Renewable Hydrogen Technologies

Production, Purification, Storage, Applications and Safety

Luis M Gandia, Gurutze Arzamedi, Pedro M Dieguez, Luis M Gandia, Gurutze Arzamedi, Pedro M Dieguez

• Éditeur: Elsevier Science
• Année: 2013
• ISBN:
  9780444563613
• Sujet: Tecnologia e ingegneria
• Sous-sujet: Risorse energetiche rinnovabili

The fields covered by the hydrogen energy topic have grown rapidly, and now it has become clearly multidisciplinary. In addition to production, hydrogen purification and especially storage are key challenges that could limit the use of hydrogen fuel. In this book, the purification of hydrogen with membrane technology and its storage in "solid" form using new hydrides and carbon materials are addressed. Other novelties of this volume include the power conditioning of water electrolyzers, the integration in the electric grid of renewable hydrogen systems and the future role of microreactors and micro-process engineering in hydrogen technology as well as the potential of computational fluid dynamics to hydrogen equipment design and the assessment of safety issues. Finally, and being aware that transportation will likely constitute the first commercial application of hydrogen fuel, two chapters are devoted to the recent advances in hydrogen fuel cells and hydrogen-fueled internal combustion engines for transport vehicles.

• Hydrogen from water and biomass considered
• Holistic approach to the topic of renewable hydrogen production
• Power conditioning of water electrolyzers and integration of renewable hydrogen energy systems considered
• Subjects not included in previous books on hydrogen energy
• Micro process technology considered
• Subject not included in previous books on hydrogen energy
• Applications of CFD considered
• Subject not included in previous books on hydrogen energy
• Fundamental aspects will not be discussed in detail consciously as they are suitably addressed in previous books
• Emphasis on technological advancements
• Chapters written by recognized experts
• Up-to date approach to the subjects and relevant bibliographic references

Chapter 1

Renewable Hydrogen Energy

An Overview

Luis M. Gandía, Gurutze Arzamendi and Pedro M. Diéguez, Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación, Universidad Pública de Navarra, Campus de Arrosadía, E-31006 Pamplona, Spain

Outline

1.1 Setting the Context: Climate Change and Energy Security

1.1.1 International Energy Outlook

1.1.1.1 Oil and Liquid Fuels

1.1.1.2 Natural Gas and Coal

1.1.1.3 Electricity

1.1.1.4 CO₂ Emissions

1.1.2 Toward Decarbonization

1.2 Is A New Energy Carrier Necessary?

1.2.1 The Hydrogen Economy

1.2.2 The Efficiency Issue

1.2.3 Hydrogen Contribution to Transportation and the Electric Grid

1.2.3.1 Hydrogen in Transportation

1.2.3.2 Hydrogen and the Electric Grid

1.3 Hydrogen Production

1.3.1 Pathways

1.3.1.1 Nonrenewable Hydrogen

1.3.1.2 Renewable Hydrogen

1.3.2 Status and Prospects of Renewables

1.4 Hydrogen Today

Acknowledgments

References

1.1 Setting the Context: Climate Change and Energy Security

The experience gained from over a decade of sustained research, development and demonstration projects corroborates that hydrogen and fuel cell technologies have strong potential to play a significant role in the new energy system that must be defined in the coming years. This energy system should provide adequate and prompt responses to the threats posed by the climate change and energy security issues.

The leaders of the Group of Eight (G8) recognized during the summit held in L’Aquila (Italy), July 2009 that, as for the dangers of climate change, the costs of inaction far outweigh the costs of moving toward low-carbon societies. But at the same time, it is obvious that secure energy availability is indispensable for social and economic development, so it is essential to ensure global energy access. It was also recognized, in agreement with the work of the United Nations (UN) Intergovernmental Panel on Climate Change,¹ that the increase in global average temperature above preindustrial levels should not exceed 2 °C. To this end, global CO₂ emissions must peak and then start to decline rapidly within the next 5–10 years to have a reasonable chance of avoiding the worst impact of climate change. The global atmospheric CO₂ concentration was about 330 ppm in 1970 and after 40 years it has increased at least 60 ppm, reaching over 390 ppm by the end of 2010. It has been projected that if atmospheric CO₂ levels increase up to about 450 ppm, a critical point could be reached at which warming exacerbated by strong positive feedbacks will seriously disrupt climate.² At the rate at which CO₂ emissions are currently growing, the critical point could be attained well before the next 40 years. In response to this serious threat, the G8 leaders expressed their willingness to share with all countries the goal of achieving at least a 50% reduction of global emissions by 2050 and to support a goal of developed countries reducing greenhouse gas (GHG) emissions by 80% or more by 2050 compared to 1990.

