The Waterberg is home to vast coal deposits. It is estimated that the coal resource accessible by open cast mining is of the order of 60 billion mineable tons insitu of which, if beneficiated, 40% would be of an Eskom type product which can be used in a conventional PF boiler (Medupi type power stations). This would be adequate for 24 additional power stations (assuming 50 year life and 6x 800 MW size units) (Eskom, 2009). The underground resource is estimated to be 100 billion mineable tons insitu which probably could also supply a number of power stations. In addition to Eskom power stations, several large industrial projects are currently planned to be constructed in the region with their
respective feasibility studies at various stages. Such projects include the potential construction of additional coal to liquids plants by Sasol.
A coal fired power station typically has an operational life of 50 years excluding life extension opportunities. It is therefore foreseeable that the region will include several additional coal fired power stations as well as various other industrial complexes. Current planning, highlighted above has indicated that an additional 220Mm3/a of water could be transferred into the area. In order to evaluate the adequacy of such demands two scenarios were investigated, in line with the scenarios modelled for the ambient air quality, in the forthcoming chapter. Both scenarios were modelled on the assumption that all future coal fired power stations would include FGD as it was necessary to test the limits of water supply (figure 3-4).
Figure 3-4 Comparison of water demand and water availaibility for all competing water users in the Lephalale region
Note: Scenarios 1 and 2 (refer to appendix 3) differ with respect to the inclusion of the Sasol
Mafuta projects. Both scenarios included the development of Medupi coal fired power stations as well as two additional dry cooled coal fired super critical power stations with FGD, associated mining activities and residential developments as associated with the expansion of the various industrial expansions. All quantities obtained for the scenario planning was obtained from Eskom’s current interaction between Eskom, DWA and Sasol. Scenarios exclude the projected agricultural allocation, which is estimated to be constant at 16Mm3/a
0 50 100 150 200 250 200 9 201 0 201 1 201 2 201 3 201 4 201 5 201 6 201 7 201 8 201 9 202 0 202 1 202 2 202 3 202 4 202 5 202 6 202 7 202 8 202 9 203 0 203 1 Year (January of each year plotted)
1 0 ^ 6 m ^ 3 /y e a r
Scenario 1 demand excl. irrigation
Scenario 2 demand excl. irrigation
Exxaro Pipeline 13.5 10^6 m^3/a
Mokolo Dam Yield 23 10^6 m^3/a
Phase 1A : Interim Scheme 50x10^6 m^3/a (July 2014) Peak demand 5.2x10^6 m^3/month
1 year slip transfer scheme Demand 73x10^6 m^3/a Delivered from Mokolo Dam
Phase 2A : 1/2 Transfer Option Crocodile (West) -110x10^6 m^3/a Mokolo Dam - 23x10^6 m^3/a (long term)
Phase 2B : Final transfer option 2030 total demand - 220x10^6 m^3/a
Crocodile (West) total -197x10^6 m^3/a
Medupi 1st unit Sep 2010
Total demand 2030 103x10^6 m^3/a, Including Matimba, Medupi (with FGD) Coal 3 (with FGD), Total demand 2030 198x10^6 m^3/a, Including Matimba, Medupi (with FGD) Coal 3 (with FGD), Coal 4 (with FGD) and two SASOL Mafuta Projects
The solid red line indicats the water availaibilty at different time periods with respect to the phasing of the various water augementation schemes. The line illustrates that additional water water will only become available in two phases the first been in 2011 and the second 2014. The blue circles highlight points of risk, owing to the fact that any potential slip in the water augmentation phasing could result in a water deficit for the Medupi Power station. The most critical point is the 2011 phasing of the projected water supply. Two scenarios were modeled (blue and purple line). Scenario two, which is a worst case scenarion indicates that the inclusion of two additional coal fired power stations to Medupi as well as the planned construction of the proposed Sasol Mafuta project would significantly limit the opportunity for any future industrial development in the region, despite the regions abundance of coal
It is clearly evident that, assuming the continued industrial expansion of the Waterberg region, there is only sufficient water for two to three additional power stations, with wet FGD. Current planned water supply in the region can be considered to be a severely limiting factor to future development, with planning unlikely to be capable of meeting the demands should the full extent of the coal resource be exploited. It should be noted that all moels excluded the amount of water required for irrigation purposes, making the projections even more onerous.
Furthermore it should be noted that the planning of future water transfer schemes will be required to span ever increasing distances from already water stressed regions, resulting in the increasing of the engineering and environmental scope. Time lines associated with the various aspects of implementing such transfer schemes (financial approvals, design, EIA, construction) are also likely to extend. In the past, partly due to projects being smaller and subjected to less onerous environmental scrutiny it was possible to implement projects relatively timeously. The increasing complexity of such transfer schemes further increases the likelihood of public appeals and environmental and social constraints.
Supplies to Medupi are at risk until the second phase of the CMWAP has been commissioned. Any delays in implementation of the pipeline from the Crocodile River will increase this risk even further.
Water scarcity in the Waterberg region is likely to, at some point in the future, severely limit the exploitation of the coal resources. Medupi power station, with and without FGD, is considered to be at risk as a result of the water supply issues.
Any decision to install FGD should, solely based on water scarcity issues be deferred as long as possible until such time that the inclusion of the technology can be justified in terms of environmental and air quality considerations. It is further likely that alternative FGD technologies, which are less water dependent will need to be investigated in an attempt to manage the scarce water resources.
Information presented in both this and previous chapters has highlighted that the installation of FGD requires the careful consideration of several interrelated environmental and technical issues all of which have significant impacts on both plant and the surrounding environment. It is therefore essential that any decision to install FGD needs to be motivated by a clear need.
4. MODELING THE EFFECT OF MEDUPI ON AMBIENT AIR