In Europe, approximately 20% of the energy used for heating buildings is lost through glazing. Replacing single glazing by double glazing with the new generation of Low-E coating saves about 480 m3 of natural gas per year in an average dwelling. This means that our low emissivity coatings can limit these losses to an absolute minimum. These days a double glazed window unit with Low-E coating can achieve U values of 1.1 or lower (compared with a single glazed U value of 5.8).
The extra CO2 emissions and energy used for applying the coatings is negligible, amounting to only one thousandth of the savings likely to be achieved during the lifetime of the product. See also the “Products” chapter.
Energy efficiency and CO2 emissions
Practically the vast majority of the direct CO2 emissions in AGC Glass Europe come from melting activities. Some 75% of the CO2 emissions from the furnaces are energy-related, with the remaining 25% caused by decomposition of the raw materials. Recycling of cullet also helps to reduce CO2 emissions by saving raw materials and energy for melting (see the “Recycling” paragraph in this chapter).
Fig. 6 shows that today the amount of energy required to produce 1 tonne of flat glass is only 10% of what it was 100 years ago. (Index: Year 1880 )
Fig. 7 shows that the direct CO2 emissions for AGC Glass Europe Primary Operations plants have decreased. This decrease is partially explained by an increase in energy efficiency, increased use of cullet, the progressive shift from heavy fuel oil to natural gas as the primary source of energy for furnaces, and also the economic recession negatively impacting our production volume. (Index: Year 2002 = 100, on a comparable basis)
Breakdown of energy by type in all AGC Glass Europe plants
The greatest part of the energy is used for the production of glass (melting the raw materials) and is obtained from natural gas (83% of the total energy use in 2019). Electricity accounts for only a minor share of 15% of the energy use in 2020 (see Fig. 8).
In 2005 the European Emissions Trading System (EU ETS) was implemented. The float glass plants situated in the European Union are part of the scheme.
During the first EU ETS phase in the European Union (2005-2007), the CO2 emissions of AGC Glass Europe exceeded the quotas received because the glass market developed better than forecast during these years, thus leading to higher glass production.
During the second EU ETS phase (2008-2012) the CO2 emissions remained below the received allocations due both to the effect of the crisis that led to a reduction in production and to the results of the measures taken to reduce the CO2 emissions. The specific CO2 emissions (tonne CO2 / tonne glass melted) were reduced by 13% between 2008 and 2012.
We are currently in phase 3 of the EU ETS (2013-2020) which endorse more ambitious targets: a reduction of 20% in greenhouse gas emissions. The AGC Group is prepared to meet this challenge, as many projects are being implemented in order to reduce the specific direct CO2 emissions from the float furnaces.
Phase 4 (2021-2030) just started with an objective of 43% greenhouse gas reduction from 2005 to 2030. At the same time, the benchmark value for the production of float glass was reduced from 0.453 tonne of CO2 per tonne of melted glass down to 0.399 for the period 2021-2025. This challenging reduction is met by AGC setting its own target of reduction at the level of -30% between 2020 and 2030.
Air pollution control projects
As already mentioned, our main environmental objective is to further reduce emissions of dust, acidifying pollutants and CO2, but tackling these in an integrated way is a complex matter. Most reduction technologies have disadvantages as well as advantages in terms of efficiency, glass quality, yield, cross-media effects etc.
Under the terms of the Industrial Emissions Directive (IED 2010/75/EU) a new Glass BAT (Best Available Techniques) reference document has been published (2012/134/EU March 2012). This document describes the environmental techniques applicable to the glass industry together with their advantages and disadvantages and associated emission limit values. http://eippcb.jrc.ec.europa.eu/reference/gls.html
Since 2003, AGC Glass Europe has systematically installed an Air Pollution Control (APC) unit at each float line cold repair. The project is led by a multi-disciplinary team (covering the sustainability, engineering, purchasing and technical coordination departments) in collaboration with the plants.
The float plant in Sagunto, Spain, was the only one which was not equipped with an Air Pollution Control unit. In 2018, before the cold repair, a completely new one was installed and put in operation.
Within this project, AGC Glass Europe also participates actively in the process of developing new techniques for minimising our environmental footprint.
Generally, in order to comply with the IED Directive and the local legislation derived from it, the main solution chosen is to install Air Pollution Control units, together with a set of primary measures. These units are made up of a DeSOx system to abate the dust and acid components, and/or a DeNOx system to reduce the NOx depending on the level of reduction required.
Fig. 9 shows the reduction in specific emissions of SOx and NOx (expressed in kg of pollutant emitted in the air/tonne of glass) since 1998 for Primary Operations. This clear reduction has been achieved thanks to the installation of DeSOx and DeNOx systems in our group, together with improvements in technology and more careful selection of our raw materials.
Waste Recycling from the DeSOx
The Air Pollution Control units at AGC Glass Europe’s plants provide an example of an integrated approach to the environment. These units remove acids and particulates from furnace flues. They are based on a two-step treatment. The first step is a gas scrubber where the acids in the flue gases react with a neutralising reagent injected into the reactor. The second step is an electrostatic precipitator that captures the dust from the flue gases as well as the products of the scrubbing reactions.
The process is specific to glass production, as the acid scrubbing reagent in the scrubber is sodium carbonate (Na2CO3), which is a raw material used in glass production. This material was chosen because the reaction of the carbonate with the sulphur oxides in the flue gases produces sodium sulphate (Na2SO4), which is also a raw material for glass.