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An Essay on the Hydrogen Economy

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University of Bath, 2008

University of Bath, 2008


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  • 1. A monumental challenge: the transition to a hydrogen economy Gregory Briner At some time in the future the fossil fuel regime will have to be replaced. Many believe that it should be superseded by an economy based on hydrogen, and proponents believe that such a hydrogen economy would have numerous benefits over the existing system. However, there are several large technological, social and economic barriers impeding the emergence of hydrogen energy technology. To steer the economy away from its dependence on fossil fuels and towards a hydrogen-based alternative will be a monumental challenge. Large-scale changes to the energy regime in the past have caused step-changes in the progress of Western civilization. The transition from horses and water wheels to coal was the driving force behind the industrial revolution of the 18th and 19th centuries. The expansion of the petroleum industry in the 20th century has shaped modern life as we know it, with its large commercial enterprises, highly centralized economic infrastructure and densely populated urban areas. The harnessing of coal, oil and natural gas has facilitated great economic growth and enabled those in the developed world to enjoy an unprecedented standard of living (Rifkin 2002). However, the benefits of fossil fuel use have come at a price. There are energy security risks for countries such as the UK and the US which are becoming increasingly reliant on the import of fossil fuels from politically unstable regions. The by-products from the combustion of fossil fuels contribute to air pollution and affect the health of humans and other wildlife. There is also “new and stronger evidence” 1
  • 2. that anthropogenic carbon dioxide emissions resulting from the burning of fossil fuels are contributing to global climate change (IPPC 2001). For these reasons alone it is desirable to look for an alternative energy regime. However, we will also be forced to do so, as coal, oil and natural gas are finite resources. For each there will come a point in the future at which half of the resource will have been consumed, after which the rate of production will be in constant decline. The question of when these peaks in global production will occur is a topic of much debate. Estimates for peak oil range from anywhere between the present day to around 2040 (Rifkin 2002). The ever-increasing price of oil following peak oil production will force an energy regime change before fossil fuel supplies run out altogether. As Don Huberts, CEO of Shell Hydrogen, has noted: “The Stone Age did not end because we ran out of stones, and the oil age will not end because we run out of oil.” (Dunn 2002). Be it sooner or later, the end of the fossil fuel regime is therefore imminent. The prospects facing any replacement regime will be daunting. Having raised standards of health care, increased agricultural output and enabled many in developed countries to lead energy-intensive lifestyles, the fossil fuel regime will leave in its wake a growing population with a seemingly insatiable appetite for energy. 83.7 million barrels of crude oil were consumed per day in 2006 (BP 2007), and if current trends continue world energy demand is projected to grow by 55% between 2005 and 2030 (IEA 2007). 2
  • 3. One candidate which many believe could face up to this monumental challenge is an economy based on hydrogen. Hydrogen is a colourless, odourless and non-toxic gas. Like electricity, hydrogen is an energy carrier rather than an energy source and may be used to store and transport energy. Hydrogen fuel cells may be used to power most vehicles, portable electronic devices and stationary energy generation systems (Hart 2007). Hydrogen may also be combusted in internal combustion engines or heating systems for buildings. In a hydrogen economy it is not envisioned that hydrogen would replace electricity altogether, but rather it would “complement electricity as an alternative energy delivery service” (Busby 2005). The attractiveness of hydrogen as an energy carrier is that it has the potential to provide an incredibly clean and efficient way of storing and transporting energy. Hydrogen is also in virtually unlimited supply as it is the ninth most abundant element on Earth, and has been dubbed the “forever fuel” (Hoffmann 1981). When hydrogen is oxidised in a fuel cell, it releases only water vapour and heat with near-zero emissions. Therefore the widespread use of hydrogen fuel cells would improve air quality and dramatically decrease carbon dioxide emissions (Hart 2007). Fuel cells also produce very low levels of noise and could be more reliable than grid- supplied electricity in developing countries (Bauen et al. 2003). Fuel cells do not suffer the Carnot thermodynamic limitations of the petroleum-based internal combustion engine and so greater fuel efficiencies are possible (Hart 2000) – fuel cell automobiles have been built which are 60% efficient, while conventional petroleum engines have an efficiency of around 20% (UKHA 2006). When hydrogen is 3
