making! PAPER
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Volume 4 / Number 2 / 2018
PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 4, Number 2, 2018 CONTENTS:
FEATURE ARTICLES: 1. UK Industry : Background on Industrial Decarbonisation Roadmap 2. MFC Composite Films : Properties of gelatine films containing MFC 3. Waste Treatment : Using fungi in waste treatment of Indian sites 4. Antibacterial Paper : Immobilised nano-silver 5. Biorefining : Major review on new generation biorefining 6. Wood Panel : Mat compression measurements on particleboards 7. Carbon Fibre Rollers : Using lightweight rollers in printing and papermaking 8. Cultural Differences : Examples of cultural difference in the workplace
9. Networking : How to survive networking events 10. Conflict : Dealing with conflict in the workplace 11. Influencing : Mastering the 3 ways to influence people 12. Leadership : Bridging the leadership gap 13. Memory Skills : Improve your memory
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The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .
Contents
Page 1 of 1
PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 4, Number 2, 2018
Industrial decarbonisation of the pulp and paper sector: A UK perspective Paul W. Griffin (1), Geoffrey P. Hammond (1,2), Jonathan B. Norman (1) 1) Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK 2) Institute for Sustainable Energy and the Environment (I•SEE), University of Bath, Bath BA2 7AY, UK The potential for reducing industrial energy demand and ‘greenhouse gas’ (GHG) emissions in the Pulp and Paper sector (hereinafter denoted as the paper industry) has been evaluated within a United Kingdom (UK) context, although the lessons learned are applicable across much of the industrialised world. This sector gives rise to about 6% of UK industrial GHG emissions resulting principally from fuel use (including that indirectly emitted because of electricity use). It can be characterised as being heterogeneous with a diverse range of product outputs (including banknotes, books, magazines, newspapers and packaging, such as corrugated paper and board), and sits roughly on the boundary between energy-intensive (EI) and non-energy- intensive (NEI) industrial sectors. This novel assessment was conducted in the context of the historical development of the paper sector, as well as its contemporary industrial structure. The findings of this study indicate that the attainment of a significant decline in GHG emissions over the long-term will depends critically on the adoption of a small number of key technologies [e.g., energy efficiency and heat recovery techniques, bioenergy (with and without CHP), and the electrification of heat], alongside a decarbonisation of the electricity supply. The present roadmaps help identify the steps needed to be undertaken by developers, policy makers and other stakeholders in order to ensure the decarbonisation of the UK paper sector. Applied Thermal Engineering, Volume 134, April 2018, Pages 152-162. (Open Access) https://doi.org/10.1016/j.applthermaleng.2018.01.126
The Paper Industry Technical Association (PITA) is an independent organisation which operates for the general benefit of its members – both individual and corporate – dedicated to promoting and improving the technical and scientific knowledge of those working in the UK pulp and paper industry. Formed in 1960, it serves the Industry, both manufacturers and suppliers, by providing a forum for members to meet and network; it organises visits, conferences and training seminars that cover all aspects of papermaking science. It also publishes the prestigious journal Paper Technology and the PITA Annual Review , both sent free to members, and a range of other technical publications which include conference proceedings and the acclaimed Essential Guide to Aqueous Coating .
Article 1 – UK Industry Decarbonisation
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Contents lists available at ScienceDirect
Applied Thermal Engineering
journal homepage: www.elsevier.com/locate/apthermeng
Research Paper Industrial decarbonisation of the pulp and paper sector: A UK perspective Paul W. Gri ffi n a,1 , Geo ff rey P. Hammond a,b, ⁎ , Jonathan B. Norman a a Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK b Institute for Sustainable Energy and the Environment (I • SEE), University of Bath, Bath BA2 7AY, UK
ARTICLE INFO
A B S T R A C T
The potential for reducing industrial energy demand and ‘ greenhouse gas ’ (GHG) emissions in the Pulp and Paper sector (hereinafter denoted as the paper industry) has been evaluated within a United Kingdom (UK) context, although the lessons learned are applicable across much of the industrialised world. This sector gives rise to about 6% of UK industrial GHG emissions resulting principally from fuel use (including that indirectly emitted because of electricity use). It can be characterised as being heterogeneous with a diverse range of product outputs (including banknotes, books, magazines, newspapers and packaging, such as corrugated paper and board), and sits roughly on the boundary between energy-intensive (EI) and non-energy-intensive (NEI) industrial sectors. This novel assessment was conducted in the context of the historical development of the paper sector, as well as its contemporary industrial structure. Some 70% of recovered or recycled fi bre is employed to make paper products in the UK. Fuel use in combined heat and power (CHP) plant has been modelled in terms of so-called ‘ auto-generation ’ . Special care was taken not to ‘ double count ’ auto-generation and grid decarbonisation; so that the relative contributions of each have been accounted for separately. Most of the electricity generated via steam boilers or CHP is used within the sector, with only a small amount exported. Currently-available technologies will lead to further, short-term energy and GHG emissions savings in paper mills, but the prospects for the commercial exploitation of innovative technologies by mid-21st century is speculative. The possible role of bioenergy as a fuel resource going forward has also been appraised. Finally, a set of low-carbon UK ‘ technology roadmaps ’ for the paper sector out to 2050 have been developed and evaluated, based on various alternative scenarios. These yield transition pathways that represent forward projections which match short-term and long- term (2050) targets with speci fi c technological solutions to help meet the key energy saving and decarbonisation goals. The content of these roadmaps were built up on the basis of the improvement potentials associated with di ff erent processes employed in the paper industry. Under a Reasonable Action scenario, the total GHG emissions from the sector are likely to fall over the period 1990 – 2050 by almost exactly an 80%; coincidentally matching GHG reduction targets established for the UK economy as a whole. However, the fi ndings of this study indicate that the attainment of a signi fi cant decline in GHG emissions over the long-term will depends critically on the adoption of a small number of key technologies [e.g., energy e ffi ciency and heat recovery techniques, bioenergy (with and without CHP), and the electri fi cation of heat], alongside a decarbonisation of the electricity supply. The present roadmaps help identify the steps needed to be undertaken by developers, policy makers and other stakeholders in order to ensure the decarbonisation of the UK paper sector.
