ltd. made headlines this week when it announced plans to produce a fuel-cell car that would run on ethanol, instead of hard-to-find hydrogen. As reported by Scientific American, the company expects to commercialize this approach by 2020, even though competitors like Toyota already have fuel cell cars in their showrooms. It's an interesting choice. Ethanol seems to offer logistical advantages over hydrogen, but the technical challenges involved aren't trivial, nor is ethanol without drawbacks from an energy or environmental perspective.

Fuel cells have long promised a different and potentially superior path to electrifying automobiles, compared to battery-electric vehicles (EVs) with their limited range and relatively long recharging times. One of the biggest obstacles has always been the lack of infrastructure and supply--hydrogen must first be liberated from water, methane or other compounds--and the problems of storing sufficient quantities of it on board. I've driven prototype fuel-cell vehicles (FCVs) and found the experience pretty similar to driving a regular car, as long as you have a hydrogen filling station handy.

Nissan makes the case that ethanol (chemical formula C2H6O) is much easier to source and distribute than gaseous hydrogen, and the process for making it give up its hydrogen is routine, at least under laboratory conditions. However, as the alternative energy research subsidiary of my former employer, Texaco Inc., found in pursuing a similar concept with gasoline, it's one thing to do this in a bench-scale device and quite another to do it in a size and shape that will fit easily and safely in a car and run as reliably as an internal combustion engine. I suspect Nissan's engineers have their work cut out for them for the next four years.

The bigger questions about this approach are more basic: Does it make sense from an economic, energy and environmental perspective, and can it find a large enough market? Consumers already have a wide range of green alternatives from which to choose, ranging from Prius-type hybrids (gasoline only), plug-in hybrids (gasoline + electricity) and battery EVs, not to mention the continuous improvement of non-electric cars. 

Nissan didn't include many numbers in the documents accompanying its press release, but the chemistry and math involved are pretty simple. At 100% efficiency, a gallon of ethanol could produce just under 0.8 kilograms (Kg) of hydrogen (H2) using the standard steam-reforming process. The best efficiency I could find for this ethanol-to-hydrogen conversion  was around 90%, so in the real world that gallon of ethanol would yield around 0.7 Kg of H2--enough to take Toyota's Mirai FCV about 46 miles. That's pretty good, considering that same gallon in a Chrysler 200 equipped as a flexible fuel vehicle (FFV) would drive an average of just 21 miles. Fuel cells are much more efficient than internal combustion engines.

The economics of operation don't look bad, either. If we use today's average US price for E85 (85% ethanol + 15% gasoline) of $1.87/gal. as a proxy for an ethanol retail price, that equates to around 4 ¢/mile, using the Mirai's published fuel economy data. That's about 15% cheaper than a Prius on regular gasoline at this week's US average of $2.40/gal., but it's also around 10% more expensive than a Nissan Leaf using off-peak electricity in northern California.

Emissions are trickier to assess. There's a lively and growing controversy about whether biofuels produced from crops can truly be considered carbon-neutral, even in places like Brazil where the yields from sugar cane are so high. There's much less controversy that the production of most US ethanol from corn is anything but a net-zero-emission endeavor. Corn requires fertilizer sourced from natural gas, and ethanol refineries consume gas (or coal) and electricity in their production process. In any case, when Nissan characterizes their planned ethanol FCV as having "nearly no CO2 increase whatsoever", they are either oversimplifying a very complex discussion or taking a large leap of faith. 

We can count the CO2 coming out of the tailpipe of such a car, and it would need a tailpipe because the onboard ethanol converter would emit about 12.5 lb. of CO2 for every gallon of ethanol converted to pure H2, plus some CO2 from the ethanol burned to heat the unit. My back-of-the envelope calculation gives a figure of 135 grams of COper mile, or 20% lower than a Toyota Prius on gasoline. It would not be a Zero Emission Vehicle (ZEV), though of course an EV running on average grid electricity isn't really a ZEV, either, except in isolated regions or at specific times of day.

