Gaseous emissions

South African standards for emissions of SO₂ and NO_x are being formulated and will be incorporated into DEAT’s 2008 national framework for air quality management. Numerous removal technologies are available to reduce the quantities of these gases prior to their release, ranging from low NO_x boilers and clean coal technologies to flue gas desulphurisation (FGD) and flue gas denitrification. FGD and denitrification systems have not been installed at any of the current power stations. However, FGD will be installed for the proposed Project Bravo coal-fired power station in Mpumalanga.

¹ Calculated annual figures based on coal characteristics and power station design parameters, excluding Camden and Grootvlei and gas-turbine power stations.

We calculate and record on a monthly basis the annual amounts of oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and carbon dioxide (CO₂) emitted from power stations, based on the coal characteristics and power station design parameters. All coal-fired power stations are installing a continuous emissions monitoring system on one unit per power station.

Ambient air quality monitoring and modelling

Eskom runs an ambient air quality monitoring and modelling programme at sites around the country to define general air quality and emissions associated with our operations.

Ambient air quality data gathered over 20 years has enabled extensive modelling of the dispersion of air emissions. Impact studies have been undertaken, including a wet and dry deposition monitoring programme, both within South Africa and in neighbouring countries.

The intention of our ambient air quality monitoring and modelling programme is to monitor ambient particulate, SO₂ and NO_x concentrations on population agglomerations potentially affected by power station emissions, and at other sites deemed necessary in order to understand the current and future impact of Eskom’s activities on ambient air quality.

Modelling of ambient particulate, SO₂ and NO_x concentrations from Eskom power stations is carried out and compared with ambient measurements at appropriate sites.

Ambient air quality In October 2007, DEAT released a discussion document on the establishment of national standards for ambient air quality. Research has been initiated to compare both measured ambient air quality data and modelled data against the proposed standards. Monitored results from 2003 to 2006 will be analysed and assessed against DEAT’s proposed standards. Impacts from all pollution sources on population densities are to be assessed and modelled.   Click here for more detail on ambient air quality monitoring.

Looking forward

Air quality

Our approach to ensure continual improvement in atmospheric air quality management is guided by the following:

• commitment to diversification of our dominant coal energy mix, including the use of cleaner coal technologies, nuclear and renewables
• minimising adverse health impacts of atmospheric emissions
• the identification and use of the best practicable environmental option to control emissions
• the use of detailed cost-benefit analyses to balance the option to control emissions against environmental risks and other factors
• source significance of emissions ranked on health impacts of the emissions, not just on the quantities
• accommodation of the interests of Eskom’s stakeholders by considering economic, social and environmental factors, as far as is reasonably practicable
• taking into account national and international requirements, comparisons and trends
• consideration of potential future legislative requirements
• developing sustainable human resource skills and advanced technology
• compliance with national legislation
• the decision to adopt mitigation technologies based on scientific studies and on a case-by-case basis

Eskom participates in government’s “Basa Njenjo Magoga” programme (the “Clean Fires Campaign”) – a programme aimed at introducing an efficient way of lighting fires in urban areas and where low-level air emissions are high as a result of household fires.

Clean coal technology research Eskom will continue its reliance on coal as its primary energy source for the foreseeable future, although it plans to reduce the coal component of its generating capacity to 70% within 20 years. Clean coal technologies that use coal for power generation in more environmentally acceptable and economically viable ways will form part of this mix. A number of clean coal technologies exist now and are expected to be available over the next 20 years. Examples of these are supercritical pulverised fuel, coal beneficiation, subcritical and supercritical circulating fluidised-bed combustion (FBC), fluidised-bed gasification (FBG), integrated gasification combined cycle (IGCC), and underground coal gasification (UCG). All of these technologies have advantages and disadvantages that need to be understood. Clean coal technologies are thus part of the Eskom research programme that focuses on assessing the different technologies under local conditions. 1MW (thermal) pilot scale pulverised fuel combustion test facility and fluidised-bed combustion and gasification pilot test facility located at the Eskom Research and Innovation Centre in Johannesburg.   Click here for more detail on clean coal research.   Click here for more detail on heavy metals and fugitive emissions.

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