Wednesday, 14 November 2018

Swapping gasoline with gas: are hydrogen fuel cells the future of land transport?

When I was a child, I recall being impressed by the sophistication of hydrogen fuel cells, a power source used in spacecraft that generated water as a by-product. What I didn't realise at the time was that the basis for fuel cell technology had been invented back in the 1830s. Now that automobile manufacturers are promoting fuel cell vehicles for consumers, is it time for the technology to expand from niche usage to mass market?

Road vehicles of all sorts have had more than their fair share of ups and downs, not least due to the conservatism of that unholy alliance between the internal combustion engine and fossil fuels sectors.  Although there were hydrogen-powered test vehicles in 1970s, it wasn't until 1991 that the development phase was completed. There are currently three car manufacturers with fuel cell models intended for personal customers: the Honda Clarity, Hyundai Nexo and Toyota Mirai. The latter two are intended to enter to take off (not literally) across South Korea and Australia respectively over the new few years, apparently selling at a loss on the assumption of beating rivals Nissan and BMW into the market. Brand loyalty being what it is, and all.

So what do fuel cell vehicles have that makes them a credible alternative to gas guzzlers and electric cars? Their primary benefit in this time-poor age is that they take only minutes to refuel – and with a range considerably greater than that of electric vehicles. Even so, this is hardly likely to be a convincing argument for petrol heads.

To anyone with even a vague knowledge of interwar air travel, hydrogen brings to mind the Hindenburg and R101 disasters. The gas is far from safe in large quantities, hence the rapid end of airship development; even with helium as a substitute, today's airships are smaller, specialist vehicles, their lack of speed making them an unlikely substitute for passenger jets. Although fuel cells themselves provide a safe power source, large quantities of hydrogen needs to be transported to the refuelling stations. A neat solution is to transport it in the form of ammonia (admittedly hardly a pleasant substance itself) and then convert it to hydrogen at the point of use.

What is less easily resolved is the cost of manufacturing the gas and the resulting high price for the customer. Most of the world's hydrogen is produced from natural gas; it can be made from renewable sources, but only at much greater expense. Wind-to-hydrogen methods are being tested, but in general there is a distinct lack of environmental friendliness to the gas production process that counteracts the emission-friendly usage in the vehicles themselves. To date, analysis is inconclusive as to whether en masse replacement of fossil fuel vehicles with fuel cell equivalents would reduce greenhouse gas emissions. Indeed, some reports claim they use three times the amount of electricity per vehicle than the equivalent battery-powered car!

In addition to the price of hydrogen, fuel cells use rare elements such as platinum, contributing to the production costs. But most importantly of all, how will the vehicle manufacturers resolve the chicken-and-egg issue of providing adequate infrastructure when there is only a small customer base? Without enough refuelling stations and repair depots, most regions are unlikely to attract new customers, but how can a corporation afford to put these facilities in place before there is a demand for them? Most private vehicle owners would require an immediate advantage to migrate to the new technology, regardless of any environmental benefit. Unlike the early days of the internal combustion engine, fuel cell vehicles do not offer the paradigm shift that the automobile had over the horse-drawn carriage.

So with continuous improvements in battery technology, is there in fact any need for the fuel cell vehicles? Aren't electric cars the best alternative to the internal combustion engine? If so, wouldn't it make more sense to concentrate on battery development and not waste effort on a far from optimal alternative that might turn out to be a dead end? Perhaps this is a case of corporate bet hedging. After all, the telecommunications industry was taken completely unawares by the personal consumer demand for mobile phones - a device that was aimed squarely at business users - so this may be a Plan B if something happens with the growth of electric vehicles. At least vehicle manufacturers aren't anti-innovation this time, unlike their voracious gobbling up of advanced steam car development in the early 1970s.

If not for private road vehicles, could there be a future for fuel cell technology in public transport? China and some European nations such as Germany have been trialling hydrogen-powered buses and tram cars, whilst Boeing is one of the aircraft manufacturers investigating the use of fuel cells in small aircraft and unmanned aerial vehicles. That isn't to say the future of commercial air travel excludes the turbofan engine; fuel cells will probably only ever be used for auxiliary power units.

I wouldn't want to disparage innovation but can't help thinking that in this instance, the self-regulating capitalist model is failing to cope with the paradigm shifts required to face the challenges of climate change. Would it be better for governments to incentivise the front-runner replacements for environmentally poor technologies, in this particular case favouring electric-powered vehicles? Solutions are needed now and I'm just not sure that there is the time to solve all the issues surrounding hydrogen fuel cells and the necessary infrastructure. Perhaps this technology should be saved for a rainy day sometime in the future, once our current crises are over and dealt with?

Monday, 29 October 2018

Space is the place: did life begin in the cosmic void?

