Renewable Gas

The Transition to Low Carbon Energy Fuels

Jo Abbess

• Publisher: Palgrave Macmillan
• Year: 2016
• ISBN:
  9781137441805
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

The author looks at the prospects for a transition from natural gas to low carbon gas, which could take several decades, and at how this will depend on the evolution of the fossil fuel industry. She investigates the technologies and energy systems for making the best use of renewable gas resources.

1

An Introduction to Renewable Gas

1.1

What is Renewable Gas?

Comfort-loving citizens in the Northern Hemisphere have good reason to take an interest in the future of gas, particularly since the demand for energy from Natural Gas in winter can be several times higher than the consumption of electrical energy (DECC, 2014a), and the rates of insulation renovations for old, draughty buildings can be slow. Unlike electricity, it is possible to store gas from season to season, making it a practical energy vector; extended storage means that gas production can be averaged out throughout the year. However, the use of Natural Gas in the long term is in some doubt as it is a fossil fuel and its combustion disturbs the deep geological carbon cycle, thus contributing to global warming. It is therefore appropriate to consider whether there might be viable low carbon alternatives to Natural Gas. Biogas, naturally occurring from the microbiological decomposition of biomass, has much to offer, but its advancement may well be hampered by changing patterns of land use, including constraints imposed by climate change. Enhanced and advanced biogas processing techniques could compensate, giving higher yields of gas from biomass (e.g. Luo and Angelidaki, 2012), although gas produced with any biological processing steps could remain slow. Consequently, industrially manufactured low carbon gas holds the most promise in terms of production volumes, although its development depends on adaptations and integration across several sectors of the economy. The manufacture of some types of low carbon gas does not even require biomass as an input feedstock, or may only need a recyclable cache of carbon from biomass as an enabler, or catalyst, to produce hydrogen from water.

For a gaseous phase energy fuel to be truly renewable, it should be produced directly from biomass (such as biogas), or indirectly from other renewable resources (such as hydrogen produced using renewable electricity). However, in what follows, a broader definition of what constitutes sustainable gas technology is adopted, covering a range of low carbon gas options (Abbess, 2014, Table 10). Some of these low carbon gases are transitional, wholly or partly manufactured from fossil fuels, in the interim. The technology platform put in place will permit the transition to fully Renewable Gas energy systems in the future, by altering the input feedstocks or feed materials. The options for manufacturing low carbon gas are, for the most part, not new technologies but a repurposing of those already in use, with the aim of making strategic, long-lasting investments, and thence a decades-long transition to a fully sustainable gas energy supply. What follows is not the promotion of an individual technology but a recommendation for an evolution in energy systems, with gas fuels taking centre stage.

The three factors that most concern policymakers in the energy sector are: sustaining energy supplies, decarbonising energy systems – thus preventing mainly carbon dioxide and methane emissions – and ensuring that energy bills don’t spiral upwards. In the last fifty years, the world’s engineers have been working to perfect devices that can capture wind, sunshine and moving water energy for zero carbon renewable electricity production, and its mass deployment has contributed to a major reduction in the cost whilst contributing to energy security. Now, it seems like the right time to look at Renewable Gas – a range of low net carbon emissions gas energy fuels. Ironically, around fifty years ago, at about the same time they took up renewable electricity pursuits, North America and Europe – although not China (Yang et al., 2014) or Hong Kong – gave up manufacturing gas and switched to Natural Gas; but now, some of that chemical processing knowledge must be resurrected, in order to prevent greenhouse gas emissions from gas energy.

