Minimizing Environmental Impact
Glass manufacture is an energy-intensive process, involving the melting of raw materials at high temperatures. Principal emissions from the process are to air and arise as products of the combustion of fuel and as CO2 from the decomposition of soda ash, dolomite and limestone used in the process.
Key message
Our environmental impact analysis of the float glass and automotive glazing production processes reveals that the significant emissions are carbon dioxide, oxides of nitrogen, oxides of sulphur and, to a far more limited extent, particulate matter.
In the operation of our float plants, heavy oil to natural gas conversion has helped to reduce carbon emissions by around 50 percent over the past 40 years, and a combination of design and operational innovations has made further progress.
View on screen a chart showing the Principal Emissions from the NSG Group in 2009
View on screen a chart showing the NSG Group manufacturing carbon emissions 2009
Recycling
Glass for recycling is a valuable resource. Wherever quality allows, we recycle any glass off-cuts or cullet within our own glass melting lines. Glass from our downstream operations and from our customers represents a potentially useful resource to us.
We gain a double benefit from the use of such cullet. Its use to make glass reduces the requirement for raw materials and avoids disposing of what would otherwise be a waste material. 10 percent cullet use saves 3 percent furnace energy and leads to reductions in CO2 emissions.
Glass for recycling is a valuable resource. Wherever practicable, we recycle any glass off-cuts or cullet within our own glass melting lines. We also recover glass from our downstream operations and from those of our customers.
In 2009, we sent 506,000 tonnes of glass for recycling and bought in 223,000 tonnes. 14,000 tonnes of glass could not be successfully recycled so was sent for disposal (59 percent reduction on 2008).
Additional information: Cullet Usage Within the NSG Group
Waste
The glass manufacturing process itself produces very little waste material. All trimmed glass is recycled back into the melting process and waste is limited to maintenance waste, occasional off-specification raw material that cannot be blended and packaging waste.
If glass is produced that cannot be remelted on-site, it is sent, where practicable, for external recycling. We use the waste hierarchy to guide our disposal options. In this system, landfill is the least favored option.
However, with significant tonnages of mineral materials arising for disposal we have not eliminated landfill completely.
We disposed of 52,731 tonnes of non-glass waste (a 26 percent reduction on 2008), of which 1,301 tonnes of hazardous (an 83 percent reduction on 2008) and 23,387 tonnes of non-hazardous waste (an 11 percent reduction on 2008) were sent to landfill. We disposed of 11,067 tonnes of hazardous waste in 2009. This remains high due to the production of LCD glass units at Suzhou, with used acid being treated off-site rather than within the facility.
Emissions to air
These arise primarily from the combustion of fuel in melting the raw materials. The principal materials emitted are oxides of sulphur and nitrogen. Some particulates arise partly from trace components in the fuel and some from the glass formation itself.
Oxides of sulphur and nitrogen
The fuels we use: oils and natural gas, all contain sulphur compounds as contaminants. Natural gas, our preferred fuel, contains less sulphur than oil. Heavy fuel oil contains the highest levels of sulphur of all our fuels, especially that readily available in Japan. Our furnaces in Japan are therefore fitted with efficient emission gas-cleaning equipment. The combustion of such fuels can produce a mixture of sulphur oxides (SOX).
Most sulphate arising from soda lime glass manufacture is released as sodium sulphate, which is of low toxicity. Nitrogen compounds released arise from the combustion air in which the fuel is burnt. At the high temperatures used in glass-making, the nitrogen in combustion air is oxidized to a mixture of nitrogen oxides (NOX).
Actions we take to reduce or prevent the emission of oxides of nitrogen
Most of the pollutant nitrogen oxides in our emissions are formed simply by the reaction of nitrogen and oxygen in the furnace at very high temperature. The amount of NOx formed is related to: the flame temperature; the air/fuel mixing rate; the “hotspot” temperature in the furnace; and the concentration of oxygen in the furnace atmosphere. We understand what operating conditions affect each of these factors and can thus minimise the formation of NOx. Other less common sources of NOx are nitrogen in the fuel and nitrate added to the glass batch and these can also be taken into account.
As well as minimising NOx formation in the furnace, we can install secondary emission control equipment to further reduce NOx emissions. This is typically based on the use of a selective catalytic reduction unit that uses ammonia to reduce the NOx to nitrogen and water vapour. Such SCR units are often installed after a scrubber and an electrostatic precipitator that reduces the amount of sulphur oxides and dust in the emissions thus providing a complete emission control system.
Reducing carbon emissions
In 2009, the NSG Group was responsible for the direct and indirect emission of 4.7 million tonnes of CO2. This represents a 10 percent reduction on 2008, but is mainly due to reductions in production levels.
Our direct emissions were 3.7 million tonnes (a 10 percent reduction on 2008). Direct emissions occur from our furnaces and from fuel used in bending and toughening furnaces in Automotive and Building Products. In Europe, externally verified, direct 2009 CO2 emissions from the Emission Trading Scheme were reduced by 17 percent compared to 2008.
In the operation of our float plants, heavy oil to natural gas conversion has helped to reduce carbon emissions by around 50 percent over the past 40 years, and a combination of design and operational innovations has made further progress.
In 2009, NSG Group employees flew a total of 44 million kilometres. This corresponds to 5,000 tonnes of CO2 emissions and represents a 47% reduction on 2008 data.
Emissions of ozone depleting substances
Ozone depleting substances include chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCFCs). Many ozone depleting substances are banned or are currently being phased out.
NSG Group are using fluorinated gases as a replacement for ozone depleting substances in refrigeration and air-conditioning equipment. These gases do not damage the ozone layer but they are powerful greenhouse gases that trap heat in the atmosphere and contribute to global warming. The refrigeration units are contained and only small quantities of material is required for top up. These gases are therefore not a significant environmental issue, however, due to the potent global warming nature of these gases it is recognised that these small quantities should be recorded and reported in future.
Spills and environmental fines
During 2009, NSG Group had one 115 litre spillage.
Fines
In 2009, NSG Froup was fined 47,500,000 VND (190,000 JPY) in Vietnam and 10,000 RUB (29,000 JPY) in Russia for non-compliance with environmental legislation.
Non-monetary sanctions
In 2009, NSG Group had 7 non-monetary environmental sanctions applied for minor issues such as very small spills or incomplete documentation.