Regrettably, results from the most recent studies lead to discouraging perspectives. The International Energy Agency (IEA) has estimated that 80% of the total CO₂ emissions permissible by 2035 in order to achieve a stabilization in 450 ppm are already “locked-in” by our current energy-related infrastructure.³ In the IEA central scenario, the so-called New Policies Scenario, in which the governments’ commitments are assumed to be implemented in a cautious manner, the trend of global emissions is consistent with a long-term average temperature increase of more than 3.5 °C. But the situation could even become much worse under the IEA Current Policies Scenario, which assumes that no new policies are added to those in force as of mid-2011. In this case, we would run the dangerous risk that the mean temperature rises 6 °C or more.³ Despite the almost generalized concern about the consequences of climate change, it is disappointing that policy makers are often faced with continuous difficulties in reaching clear compromises on the reduction of GHG emissions. The most recent demonstration occurred during the UN Climate Change Conference 2011 held in Durban (South Africa). Fortunately in this occasion, the world’s three largest pollutant emitters (United States, China and India) have agreed for the first time to sign up to a legal treaty to reduce GHG emissions. To elaborate an instrument with legal force applicable to all parties, it has been decided to create the so-called Ad Hoc Working Group on the Durban Platform for Enhanced Action.⁴ The problem is that it has been scheduled that the Working Group completes its mission no later than 2015 and that the resulting legal instrument comes into effect from 2020. This may be too late. In fact, in the absence of stringent new actions by 2017, the energy-related infrastructure in place by that year will it make impossible to accomplish the CO₂ stabilization objective without extremely high costs.³

Previous analysis gives an idea of the risks associated to the difficulties of reaching international agreements on the reduction of GHG emissions. However, to better appreciate the magnitude of the challenge posed by the energy security issue and the need of transforming the energy system, a brief international energy outlook and a summary of the milestones that have to be achieved by a decarbonized economy are presented in the following subsections. Regrettably, we will see that the role assigned to hydrogen in the current energy policies is, at least in Europe, little relevant at the moment.

1.1.1 International Energy Outlook

According to the U.S. Energy Information Administration (EIA), under the conditions of a reference case that does not contemplate the incorporation of legislation or policies affecting energy markets, the world marketed energy consumption grows by 53% from 2008 to 2035.⁵ This means that the world primary energy consumption increases from 12,726 Mtoe in 2008 to 15,599 Mtoe in 2020 and 19,404 Mtoe in 2035^a. The projected increase is modest in the case of the countries that are part of the Organization for Economic Cooperation and Development (OECD) (18%). Much of the growth takes place in non-OECD nations that increase by 85% their primary energy use during that period. The reason for this big difference mainly lies in the very different economic growth pace of these world regions. The recovery from the 2008 to 2009 worldwide economic recession makes uneven progresses. In the developed countries, the recovery is slow compared with previous economic crises; it seems that this situation will continue, at least in the short term, as suggested by the high unemployment figures and debt levels of some economies as well as financial turbulences existing within the OECD. In contrast, economic growth will remain robust in the main emerging economies due to strong capital incomes. According to the U.S. EIA reference case, China and India will continue to lead the world economic growth and the growth of the energy demand. The projected average annual gross domestic product (GDP) increase of the OECD countries during the 2008–2035 period is 2.1%, led by the OECD Americas with 2.6%. The annual energy consumption growth for the whole OECD region is 0.6% over this 27-year period. In the case of the non-OECD nations, the average annual GDP increase is much higher, up to 4.6%, led by the non-OECD Asia with a mean 5.3% GDP growth. This impressive sustained economic development is consistent with the projected average annual energy consumption growth for the non-OECD nations of 2.3% and 2.9% for the non-OECD Asia region.⁵ It is very relevant that the combined energy use of China and India more than doubles over the 2008–2035 period, reaching 31% of the world energy consumption, whereas the percentage of the OECD region amounts up to 37.4%.

In the following subsections, a more detailed outlook by energy sources as well as prospects for electricity and the energy-related CO₂ emissions will be presented.

