CIP EIA: Marine Study Info Requirements, Updated 31 Jan 2007
Environmental Impact Assessment
for the proposed Coega Integrated LNG-to-Power Project:
Information for use in the specialist study on discharges to the marine environment:
Prepared by: Roy van Ballegooyen & Paul Lochner, CSIR
Prepared for: Nico Gewers (Eskom) Mike de Pontas (iGas)
DOCUMENT HISTORY:
Date of original document: 10 August 2006
Date of updated version following marine workshop: 6 September 2006
Update from Black and Veatch (B&V): 31 January 2007
PURPOSE OF THIS DOCUMENT:This document is to be used by Eskom, iGas and their consultants, as well as members of the CSIR EIA team, to: (i) confirm key assumptions; and (ii) source relevant information required for the marine discharges specialist study.
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This document has been updated with outcomes from the marine specialist workshop held on 31 August 2006 at CSIR Stellenbosch. The purpose of this updated version is to provide a common understanding of key assumptions that will be used by the EIA team in their studies and to present the agreed programme for sourcing additional information.Presentations from this workshop have also been made available to the CSIR specialist team for use in their studies.
NOTE:
B&V Comments contained herein relate specifically to the CCGT Facility. Issues related to the LNG Facility must be addressed by iGas and Sofregaz.
1.Description of project components
There is a requirement to understand the individual capacities and linkages between the LNG terminal and the CCGT power plant as it may influence the excess/waste heat discharged.
1.1Capacities:
What are the various project components/elements and capacities being investigated:
- The proposed power plant capacity ranges from 800 MW (open cycle) increasing to 2400 MW (CCGT).
Response from Paul Lochner (PL), 10 Aug 2006: Refer to CIP operating scenarios in email from Emma Gordge to specialists on 10 August 2006, which also explains the mid-merit and baseload aspects of these scenarios. (Note updates in this document of 6 Sept 2006.)
- LNG re-gassification capacities (suggested from 1.5 MTPA to 5 MPTA)? How do we handle these capacities, i.e. do we simply assume final capacities? If so, what will these capacities be?
Response from PL (10 Aug 2006): Assume 1.7 mtpa. Refer to Background Information Document attached to email from Emma Gordge to specialists on 10 August 2006.
- What are the other aspects of marine water quality that need to be assessed? For example:
- Storm water run-off. We have assumed that storm water needs to be assessed and indications are that. (Outcome of 10/8/2006 workshop: No dirty stormwater run-off to sea from site, only a freshwater issue).
- Desalination plant emissions (e.g. brines and any other emissions);
B&V Response: Water treatment and desal system will consist of water intake structure, dissolved air floation, micro/ultra-filtration followed by seawater and brackish water reverse osmosis followed by demineralization process including condensate polishing. Process descriptions are provided in Section 1630, System Descriptions of the CCGT Works Information. Chemicals to be used have been described earlier; exact quantities have not been determined. Waste produced includes solid sludge and brine. Solid waste will be hauled off-site. Brine concentrations have been provided but are not expected to be an issue for combined cycle operation as they will be significantly diluted because SWRO rejects is send to cooling water discharge channel. Example: SWRO reject flows of 6,000 TPD will mix with cooling water flow of 2.3 million tons/day.
- Spills associated with the diesel to be used to run the plant for the first two or so years. (Priority 1:Diesel spill only to be considered. Workshop decided that there is presently no need to undertake diesel spill modeling but EIA team will assess risks. Titus Mathe (Eskom) to confirm.)
The desalination plant and diesel spill concerns were raised subsequent to the original proposal. As such they presently are not deemed to be part of the assessment, however should it be decided that they are to be included, it will be necessary to know to what discharges/effluents are likely to be associated with these project elements (desalination plant and potential diesel spills).
Action / Status1)Phillip de Souza (CSIR specialist) to provide information on storm water and desalination plant (timing to be confirmed)
2)PL to arrange marine specialist study workshop to clarify matter such as need for and possible approach to oil spill modeling (planned for late August).
1.2Integration of LNG and Port Facilities
Is the CCGT plant of a nature whereby heat from the power plant can be used in the re-gasification process, thus reducing the waste heat to be discharged? B&V Response: use of power plant waste heat for LNG vaporization was examined and determined to not be economically justified. No thermal integration between LNG Facility and Power Plant are envisioned at this time.
What are the likely deviations from these operational conditions (Table 1)? For example, what are likely to be the worst case scenarios in terms of “upset” conditions and/or phased development proposed, i.e. as a worst case scenario the “non-integrated” to be considered.
