Tag Archives: Elon Musk

Hydrogen powered trucks and busses

With all the attention to electric cars, I figure that we’re either at the dawn of electric propulsion vehicles or of electric propulsion vehicle hype. Elon Musk’s Tesla motor car company stock is now valued at $59 B, more than GM or Ford despite the company having massive losses and few cars. The valuation, I suspect, has to do with the future and autonomous vehicles. There are many who expect self-driving vehicles will rule the road, but the form is uncertain. In this space, i suspect that hydrogen-battery hybrids make more sense than batteries alone, and that the first large-impact uses will be trucks and busses — vehicles that go long distance on highways.

Factory floor, hydrogen fueling station for plug-power forklifts. Plug FCs reached their 10 millionth refueling this January.

Factory floor, hydrogen fueling station for fuel cell forklifts. This company’s fuel cells have had over 10 million refuelings so far.

Currently there are only two bands of autonomous vehicles available in the US, the Cadillac CT6, a gasoline powered car, and the Tesla. Neither work well except on highways because the number of highway problems are fewer than the number of city problems and only the CT6 allows you to take your hands off the wheel — see review here. To me, being able to take your hand off the wheel is the only real point of autonomous control, and if one can only do this only on the highway, that’s acceptable. Highway driving gets quite tiring after the first hundred miles or so, and any relief is welcome.

Tesla’s battery cars allow for some auto-driving on the highway, but you can’t take your hand off the wheel or the car stops. That battery cars compete at all for highway driving, I suspect, is only possible because the US government highly subsidizes the battery cost. Musk then hides the true cost among the corporate losses. Without this, hydrogen – fuel cell vehicles would be cheaper, I suspect, while providing better range, see my calculation here. Adding to the advantage of hydrogen over batteries, the charge time for hydrogen is much faster. Slow charge times are a real drawback for highway vehicles traveling any significant distances. While hydrogen fuel isn’t cheap — it’s becoming cheaper and is now about double the price of gasoline on a per mile basis. The advantage over gasoline is it provides pollution-free, electric propulsion, and this is well suited to driverless vehicles. Both gasoline and battery vehicles can have odd acceleration issues, e.g. when the gasoline gets wet, or the battery gets run down. And it’s not like there are no hydrogen fueling stations. Hydrogen, fuel-cell power has become a major competitor for fork-lifts, and has recently had its ten million refueling in that application. The same fueling stations that serve the larger fork-lift users could serve the self-driving truck and bus market.

For round the town use, hydrogen vehicles could still use batteries, and the combined vehicle can have very impressive performance. A Dutch company has begun to sell kits to convert Tesla model S autos to combined battery + hydrogen. With these kits, they boast a 620 mile (1000 km) range instead of the normal 240 miles. See the product here.  On the horizon, in the self-driving fuel cell market, Hyundai has debuted the “Nexo” with a range of 370 miles. Showing off the self-driving capability, Nexos were used to carry spectators between venues at the Pyongyang olympics. Japanese competitors, the Toyota Mirai (312 miles) and the Honda Clarity Fuel Cell (366 miles) can be expected to provide similar capabilities.

Cadillac CT6 with supercruise. An antonymous vehicle that you can buy today that allows you to take your hand off the wheel.

Cadillac CT6 with supercruise. An antonymous vehicle that you can buy today that allows you to take your hand off the wheel.

The reason I believe in hydrogen Trucks and Busses more than cars is the difficulty of refueling, Southern California has installed some 36 public hydrogen refueling stations at last count, but that’s too few for most personal car use. Other states have even fewer spots where you can drive up and get hydrogen; Michigan has only two. This does not matter for a commercial truck or bus because they go between fixed depots and these can be fitted with hydrogen dispensers as found for forklifts. It’s possible trucks can even use the same dispensers as the forklifts. If one needs a little extra range one can add a “hydrogen Jerry can” to provide an extra kg of H2 to provide 20-30 miles of emergency range. I do not see electric vehicles working as well because the charge times are so slow, the range so modest, and the electric power needs so large. To charge a 100 kWhr battery in an hour, the charge station would have to have an electric feed of 100 kW, about as much as a typical mall. With 100A, 240 V, the most you can normally get, expect a 4 1/2 hour charge.

The real benefit for hydrogen trucks and busses is autonomy. Being able to run the route without major input from a driver. So why not gasoline, as with the Cadillac? My answer is simplicity. If you want driverless simplicity, you want electric or hydrogen. And only hydrogen provides the long-range, fast fueling to make the product worthwhile.

Robert Buxbaum March 12, 2018. My company, REB Research provides hydrogen purifiers and hydrogen generators.

If the wall with Mexico were covered in solar cells

As a good estimate, it will take about 130,000 acres of solar cells to deliver the power of a typical nuclear facility, 26 TWhr/year. Since Donald Trump has proposed covering his wall with Mexico with solar cells, I came to wonder how much power these cells would produce, and how much this wall might cost. Here goes.

Lets assume that Trump’s building a double wall on a strip of land one chain (66 feet) wide, with a 2 lane road between. Many US roads are designed in chain widths, and a typical, 2 lane road is 1/2 chain wide, 33 feet, including its shoulders. I imagine that each wall is slanted 50° as is typical with solar cells, and that each is 15 to 18 feet high for a good mix of power and security. Since there are 10 square chains to an acre, and 80 chains to a mile we find that it would take 16,250 miles of this to produce 26 TWhr/year. The proposed wall is only about 1/10 this long, 1,600 miles or so, so the output will be only about 1/10 as much, 2.6 TWhr/year, or 600 MW per average daylight hour. That’s not insignificant power — similar to a good-size coal plant. If we aim for an attractive wall, we might come to use Elon Musk’s silica-coated solar cells. These cost $5/Watt or $3 Billion total. Other cells are cheaper, but don’t look as nice or seem as durable. Obama’s, Ivanpah solar farm, a project with durability problems, covers half this area, is rated at 370 MW, and cost $2.2 Billion. It’s thus rated to produce slightly over half the power of the wall, at a somewhat higher price, $5.95/Watt.

Elon Musk with his silica solar panels.

Elon Musk with his, silica-coated, solar wall panels. They don’t look half bad and should be durable.

It’s possible that the space devoted to the wall will be wider than 66 feet, or that the length will be less than 1600 miles, or that we will use different cells that cost more or less, but the above provides a good estimate of design, price, and electric output. I see nothing here to object to, politically or scientifically. And, if we sell Mexico the electricity at 11¢/kWhr, we’ll be repaid $286 M/year, and after 12 years or so, Republicans will be able to say that Mexico paid for the wall. And the wall is likely to look better than the Ivanpah site, or a 20-year-old wind farm.

As a few more design thoughts, I imagine an 8 foot, chain-link fence on the Mexican side of the wall, and imagine that many of the lower solar shingles will be replaced by glass so drivers will be able to see the scenery. I’ve posited that secure borders make a country. Without them, you’re a tribal hoard. I’ve also argued that there is a pollution advantage to controlling imports, and an economic advantage as well, at least for some. For comparison, recent measurement of the Great Wall of China shows it to be 13,170 miles long, 8 times the length of Trump’s wall with China.

Dr. Robert E. Buxbaum, June 14, 2017.