Biofuels and Bioenergy E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 646

Veröffentlichungsjahr: 2017

Beschreibung

With increased public and scientific attention driven by factors such as oil price spikes, the need for increased energy security, and concerns over greenhouse gas emissions from fossil fuels, the production of fuels by biological systems is becoming increasingly important as the world seeks to move towards renewable, sustainable energy sources.

Biofuels and Bioenergy presents a broad, wide-ranging and informative treatment of biofuels. The book covers historical, economic, industrial, sociological and ecological/environmental perspectives as well as dealing with all the major scientific issues associated with this important topic.
With contributions from a range of leading experts covering key aspects, including:
• Conventional biofuels.
• Basic biology, biochemistry and chemistry of different types and classes of biofuel.
• Current research in synthetic biology and GM in the development and exploitation of new biofuel sources.
• Aspects relating to ecology and land use, including the fuel v food dilemma.
• Sustainability of different types of biofuel.
• Ethical aspects of biofuel production.

Biofuels and Bioenergy provides students and researchers in biology, chemistry, biochemistry and chemical engineering with an accessible review of this increasingly important subject.

Leseprobe

Biofuels and Bioenergy

Edited by John Love and John A. Bryant

Biosciences, College of Life and Environmental Sciences, University of Exeter, UK

This edition first published 2017 © 2017 by John Wiley and Sons Ltd

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Library of Congress Cataloging‐in‐Publication Data

Names: Love, John and Bryant, John A. Title: Biofuels and bioenergy / [edited by] John Love and John A. Bryant. Description: Chichester, West Sussex : John Wiley & Sons, Inc., 2017. | Includes bibliographical references and index. Identifiers: LCCN 2016059291 (print) | LCCN 2017000214 (ebook) | ISBN 9781118350560 (cloth) | ISBN 9781118350546 (pdf) | ISBN 9781118350539 (epub) Subjects: LCSH: Biomass energy. | Algal biofuels. Classification: LCC TP339 .B5394 2017 (print) | LCC TP339 (ebook) | DDC 662/.88–dc23 LC record available at https://lccn.loc.gov/2016059291

A catalogue record for this book is available from the British Library.

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Cover image: Courtesy of John LoveAnaerobic Digestion of food or agricultural waste and sewage is a tried and tested method for producing renewable methane, or “Biogas”, which can either be used directly or to make electricity. The residues from the process are then used as fertiliser to grow crops. The cover image is of an anaerobic digestor plant at Bygrave near Baldock, England, that is owned and run by Biogen. Every year, the plant transforms 45,000 tonnes of food waste into enough electricity to power about 4,500 homes.