Even if there aren't any deal-killers here, I'm skeptical about Nissan's fundamental assumption that the ethanol infrastructure for their FCV would be that much easier to develop than the H2 infrastructure other FCVs require. That's because of the cost and ownership structure of the retail fuels business, which as I've argued previously helps explain why your corner gas station is unlikely to sell E15 (85% gasoline, 15% ethanol) any time soon, despite the EPA having approved it for newer cars

At least in the US, most gas stations are owned by small businesses, not by the oil companies whose brands they display. Margins are slim, and these folks don't have deep pockets, so adding a new fuel like pure ethanol or the ethanol-water mix that Nissan suggests, poses a difficult business decision: Do you take over an existing tank and stop selling diesel fuel, or premium gasoline with its high margins? Or do you rip up the forecourt to add a new tank, which entails being out of business for months--or even longer if you discover that one of your existing tanks is leaking? Either way, the investment costs and disruption to current customers are significant, in exchange for selling what at first would certainly be a low-volume product. When I was in the fuels supply & distribution business, we would have called that kind of decision a "no-brainer."

If Nissan can't encourage enough service stations to add ethanol or an ethanol/water blend--E85 would not work--to their product mix, do they start their own service station network? That seems unlikely. And if you buy one of these cars in a few years, should you carry a case of vodka in the trunk as an emergency range-extender? That's only half-facetious.  

I give Nissan credit for pursuing a novel option for making fuel cell cars more viable, as an alternative to today's range-limited EVs. Ethanol looks like a cost-competitive source of hydrogen, and it is at least easier to store than H2 gas or liquid H2. However, they face practical and marketing challenges that might well offset most of the advantages the company claims to see. The ethanol FCV could encounter the same chicken-and-egg dynamic as FCVs running on hydrogen, or indeed any new model requiring a fuel that is not distributed at scale today. It will be interesting to watch their progress.



Tuesday, July 16, 2013

Comparing Driving Costs of EVs and Conventional Cars

  • A new Department of Energy website helps consumers compare the energy costs of EVs to non-plug-in cars by converting kilowatt-hours into "eGallons".
  • How valid this proxy is depends heavily on assumptions about the cars being compared to EVs.  If hybrids set the bar, then DOE's eGallon prices are significantly understated.
I’ve been looking through a new website developed by the US Department of Energy (DOE) to assist consumers in comparing the energy costs of driving an electric vehicle (EV), relative to posted gasoline prices in their state. I heard about this site at the US Energy Information Administration’s (EIA) annual energy conference in Washington, DC last month. It sounded like a handy tool for both current EV owners and those considering buying one, but I couldn’t help thinking about it in the context of a presentation I saw at the same conference on the cost effectiveness of federal tax credits for EV purchases. A key question in both instances concerns just what kind of car is being replaced by that new EV.

The website uses simple math, together with the EIA’s continuously updated data on gasoline and electricity prices around the country, to come up with a national and state-by-state price for an “eGallon”. This imaginary construct is essentially the quantity of electricity that would take a typical EV as far as a gallon of gasoline would take the average new conventional car. As the text points out, it’s hard for consumers to calculate this for themselves. They see gasoline prices everywhere they drive but must dig through their utility bills to find their electricity price–not always obvious–and then might not know how to compare the two.

The site’s documentation indicates the eGallon calculation is based on the average energy usage of five specific EVs, including the Chevrolet Volt, Nissan Leaf, and Ford Focus EV, along with the 2012 EPA fleet average fuel economy for what EPA defines as small and mid-size cars. The result is side-by-side postings of the US average gasoline and eGallon prices, plus a drop-down menu to replicate that for each state. The site also includes the chart below, comparing these two prices over the last decade.

egallon

Two facts become immediately apparent. First, electricity is generally a cheaper fuel for cars than retail gasoline. That’s true for a variety of reasons, including the higher end-use efficiency of electric motors compared to internal combustion engines and the lower cost of most of the fuels used to generate electricity in the US. For example, the natural gas burned in power plants sold for the equivalent of $ 20.40 per barrel last year, while the global benchmark for oil averaged nearly $112/bbl. It also appears to be less volatile, at least at the level of national averages.