A few weeks' ago I was watching a television documentary about the search for intelligence aliens and featuring the usual SETI experts Jill Tarter and Seth Shostak when I realised that we rarely see any crossover with research into non-intelligent extra-terrestrial life. Whereas the former is often seen by outsiders as pie-in-the-sky work by idealistic dreamers, the latter has more of a down-to-Earth feel about it, even though it has at times also suffered from a lack of credibility.

Based on current thinking, it seems far more probable that life in the universe will mostly be very small and entirely lacking consciousness, in other words, microbial. After all, life on Earth arose pretty much as soon as the environment was stable enough, around 3.7 billion years ago or even earlier. In contrast, lifeforms large enough to be visible without a microscope evolved around 1 billion or so years ago (for photosynthetic plants) and only about 580 million years ago for complex marine animals.

The recent publicity surrounding the seasonal variations in methane on Mars has provided ever more tantalising hints that microbial life may survive in ultraviolet-free shelters near the Martian surface, although it will be some years before a robot mission sophisticated enough to visit sink holes or canyon walls can investigate likely habitats. (As for the oft-talked about but yet to be planned crewed mission, see this post from 2015.)

Therefore it seems that it is worth concentrating on finding biological or pre-biological compounds in extra-terrestrial objects as much as listening for radio signals. The search can be via remote sensing (e.g. of molecular clouds, comets and asteroids) as well as investigating meteorites - bearing in mind that the Earth receives up to one million kilogrammes of material per day, although less than one percent is large enough to be identified as such.

The problem is that this area of research has at times had a fairly poor reputation due to the occasional premature claim of success. Stories then become widespread via non-specialist media in such a way that the resulting hype frequently bears little relation to the initial scientific report. In addition, if further evidence reverses that conclusion, the public's lack of understanding of the error-correcting methods of science leads to disillusion at best and apathy at worst.

One key hypothesis that has received more than its fair share of negative publicity has been that of panspermia, which suggests not just the chemicals of biology but life itself has been brought to Earth by cosmic impactors. The best known advocates are Fred Hoyle and Chandra Wickramasinghe, but their outspoken championing of an hypothesis severely lacking in evidence has done little to promote the idea. For while it is feasible - especially with the ongoing discovery of extremophiles everywhere from deep ocean vents to the coolant ponds of nuclear reactors - to envisage microbial life reaching Earth from cometary or asteroid material, the notion that these extra-terrestrials have been responsible for various epidemics seems to be a step too far.

It's long been known that comets contain vast amounts of water; indeed, simulations suggest that until the Late Heavy Bombardment around four billion years ago there may have been far less water on Earth than subsequently. Considering the volumes of water ice now being discovered on Mars and the Moon, the probability of life-sustaining environments off the Earth has gained a respectable boost.

It isn't just water, either: organic compounds that are precursors to biological material have been found in vast quantities in interstellar space; and now they are being found in the inner solar system too. That's not to say that this research has been without controversy as well. Since the early 1960s, Bartholomew Nagy has stirred debate by announcing the discovery of sophisticated pre-biological material in impactors such as the Orgueil meteorite. Examination by other teams has found that contamination has skewed the results, implying that Nagy's conclusions were based on inadequate research. Although more recent investigation of meteorites and spectrophotometry of carbonaceous chondrite asteroids have supplied genuine positives, the earlier mistakes have sullied the field.

Luckily, thorough examination of the Australian Murchison meteorite has promoted the discipline again, with numerous amino acids being confirmed as of non-terrestrial origin. The RNA nucleobase uracil has also been found in the Murchison meteorite, with ultraviolet radiation in the outer space vacuum being deemed responsible for the construction of these complex compounds.

Not that there haven't been other examples of premature results leading to unwarranted hype. Perhaps the best known example of this was the 1996 announcement of minute bacteria-like forms in the Martian ALH84001 meteorite. The international headlines soon waned when a potential non-biological origin was found.

In addition to examination of these objects, experiments are increasingly being performed to test the resilience of life forms in either vacuum chambers or real outer space, courtesy of the International Space Station. After all, if terrestrial life can survive in such a hostile environment, the higher the likelihood that alien microbiology could arrive on Earth via meteorite impact or cometary tail (and at least one amino acid, glycine, has been found on several comets).

Unmanned probes are now replicating these findings, with the European Space Agency's Rosetta spacecraft finding glycine in the dust cloud around Comet 67P/Churyumov-Gerasimenko in 2016. Although these extra-terrestrial objects may lack the energy source required to kick-start life itself, some are clearly harbouring many of the complex molecules used in life on Earth.

It has now been proven beyond any doubt that organic and pre-biological material is common in space. The much higher frequency of impacts in the early solar system suggests that key components of Earth's surface chemistry - and its water - were delivered via meteorites and comets. Unfortunately, the unwary publication of provisional results, when combined with the general public's feeble grasp of scientific methodology, has hindered support for what is surely one of the most exciting areas in contemporary science. A multi-faceted approach may in time supply the answers to the ultimate questions surrounding the origin of life and its precursor material. This really is a case of watch (this) space!