Action / StatusEskom and iGas to respond to above questions and check and revise (where necessary) Table 1.
Operational scenarios to be considered in marine discharges study (developed at workshop on 31 Aug 2006): (NB: TEAM TO CHECK)
- Worst case scenario(initial 2 year operational period): 1200 MW power output, CCGT mode, with 90 000 tonnes per hour of seawater through-flow at delta T of 7 degC. Plant powered using liquid fuel (diesel).Expected to be a mid-merit power supply (i.e. 6am to 9pm from Monday to Friday).B&V Comment: Circ water flow rate of 90,000 ton/hr and 7 deg C rise are still good estimates.
- Worst case scenario: 2400 MW power output, CCGT mode, 180 000 tonnes per hour of seawater through-flow at delta T of 7 degC. From a marine discharge perspective, this scenario could be using LNG (in non-integrated mode) or using liquid fuels. Base load power supply (24h/day, 7 days/week).B&V Comment: Circ water flow rate of 180,000 ton/hr and 7 deg C rise are still good estimates.
- Likely operating scenario: 2400 MW power output, CCGT mode. LNG and CCGT plants integrated. Base load power supply (24h/day, 7 days/week). (Priority 2: Mike de Pontes (iGas) to supplyconceptual design details,such as seawater through-flow and delta T, by 15thOctober).B&V Comment: Based on relative sea water flow rates the sea water temperature rise will be 6.3 deg C. The LNG Facility sea water flow is significantly less than the power plant so the sea water cooling effect imposed by the LNG vaporization process only reduces the power plant 7 deg C rise by 0.7 deg C. Resultant, integrated sea water temp rise is 6.3 deg C.
Co-discharge scenario:Desalination brine volumes and concentration/salinity elevation:B&V Response: Reference the B&V water balance for summary of sea water & brine flow rates.Brine (from sea water reverse osmosis) reject quality is as follows based on older data from Eskom. The higher reject rates are associated with diesel fuel and lower rates with gas fuel. Note that these are just concentrations from SWRO. They will be significantly diluted during combined cycle operation because SWRO rejects is send to cooling water discharge channel. E.g. SWRO reject flows of 6,000 TPD will mix with cooling water flow of 2.3 million tons/day.
Estimated SWRO Reject QualityMax SWRO Reject Rate / 6000 / MTPD
Min SWRO Reject Rate / 520 / MTPD
Constituent / Seawater Concentration (g/kg) / SWRO Reject Concentration @ max flow (mg/l) / SWRO Reject Concentration @ min flow (mg/l)
Sodium / 10.77 / 17000 / 15000
Magnesium / 1.29 / 2100 / 1800
Calcium / 0.4121 / 670 / 570
Potassium / 0.399 / 650 / 550
Strontium / 0.0079 / 13 / 11
Chloride / 19.354 / 31000 / 27000
Sulphate / 2.712 / 4400 / 3800
Bicarbonate / 0.1424 / 230 / 200
Bromide / 0.0673 / 110 / 93
Fluoride / 0.0013 / 2.1 / 1.8
Boron / 0.0045 / 7.3 / 6.2
-log M / -log M / -log M
Helium / 8.8 / 8.6 / 8.7
Lithium / 4.6 / 4.4 / 4.5
Boron / 3.39 / 3.2 / 3.2
Nitrogen / 1.97 / 1.8 / 1.8
Fluoride / 4.17 / 4.0 / 4.0
Neon / 8.2 / 8.0 / 8.1
Aluminim / 7.1 / 6.9 / 7.0
Silicon / 4.1 / 3.9 / 4.0
Phosphrous / 5.7 / 5.5 / 5.6
Argon / 6.96 / 6.8 / 6.8
Vanadium / 7.3 / 7.1 / 7.2
Chromium / 8.2 / 8.0 / 8.1
Manganese / 8.4 / 8.2 / 8.3
Iron / 7.5 / 7.3 / 7.4
Cobalt / 9.1 / 8.9 / 9.0
Nickel / 7.6 / 7.4 / 7.5
Copper / 8.1 / 7.9 / 8.0
Zinc / 4.9 / 4.7 / 4.8
Astatine / 7.3 / 7.1 / 7.2
Krypton / 8.6 / 8.4 / 8.5
Rubidium / 5.85 / 5.6 / 5.7
Molybdenum / 7 / 6.8 / 6.9
Silver / 9.4 / 9.2 / 9.3
Cadmium / 9 / 8.8 / 8.9
Tin / 10 / 9.8 / 9.9
Antimony / 8.7 / 8.5 / 8.6
Iodine / 6.3 / 6.1 / 6.2
Xenon / 9.4 / 9.2 / 9.3
Caesium / 8.5 / 8.3 / 8.4
Barium / 6.8 / 6.6 / 6.7
Tungsten / 9.3 / 9.1 / 9.2
Gold / 10.7 / 10.5 / 10.6
Mercury / 9.8 / 9.6 / 9.7
Lead / 9.7 / 9.5 / 9.6
Thorium / 10.4 / 10.2 / 10.3
Uranium / 7.9 / 7.7 / 7.8
- “LNG only” scenario:LNG working CCGT not working: 18000 tonnes per hour at delta T = -4 at LNG discharge point (2. Mike to confirm by 15thOctober).
