정수처리시설 에너지 절감 방안 및 경제성 분석 연구

Abstract

Since the Industrial Revolution, greenhouse gas emissions have steadily increased, leading to a global climate crisis. Efforts to reduce greenhouse gas emissions are being made worldwide, with a focus on strengthening environmental regulations and promoting investment in renewable energy and high-efficiency equipment. In this context, water treatment facilities, as energy-intensive entities, need to examine their energy performance and actively explore energy-saving measures. So far, these facilities have mainly focused on expanding their infrastructure and adopting new technologies to improve treatment efficiency, resulting in inadequate consideration of energy efficiency. Therefore, there is a need for energy-saving measures such as the introduction of high-efficiency equipment to contribute to low-carbon, green growth.

Water treatment facilities consume approximately 70-80% of the total electricity in the water sector, with pumps being a crucial component. Proper maintenance of pumps is important, and efficient pump management is particularly critical. However, due to the extended lifespan of mechanical equipment for operational efficiency, the current pump replacement cycle exceeds 15 years, which is the intended service life, and pumps are being used beyond this period through partial repairs and replacements. Consequently, in this study, I selected five water treatment facilities in ○○ City to analyze pump efficiency improvement, replacement cycles, and their economic feasibility.

First, I calculated pump efficiency based on actual measurement data such as flow rate and power consumption to assess the efficiency of each facility. I then examined the energy savings resulting from efficiency improvements using return on investment (ROI) and net present value (NPV) as economic evaluation criteria. The results showed that within an NPV project feasibility period of 8 years, 9 pumps (50%) had an average efficiency of 66%, and their average operating time was more than 4,400 hours. Within a feasibility period of 9-10 years, 5 pumps (28%) had an average efficiency of 69%, and their average operating time was more than 4,200 hours. Furthermore, even with a pump installation period of 14-16 years, replacing low-efficiency pumps with high-efficiency ones resulted in a feasibility period of 5-7 years, indicating excellent economic viability. Thus, it was confirmed that replacing pumps after 15 years, which is shorter than the 20-year replacement cycle, is more effective.

I conducted sensitivity analysis on the initial input variables to determine their impact on the final amount. Through comparative analysis, considering factors such as government support covering 40% of the total investment and a 20% increase in the operating time of high-efficiency pumps, I found that with a 40% reduction in total investment, 13 pumps (72%) had an NPV project feasibility period of less than 5 years, and 4 pumps (22%) had a feasibility period of 6-7 years, significantly reducing the payback period for most pumps to within 7 years. Additionally, when the operating time of high-efficiency pumps was increased by 20%, 7 pumps (39%) had an NPV project feasibility period of less than 5 years, and 8 pumps (44%) had a feasibility period of less than 10 years, indicating a significant reduction in the payback period for most pumps to within 10 years. Therefore, to enhance the economic viability of pump replacements, it is essential to focus on reducing initial investment through government support policies and increasing the operating time of high-efficiency pumps.