However, just as there’s no single gasoline price for the whole country, neither is there a single electricity price. Even the state averages used by the DOE to calculate eGallon prices mask a bewildering variety of regional electricity price tariffs and tiers. So your cost to recharge an EV might not just vary by location, but by time of year, time of day, and the specific rate plan that applies to you.

My main concern about the site derives from something much simper: the big central assumption that EVs compete with the average cars sold in America last year. According to the eGallon site, the average small-to-medium US car in 2012 got 28.2 miles per gallon (mpg) in combined city and highway driving. Using that figure, and with residential US electricity prices averaging 11.6 ¢/kilowatt-hour (kWh) in March 2013, the national eGallon price for March would have been $1.14/gal., compared to $3.71/gal. for unleaded regular gasoline. But what if we assumed that the cars most often compared to a new EV were not average cars, but other efficient cars, as logic and my intuition suggest? If we substituted the fuel economy data for a conventional Ford Focus or Toyota Prius hybrid, the eGallon price would jump to $1.26 or $2.03, respectively.

In some respects this result is fairly obvious. If you were already contemplating buying a hybrid, an EV won’t save you as much as if you were thinking of buying a conventional mid-size sedan. However, this distinction is important enough that the DOE should consider refining its eGallon calculator. EVs are much like wind and solar installations that cost more than conventional alternatives, but are expected to produce over their lifetimes economic or environmental benefits that offset those higher costs. The attractiveness of that big up-front investment is directly proportional to those benefits. I don’t have the data that would clarify the actual comparisons EV buyers are making, but someone must, perhaps including DOE. And it turns out that this isn’t just important for calculations like eGallon, but also for assessing the cost-effectiveness of federal EV policy.

That brings me to the Congressional Budget Office’s analysis of federal EV tax credits last fall. The report merits a posting of its own, but one nugget I gleaned from the presentation at the EIA Conference was that the CBO found that the current federal credit of up to $7,500 per car was still insufficient to make most EVs cost-competitive on a full-life basis with conventional cars. Yet despite this, the effective cost to taxpayers of each gallon of gasoline saved by a Leaf-type EV was well over $6 when compared to conventional cars getting average fuel economy, and over $10 vs. high fuel-economy compact cars. That’s assuming they save any gas at all, because of the way the Corporate Average Fuel Economy rules have been structured. Implied costs for greenhouse gas emissions avoidance were even more startling, at over $400/ton of CO2 in most cases.

The desirability of a tool like “eGallon” is rooted in the convoluted way we talk about transportation fuel economy and energy costs in this country. Miles per gallon is itself a poor metric, compared to something like gallons per 100 miles, or even miles per dollar. That's because it obscures the high value of modest improvements in high-consumption vehicles, while exaggerating the value of shifting from very efficient to ultra-efficient cars. It’s also more useful for policy makers than consumers, who are ultimately concerned about outcomes in dollars per mile or dollars per trip.

Recognizing the impracticality of training 300 million consumers to think about this subject differently, eGallon might prove useful, but only as long as it is grounded in the best information we have about the vehicle choices that potential EV buyers are actually considering. Since current EV incentives apparently provide a poor return to taxpayers, an overly simplistic tool that drives consumers too far in that direction might be worse than not having such a tool at all.

A different version of this posting was previously published on Energy Trends Insider.

