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1. Sources of Emissions
Emissions into the environment arise from a variety of sources including industry, commerce and transport, communities and the natural environment. The primary emissions from power stations are typically stack emissions. The tall power station stacks were specifically designed to ensure that ground level ambient impacts are minimised.
Additional sources of information on emissions from industry and the general environment may be found in the various government and industry publications which are detailed below.
Emissions from Power Stations
Coal is commonly used for the production of electricity. Coals are usually pulverised prior to combustion.
Dust emissions (fly ash or particulate matter) from the combustion process are generally controlled to a high degree by either electrostatic precipitators or fabric filters (baghouses).
Ash is also extracted from the bottom of the boiler (bottom ash). Ash is transported to ash dams as a slurry, dense phase paste or dry. Fly ash from some power stations is utilised for blending with cement.
Ash is primarily mineral matter (generally silicon, aluminium, iron, calcium, magnesium, potassium, sodium, and titanium in their oxide forms) including traces of other metals. Ash composition depends on the coal properties, combustion technology and conditions.
Other emissions to air include carbon dioxide (CO2), water vapour, carbon monoxide (CO), oxides of nitrogen (NOx), sulphur dioxide (SO2) and minor emissions of metals and organics. Carbon dioxide and water vapour are not included in the NPI listed substances.
Emissions to Air
Emissions to air may be categorised as:
Fugitive emissions
These are emissions that are not released from a point source such as a stack. Examples of fugitive emissions include dust from stockpiles, volatilisation of vapour from open vessels, and material handling. With appropriate management these emission sources are generally minor for power stations.
Point source emissions
These emissions are exhausted into a stack and emitted through a single point source into the atmosphere. An air emission control device such as an electrostatic precipitator or fabric filter (baghouse) may be incorporated into the exhaust system to the stack prior to the atmospheric release.
The air emission sources related to fossil fuel electricity generation include:
- products of fuel combustion (from stacks)
- fugitive dust from coal stockpiles and handling equipment
- fugitive dust from ash storage
- emissions of chemicals used in water treatment
Emissions to Water
Emissions of substances to water can be categorised as discharges to:
- Surface waters (eg. lakes, rivers, dams, and estuaries);
- Coastal or marine waters;
- Stormwater; and
- Groundwater
The emission sources are typically from ash transport wastewater, water treatment plant discharges, floor drains, coal stockpile runoff, and boiler and cooling tower blowdown.
2. State of the Air and Water
The various regulatory agencies including the federal, state and local governments prepare annual tate of the EnvironmentReports which provide an overall review of the environmental health of regional areas. These reports are also complimented by issue specific reports and are usually undertaken by government departments and published throughout the year. Delta Electricity also carries out regular reviews of the environmental status of the air and water providing effective environmental management tools to ensure that environmental impacts are understood and managed.
Relevant website for viewing these reports include:
International
OECD Environmental Health and Safety www.oecd.org
United Nations Environment Program www.unep.org
World Health Organisation www.who.int
US EPA www.epa.gov/
Commonwealth or national agencies
Environment Australia www.ea.gov.au
Aust Greenhouse Office www.greenhouse.gov.au
National Pollutant Inventory www.npi.gov.au
National Health and Medical Research Council www.health.gov.au/nhmrc/
State agencies
EPA www.epa.nsw.gov.au
PHU www.hunter.health.nsw.gov.au
Councils
LMCC www.lakemac.com.au/
WSC www.wyongsc.nsw.gov.au
3. Management of Emissions
Delta Electricity aims to improve operational and environmental performance whenever possible. There has been substantial environmental expenditure (of the order of tens of millions of dollars) in both Central Coast stations since Delta formation in 1996 covering water, air, land and general environmental management initiatives.
The original emission controls at Vales Point, electrostatic precipitators, are being replaced with fabric filter technology. The timeline for fitting the fabric filters is that the first will be installed by August 2007, with the second installed prior to the summer of 2007. Local residents will no longer see any visible emissions from September 2007 with the project completed by November 2007.
It should be noted that different coals produce different visual emissions, although the actual dust burden (particulate emissions) may be the same. This is due to ash particle size and reflectivity. Delta undertakes extensive testing of coals and various blends, and has ceased supply of some coal that results in poor appearance of emissions despite the ash burden being well within regulatory limits.