Keywords: Pulp and paper sector Industrial energy analysis and carbon accounting
Enabling technologies Improvement potential Technology roadmaps United Kingdom
1. Introduction
use applications of energy, especially in terms of products manu- factured, processes undertaken and technologies employed (see Fig. 1 [3]). It is clear that the pulp and paper subsector (hereinafter denoted as the paper industry) as seen in Fig. 1 gives rise to the sixth highest industrial energy consumption in the UK; caused by a combination of drying/separation processes (40%), low temperature heating processes (28%), compressed air requirements (10%), space heating (8%) and electrical motors (6%) [3]. UK industry overall has been found to
1.1. Background
The industrial sector in the United Kingdom of Great Britain and Northern Ireland (UK) accounts for 17% of total fi nal energy consump- tion [1] and a corresponding 20% of carbon emissions [2] in 2015. There are large di ff erences between industrial sub-sectors in the end-
⁎ Corresponding author at: Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK. 1 Present address: CDP – Global Environmental Reporting System , 71 Queen Victoria Street, London EC4V 4AY, UK. E-mail address: G.P.Hammond@bath.ac.uk (G.P. Hammond).
https://doi.org/10.1016/j.applthermaleng.2018.01.126 Received 7 September 2017; Received in revised form 13 December 2017; Accepted 30 January 2018
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Nomenclature
GB
Great Britain
GHG ‘ greenhouse ’ gas GOS (the UK) Government O ffi ce of Science H:P heat-to-power ratio I&C industrial and commercial ICT information and communications technology IEA International Energy Agency IOP Index of Production (ONS statistical bulletin) IPPC Integrated Pollution Prevention and Control (EU reg- ulatory data) LA Low Action (scenario) NEI non-energy-intensive NG natural gas NP RES ‘ non-programmable ’ renewable energy sources ONS O ffi ce of National Statistics (for the UK) ORC organic Rankine cycle PRODCOM ‘ Production Communautaire ’ (Community Production – EU statistical database) PV (solar) photovoltaic (power generators) RA Reasonable Action (scenario) RA-CCS Reasonable Action together with Carbon Capture & Storage (scenario) RCUK Research Councils UK RT Radical Transition (scenario) SEC speci fi c energy consumption SIC (UK) Standard Industrial Classi fi cation SRF solid recovered fuel UED (the industrial) Usable Energy Database UK United Kingdom of Great Britain and Northern Ireland UKERC UK Energy Research Centre
Abbreviations
BAT Best Available Technology BCE before the ‘ Common Era ’ BGS British Geological Survey BPT Best Practice Technology CCA Climate Change Agreements CCL Climate Change Levy CCS Carbon Capture and Storage CCU Carbon Capture and Utilisation CE (in the) ‘ Common Era ’ CEPI CHP Combined Heat and Power CPI
Confederation of European Paper Industries
Confederation of Paper Industries (in the UK)
CT (the UK) Carbon Trust DECC (the former UK) Department of Energy and Climate Change DNO Distribution Network Operator DSF Demand-Side Flexibility DSP Demand Side Participation DSR Demand Side Response DUKES Digest of United Kingdom Energy Statistics (annual) ECN Energy research Centre of the Netherlands ECUK Energy Consumption in the UK (DECC annual statistical publication) EI energy-intensive EU European Union EU-ETS EU Emissions Trading Scheme
Fig. 1. Final UK energy demand by industrial subsector and end-use. Source: Norman [3].
and arguably cheaper for the businesses concerned).