Tuesday, August 03, 2010

Electric Vehicle Choices Expand

One of my basic assumptions about our energy future is that most automobiles will eventually be electrified. That's based on extensive scenario work done with my former colleagues at Texaco, Inc. in the late 1990s. Nothing I've seen since then has changed my view on that. However, vehicle electrification is not necessarily synonymous with "electric vehicle" (EV) in its common usage to connote a car powered only by electricity stored in batteries. It's a much broader category, covering all three electrification options now slated to be available to consumers by year-end: hybrids, plug-in hybrids, and "pure" EVs. It also encompasses fuel cell vehicles, though these have yet to move beyond the test-market stage. The characteristics of the three current varieties of electrified vehicles differ in important ways that will affect both their impact on our energy consumption and their success as consumer products.

With hybrids already well established and plug-in and EV models intended for the mass market about to go on sale, this is no longer just a theoretical comparison. Shortly, consumers will be assessing these cars against each other, as well as against more conventional choices, including clean diesels and ordinary gasoline-powered cars, which are becoming more energy-efficient all the time, as noted for the new-model Ford Explorer SUV. Only part of that comparison will hinge on how their drivetrains are energized. In order to achieve mass-market success, they must compete on the whole array of product attributes, since for many people cars are much more than simple transportation.

Start with hybrids, which are sometimes referred to as conventional hybrids, or even "non-plug-in hybrids", to distinguish them from other types. According to the June Hybrid Cars Dashboard at hybridcars.com, 26 hybrid models represented 2.3% of the cars sold in the US in the first half of 2010. That's down from about 2.8% last year. The Prius by itself accounted for half those sales, and it's still the archetypal hybrid for comparison purposes. Like other hybrids of this type it gets all its energy from the gasoline that's put in its tank, and it uses this fuel more efficiently than non-hybrid cars by recovering and recycling part of the energy otherwise lost through braking, and by avoiding idling. (The latter feature is pretty much all that some "mild" or stop/start hybrids do.) The EPA rates the 2010 Prius at 51 mpg city/48 mpg highway. The base model Prius has a sticker price of $22,800, and as far as I can tell it is no longer eligible for any federal purchaser tax credits.

The Chevrolet Volt is based on a different hybrid design, as a plug-in hybrid (PHEV) or more accurately a range-extended electric vehicle (REEV). It also represents a different car philosophy, presumably aimed at a different segment of the market than the Prius. This kind of hybrid gets its primary power from an external electricity source, stored in a battery pack that gives it a range of roughly 40 miles without using gasoline. At that point, and before the battery's charge is fully depleted, the car's onboard generator--a four-cylinder gasoline engine--kicks in to recharge the battery, which continues to send power to the electric motor. Actual fuel economy thus depends on how often and how far one drives with the generator running. I believe the EPA is still grappling with an appropriate methodology to represent this fairly. Of course even when driven only on battery power, it still consumes energy, and in most parts of the US that means that some fossil fuel will be burned somewhere to power it, most likely natural gas.

GM just announced the base sticker price for the Volt, and at $41,000 before tax credits this should make it pretty clear that GM had someone other than Prius buyers in mind. Having driven a pre-production Volt this winter, I'd see it competing more with the Lexus HS250 hybrid, which starts at $34,650, and with non-hybrid entry-level luxury cars like the Acura TSX ($29,310 MSRP but more like $32,410 similarly equipped.) If it lives up to its potential, the Volt could significantly broaden the appeal of hybrids in general, while also saving a lot of gasoline for its owners. Whether it will also save them money is much harder to assess, because the calculation hinges on the specifics of where and how the car would be used.

Nissan's new Leaf is a bolder, if technologically less-complex step than the Volt, because it relies entirely on grid power stored in a 24 kWh battery pack, with no back-up other than a cable and plug--or a tow-truck. At $32,780 before tax credits the stakes are also somewhat less daunting for buyers willing to risk a bit of range anxiety and some adjustments in their lifestyles. I'm not the only one who sees the Leaf aimed squarely at the green consumers who have formed the core of Prius buyers. That's important for several reasons. It reduces the substantial product launch risks for Nissan, which already has thousands of prospective buyers on its waiting list. However, if the Leaf cannibalizes existing hybrid sales, rather than dramatically broadening the electrified vehicle market, then its impact on US oil consumption and the economics behind those tax credits will look a lot less valuable to policy makers.