1.1.1.1 Oil and Liquid Fuels

The U.S. EIA projections show that liquid fuels, mainly from fossil origin, will remain the largest primary energy source with a market share that decreases from 34% to 29% between 2008 and 2035. Global consumption of petroleum-derived fuels and other liquids as biodiesel, bioethanol and synthetic fuels obtained from coal and gas increase altogether from 85.7 million barrels per day (bpd) in 2008 to 112.2 million bpd in 2035. Great part of this important increase corresponds to the transport sector which, in the absence of significant technological advances and despite the rising oil prices, increases the use of liquid fuels by 46%.⁵ The evolution of the monthly average prices of the Brent and West Texas Intermediate (WTI) crude oils since June 1995 is shown in Fig. 1.1. As can be seen, Brent crude oil price peaked at U.S. $145.9 per barrel (bbl) on 7th July 2008 and then decreased abruptly to initiate again a progressive increase characterized by a marked volatility, reaching $111/bbl by the end of January 2012. The average annual price in 2011 was $113/bbl, which almost coincided with that of 2008 ($112/bbl). Similarly, the WTI crude oil price peaked at $145/bbl in July 2008, and then decreased markedly to increase again reaching $98.5/bbl by the end of January 2012. Annual average prices for WTI oil crude were $98.3, $38.9 and $90.7 per barrel in 2008, 2009 and 2011, respectively. According to the EIA reference case projections, the average WTI oil crude price will reach $125/bbl in 2035. In a recent and thorough study, Sorrell et al.⁶ report that, as a result of a series of geological, technological and even definitional aspects, there is a real increase of the global average oil reserve that can be observed since 1995. The reserve growth is higher for the older (discovered before 1986) and larger onshore fields and the main contributions to this growth come from Saudi Arabia (37%), Iran (15%), Venezuela (12%) and Qatar (9%). Despite this positive finding from the point of view of the future global oil supply, as the decline rate of all currently producing fields is at least 4% per year, more than two thirds of the current oil production capacity may need to be replaced by 2030 simply in order to keep the production constant.⁶ Within this context, it is expected that during the coming decades, an important development of the exploitation of unconventional resources of liquid fuels as oil sands, extraheavy oil, shale oil, biofuels, and coal-to-liquids and gas-to-liquids technologies takes place. Global production of unconventional liquid fuels reached 3.9 million bpd in 2008 and it is projected that it increases up to 13.1 million bpd by 2035, accounting for 12% of the world’s fuel liquids supply. Main future contributions are expected to come from Canadian oil sands (4.8 million bpd), biofuels from the USA and Brazil (2.2 and 1.7 million bpd, respectively) and extraheavy oil from Venezuela (1.4 million bpd).⁵ Despite the good perspectives for this sector, especially for the Canadian oil sands (over 7 million bpd of capacity), it should be noted that these unconventional resources are characterized by significantly higher energy intensity and GHG emissions than conventional light oil.⁷

FIGURE 1.1 Evolution of the monthly average prices of the Brent and WTI crude oils since June 1995. (For color version of this figure, the reader is referred to the online version of this book.)

1.1.1.2 Natural Gas and Coal

World consumption of natural increases by 52% according to the EIA projections, that is, from 3.141 × 10⁶ million m³ in 2008 to 4.783 × 10⁶ million m³ in 2035. It is expected that natural gas continues being the preferred fuel for electric power production due to its advantages in terms of relatively low capital costs and energy efficiency associated to the use of combined cycle gas turbines. The strong position of natural gas within the energy market will be reinforced by the growth of liquefied natural gas production capacity and the recent advances in drilling technologies such as horizontal drilling and hydraulic fracturing that make now profitable to exploit many sources of unconventional natural gas as shale gas basins. It is expected that the natural gas reserve growth helps to control the gas price and increases the demand for this energy source likely above the projections. Initial estimates rise the shale gas reserve above 187 trillion m³. This figure is very significant taking into account that world-proven gas natural reserve and world technically recoverable gas resources (excluding shale oil) were 189 trillion m³ and 453 trillion m³, respectively, by January 2011.⁵ Coinciding with the shale gas production boom, concern has arisen about the environmental impact of the new drilling techniques. In a recent life cycle analysis, Burnham et al.,⁸ from the Argonne National Laboratory (IL, USA) found similar GHG emissions from shale gas and conventional natural gas production and use, which were 23% and 33% ...