Cover design by Wiley

List of Contributors

Jessica AdamsUniversity of Aberystwyth, Wales, UK

Michael J. AllenPlymouth Marine Laboratory, Plymouth, UK

John BombardiereWest Virginia State University, USA

Leah M. BrownUniversity of Georgia, Athens, USA

John A. BryantUniversity of Exeter, Exeter, UK

Christopher J. ChuckUniversity of Bath, Bath, UK

Lionel ClarkeBionerG Ltd, Chester, UK

John Clifton‐BrownUniversity of Aberystwyth, Wales, UK

Charlotte CookUniversity of Exeter, Exeter, UK

John C. CushmanUniversity of Nevada, Reno, USA

Chappandra DayanandaCentral Food Technological Research Institute, Mysore, India

Joy Doran‐PetersonUniversity of Georgia, Athens, USA

Stephen C. FryUniversity of Edinburgh, Edinburgh, UK

Astley HastingsUniversity of Aberdeen, Scotland, UK

Leyla T. HathwaikUniversity of Nevada, Reno, USA

Gary M. HawkinsUniversity of Georgia, Athens, USA

Thomas P. HowardUniversity of Newcastle, Newcastle‐on‐Tyne, UK

Christopher J. HoweUniversity of Cambridge, Cambridge, UK

Steve HughesUniversity of Exeter, Exeter, UK

C.B. JamiesonWorld Agroforestry Centre, Laguna, Philippines and

Next Generation, Hertfordshire, UK

Rhodri W. JenkinsUniversity of Bath, Bath, UK

R.D. LascoWorld Agroforestry Centre, Laguna, Philippines

David J. Lea‐SmithUniversity of Cambridge, Cambridge, UK

Alessandro Marco LizzulUniversity College London, London, UK

John LoveUniversity of Exeter, Exeter, UK

J.M. LynchUniversity of Surrey, Guildford, UK

Jon McCalmontUniversity of Aberystwyth, Wales, UK

E.T. RascoPhilRice, Munoz, Philippines

Lisa A. SargeantUniversity of Bath, Bath, UK

David A. StaffordEnviro‐Control Ltd., Devon, UK

Richard K. TennantUniversity of Exeter, Exeter, UK

Preface

A century ago, petroleum – what we call oil – was just an obscure commodity; today it is almost as vital to human existence as water.

James Buchan, Political commentator and author

The use of vegetable oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time.

Rudolf Diesel, engineer and inventor of the compression engine (quotation dates from 1912)

Most people have difficulty coming to grips with the sheer enormity of energy consumption.

Rex Tillerson, Civil engineer, businessman and President/CEO of the Exxon‐Mobil Corporation

We have to rethink our whole energy approach, which is hard to do because we're so dependent on oil, not just for fuel but also plastic … We have to think quite carefully about using oil and its derivatives, because it's not going to be around forever.

Margaret Atwood, Author, literary critic and environmental activist

We can no longer allow America’s dependence on foreign oil to compromise our energy security. Instead, we must invest in inventing new ways to power our cars and our economy. I’ll put my faith in American science and ingenuity any day before I depend on Saudi Arabia.

Senator John Kerry, US Secretary of State, 2013–2016

There is an urgent need to stop subsidizing the fossil fuel industry, dramatically reduce wasted energy, and significantly shift our power supplies from oil, coal, and natural gas to wind, solar, geothermal, and other renewable energy sources.

Bill McKibben, Author, educator and environmental activist

These quotations provide a nice series of snapshots. The world is energy‐hungry and increasingly so. The need for fuels for transport makes up a large proportion of that hunger. That need is largely met by petroleum (literally ‘rock‐oil’), 70% of which is used for transport by road, air or sea, but there are issues related to its continued use and availability (even if concerns about ‘peak oil’ – the moment when global oil production reaches its maximum – have declined somewhat). There are concerns that some developed countries’ need for oil may make them economic or moral hostages to countries that are oil producers. And above all is the realisation that burning fossil fuels (principally coal, natural gas and oil) is the major contributor to anthropogenic climate change. There is thus a drive to develop renewable sources of energy, sources of energy that do not involve burning fossil fuels. And we have to say, as is evident from Chapter 1, there has been very good progress in generation of electricity via environmental energy sources. Electricity can of course be used to power some forms of transport. but it still glaringly obvious that transport is very dependent on oil (and to a lesser extent, coal and gas), and will continue to be dependent on liquid fuels well into the future. So we come to this book, which deals with current areas of research aimed at finding ways of using renewable biological resources to provide fuels mainly for transport, research which becomes ever more urgent as the reality of climate change becomes more apparent.

Biofuels, therefore, should be viewed in the context of sustainability, either as alternatives to reduce petroleum use during the transition to other forms of transport, energy or primary materials, or as a way to mitigate climate change. The use of petroleum distillate in mass transport did not happen overnight (indeed petrol was once considered a waste product of oil refining); likewise, biofuels are at the very early stages of development. Biofuels research is intense, with new options being imagined and solutions being proposed almost weekly. Every new technology explores a previously unimagined design landscape. The issue with biofuels is that technical developments are heavily constrained by existing infrastructure, land use and global commerce in commodities. As yet, we cannot pick the future biofuel ‘winners’, but any biofuel solution (and there may be several) must be responsive to a number of criteria, including cost, technical feasibility, efficiency, reliability, sustainability and, arguably most difficult of all, our lifestyle expectations.