For the next few decades, fossil gas (Abbess, 2014, Table 10) is going to remain vital in industrial economies which are anchored to Natural Gas; even with a firm commitment to Renewable Gas, it will take some time to displace a significant quantity of Natural Gas with low carbon gas delivered via advanced energy networks. Furthermore, replacing the use of coal with Natural Gas for power generation gives an immediate reduction in carbon emissions (Venkatesh et al., 2011); thus, Natural Gas can have enormous value in the work to mitigate near-term climate change. However, for this to be meaningful progress, gas grid and fugitive emissions, particularly from hydraulic fracturing, will need to be eliminated (Biello, 2014; Dlugokencky et al., 2011; Marston, 2013; Miller et al., 2013; Nisbet et al., 2014), gas flaring and venting to the atmosphere must be prevented (EPA, 2014; GGFR, 2013; UNFCCC, n.d.), and gas well integrity improved (Cherry et al., 2014; IEA, 2012b), particularly subsurface trespass. This need to improve methane containment will become more urgent not only because of the increased demand for gas, which will increase distribution flows, but also because of ageing gas pipeline networks, and perhaps also because of the nature and accessibility of the gas resources themselves.

An added spur to making progress on Renewable Gas could be that the resources of Natural Gas brought to production in twenty years’ time are likely to be of a lesser quality and more complicated to drill than those we are using today (Patterson, 2012). This will be partly because something like a fifth of “conventional” Natural Gas reserves are associated with crude oil fields (GEA, 2012, Section 7.3.3), some of which are depleting (Aleklett et al., 2010; Hook, 2014; McGlade, 2014; Sorrell et al., 2010). Good-quality conventional Natural Gas fields (GEA, 2012, Section 7.3.2), whether or not associated with crude oil, will begin to deplete due to continuing high production, a phenomenon seen in both North America in the past and the North Sea today. They will show a peak in supply volumes in a pattern that will in all likelihood be similar to the decline in crude petroleum oil production (Laherrere, 2013a, 2013b; Rutledge, 2011, 2013). We will turn to alternative fossil gas resources, even though they might not be exploited rapidly enough to prevent a peak in total Natural Gas production. The alternatives will include deeper gas, and more acid gas, gas with more vaporised oil in it, non-free-flowing gas and gas from more complex deposits (IEA, 2011, Page 50, Box 2.1; IIASA, 2012, Tables 7.10–7.14; McGlade et al., 2012a, 2013a, 2013b; Mohr and Evans, 2011; Skorobogatov et al., 2000; Soderbergh et al., 2010). These “unconventional” Natural Gases, and the manner in which they are mined, could present a range of problems, such as higher greenhouse gas emissions (Cathles et al., 2012; Glancy, 2013; Howarth et al., 2011; O’Sullivan and Paltsev, 2012; Wigley, 2011), unless they are deliberately curtailed (MacKay and Stone, 2013).

Ultimately, however, even with methane management measures, owing to ever-tightening carbon budgets set by climate protection policies, the carbon dioxide emissions from the burning of Natural Gas will begin to be the main concern. We will not be able to continue to burn Natural Gas “unabated” (UCS, 2013) – the fossil gas that we will use, within twenty to thirty years from now, will need to have the carbon taken out, and either permanently sequestered (IEA, 2011, Page 121; IPCC, 2014a, Sections 7.5.1, 7.6.3) or recycled, for instance, into fresh gas fuels. Permanent sequestration of carbon dioxide resulting from fossil fuel combustion is likely to remain costly, and so it can be expected that there will be a gradual shift towards low carbon gas supply technologies to prevent emissions at source. The first progress could possibly be seen in a variety of methods to reduce the carbon impact of gas carried by the grid networks: some carbon-rich waste, flue and exhaust gas will begin to be recycled into manufactured gas through chemical engineering. However, this will only be a proof-of-concept beginning, as there is much that can be done additionally. Key developments are likely to arise in crude petroleum oil refineries and Natural Gas processing plants – initially to answer processing problems with the worsening quality of fossil fuels, and to reduce the environmental impact of refined fuels – but these will eventually lead to manufacturing low carbon gas. Petroleum refineries could transition to being low carbon gas suppliers, and the refiners of biofuels.