consist of some 350 separate combinations of sub-sectors, devices and technologies [4,5]. Nevertheless, it is the only end-use energy demand sector in the UK that has experienced a signi fi cant fall of roughly 60% in fi nal energy consumption over the period 1970 – 2015 [1]. This was in spite of a rise of over 40% in industrial output in value added terms. However, the aggregate reduction in energy intensity (MJ/£ of gross value added) fell by 38 per cent during 1990 – 2015 [1], but this masks several di ff erent underlying causes: end-use e ffi ciency {accounting for around 80% of the fall in industrial energy intensity; largely induced by the price mechanism [4,5]); structural changes in industry [a move away from energy-intensive (EI) industries towards non-energy-intensive (NEI) ones, including services [4,5]}; and fuel switching (from coal and oil to natural gas and electricity that are cleaner, more readily controllable,
1.2. The issues considered
The present study builds on work by Dyer et al. [4], commissioned by the UK Government O ffi ce of Science (GOS), Hammond and Norman [6], and on a recent ‘ Advanced Review ’ by Gri ffi n et al. [7]. In each case, a variety of assessment techniques for determining potential en- ergy use and ‘ greenhouse gas ’ (GHG) reductions were discussed. Gri ffi n et al. [7] then evaluated the wider UK industrial landscape with the aid of decomposition analysis [8] in order to identify the factors that have led to energy and carbon savings over recent decades. They conse- quently assessed the improvement potential in two sectors: ‘ Cement ’
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west. Indeed, the Islamic civilisation was in direct contact with the Far East by the Early Middle Ages (6th to the 10th Century CE) [12]. The Arabic world imported from the east valuable materials (including high-quality steel, paper, porcelain and silk) and other elements of knowledge, such as the Indian system of mathematical notation (which is still known today as ‘ Arabic numerals ’ ) [14]. The fruits of Arabic science and technology progressively migrated across Europe. But the only signi fi cant advance made in the Ancient Greek and Roman civilisations in terms of writing was in the replace- ment of papyrus by parchment [14]. This parchment was made from untanned leather, with the best quality ( ‘ vellum ’ ) being made from the skin of a very young calf or kid [15]. It was worked and soaked in lime to get rid of dirt and large amounts of natural grease; dried on a stretching-frame; shaped with a knife; and then smoothed to produce a perfect writing-surface [14]. (In the UK, Acts of Parliament are still printed on vellum for archival purposes.) However, parchment was mainly replaced by paper; the earliest paper being referred to as ‘ cloth parchment ’ . The invention of printing with movable type by Johannes Gutenberg (the German blacksmith, goldsmith, printer and publisher; c. 1398 – 1468) [16] and the increasing demand for books ultimately led to the development of good quality paper from rag pulp [15]. It was in fact produced from various raw materials of a fi brous nature, not just rags from linen or cotton, but also from straw or wood [14,17]. Pulp was manufactured by pulverising such cellulosic ingredients, highly diluted with water, in order to disperse the fi bres [11,14,16], and then pouring the resulting thick liquid pulp into sieves (or ‘ moulds ’ ) [15]. This would ensure that the fi bre retained the necessary shape from which it could be sequentially pounded in a vat and dried [15,17]. The rectangular mould - a screen or tray with a fi ne wire screen surrounded by a wooden frame (or ‘ deckle ’ ) across the bottom [11] - was dipped into the vat and then held up to drain. In the 15th Century there were about 11 wires to the cm, but this was gradually increased to produce fi ner paper [12]. The paper on the bottom of the tray was then placed onto woollen felt [14], and constructed as a ‘ quire ’ of some 144 sheets and felts [17]; prior to going under a screw press. Sheets of pressed paper would be separated from the felts, and subsequently laid out on drying racks in the atmosphere; typically in a loft [11,15]. Additives, such as china clay or gypsum, were mixed with the pulp to provide ‘ fi lling ’ and gloss, thereby improving the quality of the fi nished paper for artwork or il- lustrations [11,14,15]. Thus, by the age of the English literary writer Dr. Samuel Johnson (1709 – 1784) printing was already 300 years old and, from the perspective of the user (in contrast to the maker), the printed book was not fundamentally di ff erent from books today [14]. In 1700 there were around 100 paper mills in England; over half were in the South East (clustered around London), and the rest quite widely spread [17]. By this time water power was often used at paper mills to drive the machinery that pounded the rags into pulp [17]. A good supply of pure water was also essential for mixing with the rags.
and ‘ Food & Drink ’ , which represent the EI and NEI industrial sectors respectively. Here the pulp and paper sector of UK industry is examined in terms of their energy use and GHG emissions, as well as its im- provement potential. It can be characterised as being heterogeneous (having a diverse range of product outputs, including banknotes, books, magazines, newspapers and packaging, such as corrugated paper and board), and as sitting on the rough boundary between EI and NEI in- dustries (see Fig. 2 [7]). [A high value in any of the measures shown in Fig. 2 suggests that a given sub-sector would be EI.] However, the Confederation of Paper Industries (CPI), the trade association, regards the industry as being EI. It accounts for some 6% of GHG emissions from UK industry as shown in Fig. 3 [7]. Notwithstanding the growth of elec- tronic media, domestic consumers and businesses continue to make use of paper in all its many forms. The opportunities and challenges to reducing industrial energy de- mand and carbon dioxide equivalent (CO 2e ) emissions (carbon dioxide is the principal GHG [5]) in the British paper industry have been eval- uated, although the lessons learned are applicable across much of the industrialised world. The data here has been largely extracted from an industrial Usable Energy Database (UED) that was produced for the UK Energy Research Centre (UKERC) [actually an academic community or network funded by the Research Councils UK (RCUK) Energy Programme ] by the present authors (see Gri ffi n et al. [7,9,10]). A set of industrial decarbonisation ‘ technology roadmaps ’ out to 2050 are fi nally reported, based on various alternative scenarios: named Low Action (LA), Rea- sonable Action (RA), Reasonable Action including Carbon Capture and Storage (CCS) [RA-CCS], and Radical Transition (RT) respectively. Such roadmaps represent future projections that match short-term (say out to 2035) and long-term (2050) targets with speci fi c technological solu- tions to help meet the key energy saving and decarbonisation goals. Their contents were built up in the present study on the basis of the improvement potentials associated with various processes employed in the paper industry and embedded in the UED [7,9,10]. They help identify the steps needed to be made by industrialists, policy makers and other stakeholders in order to ensure the decarbonisation of the UK paper sector.