We are bound to say that the book has been a long time coming. It is actually several years since a conversation in an Oxford coffee shop between JAB and Rachel Wade of Wiley‐Blackwell led to the idea of an edited text on Biofuels. It took a long time to recruit authors and even then, other factors outside the control of editors and publisher, led to further delays and loss of some of the planned and contracted chapters. Against this background, we are especially grateful to those authors who have remained with the project and provided the excellent and interesting range of chapters presented here. A number of them have been remarkably patient as they waited for news of further progress after submitting their chapters. We are also grateful to colleagues who have given us their time in discussion and/or provided diagrams and figures for us to use. JAB expresses special thanks to Dr David Stafford of Enviro‐Control Ltd, Professor Jim Lynch of the University of Surrey and Professor Steve Hughes of the University of Exeter for their long‐term friendship, support and readiness to share their knowledge and expertise; also to environmental engineer, Rachel Oates of the Lee Abbey Community, Devon, for her knowledgeable enthusiasm and readiness to talk about environmental energy sources, especially ‘micro‐hydro’ (see Chapter 1). JL is especially indebted to Professor Rob Lee of Royal Dutch Shell, his ‘partner in slime’ for the past 15 years and to Drs Mike Goosey and Jeremy Shears, both directors of Shell Biodomain, for their positive and supportive vision of open innovation between academia and industry to solve global problems. Heartfelt thanks also to all of the current and past members of the Exeter Microbial Biofuels Group for their talent, commitment, professionalism and humour, to our numerous collaborators in academia and in industry, and to the BBSRC for supporting our research. Our programme would not be possible without the direct support of the University of Exeter. JL is personally grateful to our Vice Chancellor Professor Sir Steve Smith and to our Deputy Vice‐Chancellor for research, Professor Nick Talbot, FRS (formerly his head of department) for their genuine and sustained interest, and to his all colleagues in professional services, notably Linda Peka and Caroline Hampson, for their immeasurable patience in underpinning our research.

Finally, we want to say a big ‘Thank You’ for the patience of our publishers at Wiley‐Blackwell and especially those closely involved with this book, Rachel Wade at Oxford who helped to initiate the project, Fiona Seymour at Chichester who was for a long time ‘our’ editor, Audrie Tan at Singapore who took over from Fiona as the last few chapters came in and Vinodhini Mathiyalagan together with Shummy Metilda who supervised the book’s production. It would have been so easy for these individuals and for Wiley‐Blackwell themselves to abandon the book as we sought yet another re‐scheduling. We are very grateful that they stuck with us.