My skepticism about the Leaf goes a lot farther than Nissan's incredible claims concerning its equivalent miles per gallon. In the basic architecture of the Leaf I see many of the same issues that caused the launch of GM's ground-breaking EV-1 electric car to fail. Attitudes towards oil and the environment have changed significantly in the last decade, and the government is pushing recharging infrastructure much harder and with much more financial support than when the EV-1 was launched. The Leaf also benefits from not being the only plug-in vehicle coming to market, though it requires its plug, whereas the Volt merely works better with one. Fundamentally, however, I just don't know if enough Americans are ready for a car that can only go about 100 miles on a good day, and potentially a lot less than that when conditions aren't ideal. That's particularly important when we recognize that at the price points for both the Leaf and Volt their realistic market isn't first-time buyers in their early twenties for whom basic assumptions about range and refueling times might not be so ingrained. Taking advantage of the entire $7,500 federal tax credit would require an adjusted gross income of at least $55,000 for single taxpayers ($74,000 for married couples), based on last year's tax tables--and probably even higher when taking into consideration itemized deductions, dependents, and other factors. In my view, likely buyers for both cars would be solidly middle-to-upper-middle class.

Rather than making expansive predictions based on guesses about how well these new cars will do with real consumers, I will be watching the start of this grand experiment with great interest. If the Leaf catches on as well as Nissan hopes, then the trickle of other EV launches that are expected to follow could turn into a tidal wave of automotive innovation. If the Volt does better than the Leaf, despite its higher price, that could signal that consumers still value the comfort of knowing they can pull into a gas station and refuel in three minutes--rather than several hours--more than they value their independence from oil. And if both do well without eroding the sales of conventional hybrids, then that would bode well for a much more efficient vehicle fleet in the years ahead, relying on a much wider mix of energy sources than today's.

Wednesday, February 04, 2009

Building Bridges to Greener Wheels

It's a heck of a time to hold a car show, when new figures indicate car sales last month were off 37% compared to the prior January, and with a brand new administration for which cars must surely seem to be a much bigger problem than opportunity. But then the 2009 Washington Auto Show, with its theme of "The Automotive Seat of Power", had a very different feel from most of the car shows I've attended in the past. While there was no shortage of glitzy new models and concept cars, the emphasis was squarely on making cars much more efficient and environmentally-friendly. Visiting dignitaries included the new Administrator of the Environmental Protection Agency. In remarks at a presentation on the new EcoCar competition--the follow-on from the Challenge X competition I described last year--one of her deputies emphasized three overarching imperatives for the industry: economic stability, energy security, and emissions reduction. The auto company officials I spoke with were already on board with that message.

I can't fit all my experiences and a proper assessment of the issues involved into a single posting, so instead I'll just recount the highlights of attending the media-only preview of the show, and a dinner for a small group of bloggers organized by General Motors the previous evening. I hope to expand on much of this in subsequent postings.

The GM dinner was certainly a highlight. I met the head of the Chevrolet division and had a lengthy conversation with Tony Posawatz, who leads the design team for the Chevrolet Volt plug-in hybrid, the latest prototype of which was on display at the show. I had a chance to ask all of my questions about the Volt's configuration and how it will perform once its approximately 40 mile electric-only range is exhausted. I was particularly impressed with the Chevy team's underlying philosophy on the eventual electrification of most vehicles, which would greatly diversify the sources of transportation energy, and by their understanding of the complexity of the larger energy and environmental challenges involved. Cost remains a crucial hurdle for EVs and plug-ins, with battery packs still tremendously expensive and fuel so cheap, just now. I was assured that the Volt is on-track for its launch in the latter part of 2010.

