With increasing evidence and media coverage on Climate Change and Global Warming brought on by anthropogenically produced CO2 in our atmosphere, we are well aware of the problems associated with the carbon economy, which is based on coal, oil and gas. But with what do we replace it? Electric power is great, but it is mostly still generated by burning hydrocarbons. If we could duplicate and harness fusion, which is what happens in the sun, enormous amounts of energy could be released, cleanly. We already have fission energy in nuclear power, which also releases vast amounts of energy, but after Chernobyl, Three Mile Island and Fukushima, agencies and governments (Japan and Germany) are moving to alternate sources of power. Nuclear energy also has a massive carbon footprint, expensive decommissioning and radioactive pollution, hence countries like New Zealand remain nuclear free. Sustainable energy is already with us in the form of photovoltaic solar power, wind, geothermal, wave and tidal energy, but increasing attention is being focussed towards the hydrogen economy. In 2002, Jeremy Rifkin wrote a book on the Hydrogen Economy. Unlike carbon compounds, hydrogen burns cleanly to yield water and it is also plentiful, but it needs energy to produce it.
In his 1874 book ‘the Mysterious Island’ Jules Verne predicted that water would be the coal of the future, while almost a century ago J B Haldane envisaged wind power to generate hydrogen, which weight for weight, is the most efficient way to store energy. Perhaps they are right; hydrogen was used as the rocket fuel of choice for the Shuttle launches (NASA), while fuel cells are used as a source of power and water in space. The first fuel cells were invented back in 1838 but were only used commercially a century later. Essentially the fuel cell has an anode (a catalyst like platinum), electrolyte (phosphoric acid, potassium hydroxide) and a cathode (a catalyst like nickel), and the fuel (usually hydrogen but hydrocarbons can be used, but they produce C02) is oxidised to produce water and electricity. The efficiency varies between 40 to 60%, but if waste heat is scavenged, efficiencies rise to 85%. This compares favourably with the maximum theoretical efficiency of 58% for internal combustion engines. Although less electricity is generated by a fuel cell than was used to make the hydrogen, hydrogen vehicles can be refuelled within minutes and have ranges of several hundred kilometres.
Hydrogen powered cars, buses, trams and trains are being now being produced. In 2004 the Governor of California and actor Arnold Schwartzenegger spearheaded an initiative to have a ‘hydrogen highway’ in place by 2010, (Nardi et al., 2015). The launch of the fuel cell hydrogen Toyota Mirai (featured) there is further driving a rapid expansion of this highway into 2020 and beyond. There are now 23 hydrogen refuelling stations in California, while in Florida the first hydrogen refuelling station was opened back in 2005. Fuel cell buses were being launched in London as early as 2010 (The Guardian, Environment) and are already running in Perth, W Australia and Germany. In China, fuel cell powered transport including buses is rapidly expanding due to a fuel cell subsidy which brought 300 new fuel cell powered buses into use in 2017. In Brazil fuel cell buses have been deployed in Sao Paulo. Because fork lift vehicles work indoors, they cannot emit toxic carbon fumes, so fuel cell technology is favoured; way back in 2013, over 4000 fuel cell fork lifts were operating in the US and it was predicted that this market would be the largest driver for fuel cell demand by 2020. Fuel cells have also been employed in bicycles, motorbikes, boats and submarines. Understandably, hydrogen production and its consumption in fuel cells has gone hand in glove. In Sydney, hydrogen generated by electrolyser can now be stored and used in the existing gas networks at 10%, with an ultimate goal of completely replacing the hydrocarbons. Hydrogen stores much better than electricity in batteries, which slowly lose their charge (Hydrogen, Europe). Australia has recently signed a deal with Japan to supply it with liquid hydrogen which will be carried in tankers built by Kawasaki (The Guardian, 2017). And as oil companies are now looking to diversify and attempt to ‘go green’, even Shell, with their terrible environmental record, or maybe because of it, are looking seriously at hydrogen. In Hamburg, Germany, hydrogen is produce from wind turbine electricity to supply refuelling stations (the first was in 2011, with a projected 400 country-wide by 2023), while in Canada the first hydrogen refuelling station was launched last year.
In Scotland, the University of St Andrews has a whole team (JTSI) working on fuel cell technology and hydrogen, which link in with the Energy Park in Leven. Here a massive offshore 750kW wind turbine produces electricity to power a 250kW electrolyser to make hydrogen which is used locally in a 100 kW fuel cell and to power a fleet of 17 vehicles, 10 of which are Renault Kangoo hydrogen-electric vans, while the remainder are hydrogen-diesel hybrids and include two refuse vans. In the Orkneys, electricity generated by waves has been used to electrolyse and generate hydrogen and the gas produced will be used to power new fuel cell boats to replace their aging diesel powered ferries, which is good for local enterprise, tourism and lower the islands carbon footprint. Perhaps the emergent Hydrogen Economy there will move further south to cover the rest of Scotland and beyond? There is some irony here as for decades, carbon, first in the form of coal, then oil and gas has driven the Scottish economy from the Industrial Revolution to the present, though, unlike Norway and Statoil, with its trillion dollar wealth fund, we have little to show for it. Already after peak oil, with less demand and decommissioning, Aberdeen is losing its title of Oil Capital of Europe. That has to be a good thing and perhaps all that offshore technology and experience can be redirected towards renewables in the form of wind, tidal and even hydrogen power. One way or another, we have to wean ourselves off our carbon addiction which is destroying the planet.
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