It’s often said that a good idea will always win out in the end. But it’s also true that bad ideas sometimes linger in the public consciousness, attracting funding and media attention long past the point at which they should have died natural deaths.
- This article comes to us courtesy of EVANNEX (which also makes aftermarket Tesla accessories). Authored by Charles Morris. The opinions expressed in these articles are not necessarily our own at InsideEVs. Lead Image Source: Look out, Zombies! (Flickr: GoToVan)
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Scientists and engineers may try to kill these ideas with facts, but like zombies, they continue to trouble the living, kept half-alive by a credulous press, by business interests with axes to grind, or just because they seem cool to those with little understanding of the science behind them.
Paul Martin, a chemical engineer and clean energy advocate who once built his own electric vehicle, teamed up with James Carter, an automotive industry veteran and New Mobility consultant, to write a series of articles for Electric Autonomy Canada about four of these zombie technologies.
As Martin and Carter define the term, a zombie technology is one that seems to have huge potential, but has a set of inherent problems that keep it from progressing beyond the prototype stage. Sometimes these zombies face technological limitations, sometimes they are doomed by financial realities, and sometimes they’re up against the basic laws of physics.
DRIVING ON SUNSHINE
The first zombie that Martin and Carter attempt to slay is the idea of mounting solar panels on cars. If you’ve been involved with EVs for any length of time, you’ve probably had a dozen people ask you about this one. Even years ago, before viable EVs were a reality, some people were convinced that we could have solar-powered cars that would run forever for free, but that (of course) the auto and oil industries were suppressing the technology.
Yes, it is possible to build a car that’s powered by its own solar panels. Teams of engineers have been doing so since 1990 for the American Solar Challenge. One participant was a young JB Straubel, who called his experience with the Stanford Solar Car Project one of the keys to Tesla’s founding.
However, these are purpose-built prototypes, designed for minimum weight and maximum range. The goal of the Solar Challenge is not to build a street-legal automobile, much less one that could be profitably mass-produced. Like Bertrand Piccard’s Solar Impulse, a solar-powered plane that circumnavigated the Earth, these vehicles represent important technological milestones, but they won’t be viable replacements for fossil fuel vehicles any time in the foreseeable future.
As Paul Martin points out, photovoltaic (PV) panels work wonderfully on buildings, where they are stationary and mounted at the optimal angle to the sun. They’ll generate electricity at zero marginal cost for 20 to 30 years, paying back the energy used to make them many times over. As Tesla has long realized, EVs and PVs are a winning combination. Many an EV owner, including this writer, uses roof-mounted panels to drive on sunshine.
Above: The solar roof on Toyota's Prius Prime (Image: Motor1 via Toyota)
The viability of mounting panels on a car, however, is doomed by simple math, as Mr. Martin explains: “A 300W solar panel is about 1.5 square metres in area. Let’s say you managed to fit 1,000W (1 kW) worth of panels on your roof, hood and trunk lid (4.5 square metres worth for a large car). Assuming your car is never in the shade of a building or tree, an economical photovoltaic (PV) panel in Toronto could make on average about 1,000 kWh per year. That’s an average of about 2.74 kWh per day - enough to drive your car about 11 kilometres per day.”
This generous estimate doesn’t account for the amount of time a car spends parked in a garage or in the shade, nor for the fact that the panels are useless when the battery is full. Furthermore, it’s safe to assume that a solar panel that conforms to the aerodynamic shape of an automobile, and meets safety standards, might be a tad expensive. The conclusion: put your solar panels on the roof (of your house, that is).
Some automakers apparently believe that marketing considerations outweigh mathematical ones (in the fashion-driven auto industry, they often do). Toyota offers a version of the Prius Plug-in in Japan with panels that can deliver up to 3.8 miles worth of energy per day, and is experimenting with a new Prius Prime equipped with 860 watts worth of solar panels - on an ideal sunny day, the company says the panels could deliver up to 27.6 miles worth of energy. In 2018, Hyundai/Kia announced plans to introduce solar roof charging technology not only on EVs, but also on gas-powered vehicles (!).
CUTTING THE CORD
Wireless charging (aka inductive charging) is another technology that Messrs. Martin and Carter consider to be a zombie. The obvious promise of wireless is that it would free drivers from the slight inconvenience of plugging in a cable. (An exec from a wireless tech company once told me, “never underestimate the laziness of the American consumer.”) However, it could also reduce the need for maintenance by eliminating the need for connectors to physically touch each other. Someday in the future, autonomous vehicles could drive themselves to wireless charging stations at night, freeing drivers from ever needing to think about charging at all.
Unlike the solar panel thing, wireless charging is an active area of R&D in the EV world. SAE has published a standard for wireless power transfer (WPT), and automakers including VW, BMW and Honda are working on wireless-equipped models. Wireless charging systems for electric buses are currently in service in a few places. Startup WiTricity acquired Qualcomm’s Halo wireless technology platform earlier this year.
