Wednesday, 14 December 2016
Hydrogen fuel cells: yes or no?
Whose voice should we listen to: the lone voice in the wilderness or vehicle makers preparing to peddle their wares in years to come?The question arises because last Thursday, in Salt Lake City, Nikola Motor Company unveiled the Nikola One, the world’s first Class 8 hydrogen fuel-cell electric freight truck.
The full-scale, zero-emission semi-trailer rig will offer, according to Nikola, a range between 800 and 1,200 miles, and produce 1,000 bhp, which the company proclaims is “about twice that of an average diesel truck”. The company also claims it will operate at half the cost of a comparable diesel truck.
The truck will also feature regenerative braking, weigh about 2,000 lb less than a diesel truck, and have 2,000 lbft torque, allowing it to accelerate with a full load much faster than a diesel truck.
In a nutshell, Nikola is saying its hydrogen-fuelled truck is “lighter, cheaper, and more powerful than a diesel”.
But hang on a minute. Back in the UK, where the fuel cell was first developed, there is the sound of the lone voice crying in the wilderness, namely that of Professor David Cebon, director of the Centre for Sustainable Road Freight at Cambridge University, who was reported as saying “The use of hydrogen as an alternative fuel is a disaster.
Speaking at the London headquarters of the SMMT, Professor Cebon told visitors: “Hydrogen is a disaster. It’s something that everybody should be saying ‘no, don’t do this. Don’t spend money on this’.”
Cebon claimed that 100kWh of generated electricity, once it has been sent through the national grid to a battery, will provide about 65kWh of power at the road wheels.
However, taking the same 100kWh and using it to generate hydrogen, with that hydrogen stored in a vehicle and run through a fuel cell to create electricity to power the vehicle, it would translate to just 23kWh at the wheels.
That process, said Cebon, is “extremely wasteful”.
In May of this year, the UK government committed £2 million to a fund to encourage more businesses to move to using hydrogen vehicles. In 2014, it also spent £5 million on the Hydrogen for Transport Advancement Programme, which funded 12 hydrogen refuelling stations across the country.
Later, Professor Cebon, bounced back to respond: “That is not exactly what I said. The sentiment is correct but the facts aren't quite correct.”
Professor Cebon explained: “If you take 100kWh of electricity (which is assumed to come from low carbon sources in future), transmit it via the grid, put it into a battery, then run an efficient electric vehicle with it, you will end up with about 69kWh energy at the wheels.
He added: “The route via hydrogen is extremely wasteful, because converting electricity into hydrogen (by electrolysis) is only about 75 per cent efficient and converting hydrogen into electricity (in a fuel cell) is only about 50 per cent efficient, at best.
“There are other ways to make hydrogen, particularly by steam reforming of methane,” he commented. “However, unless there is a viable Carbon Capture and Storage scheme to sequester the CO2 (the UK Government cancelled CCS research in 2015), the total greenhouse gas emissions are just as bad as burning the methane directly in gas engines (which are commercially available now). The latter are about 43 per cent efficient, compared to 29 per cent for methane-via hydrogen-to electricity.”
“So the only way that hydrogen can possibly make sense from an energy viewpoint requires CCS as a per-requisite. That doesn't look like it is going to happen any time soon,” he concluded, noting: “The best strategy to reduce GHG emissions and energy cost is simply to use electricity to charge the batteries of electric vehicles. Forget the hydrogen.”
A British invention
Francis Thomas Bacon, who died in 1992, was an English engineer who developed the first practical hydrogen–oxygen fuel cell.
Bacon, a direct descendant of Francis Bacon, became an apprentice (after first obtaining a degree from Cambridge) with the Newcastle engineering firm owned by Sir Charles Parsons and was strongly influenced by him.
The principle of the fuel cell had been demonstrated by Sir William Grove in 1839 and other investigators have experimented with various forms of fuel cell. However unlike previous workers in the field, Bacon being an engineer and comfortable working with machinery operating at high temperatures and pressures, initially experimented with Grove's use of activated platinum gauze with a sulphuric acid electrolyte, but quickly moved on to use activated nickel electrodes with an aqueous potassium hydroxide electrolyte.
In January 1940, he developed a double cell, with one unit for generating the hydrogen and oxygen gases and the other for the fuel cell proper. This could be reversed so that it acted as both an electrolyser and a fuel cell. Problems were encountered due to the high operating temperatures and pressures and the corrosive nature of the chemicals.
Work progressed from 1946 under various funding arrangements to the point that by 1959, using support from Marshall of Cambridge Ltd. (later Marshall Aerospace) a 5kW forty-cell battery, with an operating efficiency of 60 per cent, was demonstrated publicly.