John LoveJohn A. BryantExeter, August 2015

List of Abbreviations

AAT

ATP‐ADP translocase

ACC

Acetyl‐CoA carboxylase

ACL

ATP‐citrate lyase

Ack

Acetate kinase

ACP

Acyl carrier protein

ACS

Acyl‐CoA synthetase

AD

Anaerobic digestion

ADH

Alcohol dehydrogenase

AdhE2

Butaraldehyde/butanol dehydrogenase

AFEX

Ammonia fibre expansion

ADO

Aldehyde decarbonylase

ALR

Airlift reactor

AS

ATP synthase

ATJ

Alcohol to jet

AtoAD

Acetoacetyl‐CoA transferase

ATP‐CL

ATP‐citrate lyase

B100

100% biodiesel

BBSRC

Biotechnology and Biological Sciences Research Council

bbl

Barrels

Bcd

Butyrl‐CoA dehydrogenase

BCKD

Branched chain ketoacid dehydrogense

BDC

Buoyant density centrifugation

BDGC

Buoyant density gradient centrifugation

BIS

Bisbolene synthase

BOD

Biological oxygen demand

BTL

Bio‐to‐liquids

CAR

Carboxylic acid reductase

Ccr

Cronotyl‐CoA reductase

CCX

Chicago Climate Exchange

CFPP

Cold Filter Plugging Point

CH

Catalytic hydrothermolysis

CI

Cetane index

C/N

Carbon to nitrogen ratio

CN

Cetane number

CP

Cloud point

CRP

Cyclic AMP (cAMP) receptor protein

CSL

Cellulose synthase‐like

CtfAB

Coenzyme A transferase, A and B subunits

DAG

Diacylglycerol

DAGAT

Diacyglycerol acyltransferase

DDG

Dried distillers grain

DDGS

Dried distillers grains with solubles

DEFRA

Department of Food, Rural Affairs and Agriculture

DIC

Dicarboxylate carrier

DM

Dry matter

DMAPP

Dimethylallyll diphosphate

DMSO

Dimethyl sulfoxide

DoE

Department of Energy

DPF

Diesel particulate filter

DSHC

Direct sugar to hydrocarbons

E85

85% ethanol

EBI

Energy Biosciences Institute

ECM

Extracellular matrix

EJ

Exajoules

ELA

Extremely low acid

EMP

Embden‐Meyerhof‐Parnas

EPA

Environmental Protection Agency

EPIC

Environmental Policy Integrated Climate

ER

Endoplasmic reticulum

EU

European Union

FA

Fatty acid

FAAE

Fatty acid alkyl esters

FACS

Fluorescence activated cell sorting

fadD

Fatty acyl‐CoA synthetase

FAEE

Fatty‐acid ethyl ester

FAME

Fatty acid methyl ester

FAO

Food and Energy Organisation

FAR

Fatty acid reductase

FAS

Fatty‐acid synthase

FCM

Flow cytometry

FPP

Farneseyl pyrophosphate

FS

Farnesene synthase

G‐3‐P

Glycerol‐3‐phosphate

GAT

G‐3‐P acyltransferase

GC

Gas chromatography

GDSL

Gly‐Asp‐Ser‐Leu

GGPP

Geranylgeranyl pyrophosphate

GHG

Greenhouse gases

GIS

Geographic Information System

GM

Genetically modified

GPP

Geranyl pyrophosphate

GTL

Gas‐to‐liquids

GTME

Global transcriptional machinery engineering

GW

Gigawatts

Hbd

3‐hydroxybutyrl‐CoA dehydrogenase

HCCI

Homogenous charge compression ignition

HDCJ

Hydrotreated depolymerised cellulosic jet

HEFA

Hydroprocessed esters and fatty acids

HGA

Homogalacturonan

HMF

Hydroxymethylfurfural

HRAP

High rate algal pond

HT

Hydrotreatment

IFES

Integrated food‐energy systems

IFQC

International Fuel Quality Centre

iGEM

Internationally Genetically Engineered Machines

LA

Lysophosphatic acid

ILUC

Indirect Land Use Change/integrated land use change

IOU

Investor‐owned utilities

IPP

Isopentenyl diphosphate

IPPC

Inter‐Governmental Panel on Climate Change

ispS

Isoprene synthase

KDC

Ketoacid decarboxylase

kW

Kilowatts

LB

Lipid bodies

LCA

Life cycle analysis/Life Cycle Assessment

Ldh

L‐lactate dehydrogenase

LED

Light emitting diode

LNG

Liquefied Natural Gas

LNS

Light natural sandwich

lpa

Lysophosphatidic acid

LPAAT

Lysophosphatidic acid acyltransferase

LS

Limonene synthase

LUC

Land Use Change

MAG

2‐monoacylglycerol

MDH

Malate dehydrogenase

ME1

Malic enzyme

MEP

2‐C‐methyl‐D‐erythritol‐4‐phosphate

MEV

Mevalonate

MIT

Massachusetts Institute of Technology

MLG

Mixed‐linkage glucan

MSW

Municipal solid waste

MW

Megawatts

MXE

MLG:xyloglucan endotransglucosylase

NDP

An

N

