2.1. A Brief Historical Overview
Since the Stone Age, people have used naturally occurring glass formed from common elements present in the earth’s crust, fused by high volcanic heat, and vitrified by rapid air cooling. Pliny the Elder, in his Naturalis Historia
, places the discovery of glass by certain merchants in today’s southern Lebanon, where analyses of the sand of the Belus river have revealed high-silica sand containing sufficient quantities of calcium components [15
]. The date of the first production of man-made glass is uncertain, because it is lost in time, but was first probably developed in a region of Mesopotamia [16
Around 1500 B.C., glass manufacture appeared as a major industry in Egypt [17
]. The fundamental breakthrough in glassmaking was the discovery of blowing in the last century B.C., and the ancient Romans greatly increased the variety of shapes for hollow glass items and successively began to use glass for an architectural purpose. The Romans also spread glassmaking technology through conquests and trade relations across western Europe and the Mediterranean. The Roman tradition of very fine glass products did not continue in the Middle Ages, when Venice assumed the role of glassmaking centre of the western world [18
In 1291, the Venetian authorities ordered a transfer of glass manufacturing for fire safety reasons to the island of Murano, where in the second half of the 15th century, craftsmen started to produce crystal using quartz sand and potash from sea plants. To this day, the island remains a world-renowned centre for fine glassware. The subsequent development of lead glass crystal has been attributed to the English glassmaker George Ravenscroft [19
], who patented this new product in 1674. In the same period (i.e., in 1688), an innovative process was developed in France to produce plate glass, mainly for high quality mirrors and optical products.
It was only in the latter stages of the Industrial Revolution that mechanical innovations for the mass production of glass and scientific research on glass composition, its properties, and applications took place.
Modern glass technologies make use of important discoveries, mainly related to automation processes, occurring in different sectors of the glass industry. Consider, for example, Michael Owens’ bottle-blowing machine invented in the early years of the 20th century, or the automated production of the Belgian Fourcault, which managed to draw vertically a continuous sheet of glass from a tank, or to the latest technological innovation known as the ‘float process’. In this latter process, developed after the Second World War by Britain’s Pilkington Brothers Ltd., molten glass is poured across the surface of a bath of molten tin, forming a floating ribbon with perfectly smooth surfaces on both sides.
Obviously, technological innovations continue, using multiple contributions from the most diverse scientific fields, ranging from electronics to chemistry, from nanotechnologies to space engineering, from life science engineering to renewable energy, biotechnology, etc.
2.2. The European Glass Industry Landscape
The European global glass production for 2006–2015, reported in Figure 1
, shows that after a drop in production in 2009 (32.2 Mt), it is currently at almost the same level as it was 10 years ago (around 36 Mt).
shows the evolution of European glass production (Mt) by sector during 2006–2015.
The two most important European glass sectors are container and flat glass, accounting for about 70% and 25%, respectively, of total glass production, followed by the combined production of domestic glass (2%), continuous-filament glass fibre (2%), and special glass (1%) [22
The European container glass industry is capital intensive, and with its 160 manufacturing plants, employs directly about 50,000 individuals, representing a fundamental part of Europe’s packaging sector as well as an important contributor to its economy. It produces high-quality glass packaging products for food and beverages in addition to flacons for perfumery, cosmetics, and pharmacy for the global market. Glass packaging is a resource-efficient and endlessly recyclable material, which makes it a useful packaging resource in the context of sustainable consumption and production [21
The flat glass sector includes all glass produced in flat form, regardless of the type of manufacturing process involved. There are two types of flat glass production processes: float and rolled glass. The first, used in about 50 plants, dominates the sector’s output (over 95% of total flat glass production in Europe). The end-products of the float process, large sheets of glass, are fairly homogeneous and are often further processed to give the glass specific characteristics. The sector employs directly approximately 15,000 individuals and many more in downstream treatment. The two most important markets for flat glass are the building (windows and facades) and automotive industries (windscreens, side- and rear-side glazing, etc.), followed by solar energy applications (photovoltaic and thermal panels) [21
The domestic glass sector accounts for more than 300 facilities, mainly small and medium enterprises, and comprises the manufacturing of glass tableware, cookware, and decorative items such as drinking glasses, bowls, plates, cookware, vases, and ornaments [21
The European glass fibre sector employs directly approximately 5000 individuals, and produces principally continuous filament glass fibres known as fibre-reinforced polymers or glass-reinforced plastics. These products have a relatively high value-to-mass ratio, and are mainly used to produce composite materials as weight-lightening reinforcement components in sectors ranging from the automotive and transportation (e.g., aircraft) sectors to the wind energy, agriculture, construction, communication, electrical, electronic, and sport and leisure sectors [21
The special glasses sector regroups a large range of products, such as lighting glass, glass tubes, laboratory glassware, glass ceramics, heat-resistant glass, optical and ophthalmic glass, and extra thin glass for the electronics industry, having a high added value due to the intense technological content.