4. Standards
The power stations operate according to a licence issued by the Environment Protection Authority (EPA). These licences require continuous monitoring of dust in the flue gas exiting the chimneystack, and specifies a maximum allowable concentration of 0.25 grams per cubic metre at 12%CO2. In addition, oxides of nitrogen and sulphur are also continuously monitored. Delta is required to submit regular reports detailing the results of this monitoring and notify the EPA of any exceedance of our licence limit. The monitoring facilities may be audited by the EPA at any time.
On 26 June 1998, the National Environment Protection Council made Australia's first national ambient air quality standards.
The National Environment Protection Measure for Ambient Air Quality (the "Air NEPM") sets national standards for the six air pollutants to which most Australians are exposed, namely carbon monoxide, ozone, sulfur dioxide, nitrogen dioxide, lead and particles (as PM10). Under the Air NEPM, all Australians enjoy the same level of air quality protection.
The standards, which are set out below, are legally binding on each level of Government, and must be met by the year 2008. All jurisdictions will commence formal reporting against the Air NEPM standards in 2002.
The Air NEPM will allow us to be confident that our air quality is the best in the world. And because it requires us to monitor air quality, it will also help us identify potential air quality problems in the future.
The full documentation of the Air NEPM can be viewed at the National Environment Protection Council website at www.nepc.gov.au.
5. Health
Delta Electricity's ambient air quality data collected in the Central Coast region, prior to the fitting of the fabric filter technology, can be summarised as follows:
- All ambient monitoring concentrations were within the relevant air quality criteria. The criteria referenced are those of the National Health and Medical Research Council (NHMRC), the National Environmental Protection Measure for Ambient Air (NEPM) and the World Health Organisation (WHO).
- The highest ambient nitrogen oxide concentrations recorded in the region are associated with motor vehicle emissions.
- Atmospheric fluoride levels, monitored at Wyee and Dora Creek remain well below Australian and New Zealand Environment Council goals for very sensitive vegetation.
- Concentrations of Total Suspended Particulates, measured at the Wyee site, were well below relevant health criteria.
- Dust levels in the vicinity of power station operations, and regionally, were well within the Environment Protection Authority's guidelines.
6. Reporting
Delta provides environmental information each year in the annual environmental reports which are made available to the public in hard copy as well as on the web. This report is complemented by other community information initiatives as outlined below.
Delta has recognised that its icence to operateis linked to the development of long term sustainable relationships with local communities.
To facilitate this, Delta must maintain the respect and trust of all stakeholders through recognising and responding to the needs of both the local and wider environment.
Around Vales Point and Munmorah this active participation has a number of key elements:
- A Community Access Regional Environment (CARE) Forum has been in place for more than ten years, providing feedback on current and proposed activities. This forum is community and environmentally based and links into existing community networks, providing an outlet for community concerns. Performance of the electrostatic precipitators is a standing agenda item.
- Newsletters are distributed from time to time to communities near the two power stations.
- Community research is undertaken regularly. Areas researched included the overall perception of Delta and its environmental, social and economic performance. Where there were concerns, they related largely to stack emissions, truck movements and water discharge. Issues such as jobs and infrastructure remain important as does the local environment. Air and water quality is particularly important.
- Senior management staff regularly attend community and environmental committees and forums where environmental performance issues are discussed.
- Delta produces an annual Sustainability Report detailing a range of environmental issues and performance.
- Community Enquiries - All community inquiries are recorded and reported and Delta environmental officers personally contact the person to ensure the issue is addressed to their satisfaction.
7. Monitoring Data
Delta undertakes continuous monitoring for a range of air and water quality parameters as part of Vales Point and Munmorah environmental licence condition requirements. Air parameters monitored include oxides of nitrogen and sulphur, total suspended particulates, and fluoride which are measured at four locations in the Lake Macquarie and Central Coast regions (two are operated by Delta and two by Eraring Energy) with reports provided to the EPA on a regular basis. Water quality monitoring data is also undertaken on a regular basis both on cooling water and ash dam water discharges as well as the surrounding lakes.
Stack emissions are monitored continuously and usually the station operates well below the maximum limit for dust emissions of 0.25 g/m3, with concentrations of 0.15 g/m3 being typical and NOx and SOx emissions are also well below the licence limits with no licence limit exceedance to date. Full compliance with environmental licence conditions has been achieved over the last two years.
The following graphs provide information on all of Delta power station stack emission performance since 1997 as well as providing a benchmarking comparison with both NSW regulatory limits and relevant international limits. The graphs indicate that Delta power annual station emission rates are well within the regulatory limits.
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