  • 4. combusted directly in an internal combustion engine the production of nitrogen oxides is reduced by more than 90% in comparison to petroleum (Cho 2004). Hydrogen could also offer the solution to the intermittency problem that is restricting the progress of renewable energy sources such as wind, wave and tidal energy (DTI 2003, Carrasco et al. 2006). The variable output of such renewable energy sources currently causes problems for grid integration. However, by using these energy sources to generate hydrogen during times of excess production and then converting it to electricity during times of lean production, the electrical supply to the grid may be “smoothed out”. A hydrogen economy could have further benefits. Hydrogen may be extracted from water using any source of renewable electricity (Adamson 2004) or produced directly by the biological activity of algae and bacteria (Das and Veziroğlu 2001), and this large range of potential sources would greatly improve energy diversity (Busby 2005, Tseng et al. 2005). The increased flexibility of supply could lead to a decentralization of the energy grid, and such a decentralized energy infrastructure would be less vulnerable to terrorist attacks (Rifkin 2002). Consequently hydrogen energy research and development is an area of great international activity. The greatest focus so far has been on transportation. The transport sector is heavily reliant on petroleum, which accounts for over 99% of all transport fuel in the UK (DfT 2007), and this means that there is a greater demand for competitive hydrogen technology in this sector than other less homogenous energy sectors (Solomon and Banerjee 2006). Over $3 billion is being invested into 4
  • 5. hydrogen vehicle research annually by the automotive industry and governments. The Japanese Millennium Project aims to have 50,000 hydrogen fuel cell vehicles on the road by 2010, while in the US the Bush administration launched a $1.2 billion program in 2003 with the aim of bringing hydrogen fuel-cell cars into the marketplace by 2020 (Hart 2003). In 1998 Chris Fay, then Chief Executive of Shell UK, made the statement: “We believe that hydrogen fuel cell powered cars are likely to make a major entrance into the vehicle market throughout Europe and the US by 2005” (Hoffmann 2001). However, this has still not been achieved and according to energy experts such as Ernest Monitz at MIT, hydrogen technology is still “very, very far away from substantial deployed impact” (Service 2004a). The development of hydrogen technology is taking longer than predicted primarily due to the enormous technological challenges involved in finding economic methods for the production, storage, and distribution of hydrogen. Elemental hydrogen does not occur naturally on Earth and so must be extracted from hydrogen-containing compounds such as natural gas or water. Hydrogen is tightly bound within these molecules, and so extraction processes require large amounts of energy and are expensive compared to the techniques used to harvest fossil fuels (Kreith and West 2004). Currently the most cost-effective method of hydrogen production is steam reformation of natural gas, but this releases carbon dioxide and continues to rely on depleting fossil fuel supplies (Turner 2004). Although hydrogen is often described as a “clean” fuel, it is only as clean as its source and it is important to assess the impacts of the full lifecycle of a product before using such a description 5
  • 6. (Refocus 2004). Until production methods using low-carbon renewable energy sources become economically competitive, natural gas will remain the principal source of hydrogen fuel. Carbon sequestration could be used to reduce carbon dioxide emissions during this interim period, but this would add 25-30% to the cost of production (Hart et al. 1999, Service 2004b). The extremely low density of hydrogen makes it a difficult substance to store in a fuel tank. Although it contains about three times more energy per unit weight than petroleum, due to its low density hydrogen gas contains around four times less energy per unit volume (UKHA 2006). To store enough hydrogen in the fuel tank to give a vehicle an acceptable driving range, the hydrogen must be pressurized, liquefied, bound within metal hydrides or stored in absorbent materials. Fuel tanks have been designed which can store hydrogen at pressures of up to 700 atmospheres (Cho 2004), but such