A brief conversation at the Honda display underlined that cost concern, in the context of Honda's redesigned Insight hybrid, which is aimed at reducing the price premium of hybrids over non-hybrids and making them more affordable for a mass market. The new Insight has more than a few styling similarities to the Prius--"The same equations have the same solutions", as the great physicist Richard Feynman once said--and has no non-hybrid version to compare with. Both are probably smart moves on Honda's part. I also saw the new, third-generation Prius, which will apparently get even better fuel economy than the current model. If you liked the look of the old one, you will probably find this version sleeker and more graceful. Otherwise, it's yet another jellybean.

The other big highlight for me was the opportunity to drive three different European-style diesel cars, courtesy of the folks at Bosch, which makes the components that transform today's diesel engine from the smoky, noisy, balky device that Americans normally associate with this fuel into a smooth, clean and relatively quiet powerplant. The Mercedes ML320 and VW Tuareg and the 41 mpg (highway) Jetta TDI were all fun to drive, and their advanced particulate control systems meet the air-pollution requirements of all 50 states. I was also impressed with the Jetta's "double clutch" electronic transmission, which shifts almost imperceptibly. This model, which qualifies for a $1,300 fuel economy tax credit, will certainly be on my short list when I next go car-shopping. The other treat provided by Bosch was a ride in a test car that integrates advanced safety features with radar-based adaptive cruise control. If you haven't experienced it before, it's a bit eerie watching the cruise control handle city traffic, coming to a full stop without driver intervention. We are rapidly approaching the point at which computers can drive our cars better than we can, or at least make better use of their capabilities, including achieving the car's maximum fuel economy potential.

The emphasis on fuel economy and green credentials yesterday was pervasive, if not necessarily in all the models filling the DC Convention Center's halls, then at least in the ones that the companies emphasized. I found it remarkable that Chevrolet's new Camaro was touted for the 27 mpg (highway) fuel economy of its standard V-6--an engine unlikely to have been of much interest to the car's target demographic prior to last year's fuel price roller coaster--rather than its acceleration. And the new 40 mpg Cruze non-hybrid compact, already on sale in Europe, garnered as much attention. The proximity of so many cars delivering appreciably better mileage than most of those on the road in the US today to the really high-tech cars such as the Volt, Fisker Karma, Tesla Roadster, and Mini-E kept reminding me of a phrase I heard several times from the engineers from Bosch, in the context of their diesel technology: a bridge to the future, in the form of cars built with the best of today's technology, at an affordable cost, while the engineers and early adopters drive down the cost of the next generation everyone wishes we could all have now, but can't.

Friday, April 06, 2007

Post-Vacation

Only two news items penetrated my vacation mindset this week. The more immediate one was Iran's release of the UK military personnel they were holding hostage, which ought to reduce oil price risk at least a little. I don't see the resolution of this crisis as quite as much of a victory for Iran as the pundits are proclaiming. However deftly Ahmadinejad and the mullahs may have outmaneuvered the UK, the reminders of an earlier hostage crisis will not enhance international confidence in the regime. It remains to be seen whether the dynamics of the nuclear controversy have changed.

The other item that caught my attention was a report on US auto sales, indicating that Detroit has lost more market share to Toyota and other imports, at least partly on the back of the growth of the Prius and other hybrids. At a 200,000 unit/year clip, the Prius looks successful as a car model, not just a technology platform or loss-leader. We're not far from the day when US auto firms sell less than half the cars in America, and the shift looks to have more to do with strategic mistakes than lingering concerns about quality. The Chrysler 300 rental car we just drove from Arizona to Southern California was as nice as any import in its class, and it averaged 27 mpg on the highway. But Detroit needs a dozen such hits, if it's going to recapture any lost ground, and it's not clear that GM has the vision to leverage its coming Chevrolet Volt plug-in hybrid in the same way that Toyota has done with the Prius.