Hvor står afsaltning energimæssigt? Chefingeniør Christian Stamer Krüger A/S. DWF temamøde Vand og energi-effektivisering torsdag den 28.

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1 Hvor står afsaltning energimæssigt? Chefingeniør Christian Stamer Krüger A/S DWF temamøde Vand og energi-effektivisering torsdag den 28. april 1 -

2 Energi til afsaltning omfatter i bredere forstand både anlæg og drift. Vi behøver en fælles standard for at kunne sammenfatte det totale energikoncept. I Veolia har vi valgt at benytte begrebet Carbon Footprint, som udtrykker den ækvivalente mængde CO2, som aktiviteten belaster kloden med set over en lang årrække. Veolia har udviklet et særligt værktøj til dette formål, som jeg vil anvende i det følgende. 2 -

3 Which tools to calculate the Carbon Footprint? Computes the GHG emissions based on basic process models Excel spreadsheet dedicated to Carbon Footprint Other impact indicators Human Health (human toxicity, respiratory effect ) Biodiversity (aquatic and terrestrial ecotoxicity ) Resource depletion (e.g. «water footprint» under development) Carbon Footprint = Perimeter (construction, operation, decommissioning) n i 1 Ai * EFi Emissions Factor (in kg.co2eq per) Activity Data (tons of steel, KWh elec ) Conversion factor: Global Warming Potential (GWP) over 100 years Gas GWP over 100 years (CO 2 eq) Carbon dioxide (CO 2 ) 1 Methane (CH 4 ) 25 Nitrous oxide (N 2 O) 298 Hydrofluorocarbons 12 to 12,000 Perfluorocarbons 5,700 to 11,900 Chlorofluorocarbons 4,600 to 14, One single unit, ton CO 2 eq, reflecting the impacts of all GHG

4 How to assess the Carbon Footprint? Life Cycle Inventory INPUT FLOWS Fossil fuels Minerals Background processes Production of chemicals Production of concrete Production of electricity Ecoinvent database For Emission Factor Plant perimeter OUTPUT FLOWS Indirect GHG Emissions Construction Raw water Inventory of intermediates Technical modeling of process units Operation Intake pumping Water treatment Water distribution Decommissioning Potable water Direct GHG emissions LCA scope 4 -

5 Emission Factors Construction Concrete: 260 kg.eq CO 2 / m 3 Steel: 2770 kg.eq CO 2 / t Power impact of local energy mix Operation FeCl 3 40%: 719 kg.eq CO 2 / t Ca(OH) 2 : 750 kg.eq CO 2 / t NaOCl 15%: 813 kg.eq CO 2 / t Polymer: 1.57 kg.eq CO 2 /kg France: 0.09 kgco 2 /kwh Spain: 0.35 kgco 2 /kwh Saudi : 0.75 kgco 2 /kwh Australia: 0.92 kgco 2 /kwh 5 -

6 SWRO desalination plant Green House Gases emissions in kg CO 2 -eq/m 3 of potable water 3 2,5 2 1,5 1 0,5 0 Construction < 2% of GHG emissions Membrane renewal Plant and piping network construction Disinfectant NaOCl production Remineralization chemicals production CIP chemicals production Antiscalant production Coagulant / Flocculent production Electricity production for water treatment Electricity production for intake and distribution RO pumping needs > 75% of GHG emissions 6 -

7 Impact of local energy mix GHG emissions in kg CO 2 -eq/m 3 of potable water 4,5 4 3,5 3 2,5 2 1,5 1 0,5 0 Australian model Power supply UAE grid mix Saudi Arabia grid mix Australian grid mix Spanish grid mix Nuclear thermal plant Wind turbine Photovoltaic cells Combined cycle gas turbine Oil fired plant Coal thermal plant UAE Saudi grid Australian Spanish Arabia mix: 99% grid mix: grid gas 75% mix: turbines, 47% coal, 22% gas coal, 20% 1% turbines, gas, oil 30% fired 5% gas 53% plants hydro/wind turbines, oil fired plants 20% nuclear electricity, 18% hydro / wind But, energy mix is not within the scope of the suppliers of water technology 7 - Need to look at the C footprint of the water treatment schemes