2. The pulp and paper sector
2.1. Historical development of the paper industry
The historical context in which the various industrial sectors are viewed has changed over time. Sir Neil Cossons (an industrial archae- ologist and former Director of the Science Museum in London, 1986 – 2000), for example, placed the paper sector under the broad umbrella of ‘ The Chemical Industries ’ [11]. This was because (at least since the 1870s) pulp - from which paper is produced - had to be boiled, along with a variety of acid and alkaline reagents, in order to purify or remove contaminants. But it was Arabic science from about 3500 BCE, based largely in Egypt and the Near East, that led to what is now re- cognised as chemicals [12,13]: the early smelting of metals [especially copper, gold and mercury (or ‘ quicksilver ’ ), as well as alloys like bronze] gave rise to an understanding of the properties of their chemical com- pounds. The Egyptians had paper and ink with which to write [14]. They made paper from the pith of the papyrus reed, which was cut into strips and laid across each other at right angles, then pressed, dried, smoothed, and gummed together in order to form a roll. Ink was made from a lamp-black and gum solution, and their pens (used brush-wise at fi rst, but later cut into quills) from rushes. Ancient Egypt had a monopoly on papyrus, but was obviously able to export it [14]. They had no need to resort to cuneiform writing [12]; fi rst developed by the ancient Sumerians of Mesopotamia (c. 3500 – 3000 BCE). This term originally came from the Latin ‘ cuneus ’ , whereby a wedge-shaped stylus was used to make impressions on a clay or similar surface. Egypt ’ s hieroglyphic script meant that it provided a major stimulus to the spread of writing amongst its neighbours [14]; both to the east and
Fig. 2. Primary energy intensity, percentage of costs represented by energy and water, and mean primary energy use per enterprise (re fl ected by the area of the data points). Source: adapted from Gri ffi n et al. [7].
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the manufacture of single or multi-ply grades of paper, and is capable of extremely high operating speeds. The contemporary paper industry is a relatively high technology sector that takes full advantage to modern developments in electronics and Information and Communications Tech- nology (ICT), such as for the automatic control and monitoring of paper- making plants [19]. Wood-pulp for the British industry is now typically produced from resources obtained via the timber industries in Canada and Scandinavia, as well as from Scotland [15]. The UK paper sector has continued to innovate and has invested heavily, for example, in a modern newsprint machine (producing 400,000 tonnes of newsprint per year) and £300 M in a state-of-the-art containerboard machine to produce lightweight paper [19]. The consumption of paper and board products in the UK amounted to just over 10.5 Mt in 2010 (the baseline year for the present study) according to the national trade association: the Confederation of Paper Industries (CPI) [20]. There was a modest decline of some 2% per annum thereafter. Corrugated paper demand corresponded to around 2.15 Mt in 2010, which has risen modestly in recent years (to ∼ 2.3Mt in 2015) [20]. These demands were met with the aid of 3.8 Mt of re- covered or recycled paper in the base year. Indigenous production of paper and board was about 4.3 Mt in 2010 from just over 50 paper mills of varying sizes and specialisms [20] (having ∼ 9000 employees). Parent reel tissue production was only around 730 kt. These mills uti- lised 1.1 Mt of wood-pulp (0.9 Mt from indigenous sources and 0.2 Mt imported), as well as sawmill residues, like wood chips [20]. Timber extracted in the UK for pulp and paper production amounts to less than 5%, and comes typically via virgin wood fi bre from sustainably man- aged and certi fi ed forests [19]. Recovered paper has steadily increased since the 1950 s [19] to the current level of 3.75 Mt. Indeed, the British paper industry has a recycling rate of ∼ 80% (collected from both households and businesses), which is the highest of any material. However, there are constraints on the quantity of paper fi bre that can be recycled [19]. Around only 19% is not recyclable, because (i) it increasingly degrades as it is goes through successive recycling phases (up to about a maximum of 7 times, although in Europe it now stands at 3.4 cycles); (ii) it is kept embodied in artistic works, books, photographs or wall paper; or (iii) it disintegrates when used in the form of cigarette or sanitary papers [19]. The UK was a signi fi cant exporter of recovered paper amounting to some 4.3 Mt that went to China ( ∼ 75%), the European Union (EU) ( ∼ 14%), India ( ∼ 5%), Indonesia ( ∼ 3%), and the Rest of the World ( ∼ 3%) [20]. This helps reduce ‘ carbon footprints ’ of paper-making elsewhere around the world. Fuel consumption in the UK paper and board sector is dominated by boiler and combined heat and power (CHP) or co-generation plants for process electricity and steam production. Energy is required to drive machinery and to generate heat to dry the paper produced [19]. Fuel demands are mostly met by natural gas (NG), although biomass is in- creasingly being utilised and presently accounts for about 15% of sector
Fig. 3. Greenhouse gas (GHG) emissions from UK industry. Source: adapted from Gri ffi n et al. [7].
Signi fi cant innovations in paper-making accompanied the so-called Industrial Revolution in the UK from about 1760 CE onwards [11,14,15] accompanying, for example, the discovery of ways of bulk-producing acids and alkalis. Such developments came about from a fusion of empirical ‘ rules of thumb ’ with the basic sciences [12]. The fi rst steam engine to drive a paper mill was installed at Wilmington near Hull in about 1786, and there were several steam-powered mills located in various parts of Britain by 1815 [17]. Machines to make paper on an endless ‘ web ’ (similar to that patented by John Gamble in 1801) were built by the London inventor and engineer Bryan Donkin [17] in 1804 in order to replace the earlier batch type of process [11]. Pulp was poured onto a moving web (belt or cylindrical drum) from which it was drawn out as a continuous sheet, and then dried on rollers [15]. Var- iants of this design were installed by Henry and Sealy Fourdrinier in paper mills that continuously produced paper or board at Two Waters and Frogmore in Hertfordshire, and at St Neots in Huntingdonshire (see Fig. 4 [18]). Donkin subsequently developed a rotating type bed that came into practice in 1813 [17], and which further increased the speed of printing [14]. A dramatic rise in the reading public in the latter half of the 19th Century led to a signi fi cant increase in the consumption of paper, even before the excise duty was abolished in 1861 [14]. The provision of the fi rst municipal libraries in Britain around 1850 gen- erated interest in books and, after the newspaper tax was repealed (in 1855), the number of newspapers trebled in forty years [14]. This de- mand could not be met from linen and cotton rags and straw, and Esparto grass from Spain and North Africa began to be imported [14]. However, the real solution to this problem was the use of wood-pulp, which progressively replaced rags with cellulose fi bre from coniferous trees [11,14]. The pulp was initially prepared by using grindstones immersed in water containing ready-cut logs. But this did not remove detrimental resin and other impurities, and from 1873 onwards che- mical wood-pulp was employed by boiling wood chips with soda or sulphite solutions. This provided most of the input material for the great rolls needed by the emergent newspaper industry [14].