Above: BMW tests wireless charging tech (Image: Motor1 via BMW)
However, James Carter sees technical problems that he believes will eventually drive a stake through the heart of this zombie. The first is efficiency - while some inductive charging suppliers claim to have achieved efficiency levels as high as 94.5% in the laboratory (the best plug-in charging systems achieve over 99% efficiency), Carter writes that real-world results are limited by problems such as imprecise alignment of the two coils and environmental conditions such as snow, ice, rain and road debris.
Furthermore, wireless systems create high levels of electromagnetic radiation, which can generate noise in electronics and heat up nearby ferrous objects, creating a fire hazard. Neutralizing these problems requires heavy shielding, which runs counter to the imperative of keeping vehicle weight to a minimum.
The coup de grace, according to Mr. Carter, is that “almost no OEMs have supported [wireless] beyond laboratory and prototype testing due to the challenges cited. If there are no cars that use a wireless charging standard, supplying wireless charging infrastructure is not commercially viable, meaning the technology is dead.”
CHARGE AS YOU GO
The next step from wireless charging - and one that’s even farther from commercial viability - is dynamic charging, the concept of charging a vehicle as it travels on a road. Not only would this be neato, it would allow batteries to be smaller, reducing vehicle weight and increasing load capacity.
Utah State University and Qualcomm have each been working on dynamic charging for years - USU recently demonstrated a prototype system powered by a solar DC microgrid - but commercialization doesn’t seem to be in sight. Carter argues that inefficiency and alignment problems will send this zombie back to the graveyard.
Above: Dynamic Charging (Image: InsideEVs via Fully Charged)
A related concept is conductive charging using an overhead catenary. This is of course a technique that’s used all over the world by trains, street trams and rubber-tired trolleybuses, and some believe that it could have applications for battery-electric trucks. The idea is that trucks can be powered by overhead wires while traveling down a highway, then switch to battery power for the “last mile.” Siemens has tested such a system in Sweden, and Volvo subsidiary Mack Trucks has demonstrated a system near the ports of Los Angeles and Long Beach.
Perhaps the most gruesome zombie of all is the concept of embedding solar panels directly in roads. To the horror of anti-government-waste crusaders, a company called Solar Roadways apparently firked $850,000 out of the DOT’s Small Business Innovation Research program in 2011 to research this idiotic idea. (If someone can explain to me why it makes more sense to put solar panels on roads instead of simply putting them on rooftops - or alongside roads, for that matter - I’ll reconsider my uncomplimentary adjective.)
THE CELLS THAT WOULD NOT DIE
The previous three zombies may wreak havoc on a small scale, but hydrogen fuel cells are staggering relentlessly forward, and they could create a true Zombie Apocalypse. Toyota, Honda and Hyundai are currently selling fuel cell vehicles, and Toyota execs have often indicated that they prefer the technology over battery EVs. Fuel cells have attracted significant political support, and most government incentives for EVs also apply to fuel cell vehicles.
Paul Martin has written eloquently and at length elsewhere about the reasons that hydrogen is a dead end for passenger vehicles. So have others, including Elon Musk, Martin Eberhard and Marc Tarpenning (when they founded Tesla, the two engineers did a thorough analysis of fuel cells before concluding that batteries were the way to go), as well as EV journalists including Electrek’s Fred Lambert, Green Car Reports’ John Voelcker and, if I may say so, myself. We’ll offer no detailed discussion of the highly contentious fuel-cell-vs-battery battle here, but rather refer you to previous articles about Asian automakers’ devotion to fuel cells; the admission by the Toyota Mirai's chief engineer that battery-electrics are superior; the inefficiency of hydrogen as an energy storage medium; and a head-to-head comparison between the Mirai and the Tesla Model 3.
Above: Hydrogen fuel cells vs. electric cars (Youtube: EV Digest)
The only benefits to consumers that we’ve heard offered for hydrogen are longer driving range and faster refueling times, both temporary issues that improving battery tech is gradually making moot. However, the fossil fuel industry has good reason to see hydrogen as a lifeline. As Mr. Martin points out, 96% of the hydrogen produced today is made from fossil fuels. The proportion that’s made using renewable energy via electrolysis will surely increase, but this will do nothing to improve the efficiency of storing energy in hydrogen (according to Martin’s best-case calculations, about 37%, compared to 90% for lithium-ion batteries), which is governed by the laws of physics.
Replacing gasoline with hydrogen would mean sticking with the existing model of stopping at fueling stations to buy fuel centrally produced by giant multinational corporations, and unfortunately this may prove more appealing to certain policymakers than would moving to a new, more consumer-empowering paradigm of charging at home with energy produced on residential rooftops.
Unlike the other three zombies identified by Martin and Carter, hydrogen may prove difficult to destroy.
While hydrogen looks like a dead end for cars, its greater energy density may give it an edge over batteries in certain heavy-duty long-haul vehicle applications, as even Martin concedes. Nikola Motor Company, an Arizona manufacturer of Class 8 fuel cell trucks, seems to have a bright future - in 2018 Anheuser-Busch ordered 800 of Nikola’s trucks, to be delivered beginning in 2020; and in September Nikola formed a partnership with the maker of IVECO commercial vehicles, which came with an investment of $250 million.