The patents for the fuel cell were licensed by Pratt and Whitney as part of a successful bid to provide electrical power for Project Apollo. The fuel cells were ideal in this regard because they could achieve rising levels of efficiency with decreasing load (unlike heat engines). Hydrogen and oxygen gases were already on board the spacecraft for propulsion and life support and the by-product water could be used for drinking and humidifying the atmosphere of the capsule.
Technical details lacking
Fast forward to Salt Lake City in early December and we find that US Xpress Enterprises of Chattanooga, and Tennessee’s biggest trucking carrier is set to go along with the Nikola Motors’ electric vehicle and which it will introduce into some of its fleet. This will happen in the next three to five years.
It seems US Xpress Enterprises is attracted to the idea of electric heavy-duty commercial vehicles. It has agreed to test some of the first new electric articulated commercials to be built by the new truck manufacturing company, Nikola Motor Company.
Trevor Milton, a 34-year-old entrepreneur and chief executive officer and founder of Nikola Motor Company, is a very ambitious man. He wants to be instrumental in revamping North America’s trucking industry by replacing diesel engines with hydrogen fuel and battery-powered electric motors. And thereby presumably putting many diesel-making jobs on the line! There are an estimated 15 million articulated commercial vehicles on the road in North America and Milton is aiming to replace many of them.
The company says it will begin delivering its ground-breaking vehicles in 2020, partnering with Fitzgerald to build the first 5,000 vehicles. It will start work on its own production facility next year, and claims that after that it will be able to build 50,000 trucks a year.
To achieve his goals, Milton said he plans to build a $1 billion factory to assemble the new Nikola One electric-powered trucks within the next five years. But the initial models are expected to be built in Tennessee, and some of the first will be driven by U.S. Xpress drivers.
Interestingly, as with many US vehicle launches or ‘reveals’, Press interest focused more on the detail design of headlights, the comfort of cab interiors, or the instrument cluster arrangement. As to the finer technical details of how Nikola will handle fuel cell design, manufacture and sourcing little, if anything, bubbles to the surface. Technology details are something Milton likes to keep close to his chest until the moment he needs to reveal. As to hydrogen sourcing, some details are forthcoming.
Limited and scattered
According to Nikola Motors, the company will solve that problem through vertical integration, producing and distributing its own hydrogen. The company will deploy 364 hydrogen stations across the US and Canada, which Milton claims will be completed within 10 years.
That appears to be just one of several ways the company is shadowing Elon Musk’s Tesla Motors. Reports suggest Milton took the company’s name from 19th century innovator Nikola Tesla.
Nikola Motor Company was launched in only May of this year, but Milton says he has been working in “stealth mode” for years to perfect its products. The Nikola One showcased last week was, according to reporters on-site, fully functional.
Nikola Motors claims to have over 7,000 reservations for trucks giving a value of US$2.3 billion. However, these funds are derived from refundable $1,500 reservations. In addition to the Nikola One, Nikola Motors is also promising to produce the smaller Nikola Two short-haul tractor unit, and the Nikola Zero electric off-road vehicle.
Meanwhile, another enthusiast, chairman and chief executive officer of US Xpress Enterprises, Max Fuller, who founded U.S. Xpress 30 years ago, said his company has been a pioneer in testing new satellite communications, aerodynamic wind resistance designs and vehicle safety systems over the past three decades.
"Any time there are new technologies in the market that we think will be a game changer, we try to participate with the manufacturers that are coming to the market and try to help them understand what's needed in our industry," Fuller has told reporters.
"We probably have eight to 10 technologies on our trucks today that no more than two or three other companies are running because we want to stay ahead in our industry.”
So, who do you believe? Professor Cebon or Messrs Milton and Miller? Not to mention the car makers busy with their hydrogen fuel cell programmes.
Meanwhile, exactly, a year ago, Audi unveiled the hi-tron Quattro concept car at the NAIAS 2016 in Detroit – a sporty SUV that uses hydrogen as its energy source.
Audi then said: "The concept car combines a highly efficient fuel cell achieving an output of up to 110 kW with a battery that provides a temporary boost of 100 kW. Audi’s fuel cell technology paves the way for sustainable mobility with the sporty performance for which the brand is renowned.
The Audi claimed the “hi-tron quattro concept uses only around one kilogram (2.2 lb) of hydrogen per 100 kilometers (62.1 mi). It takes only about four minutes to fill the tank, giving the car a range of up to 600 kilometers (372.8 mi). The conspicuously aerodynamic design with a Cd value of 0.27 plays a major part in its outstanding efficiency."
Others in the hydrogen 'race' include: BW, Daimler, Fiat, Ford, General Motors, Honda, Hyundai, Kia, Mazda, Nissan, Renault, Toyota, Volkswagen and, the UK’s Riversimple.And is this the moment when Cummins’ executive in Columbus, Indiana should start worrying?