2.2. Structure of the modern pulp and paper sector
A modern paper-making machine is usually an enhanced version of the Fourdrinier type [11] (see again Fig. 4), which uses a specially woven plastic fabric mesh conveyor belt that is often several hundred metres long. The proportion of the machine involved in removing water from the web either by drainage or steam represents over 90% of the total length [11]. The speed at which paper, and more particularly multi-layer boards can be produced is determined by the rate at which the water can be removed from the webs [11]. An innovative devel- opment in the early 1960 s was the ‘ Inverform ’ machine in which water is removed under gravity from below and with the aid of a vacuum box from above the webs [11]. This paper-making device can be used for
Fig. 4. The traditional Fourdrinier paper-making machine of the type built by Bryan Donkin. Source: adapted from the University of Michigan, 1920 [18].
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based on available statistical data, and uses this data to determine en- ergy use, output, energy intensity and other measures for which data is available. This approach has the advantage of covering a large pro- portion of energy demand, but it is limited by the level of disaggrega- tion available from industry-wide statistical sources. Thus, the conclu- sions that can be drawn from such top-down studies are often only indicative in nature. In contrast, a bottom-up approach would typically focus on a single industrial sub-sector. Energy use can then be separated into lower order sub-sectors, processes or manufacturing plants. The data used for this type of bottom-up study typically comes from more speci fi c information sources, such as trade associations, company re- ports, and case studies. Such a bottom-up study can therefore be useful in terms of presenting more accurate fi ndings [22,23], although it will be limited in the breadth of its application. An innovative hybrid approach was employed to develop the in- dustrial Usable Energy Database (UED) [9,10], produced by the present authors for the whole of the UK industrial sector as part of the research programme of the UK Energy Research Centre (UKERC). Aspects of both top-down and bottom-up models were adopted, with detailed bottom- up studies set within a top-down framework. Using this novel approach would normally entail focusing on a number of sub-sectors for the bottom-up study [7], with the remainder of the sector being treated in a generic manner. Sub-sectors that use a large amount of energy are obviously prioritised for bottom-up studies. In additional, sub-sectors that use energy in a relatively homogeneous manner are easier to analyse, and this may also be considered when selecting appropriate sub-sectors. Sub-sectors that are not the subject of detailed bottom-up modelling require a focus on the potential reduction in emissions through widely used, ‘ cross-cutting ’ technologies can be useful [7,9,10].
fuel consumption. Paper is formed and dried from pulp, and fi nished into paper products. Just two mills were fully integrated pulp and paper operations. Final energy demand at typical mills is dominated by the dryer section in which steam-heated cylinders heat the paper fi bres to around 100 °C [21]. The physical unit of production for the sector is tonnes of paper and board (tpb). UK sector energy demand in 2010 was 60 PJ; of which fuel demand was 53 PJ. Imported electricity was 8.5 PJ, whilst the corresponding power supplies exported was 1.5 PJ. The UK paper-making industry reduced its total energy consumption by 34% per tonne of paper made between 1990 and 2010 [19]. Production was 4.3 Mtpb in 2010; resulting in a direct speci fi c energy consumption (SEC) of 12.2 GJ/tpb and primary SEC of about 19 GJ/tpb. Energy costs amount to about 30% of the total cost of paper-making [19]. Direct GHG emissions were some 2.3 MtCO 2 e; a reduction of 42% over the period 1990 – 2010, due to investment in lower carbon energy sources [19]. The corresponding total emissions, including those attributable to net electricity, were 3.3 MtCO 2 e. Large and complex paper mills typi- cally take control of their energy supplies by building CHP plants that are more e ffi cient than separate supply of electricity and heat, and re- duce GHG emissions and generating costs [19]. A number of such CHP plants use biogenic (wood) waste, which is a renewable resource and gives rise to further reductions in GHG emissions. The UK paper sector is the largest user and producer of bioenergy in Europe [19].
3. Methods and materials
3.1. A Hybrid top-down/bottom-up approach
There are two broad ways to modelling the industrial sector [7]: top-down and bottom-up approaches, as illustrated in Fig. 5 (adapted and elaborated from those presented by Dyer et al. [21] and Gri ffi n et al. [7]). A top-down approach splits industry into sub-sectors, usually
Fig. 5. Schematic representation of an integrated top-down and bottom-up modelling approach for the UK industrial sector. Source: elaborated from the diagrams presented in Dyer et al. [21] and Gri ffi n et al. [7].