reinforced tanks are heavy. To liquidise hydrogen it must be cooled to –253°C, and this consumes a large amount of energy (Kreith and West 2004). Metal hydrides with high hydrogen contents have been synthesised (eg. Wang et al. 2007), but to release the hydrogen within them metal hydrides must be heated to around 300°C which again consumes energy. Research into novel materials such as carbon nanotubes and heavy metal complexes which can store and release hydrogen at near- ambient temperatures is being conducted at the University of Bath (Yin et al. 2000, Brayshaw et al. 2007). Distribution problems are caused by the small molecular size of hydrogen, which allows it to diffuse easily through small fissures. Natural gas pipelines would have to be modified in order to carry hydrogen, as existing pipelines would leak and hydrogen 6
  • 7. would cause embrittlement of the metal (Rahman and Andrews 2006). This would be expensive, and improved methods for leak detection would have to be developed. The transport of pressurised hydrogen by lorry is also uneconomic, as it is estimated that 20% of the energy content of the fuel would be consumed during a journey of 300 km (Bossel 2006). A distributed energy generation grid which allows hydrogen to be generated locally would be more practical. Such local generation could consist of stationary fuel-cell power plants in homes and offices into which hydrogen-powered cars may be “plugged in” (Lovins and Williams 2001), but again it will be many years before this technology is available. There are also social and economic factors obstructing the emergence of a hydrogen economy. Public acceptance will be essential if hydrogen is to succeed in the marketplace (O’Garra et al. 2007). A review by Schulte et al. (2004) showed that although attitudes towards hydrogen are generally positive, fears remain about its safety. It was found that those who have not had personal experience of the technology are more likely to see a greater risk, while associations with the hydrogen bomb and the 1937 Hindenburg airship disaster persist particularly amongst older generations. Scientific assessments have suggested that hydrogen poses a comparable or even lower risk than conventional fuels (Adamson and Pearson 2000, Carpenter and Hinze 2004, Winter 2006), particularly as its low density and tendency to dissipate quickly means that it does not form pools of flammable material (Verfondern and Dienhart 2007). Hydrogen has been used safely on large scales for many years in bulk chemicals manufacture and for the hydrogenation of oils. Although public fears about the safety of hydrogen may be unfounded, they are likely to persist until people become more familiar with the technology (Schulte et al. 2004). 7
  • 8. The public acceptance of hydrogen technology could be damaged by premature demonstrations of the technology. Demonstrations are an important part of promoting an emerging technology (O’Garra et al. 2007), and around 400 hydrogen energy demonstration projects are currently in progress worldwide (IEA 2005). However, because it is still many years before many hydrogen applications will become commercially available, some fear that demonstrating such technology too early on could cause a negative “backlash” (Romm 2004, Service 2004a), especially as there is now perhaps a greater public expectation for new technology to be developed quickly following the rapid proliferation of technologies such as the internet and mobile phones (Leiner et al. 2003, Banks and Burge 2004). In the transport market, hydrogen faces tough competition from more established technologies such as biofuels and electric cars (IEA 2005), while the longer timescales involved in the development of hydrogen energy are less likely to attract investors seeking quick returns (Agnolucci 2007). Studies suggest that marketing hydrogen-powered cars on their environmental credentials alone would not be a successful method, as price, convenience and performance are also important to consumers (Schulte et al. 2004). As Andreas Klugescheid, a spokesman for BMW has put it: “Our customers don’t buy a car just to get from A to B, but to have fun in between” (Cho 2004). In addition, the proliferation of hydrogen-powered cars is being delayed by a “chicken-and-egg” relationship between car manufacturers and energy providers (Schwoon 2006). The car manufacturers are hesitant to spend large amounts of money on producing hydrogen-powered cars for which there are few 8
