The Study of Water-Energy Nexus With Water Supply System of Pattaya City in Thailand

Tourism cities use more water and energy resources than other city types. Therefore, the water-energy nexus and CO2 emissions are urgent issues to manage. This paper studies the nexus between water distribution systems and energy usage. It studies the improvements of the water distribution system to reduce water production and estimates energy-related CO2 emission reductions in water supply systems. The water supply systems are improved by installing electric control values in a case study (Pattaya city) at five water supply stations. Moreover, it was found that the original Mabprachan station emitted CO2 as much as 1,247 kgCO2eq/day after adjusting the valves to 873 kgCO2eq/day. The original Bang Lamung station emitted 2,027 kgCO2eq/day after adjusting the valves to 1,294 kgCO2eq/day. The original wreck station was liberated 779 kgCO2eq/day after valve adjustment was reduced to 390 kgCO2eq/day, former Na Jomtien station emitted up to 1,715 kgCO2eq/day after valve adjusted down to 1,590 kgCO2eq/day, old Chaiyaphon Way station emitted up to 1,715 kgCO2eq/day after valve adjustment reduced to 951 kgCO2eq/day. The water supply systems are designed in the EPANET model to simulate and investigate the water supply capability in the service pipes of five water supply stations with flow rates between 800-1,300 m3/hour and pressures between 20-45 m. Results are shown that the water supply reductions decreased the amounts of water production from the original production of 115,200 m3/day to 78,480 m3/day. The electricity consumption is 12,856 kWh/day, and the energy-related CO2 emissions are 7,483 kgCO2eq/day. Adjusting electric control values at the five stations regulates the flow rate and follows the water supply demand. Consequently, the electricity consumption is 8,759 kWh/day. Total electricity consumption and CO2 emissions are reduced by 1,495,400 MWh/year and 870,530 tCO2eq/year, respectively.