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CIP EIA: Marine Study Info Requirements, Updated 31 Jan 2007
Table 1:Table with CIP Modes of Operation
Mode of operation / Period of operation / Normal operation / Upset conditions / CommentMode 1:
- Open/single cycle power plant running on diesel (800 MW) and providing mid-merit power (6am to 9pm Monday to Friday).
- No once-through water cooling system required
- Diesel off-loading in port (with possibility of spills in port).
- Desalination plant operation.
- No LNG terminal and re-gasification plant.
- Open/single cycle power plant operating on diesel fuel.
- No cooling water requirements.
Mode 2:
- Closed cycle power plant running on natural gas (2400 MW) and providing baseload power (day and night continuously).
- Once-through water cooling system
- Diesel off-loading in port (with possibility of spills in port).
- Desalination plant operation.
- LNG terminal and re-gasification plant capacity with 1.7 mtpa LNG import
- Once through CCGT plant operating on LNG.
- Once-through cooling with no integration with cooling facilities.
Mode 3 (back-up option):
- Closed cycle power plant running on diesel (2400 MW), used when LNG unavailable (check?).
- Once-through water cooling system
- Diesel off-loading in port (with possibility of spills in port).
- Desalination plant operation.
- No LNG terminal and re-gasification plant.
- Once through CCGT plant operating on diesel fuel.
- Once-through cooling with no integration with cooling facilities.
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CIP EIA: Marine Study Info Requirements, Updated 31 Jan 2007
2.Number, location and volume of marine water intakes
There are a number of issues and potential impacts associated with the location and design of the water intakes for the project. The re-gasification process uses marine water for heating the LNG and the CCGT power plant uses marine water for cooling purposes. Furthermore, the layout maps in the original ToR (Figure 1) indicate that the CCGT power plant cooling water intake is currently planned to be located inside the port.
Figure 1:Nominal intake and outfall locations as proposed in the original ToR.
A single intake structure is proposed for all of the intake requirements including water for the re-gasification process, the cooling water and water for the desalination plant. It is assumed that the intake will be designed accordingly.
Specific detail of the actual intake design is required, including the likely entrainment velocities for the various intake volumes proposed at the various stages of the project and specific mitigation measures in the design to minimise entrainment impacts. Based on that “initial” design we can make an assessment and recommendations.
Action / StatusEskom and iGas to provide information. / This information will not be available until the EPC Contract is awarded and the contractor performs detail design. Velocities will have to be assumed at this time and any limitations determined during the evaluation by CSIR can be imposed on the Contractor.
The intake location (and design) with respect to the admin craft harbour as well as the LNG berth needs to be specified so that potential localized impacts can be assessed.
Action / StatusEskom and iGas to provide information. / Eskom and iGas to address this item. Discussions are being held with NPA to revise the small craft harbor location and adjust the LNG ship unloading berth. The intake structure will still be located within the harbor but exact location may be affected. PRDW and iGas may have access to current information.
Design and nature of the admin craft harbour must be provided.
Action / StatusPaul Lochner (CSIR) to facilitate access to information, and marine specialist to source directly from NPA/PRDW. Meeting with NPA/Transnet and HMG on 7th August in Woodmead confirmed in principle that CSIR could make arrangements to contact PRDW directly and source relevant information.
Specific requirements are the likely intake volumes and velocities for the various project phases (i.e. modes of operation) as shown in Table 2.
Table 2: Intake volumes and velocities for the project modes of operation
Mode of operation / Normal operation / Upset conditionsIntake Volumes
(m3/s) / Intake velocities
(m3/s) / Intake Volumes
(m3/s) / Intake velocities
(m3/s)
Phase 1 – 1200 MW
LNG / 0 / 0 / 0 / 0
CCGT / 90,000 ton/hr / unknown / 90,000 ton/hr / Unknown
Desalination / 400 ton/hr / Unknown / 0 / Unknown
Phase 2 – 2400 MW
LNG / 0 / 0 / 0 / 0
CCGT / 180,000 ton/hr / Unknown / 180,000 ton/hr / unknown
Desalination / 800 ton/hr / Unknown / 0 / Unknown
Phase 3 – 2400 MW
LNG / ?? (1.7 MTPA) / ?? / As for normal? / As for normal?