8 kg CO2 eq/ m3 potable water 4 Greenhouse Gaseous emissions in kg CO2 eq/m3 for desalination plants 3,5 3 Membrane renewal 2,5 Plant and piping network construction kwh/m3 average per year g/l TDS 28 C 3.84 kwh/m3 average per year Sodium hypochlorite / sodium bisulfite production Sulfuric acid, sodium hydroxide, CO2 production 1,5 1 Energy mix: 98% gas 2% oil Energy mix: 82% gas 18% oil Energy mix: 79% coal 12.14% gas 6.36% hydro Antiscalant and cleaning chemicals production Coagulant and polymer production Electricity production 0,5 0 FUJAIRAH OMAN SUR SYDNEY Projects Results from Eolia TM February 2009 François Vince 8 -

9 Pressure Case Study: Oman Salinity/ temperature impact on 1st pass RO pressure Pressure 1 st Pass 80,0 TDS g/l 75, ,0 65,0 60,0 max 64,5 bars Gap: 6,5 bars ,0 min 58 bars 55 50, Temperature 32

10 Case Study: Oman Where is the electricity consumption the highest: 1st pass Intake Booster HP pump Seawater Pretreatment Reverse osmosis Permeate Post treatment Drinking Water Variable frequency drive ERD Concentrate Variable Frequency Drive on RO booster pumps allows flexibility to adapt to pressure variations 10 -

11 kwh/m3 Kg CO2 eq/ m3 Case Study: Oman Electrical consumption Breakdown on RO 1st pass 2,50 Emission factor at Oman: 0.92 kg CO2eq/ kwh 2.3 2, ,50 1,00 DWEER = Dual Work Exchanger Energy Recovery , ,00 1 -HP RO Booster pumps 2 -DWEER Booster pumps 4-1st PASS HP pumps 5-Recirculation pump for DWEER HP RO Booster DWEER Booster HP Pump DWEER Recirculation type of pump

12 Case Study: Oman Where is the electricity consumption the highest? Example at Oman Sur : up to 76.5% of electrical consumption on the first pass Electrical consumption Breakdown on Oman Sur Pretreatment 5% 1 -HP RO Booster pumps 2 -DWEER Booster pumps 4-1st PASS HP pumps 5-Recirculation pump for DWEER 6-Second pass RO pumps 1st pass RO 67-76,5% 7-Intake pumps 10-Existing plant 11-Others 12 -

13 Impact of the choice of membrane on electrical consumption HYDRANAUTICS DOW 1st PASS Pressure at maxi conditions - worst case (TDS max / T C min - 4,5 years) 60,0 62,5 Boron in permeate 1st pass - worst case (4,5years - 35 C) 3,23 2,01 2nd PASS Pressure at maxi conditions (TDS max / T C min - 4,5 years) 12,0 10,2 Feed ph max 10,4 10,2 Boron in permeate 2nd pass - worst case (4,5years - 35 C) 0,37 0,

14 kwh/m3 - kgcoeq/m3 Impact of Energy Recovery Device Pelton Turbine: 80% DWEER - ERI: 95% 3,5 3 2,5 DWEER - ERI - 95% Pelton - 80% 2 1,5 1 0, Power Consumption (kwh/m3) Carbon Footprint (kco2eq/m3)

15 CONCLUSIONS Tools available: Compare water supply scenarios and main process trains Excel spreadsheet to get into more details in the calculation Carbon footprint of SWRO plants: 80-90% from energy consumption How can we reduce the Carbon footprint Use the most efficient ERD optimal pump Find new membrane system configurations Use the most energy-efficient membranes => e.g. NanoH2O Desalination systems powered by renewable energies 15 -