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3.3. Improvement potential
3.2. The baseline conditions
The energy inputs to the UED pulp and paper section were based on information from the trade association (David Morgan, CPI, private communication, 2013). This covers all paper mills (51 sites) in the UK (see the Sankey-type energy fl ow diagram presented in Fig. 6), but not the manufacture of “ fi nished paper products ” that use energy in a dif- ferent manner. The information here covers the UK Standard Industrial Classi fi cation (SIC) Code (2007) 17.12 [24]. Their energy use covered around 50% of energy demand at the 3 digit SIC level (i.e., SIC 17.1 - Manufacture of pulp, paper and paperboard) , according to the UK Gov- ernment ’ s former Department of Energy and Climate Change (DECC) [25]. Output from these mills was taken from the information submitted by industrial companies as a requirement of Climate Change Agreements (CCA) and collated by AEA [26]; what is now the consultancy Ricardo Energy & Environment . CCA are voluntary agreements between UK in- dustry and the UK Government ’ s Environment Agency aimed at deli- vering reductions in energy use and GHG emissions. Operators receive a discount on the Climate Change Levy (CCL), e ff ectively a tax on energy delivered to UK non-domestic users, of 90% on electricity bills and 65% on other qualifying input fuels. The CCA for the paper sector is ad- ministered by a wholly-owned subsidiary of the CPI [27]; the Paper Sector Climate Change Management Co. Ltd . Direct GHG emissions come under the remit of the EU Emissions Trading Scheme (EU-ETS). SEC data is reported for the paper sector for some 46 UK paper mills in 2015 [27]. The basis of this information was again con fi rmed by the CPI (David Morgan, CPI, private communication, 2013), although the energy de- mand di ff ered slightly from that reported under the CCA, due to the inclusion of renewable energy sources (that is not reported under CCA). Economic output was taken from the UK Government ’ s Annual Business Survey [28]. Fuel use by CHP plants was based on reported auto-generated electricity (again via David Morgan, CPI, private communication, 2013), and sector heat-to-power (H:P) ratio was calculated from the Digest of United Kingdom Energy Statistics (DUKES) [29]. Similarly, the overall e ffi ciency of CHP was taken from DUKES. Information on ex- ported electricity from CHP was given by the CPI (Morgan, 2013). The fuel used in producing this exported electricity was calculated based on information from DUKES [29]. The Sankey diagram (shown in Fig. 6) depicts the 2010 baseline division of energy inputs (fuels and primary electricity) against comparative outputs (associated with the core paper machines and ancillary processes). The thickness of the ‘ arrows ’ , ‘ links ’ , or ‘ lines ’ is proportional to the quantity of energy. The major role of CHP plants in providing both heat and power is illustrated as an in- termediate node or process. Non-CHP fuel input is assumed to be used in steam systems, based on a report by the UK Carbon Trust (CT) [30]. The SEC of the various processes was then based on information adopted from that study [30], although they were scaled to match the total electricity demand reported by the CPI (Morgan, 2013). Using the same scaling factor for steam use yielded a boiler e ffi ciency of 82%. This is high in comparison to the average for the industrial sector, but not unreasonably so.
3.3.1. The overall context Improvement potentials were initially extracted from the CT study [30], which particularly focuses on UK paper manufacturing rather than on the pulp sub-sector. This mainly covers short-term opportunities, and so was therefore supplemented by information from alternative (international) sources that cover opportunities that involve more major changes to the production process [21,31,32]. There may be some potential for greater use of the wastes from paper production as fuels, for example, and this was considered in the UED in terms of CHP gasi fi cation. However, there was insu ffi cient technical information available to give greater consideration of this opportunity. Pulp pro- duction is comparatively small in the UK. The sector already uses both a substantial amount of recycling and imported pulp. Domestic pulp re- presents just ∼ 6% of the sector input [30], with only two integrated mills in the UK that use mechanical pulping. They could technically convert to chemical pulping, and use the products produced (so-called ‘ black liquor ’ ) to become net zero GHG emitters. Thus, pulp production was not included in the UED. 3.3.2. Fuel switching - towards a bio-economy The Confederation of European Paper Industries (CEPI) [33], a Brus- sels-based non-pro fi t-making organisation representing the European pulp and paper industry, has recommended the further conversion of industrial installations to low or zero carbon energy use, particularly from renewable sources. Bioenergy can be produced from either bio- mass (any purpose-grown material, such as crops, forestry or algae) or biogenic waste (including household, food and commercial waste, agricultural or forestry waste, and sewage sludge). Sustainable bioe- nergy is a renewable resource that is often low carbon, and potentially leads to ‘ negative emissions ’ when coupled to CCS facilities [34]. It has more recently been proposed in a Swedish context [35,36] to integrate a biore fi nery with pulp and paper mills in order to produce high value chemical products [23] alongside conventional outputs. The UK Gov- ernment ’ s UK and Global Bioenergy Resource Model (an updated feed- stock availability model) suggests that there is substantial quantities of indigenous biomass and biogenic waste available even accounting for the application of more stringent sustainability and land use criteria [37]. The total 2030 UK bioenergy resources might be equivalent to some 850 – 1120 PJ; with accessible resources of perhaps 580 – 672 PJ. But many industrial sectors will be competing for this resource along- side, for example, power generation. This is likely to, in any case, drive up biofuel prices. Nevertheless, the UK pulp and paper sector is already substantially invested in the use of biomass feedstock as both a raw material and fuel, although the CPI has advocated further government support for the expansion of UK agricultural land use for woody bio- mass. On-site residuals from paper production (such as ‘ black liquor, waste fi bre, bark and fi nes) are used to generate a biogenic replacement ( syngas ) for natural gas via gasi fi cation. This can be obtained using a variety of feedstocks: solid recovered fuel (SRF), waste wood, and other waste materials. Unfortunately, in their stakeholder engagement with the UK Government, representatives of the paper industry (via the CPI)
Fig. 6. Sankey energy fl ow diagram of the UK Pulp and Paper sector as modelled here; baseline data in 2010. Source: Gri ffi n et al. [9].