The engineering and research communities are already occupied with the technologies of Renewable Gas, but as with every major transition, governments, and engineering and energy companies have yet to make strategic decisions about forks in the road ahead. What follows will venture to lay out the map for the journey to low carbon gas, to cover the technological and process engineering ground, and create a snapshot of the choices that will present themselves, and the options for scaling the obstacles in this dynamic field. The remainder of this chapter looks at trends, opportunities and risks in the use of gas energy, and why low carbon gas is important. Chapter 2 explores the need for energy sector investment and discusses the limitations of various technology choices and policies. Chapter 3 addresses the potential for gas energy and a transition to Renewable Gas, and how Renewable Methane, in particular, can be of significant value. Chapter 4 reviews the history of manufactured gas and Natural Gas to illustrate previous transitions in gas energy. Chapter 5 describes the evolution of energy systems, to show the natural transition possible from fossil fuels to the hydrogen economy. It ends with an analysis of choices for the next few decades. It also introduces a generic design for a Renewable Gas system, and where each component’s technology is already used. Chapter 6 analyses the technology of Renewable Gas, weaknesses, pinch points and opportunities for system integration. Chapter 7 covers the policy framework for the introduction of Renewable Gas in the context of other changes. Chapter 8 is a collection of reflections and conclusions.

1.2

A rationale for Renewable Gas

In order to comprehend why a transition to Renewable Gas warrants consideration, it is necessary to unpack trends in gas energy, and make some reasonable conjectures about future changes.

1.2.1

Growth in the energy sector

Energy is widely regarded as a pivotal sector of the global economy, and likely to grow, as markets, under governance, answer energy security concerns with new resources, refreshed and expanded infrastructure, energy efficiency services and improved access (BP, 2013a, 2014a; IEA, 2003a, 2006, 2008, 2010a, 2012a, 2014a; IRENA, 2014; SE4ALL, 2014; Shell, 2008, 2011, 2013; Statoil, 2013; WBCSD, 2012; WEC, 2007a, 2007b; World Bank, 2013). Industrialised regions have accelerated the deployment of renewable energy, mostly in the form of wind power and solar power. The lead times for adding renewable electricity capacity are short, and renewable electricity can be rapidly integrated into gridded power networks. Accordingly, there are some projections that renewables can eventually supply very significant proportions of power demand (AEMO, 2013; CAT, 2013; CCCC, 2009, 2010; CSC, 2013; Denmark, 2011, 2012; Greenpeace, 2010; Jacobson and Delucchi, 2009; Moser et al., 2014; Peter and Lehmann, 2008; PwC, 2010; WWF, 2011). Home-grown, sustainable, low operational cost (Czisch, 2011a, 2011b), climate friendly and pollution free, renewable power is clearly to be viewed as a genuine asset, providing sound returns on investment; but experience is showing that there are two residual and connected issues with its adoption. The provision of renewable electricity is variable, at all timescales; and in addition, it is unlikely to become possible to use batteries, capacitors or other solid state technology to store power at low cost and at large scale for long periods. As the uptake of renewable electricity continues, the geographical spread of the power generation equipment can help to balance supply (Archer and Jacobson, 2013). For example, in the European Union, it is calculated that variations in weather-dependent and season-dependent wind power in the north of the region can be largely balanced by diurnal solar power from the south (Brouwer et al., 2014; Creutzig et al., 2014; Czisch and Schmid, 2006; EWEA, 2005; Heide et al., 2011; Rodriguez et al., 2014; Santos-Alamillos et al., 2014; Trieb and Muller-Steinhagen, 2009). In Germany, winter wind is complemented by summer sun (Fraunhofer, 2013, 2014). Yet, no matter how extended the grid, there will always be times when this instant’s power demand cannot be met by the current moment’s renewable electricity supply. Conversely, there will always be times when not all renewable electricity can be used by the power grids. Therefore, looking beyond electricity into the wider energy economy is essential in addressing these concerns.

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1.2.2

The partnership and synergy between gas and power

Table of contents

• Cover Page
• Title Page
• Copyright
• Dedication
• Contents
• List of Tables and Figures
• Series Editor’s Preface
• Acknowledgements
• 1 An Introduction to Renewable Gas
• 2 Energy Change and Investment Challenges
• 3 Energy Transitions and Renewable Gas
• 4 A Brief History of Gas
• 5 Renewable Gas Systems
• 6 The Technology of Renewable Gas
• 7 The Energy Policy Context for Renewable Gas
• 8 Reflections and Conclusions
• References
• Index