‐galacturonoyl amide

NGO

Non‐Governmental Organisation

NMR

Nuclear magnetic resonance

NO

x

Nitrogen oxides

OECD

Organisation for Economic Cooperation and Development

OEM

Optical Emission Spectroscopy

OPEC

Organization of the Petroleum Exporting Countries

PA

Phosphatidic acid

PAP

Phosphatic acid phosphohydrolase

PBR

Photobioreactor

PC

Pyruvate carboxylase

Pdc

Thiamine pyrophosphate

PDH

Pyruvate dehydrogenase

PHB

Polyhydroxybutyrate

PME

Pectin methylesterase

PP

Pour point

PPi

Pyrophosphate

ppm

Parts per million

PPP

Pentose phosphate pathway

PS

Pinene synthase

PT

Pyruvate transporter

Pta

Phosphate acetyltransferase

PV

Photovoltaic

PVC

Polyvinyl chloride

PVP

Polyvinylpyrrolidone

QTL

Quantitative trait locus/loci

R&D

Research and Development

REACH

Registration, Evaluation and Authorisation of Chemicals

REC

Renewable Energy Certificate

RED

Renewable Energy Directive

REDD +

Reduction of Emissions Due to Deforestation and Forest Degradation

RFS

Renewable Fuel Standards

RME

Rape‐seed methyl ester

RG

Rhamnogalacturonan

RPS

Renewables Portfolio Standard

RVP

Reid Vapour Pressure

S‐AM

S‐adenosyl methonine transferase

SI

Spark‐ignition

SCO

Single‐cell oil

SOC

Soil organic carbon

SSL

Squalene synthase‐like

TAG

Triacylglycerol

TBA

Tertiary butanol

TCA

Tricarboxylic acid

TCL

Thermo‐chemical liquefaction

Te

Thioesterase

TFA

Trifluoroacetic acid

Thl

Thiolase

TIC

Tricarboxylate carrier

TPP

Thiamine pyrophosphate

TW

Terawatts

ULS

Ultra‐low sulphur

USDA

US Department of Agriculture

USDoE

US Department of Energy

USPS

US Postal Service

UV

Ultra‐violet

WRAP

Waste Resources Action Programme

XEG

Xyloglucan endo‐glucanase

XET

Xyloglucan endotransglucosylase

XTH

Xyloglucan endotransglucosylase/hydrolase

1Biofuels: The Back Story

John A. Bryant and John Love

College of Life and Environmental Sciences, University of Exeter, Exeter, UK

Summary

This chapter looks at the history of the use of fossil and non‐fossil fuels and of environmental energy sources from the earliest phases of human society right up to the present day. Factors, especially climate change, which affect the use of particular fuels are discussed. The chapter ends with an overview of biofuels, thus setting the scene for the rest of the book.

1.1 Introduction

The earliest recorded use of the word biofuel was in 1970 when it was defined as ‘a fuel (such as wood or ethanol) composed of or produced from biological raw materials.’ Use of the term gradually became more frequent but it is only in last 15 years or so that it has entered into everyday speech. The definition has also widened: the Oxford Dictionary On‐line now simply states ‘a fuel derived immediately from living matter’. This clearly covers much more than wood and ethanol; the range will be apparent from the chapters in this book. The purpose of this chapter is to provide the context for, and to discuss the reasons behind, this increased interest in biofuels. It is an unfolding story of human ingenuity and inventiveness in the search for sources of light and heat and of energy for industry, transport, commerce and domestic appliances. It is a fascinating story that sets the scene for the rest of the book.

1.2 Some History

1.2.1 Wood and Charcoal

Although the first recorded use of the word was relatively recent, the use of biofuels actually goes back much further. Biological materials have been used as energy sources throughout human existence; indeed it is likely that the Neanderthals had discovered fire and the use of wood as a fuel. On a small local scale, burning of wood as a fuel may be regarded as having a very small ‘ecological footprint’, especially since, reflecting our modern concerns, it releases only recently fixed CO2 into the atmosphere.