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MtCO 2e /yr in comparison to supplying the energy outputs in a con- ventional manner [6]. A network and market for trading in heat, along with the wider use of district heating systems, could also open sig- ni fi cant potential for exporting heat from industrial sites to other users. A range of Best Practice Technologies (BPTs) – those that represent the ‘ best ’ technologies, which are currently in use and therefore econom- ically viable – for both energy e ffi ciency improvements and heat re- covery has been advocated for introduction into the pulp and paper sector in future [21,26,30 – 32]. 3.3.4. Demand-side fl exibility Demand-side fl exibility (DSF) is the ability to change electricity de- mand from an industrial plant or other user in response to an external signal from a power supplier [46,47]. The use of tools such as Demand Side Response (DSR) – where levels of electricity demand are increased, reduced or shifted - and on-site energy storage enable the optimisation of electricity usage and has major advantages in the context of an en- ergy infrastructure designed to meet occasional peak demands. This will be particularly important in the transition towards a low-carbon future. Demand Side Participation (DSP) concepts are mainly short-term (minutes to hours) [48], whereas fl exibility is needed over several days or more. The rigid patterns of power supply based on life-long experi- ence of fossil-fuelled supplies make such fl exibility challenging, but are important to explore. Fully automated DSR concepts, such as ‘ smart ’ controllers for EV charging and heat-pumps, have been studied in some detail. Industrial and commercial (I&C) customers can bene fi t fi nancially byo ff ering DSF services to market actors (e.g., the various ‘ aggregators ’ - companies who aggregate small loads and then participate in demand- side markets on behalf of customers - or the National Grid , the ‘ System Operator ’ for the Great Britain (GB)). Distribution Network Operators (DNOs), who run and maintain regional distribution systems, can em- ploy DSF to manage local network restrictions. This can reduce stress at peak times, support planned or unplanned network outages, and defer or avoid the need for network reinforcement [46]. In both cases, the operators are motivated by the growing share of so-called ‘ non-pro- grammable ’ renewable energy sources (NP RES) on the network [49]. The contribution of DSF in GB electricity markets is currently small and mainly for grid balancing on a second-by-second basis. It is therefore a largely ‘ untapped ’ resource. DSF will inevitably be required in future in order to manage the system and market risks [38]. Smart power in- novations - a combination of interconnectors, storage and demand fl exibility (or DSR) - could generate £8 bn per year of savings; according to a report for the recently-established UK National Infrastructure Com- mission [50]. The National Grid (NG) in GB aims to address various barriers to customer participation, and is initially focusing on interacting with I&C customers [46]. Those customers who o ff er demand-side fl exibility gen- erally do so to reduce their electricity costs and generate new revenue streams, enabled by new ICT (e.g., metering and automation). But pilot demonstrations will be necessary in order to overcome the fears of some I&C customers that disturbances to their production processes might lead to reduced outputs or quality. Many such customers work with ‘ aggregators ’ , because current DSR markets in the UK are seen as complex, or their volumes are too small to access DSF tools directly [46]. On-site or ‘ back-up ’ generation provides much of the DSF today [46]. Nevertheless, leveraging further on-site CHP or co-generation plants from the paper industry will enable the sector to interact more easily with the energy market [49]. The Confederation of European Paper Industries (CEPI) has suggested that mechanical pulping, an electro-in- tensive process, can be used for ‘ peak shaving ’ programmes [33]. It can react at reasonably short notice, ranging from as short as 15 min up to one hour, depending on the frequency and schedule of interruptions. In some European countries (e.g., Austria, Belgium and Norway), the paper industry is also involved in ‘ valley fi lling ’ programmes, whereby the whole production process is shifted to the night or to the weekends so as to optimise baseload electricity generation [49]. But, in the paper-
noted that the costs of such gasi fi cation are high and rather unreliable. Presently all direct heat, around 13.5% of that is generated in the UK paper industry, is produced from the burning of NG. Some 2.2 TWh is produced from biofuels - constituting 23% of all fuels utilised in the sector. Indeed, the CPI have suggested to the UK Government that it could be a promising candidate for an above average share of biomass for electricity and heat (> 7% by 2030). That would be equivalent to a growth of biomass use of around 4% per annum, or some 22,000 tonnes of additional resource. According to the CPI, the main technological opportunities going forward are likely to be in the areas of CHP and, in the longer term, CCS. Residuals from paper-making can be employed as a new feedstock for low-quality paper, as a source of minerals, or else applied in the construction sector. A downside of paper waste utilisa- tion is the production of ash from its incineration, which is con- taminated with heavy metals from dyes, inks and surface treatments. 3.3.3. Energy e ffi ciency and heat recovery In meeting the twin challenges of climate change mitigation and energy security, the UK Government ’ s Carbon Plan [38] set out a number of guiding principles. The fi rst among them was to use less energy in the most cost-e ff ective manner in industry as elsewhere. This central role for energy e ffi ciency improvements were echoed at an in- ternational level by the International Energy Agency (IEA) [39], by the EU [40], and countries like Germany [41] and Sweden [42,43]. The IEA have attempted to capture the highest potential reduction in global emissions from e ffi ciency measures in their clean energy pathways or roadmaps out to 2050 [39]. They argue that the cost savings accrued from reducing energy demand could outweigh additional costs by 2.5:1 and, after discounting future savings to present money with a 10% discount rate, save several trillion US dollars. The IEA suggest that the implementation of Best Available Technologies (BATs) - those that are proven technologies, but which may not yet be economically viable - could reduce energy consumption by 20% from current levels [39]. They argue that the BATs o ff er some of the most promising least-cost options for reducing energy consumption and GHG emissions in in- dustry. But action