The extreme diversity of the European glass industry is not only in the products made, but also in the manufacturing techniques employed. For instance, manufacturing techniques vary from the small electrically heated furnaces in the high-temperature insulation wools sector to the cross-fired regenerative furnaces in the flat glass sector, producing up to 1000 t per day. This industry also includes many smaller installations that fall below the 20 t per day threshold. Natural gas is the primary source of fuel in European glass production, typically accounting for more than 70%, while electricity accounts for around 25%, and other fuels (mainly fuel oil) make up the remaining 5%. Melting furnaces—employing combustion-heating (with air- or oxy-fuel burners), direct electrical heating, or a combination of the two (electric boosting)—are the major energy users. Usually, the energy necessary for melting the glass may account for around 75% of the total energy (in terms of final energy) requirements of glass manufacture [22
]. Typically, melting furnaces operate with an overall efficiency of 50–60%, where structural and flue gas losses represent, respectively, 20–25% and 25–35% of total losses [5
]. Therefore, melting furnaces are the most important for improving technological efficiency in glass manufacturing, followed by refining and conditioning [23
Until the mid-1970s, manufacturing industries with higher energy and raw material intensities, such as the glass industry, accrued large efficiency savings, improving resource productivity and minimizing environmental impacts as a result of the significant increase in energy prices after the oil crises in the 1970s. Over time, a greater awareness of the complex environmental implications of many industrial activities has emerged worldwide, leading policy-makers and institutions responsible for protecting the environment and safety to increase legislative pressure and implement various policies and measures. In the late 1990s, the glass industry went through a period of reorganization to reduce costs and compete more effectively in the global market. To benefit from economies of scale, companies merged, and the groups dominating the sector became more international in their operations.
Particularly, the decoupling of both energy and natural resource demand from economic growth has been attempted through the adoption of a wide range of mandatory and voluntary tools. Over the past decades, the European glass industry has applied various measures, such as technological innovations spanning both plant modernization, improvements in material and energy efficiency, and a higher substitution of primary raw material with cullet and fuel oil with natural gas, to promote competitiveness and environmental performance. The main reasons are due to the coming into force of the Industrial Emissions Directive (IED) 2010/75/EU and the legislative proposal of the EU ETS revision, presented to the European Commission in July 2015 for phase 2021–2030 (phase 4), in line with the EU 2030 Climate Energy Policy Framework, to reduce EU GHG emissions by 43% compared to 2005.
The IED Directive outlines EU-wide thresholds for air and water emissions for different industrial sectors, applicable from 2016 onward. The thresholds for ‘Manufacture of Glass’ are determined by the Best Available Techniques (BAT) Reference Document (BREF), originally adopted by the European Commission in 2001 and revised in 2013, that defines permit conditions for glass installations in Europe. Important issues for the implementation of Directive 2010/75/EU in glass manufacturing are the reduction of air polluting emissions; the efficient use of energy and raw materials; the minimization, recovery, and recycling of process residues; and the effective implementation of environmental and energy management systems. This will possibly determine the investment for future environmental measures in the European glass industry to increase considerably: by 2020, about EUR 14 billion will be invested, with an annual increase of up to 45% [24
]. Based on BAT Reference data [3
] (p. 92), the melting energy requirements experienced in the various glass sectors vary widely, from about 3.3 to over 40 GJ/melted t. However, most European glass is produced in large furnaces and the average direct energy requirement for melting is generally around 8 GJ/t [1
]. For the container glass industry, fuel and direct CO2
intensity result in an average of 6.4 GJ/t and 0.48 tC02/t, respectively [2
The final energy consumption (fuel and electricity) and total CO2 emissions (direct or verified emissions from process and combustion, and indirect emissions from electricity utilization) for the European glass industry (EU25/27), and its sub-sectors, based on data gathered in the framework of the European Union–Emission Trade System (EU–ETS) during 2005–2007 (phase 1) has been reported by Schmitz et al. in 2011. The overall final energy consumption (2007) of the EU25 and EU27 was, respectively, 344 PJ and 352 PJ, with a share of electricity of around 17%. The European container glass industry contributed 46%, by 158 PJ (EU25) and 161 PJ (EU27). Overall, CO2 emissions (direct and indirect) were, respectively, 26.9 Mt (EU25) and 27.5 Mt (EU27) for the global glass industry, and 12.4 Mt (EU25) and 12.6 Mt (EU27) for the container glass industry, of which about 80% are direct emissions (combustion and process emissions).
The specific energy consumption for glass products and related emission data are provided in an aggregate form due to restrictions derived mainly from competition issues [3
] (p. 407). Unfortunately, this limitation does not allow for a comprehensive analysis on the various industrial approaches adopted by major European glass producing countries so as to compare improvements in resource efficiency and pollution reduction.
The lack of public data both at the European and national levels concerning final energy consumption and the different energy sources used in various glass sectors limit the provision of a benchmark related to the best practices developed to date, as well as the suitability of sustainability initiatives implemented.
The European glass industry has been particularly affected by the economic crisis, since its activity relies heavily on the economic health of other sectors, such as the construction and automotive as well as packaging sectors. This could severely limit the investment capacity that would address issues related to the environmental performance required by the IED Directive. Weak economic growth and slower domestic demand are specifically due to austerity policies at the European level and together account for the crisis affecting this sector.
Between 2005 and 2010, flat glass was affected by a 7% decrease in production following the crisis of 2008, and, in 2013, 15 out of a total of 60 floats in Europe have ceased production. Several have closed or are in danger of disappearing. Following a constant increase in demand until 2007 for flat glass, from 2008 onwards the demand dropped sharply due to a decrease in the production of the automotive industry, together with the relocation of assembly lines, competition from China for solar panels, and the slowing down of the construction sector. These four factors have resulted in an unexpected 20% overcapacity for floats due to the traditionally risky strategies of multinational companies. From 2000 to 2010, the sector lost 32% of its jobs, mainly in Germany, Poland, France, the Czech Republic, Italy, Belgium, and Austria [26
Meanwhile, during the same period, the European container glass sector has experienced a decrease of more than 10% because of the economic crisis and the relocation trend. The same pattern was observed in the glass fibre sector, as many producers have had to temporarily shut down some of their furnaces to adapt to the volatile market demand, which led to the postponement of several investment projects. However, this sector now appears to be picking up once more [26