Pyrolysis of wood in the absence of air produces charcoal, a form of carbon that burns at a higher temperature than wood and can thus be used in metal smelting. The use of charcoal as a fuel dates back at least 6,000 years (and probably longer). Initially it was confined to Egypt and what is now known as the Middle East. Its use soon spread across Europe so that by the Middle Ages, charcoal production was very widespread and resulted in extensive deforestation over large areas. It thus had an ecological/environmental impact that today we would regard at least as undesirable.

With the invention of a method for making coke from coal (i.e. a fossil fuel), charcoal production declined dramatically, especially from 1900 onwards (although one of us can remember seeing charcoal burners in woods in Surrey in the middle years of the 20th century). Today the use of charcoal as a fuel1 in developed countries is largely confined to domestic barbecues. However, across the world, wood and charcoal are still the mostly widely used fuels. This includes the use of wood‐burning stoves in people’s homes and wood‐burning power stations, often regarded as environmentally friendly because, as noted before, it is recently fixed CO2 that is released. This CO2 release may be further mitigated by the planting of replacement trees in managed forestry systems. However, there is no universal agreement on this; some think that growing wood just for burning is not wise when the wood could have so many other uses2. Furthermore, in many parts of the world where emissions are less stringently controlled, burning of wood often causes serious smoke pollution and damaging effects on human health.

1.2.2 Dung as Fuel

Evidence for use of dried animal dung as fuel dates back about 9,000 years to Neolithic communities in which cattle, sheep, goats and pigs had been domesticated. It is still used today in many less‐developed countries. There is also evidence for use by Native Americans of dung from wild bison in the prairies where wood fuel was very scarce or non‐existent. There is undoubtedly today support for increased use of dung as fuel, both in what we might call traditional or semi‐traditional methods and by anaerobic digestion (see Chapter 3).

1.2.3 Oils and Fats

The use of natural oils for lighting dates back to about 15,000 years. Most ancient oil lamps ran on plant oils. Thus the lamps referred to in the Old and New Testaments of the Bible and in the Qur’an were fuelled with olive oil. Both plant and animal oils were also used for lighting in ancient Egypt, dating back to about 3000 BC: rushlights, precursors to candles, were made by dipping rolled‐up papyrus into oil or into melted beeswax or melted animal fat. The Romans are generally credited with invention of the true candle containing a wick that ran through the length of a cylinder of bees’ wax (other solid animal fats may also be used).

Another animal‐based biofuel is whale oil, which was used for lighting from the 17th until the second half of the 19th century, when it was finally displaced by kerosene and by coal gas (see also Sections 1.3.2 and 1.3.3). It was noted that ‘sperm oil’ (from the head of the sperm whale) gave a much cleaner and less odoriferous flame than whale blubber oil and this was one of the factors that led to intensive hunting of sperm whales in the 18th and 19th centuries. Thus, in the period between 1770 and 1775, the northeastern United States produced about 7.16 million litres of sperm oil per year. At least 6,400 sperm whales would have been killed annually to supply this amount of oil. Hunting at this intensity continued until the second half of the 19th century and of course was not confined to US‐based whaling fleets. It is estimated that the world population of sperm whales declined by about 235,000 in the 18th century alone and it seems very likely that they would have been hunted to extinction3 had petroleum oil and oil‐based products not displaced sperm oil as fuels of choice.

1.2.4 Peat

The last traditional biological fuel we wish to consider is peat. This occurs in the wetter areas of the world, covering between 2% and 3% of the global land area, and consists of compressed and partly rotted remains of plants, especially Sphagnum moss. It may thus be regarded as being part way to forming lignite, a form of coal. Peat is cut from the bog in slices, known in Ireland and Scotland as turves (singular turf), which are left to dry before being burned as fuel. One of the problems with peat is that it takes a long time to form, growing at a mean rate of 1 mm/year in a typical peat wetland. It is thus regarded as a semi‐renewable fuel. However, in many areas, the rate of exploitation far exceeds the rate of re‐growth, resulting in denudation of the peat bog and increased run‐off of water, leading to flooding.

