Energy Consumption Analysis and Energy Saving Opportunities: A case study of Mahankalchaur Water Treatment Plant, Mahankalchaur, Kathmandu, Nepal

Abstract

The first systematic water supply system, known as Bir Dhara, in 1895 the first water treatment facility was built in Sundarijal with Indian assistance to treat the tail race water pouring out of the Sundarijal Hydropower Station. Actual energy consumption can be found by an energy audit, which gives the idea of energy-saving possibilities. Electrical energy consumption in water treatment plant with energy auditing find out energy consumption, energy saving area and cost-saving opportunities with simple and discounted payback period. The Mahankalchaur water treatment plant is the largest water treatment plant inside Kathmandu valley. Data collected by interview and walk though survey. There is a 500 KVA transformer with 450 KVA. Power factor varies from 0.73 to 0.93 and 75 KVAr of is present in plant need to extra 44 KVAr to maintain 0.99 power factor. From preliminary audit there is 482.39 kW connected load with transmission pump. Kapan supply pump and tanker filling pump as major electricity consuming derive. Energy bill of twenty-two month analyze, it was found that peak hour consumption and off peak hour consumption is half of normal hourly consumption. Demand varies from 91 KVA to 274 KVA. Average monthly energy consumed was found 72.56 MWh, with an average monthly bill paid for energy tariff is NRS.3, 55,309.48 and 85.75 mu with average energy cost NRS. 4, 16,857.31 per month in during 2077 and 2078 BS respectively. Specific energy consumption inside the plant is 0.1338 kWh/cubic meter. From detail energy analysis, inefficient replaces by 20 watt led bulb save 0.12 % of total kWh and 0.16% of the total annual bill with simple payback 1.88 years and discounted payback period of 2.28 years. Two hours of Peak hour shift can, save annual 1.05% of the energy bill. Efficient pump installation on the transmission pump save, annual 21% of energy and 20.58 % of annul energy bill with simple payback 3.31 years while 19.28% annual bill could save with discounted payback period 3.25 years. For Kapan water supply system at 5% load variation, VFD saves 7.06% energy and 6.92% of annual bills while considering MARR 10% with 1% annual maintenance can save 6.7 % of annual energy bills. Overall, 10.69% energy and 27.66% energy bill with NRS 3178115.00 investment could save annually using led, efficient pump and VFD. Considering MAAR 10% and annual maintenance cost overall, 26.13% of annual energy bill could save.