is needed to invest in new facilities and to retro fi t equipment that reach BAT levels, otherwise this capacity will be sub- optimal and very costly to upgrade. Energy e ffi ciency measures have therefore been widely re- commended for the pulp and paper sector and other industries [38 – 43]. Likewise heat recovery opportunities are seen as having a signi fi cant improvement potential [21,26,30 – 32]. In the UK, Hammond and Norman [6] employed a database of the heat demand, heat recovery potential and location of industrial sites involved in the EU-ETS to es- timate the potential application of di ff erent heat recovery technologies. The options considered for recovering the heat were recovery for use on-site (using heat exchangers); upgrading the heat to a higher tem- perature (via heat pumps); conversion of the heat energy to ful fi ll a cooling demand (employing absorption chillers); conversion of heat to electricity (adopting organic Rankine cycle (ORC) devices; see also Chen et al. [44]); and transport of the heat to ful fi ll an o ff -site heat demand. Similarly, the Energy research Centre of the Netherlands (ECN) have ex- amined the potential of modern industrial heat pumps that could gen- erate steam up to 200 °C utilising waste heat [45], including a test cell programme related to the particular needs of the paper industry. The UK analysis by Hammond and Norman [6] provided an indicative assess- ment of the overall potential for the various technologies. The greatest potential for reusing surplus heat was found to be recovery at low temperatures (via heat exchangers), and in its conversion to electrical power (mostly utilising ORC technology [44]). Both these technologies exist in commercial applications, but are not well established. Support for their further development and installation could therefore increase their take-up. A broad analysis of this type, which investigates a large number of sites, cannot accurately identify all site-level opportunities. Nonetheless, the overall heat recoverable in the UK using a combination of these technologies was estimated at 52 PJ/yr, saving over 2.0
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would give rise to ‘ carbon sinks ’ or ‘ negative emissions ’ . However, given the output produced and the size of sites this is considered by some to be unlikely to be realised [34], and have instead advocated carbon capture and utilisation (CCU) in order to use CO 2 to produce fuel, chemicals [23] and other materials [5]. The CEPI believe that other innovative (so-called ‘ disruptive ’ ) technologies could complement the GHG emissions reduction by some 3 MtCO 2e in Europe by 2050 [33].
making process, the fl exibility margin is very small [49] and most of the energy required by the sector (steam and electricity) is generated on- site, therefore mostly ‘ o ff -grid ’ . Nevertheless, the widespread geo- graphical distribution of paper mills across Europe would permit the cost-e ff ective absorption of excess electricity from NP RES, substantially reducing the need for costly investments in grid extensions [49]. Policy makers, and actors in the energy sector more broadly, envisage that the scale and value of DSF is likely to grow in the future as part of a smarter system and with technological advances [4]. DSP will necessarily re- quire the adoption of an appropriate regulatory framework, clear market roles, and a standardisation of processes to reduce transaction costs for aggregators. 3.3.5. Emerging and breakthrough technologies Carbon sequestration from forestry and vegetation is an important part of the Earth ’ s carbon cycle. Worldwide, carbon sequestration technologies capable of removing CO 2 fromthe fl ue gases of fossil fuel- fi red power plants are now being investigated as a matter of some priority [26,32,51]. They are perhaps the key innovative technology in this area. The paper industry has long used biogenic process waste as an energy source, and over half of the energy utilised by the European industry is generated from biomass [52]. The UK industry, represented by the CPI [19], argues that paper production drives sustainable (and certi fi ed) forest growth. Here the IEA worked jointly with the ‘ Carbon Sequestration Leadership Forum ’ and the ‘ Global CCS Institute ’ [53]. They noted that the deployment of large-scale CCS demonstration projects is critical to the deployment of the technology. The IEA progress review [53] suggests that government and regional groups had made com- mitments to launch 19 – 43 such demonstrators by 2020. These devel- opments were identi fi ed in the USA, the EU ( “ particularly the United Kingdom ” ), Canada and Australia. But the partners noted that im- plementation of such a programme would be challenging. The 2008 economic ’ downturn ’ , and the more recent Eurozone fi nancial crisis, have both made the economic situation far more di ffi cult in terms of potential public investments in large-scale energy projects of all kinds. If CCS facilities could be employed together with bioenergy, then it
4. UK pulp and paper ‘ technology roadmaps ’ to a low carbon future by 2050
4.1. Background
A set of technology roadmaps have been developed in order to evaluate for the potential deployment of the identi fi ed paper sector technologies out to 2050. (Alternative modelling approaches have been adopted by the EU [54] and in the USA [55].) The extent of resource demand and GHG emissions reduction has been estimated here and projected forward. Such roadmaps represent future projections that match short-term (say out to 2035) and long-term (2050) targets with speci fi c technological solutions to help meet key energy saving and decarbonisation goals. A bottom-up technology roadmap approach has been adopted, based on those that were initially used by Gri ffi n et al. [7,23,56] to examine the impact of UK cement decarbonisation (for further details see Gri ffi n [57]). Thus, their contents were built up on the basis of the improvement potentials associated with various pro- cesses employed in the paper industry and embedded in the UED [7,9,10].
4.2. Benchmark UK paper technology projections
The projected benchmark is a ff ected by sector output, grid dec- arbonisation, and deployment of BPT/BAT. It is assumed that the GB grid will decarbonise by around 85% over the period 2010 – 2050. GHG emissions pathways of illustrative technology roadmaps for several of the smaller UK so-called energy intensive industrial sectors - pulp and
Fig. 7. Greenhouse gas (GHG) emissions splits of 2050 technology roadmaps of some UK energy- intensive industries under the Reasonable Action (RA) scenario: pulp and paper, lime, glass, and bricks. {The overall trend under a more Radical Transition (RT scenario) is also depicted.} Source: Gri ffi n [47].
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