Peat is a less efficient fuel than coal and natural gas, which means that per unit of energy, peat releases twice as much CO2 as natural gas and 15% more than coal. This difference is only partly mitigated by the slow renewal of peat fuel (as mentioned above). Large‐scale peat fires, sometimes initiated by lightning strikes and sometimes by illegal ‘slash and burn’ activities, in addition to releasing large amounts of CO2 into the air, also cause very extensive particulate pollution. One of us was working in Singapore during the notorious 1997 Southeast Asia haze, caused by illegal burning of forest trees and subsequent out‐of‐control peat fires in Indonesia. Visibility was very poor, the air smelt of smoke and we were advised not to exercise outside. Right across the region there were deleterious effects on human and animal health. Similar hazes have occurred several times since 1997, as exemplified in Figure 1.1.

Figure 1.1 Haze over Singapore 2013.

Peat may be regarded as being on its way to becoming a fossil fuel. However, the true fossil fuels are coal (including lignite), oil and natural gas. We thus move on to discuss the history of their use.

1.3 Fossil Fuels

1.3.1 Coal

On Caerphilly Common, between Cardiff and Caerphilly in South Wales, are some shallow depressions and some small mounds. These are the remains of bell pits and their associated spoil tips, providing evidence of coal mining in the area dating from the 14th century. However, use of coal as a fuel for heating, cooking and even smelting metals actually goes back several thousand years. Its use was recorded in China at around 1000 BC and in Ancient Greece at around 350 BC. In Britain, surface or outcrop coal has been used since the Bronze Age (2000–3000 BC). In Roman times, houses and baths were heated by burning coal and a brazier of coal was kept permanently alight in the Temple of Minerva in Aquae Sulis (now known as Bath). The Romans also used coal for smelting iron.

However, it was not until the end of the 18th century that coal mining became really organised. Those simple bell pits at Caerphilly Common were tapping into the enormous South Wales coalfield and it was coal mined from this field that fuelled the Industrial Revolution in that part of Britain. Indeed, the Industrial Revolution led to a large increase in the demand for coal, which was mined in nearly all of the countries in which industry was increasing. Coal mining in the UK has nearly ended now, not because stocks have run out but because it has become uneconomical to mine it. Nevertheless, coal is still mined in many other countries and known global reserves will last for centuries, even taking into account the acceleration in use in countries like India and especially China. Consumption of coal currently runs at nearly 8 × 109 tonnes per year, with China being responsible for just over 50% of that total. Combustion of that amount of coal, assuming that it is all carbon, releases 22.88 × 109 tonnes of CO2 into the atmosphere.

1.3.2 Petroleum Oil

As with coal, the use of petroleum oil as a fuel goes back much further than we might suppose. Oil, pitch and asphalt were all known in Babylon and Persia about 4,000 years ago and were used for lighting, heating and in building work. The first recorded drilling for oil occurred in China in the 4th century AD and oil was first distilled to make lighter products such as kerosene in Persia in the 9th century. From there the practice of distillation spread through the Arab world and eventually reached Spain, via Morocco, in the 12th century. Deposits of oil and/or asphalt were also known from many locations in Europe, including France, Greece and Romania and some of these have been worked until the second half of the 20th century. The first recorded oil refinery was built in Russia in 1745, producing kerosene, mainly for lighting of churches, monasteries and the homes of aristocrats. Oil and associated products were also known from the New World. In 1595, Sir Walter Raleigh described the asphalt lake in Trinidad and from the beginning of the 17th century onwards, oil springs and other types of oil deposits were discovered in many places in North America, including the now‐notorious tar sands in Canada.