  • 9. refuelling stations, while energy companies are reluctant to invest heavily in a refuelling infrastructure for which there would be very few customers. The Stern Review concluded that carbon dioxide emissions must be reduced to 25% below present levels by 2050 to avoid risking the worst impacts of climate change, and immediate action is recommended (Stern 2007). The transport sector is the fastest-growing source of carbon dioxide emissions, increasing by over 2% per year (IEA 2001), and already accounts for over a quarter of global carbon dioxide emissions (IEA 2000). Given the numerous barriers restricting the proliferation of hydrogen technology, particularly in transportation, some believe it unlikely that the deployment of hydrogen-powered devices will significantly reduce carbon dioxide emissions within this timescale (Romm 2004). Others warn that the pursuit of hydrogen energy may in fact exacerbate the global warming situation, because generating hydrogen from natural gas is less efficient and emits more carbon dioxide than burning the natural gas directly (Kreith and West 2004). It is argued that energy policies should instead focus on developing existing energy-efficient technologies, such as electric hybrid cars, rather than hydrogen (Romm 2004, Van Mierlo and Maggetto 2007, Bossel 2006, Demirdöven and Deutch 2004). Despite these criticisms, the hydrogen movement is gaining momentum (Veziroğlu 2000). Many believe that investment in hydrogen energy is justified as the technological challenges could be overcome with greater funding and government support (Hart 2003, Dunn 2002), and should be viewed as opportunities rather than barriers (Clark and Rifkin 2006, Tseng et al. 2005). It is pointed out that much of the research into hydrogen energy is socially beneficial in other ways (LHP 2007, 9
  • 10. Rahman and Andrews 2006), and that innovation in hydrogen technology is to be encouraged as it creates added value from its environmental benefits and by accessing previously untapped sources of energy (Winter 2006). It also increases the number of technological options available to society, which may be regarded as a form of knowledge capital (Winnett 2007). Institutions such as the International Partnership for the Hydrogen Economy (IPHE) and the IEA Hydrogen Implementing Agreement have been established to coordinate an international transition towards a global hydrogen economy. However, in their domestic energy policies, different governments are promoting hydrogen energy to varying degrees. Iceland announced its intention to become the world’s first complete hydrogen economy in 1998, and Professor Bragi Arnason, formerly of the University of Iceland, believes that this could be achieved by 2050 (CNN 2007, MIC 2003, Vogel 2004). Japan, Brazil, Canada and some states such as California and Hawaii in the US are also pursuing ambitious policies intended to increase uptake of hydrogen energy (Solomon and Banerjee 2006). Although it is a member of the IPHE and the IEA and continues to fund hydrogen energy research projects, the UK government is yet to commit itself to a hydrogen- powered future, stating that “whether or not hydrogen will contribute to our future energy needs is still a matter of great uncertainty” (DTI 2003). An assessment of the prospects of hydrogen as a fuel in the UK, commissioned for the DTI in 2003, concluded that the resource potential for hydrogen generation from renewable energy sources is large, and that the knowledge base is strong in bulk hydrogen handling, hydrogen storage, fuel cells and energy economics (Hart et al. 2003). Therefore the 10
  • 11. UK is well equipped to sustain a hydrogen economy should the government commit to doing so, although its implementation would remain a huge challenge. Even if a transition to a hydrogen economy should become possible in the future, history should tell us to proceed with caution. The consequences of such a major paradigm shift may not all be favourable. As Gary Staunton of the Carbon Trust has remarked: “The issue with solving today’s problem is that you create tomorrow’s problem” (Observer 2007). Some potential issues have already been identified, such as increased vehicle use, hydrogen-induced ozone depletion and land use conflicts (Cherry 2004, Tromp et al. 2003), and other adverse effects are sure to be discovered if a transition is made. In conclusion, a change in energy regime is imminent and an attractive successor is an economy based on hydrogen energy. Although progress is being made in hydrogen technology, there is still a long way to go before a hydrogen economy becomes feasible. The technological, social and economic barriers restricting the proliferation of hydrogen energy technology are numerous and formidable. Even if the monumental challenge of a successful transition is achieved, it may be that more than simply a change in technology is required in order to realise the full benefits of a hydrogen economy. It is perhaps more our current attitudes and habits of excessive consumption rather than the fossil fuels themselves which are responsible for the severity and urgency of the situation we now face. 11
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