CCGT / 180,000 ton/hr / unknown / 180,000 ton/hr / unknown
Desalination / 800 ton/hr / unknown / 0 / Unknown
There needs to be consistency between the figures in the table above and those in the Table indicating the discharges.
Action / StatusEskom and iGas to check Table 2 and revise where necessary.
Are there any limitations in terms of water quality at the intakes for the various water usages (particularly the desalination plant)? Specific concerns that may arise are:
- If ships stir up sediments resulting in turbid water being drawn into the cooling system, is this potentially a problem? Are there any quantitative tolerances in this regard?
B&V Response: no quantitative tolerances at this time. Increased turbidity will result in increased filer cleaning or backwash frequency. The water treatment system will be designed to handle a small amount of oil or diesel in the intake water. I diesel spill would likely result in a shutdown of the water treatment system. The power plant would need to be shut down in the event of a diesel spill in order to contain the spill within the harbor.
- Please specify any criteria with respect to water quality design (i.e. engineering process) criteria at the proposed intake.
Action / Status
Eskom and iGas to respond.
- Are there any water discharges located near the proposed intake?
B&V Response: No planned discharges from the power plant.
Action / StatusPhilip de Souza (CSIR specialist) to ask CDC/NPA for update on water discharges/stormwater planning, and forward to Roy.
Location of sweater intake is planned to be north of the proposed admin craft basin(Priority 1: RoyvB to confirm with Allan Wijnberg)
Permeability of the breakwater (Priority 1:RoyvB to confirm with Allan Wijnberg)
4.Number, location and volume of water discharges to the marine environment
The Client should be informed that legislation requires that there is full disclosure of all effluents and constituents in those effluents.
Scenarios identified at the marine workshop of 31st August 2006: (CHECK)
Assumed total seawater through-flow of 180000 m3/h for CCGT and that approx 10% would be directed to the LNG terminal for integrated option.
B&V Comment: LNG and Power Plant discharges are combined in to a common effluent channel discharging in to the surf zone. Refer to site plan for exact location of discharge. Refernce the B&V Water Balances for combined desalination and circulating water flow rates to the effluent channel. Separate water balances were developed for burning diesel and natural gas but flows are nearly identical (approx 96,000 ton/hr). Delta T is +7 deg C in all cases when LNG facility is not on line. Delta T is approx +6.3 deg C when water from the LNG vaporization process is included in the effluent. The LNG terminal will have separate, dedicated seawater cooling (ORV) pumps.
Scenario No. / Single CIP discharge or Separate discharges for LNG and CCGT facilities / LNG / CCGT1. No discharge from LNG, eg. CCGT using diesel fuel & no re-gasification occurring / Separate discharges / Vol = 0 m3/h
(no discharge) / Vol = 180000 m3/h
2. Both LNG & CCGT in operation, with seawater systems integrated systems / Separate discharges
(a)to surfzone
(b)to 350m offshore / Vol = 18000 m3/h
Delta T = +4.degC???
First consider discharge to surfzone, as smaller volume.
NOTE: In future, if LNG import increased to 5 MTPA, this discharge could increase and relative balance of flows between the CCGT and LNG would change (beyond scope of this EIA, but motivates for using one discharge pipeline). / Vol = 162000 m3/h
Delta T = +7 degC
Consider both surfzone and offshore discharge.
3. Both LNG & CCGT in operation, with seawater systems integrated systems / Single pipeline (in front of CCGT) / n/a / Vol = 180000 m3/h
Delta T = just less than +7 degC
Note: this scenario is covered by scenario 1, which is assumed worst case in this regard.
Note:Drawing on professional experience, participants at the workshop of 31st August 2006 concluded that a single pipeline from opposite the CCGT facility to the offshore environment with discharge at a distance of approx 350m offshore and depth of approx 10m, may well be the only environmentally acceptable option.
Priority 1: RoyvB to confirm bathymetry estimates (350m offshore at 10m depth) with Allan Wijnberg.
Priority 1: For model set-up assume that we can use the pipeline locations as indicated for LNG and CCGT in Titus’s presentation on 31/8/2006. Titus to confirm and provide exact location coordinates).