THE DECISION TO INSTALL FLUE GAS DESULPHURISATION ON MEDUPI POWER STATION: IDENTIFICATION OF ENVIRONMENTAL CRITERIA CONTRIBUTING TO THE DECISION MAKING PROCESS Tyrone C Singleton THE DECISION TO INSTALL FLUE GAS DESULPHURISATION ON MEDUPI POWER STATION: IDENTIFICATION OF ENVIRONMENTAL CRITERIA CONTRIBUTING TO THE DECISION MAKING PROCESS Tyrone C Singleton A research report submitted to the Faculty of Engineering and the Built Environment , University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg 2010 DECLARATION I declare that this research report is my own unaided work. It is being submitted to the Degree of Master of Science in Engineering to the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination at any other University Tyrone C Singleton Day of year 2010 ABSTRACT Survival of society has always been dependent on ensuring that a balance is continually maintained between the variables of social needs, resources and the environment. The difficulty is that these three elements are more often than not in conflict with each other. Arguably without such conflicts environmental decision making would be far simpler in the knowledge that the potential solution, although not pleasing everyone would be capable of responding to a range of ecological and economic concerns. Environmental decision making requires a structured holistic approach that allows for the evaluation of alternative solutions against an array of often conflicting objectives, although no specific decision making structure is advocated multi criteria objective decision making provides a means to achieve such ends. The methodology provides for the identification of all objectives which are then used to evaluate alternative scenarios or solutions against. The following research report seeks to identify the environmental criteria that would need to be considered as part of a multi-criteria decision making structure. The report highlights the complexities and often conflicting elements that exist even within the narrow scope of environmental objectives. All discussions are made with specific reference to Eskom’s requirement to comply to future air quality legislation and the potential requirement to install flue gas desulphurisation technologies on its Medupi Power Station. Legislative, technological, water and air quality issues are identified and explored as to how they should be evaluated as part of the overall environmental decision making criteria. Through the identification of the environmental criteria it is hinted that Eskoms narrow mandate of electricity production at the lowest cost could potentially prevent the organisation of fully engaging in a holistic decision making process. ACKNOWLEDGMENTS I would like to acknowledge the following people: • My wife, Ashleigh Singleton, for her understanding and support through the past three years • My supervisor, Dr Linda Jewell, for her encouragement and assistance in finalising this research report • My Eskom colleagues: o Ebrahim Patel for all his technical input and explanations o Naashaud Hairparshad and Justice Bore for their provision of technical information and explanation o Kristy Ross for her dedicated assistance on all ambient air quality modelling o Alwyn van der Merwe for is explanations concerning the crocodile west water transfer scheme • Eskom for providing me with financial assistance i PREFACE South Africa currently has a regulated national electricity distribution grid, mainly coal based electricity generation portfolio, as a result of the abundance of coal. In addition to coal the country also has small amounts of nuclear (5%), pumped storage and hydro (2%) generating capacity (Heinrich et al, 2007a). South Africa’s base load coal fired power stations are all of the pulverised fuel (PF) type and utilise either electrostatic precipitators or pulse jet fabric filters to remove particulate matter from the flue gases. To date no South African power station makes use of any gaseous emission pollution control (Eskom, 2009). The South African economy is currently experiencing greater than expected economic growth, resulting in a rapidly declining surplus of power. In South Africa, demand for power is expected to grow at around the same pace as gross domestic product, with long-term forecasts putting electricity demand on a growth path of 4%. This forcast is based on the 6% GDP growth included in the Goverments ASGISA commitments. Despite the economic crises in 2008/09 and the subsequent decrease in electricity demand current levels of electricity demand for the 2010/11 financial year have indicated an approximate increase of 8% from 2008 levles. In 2003, there was an installed capacity of approximately 40 000 MW, but South Africa's excess capacity, built up over the last 15 years, is close to being exhausted, requiring new capacity to be built. (Engineering News, July 2005) As a result of the increased demand, Eskom is currently engaged in an extensive build programme. Medupi will be the first of the large base load power stations to be constructed as part of Eskom’s new build programme. Medupi Power Station will be the first coal fired power station to be constructed by Eksom since the completion of Majuba in the 1990’s. An environmental authorisation was issued to Eskom, in 2006, allowing for the commencement of construction, subject to several conditions including the compliance to current and future air quality legislation. Medupi Power Station will include pulse jet fabric filters as well as low NOx burners, therefore the abatement of particulate matter and nitrogen dioxide was not considered to be a significant concern. Sulphur dioxide emissions were however identified as a potential cause for concern ii SO x both the organic sulphur and pyrite sulphur contained in the coal are oxidised to sulphur dioxide (SO 2). Depending on the combustion conditions, a small amount of sulphur trioxide (SO 3) may also be formed. Sulphates represent a small fraction of the total chemical composition of coal and have no significant role in the combustion process itself or in contributing to emissions. The amount of sulphur emitted from coal combustion is a complicated function of the relative amounts of pyrite and organic sulphur in the coal and the combustion conditions (Alphen, 2008). Generally, 5–10% of the sulphur may be retained in the fly ash, the remainder and indeed the vast majority, in the absence of flue gas desulphurisation is released into the atmosphere as SO 2 (Gerricke, 2007) Internationally, the significant amount of SO 2 produced by the combustion of coal in PF power stations is scrubbed out of the flue gases by various flue gas desulphurisation technologies. The implementation of flue gas desulphurisation (FGD) at international power stations has largely been the result of stricter environmental and air quality legislation (Nalbandian, 2000). Typically, South Africa, has lagged behind international legislation with environmental trends often been driven by a series of socio-political and economic factors resulting in what has been considered as less stringent environmental requirements. However, since 1998 and the promulgation of the National Environmental Management Act, 1998 (Act No 107 of 1998) South African environmental legislation has been systematically tightened and in many cases aligned with international trends. Several Flue Gas Desulpurisation (FGD) technologies exist, all of which are considered to be associated with significant capital and operating costs to the electricity industry. The most common technology for reducing sulphur dioxide (SO2) emission is by scrubbing with water containing an alkaline substance known as sorbent such as limestone or any other alternative calcium carbonate substance, for example dolomite (Soud, 2000). It is the aim of this research report to identify and where applicable model the potential impacts of Medupi, with and without FGD, via dispersion modelling, impact identification and the requirements of water relative to the availability of the resource for the installation of wet FGD. As such it is an evaluation of certain technical iii environmental information which will be required for a comprehensive Multi Criteria Decision Assessment This research report is divided into five chapters. In Chapter 1 the background of this study is introduced. A general literature review briefly discusses sustainability and how the various elements which make up sustainability contribute to decision making. The narrow mandate of Eskom is questioned within this context as illustrated by discussing the potential requirement to install flue gas desulphurisation on Medupi power Station. In addition the chapter will provide an overview of the air quality legislation including emission and ambient air quality standards as a means for countries to ensure that air pollution is brought under control and that the detrimental effects on human health are minimised. The introduction of legislative and technonological issues will provide a contextual backdrop for all modelling and technical discussions in the forthcoming chapters. Multi Criteria objective decision making is identified as a potential tool for sustainable decision making. The chapter is a precursor to the forthcoming chapters which seek to identify the technical environmental criteria which will be the input into a decision making matrix. Chapter 2 identifies the origin of