How can cities reduce water-energy nexus pressures?

By Robert C. Brears, author of Urban Water Security (Wiley)

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Cities over the past century have become the driving force of the global economy. Accounting for over half the world’s population and generating around 80% of global GDP, cities provide numerous opportunities for development and growth. Cities however bring about risks and challenges to people and the environment.

By 2050, demand for water is projected to increase by 55% mainly due to increased demand from urban populations. At the same time demand for energy in providing water and wastewater treatment services will increase.

Water and energy interconnected

Energy and water are interlinked in two ways, first, water is used in the production of nearly all types of energy (coal, geothermal, hydro, oil and gas, nuclear), and second, energy is the dominant cost factor in the provision of water and wastewater services (extracting and conveying water, treating water, distributing water, using water and collecting and treating wastewater). In fact, energy can account for up to 30% of total operating costs of water and wastewater utilities: in some developing countries this can be as high as 40% of the total operating cost. Meanwhile, on average 15% of the world’s total water withdrawals are used for energy production.

Reducing water-energy nexus pressures

Cities around the world have nonetheless initiated innovative processes that attempt to disconnect rising urban populations from increased demand for water and energy. Examples include Dubai of the UAE and Phnom Penh of Cambodia using technological and management innovations to reduce urban water-energy nexus pressures.

Case 1: Smart meters in Dubai

In its pursuit of being water and energy smart the Dubai Electricity and Water Authority (DEWA) is installing smart meters across the Emirate enabling customers to receive real-time information on water and energy consumption. This will enable them to monitor actual consumption to better understand and manage bills. Specifically, in addition to providing current consumption data, DEWA’s smart meters will provide customers with historical consumption data as well as a breakdown of consumption processes that use water and energy. This will enable customers to identify water and energy efficiencies in their homes. The smart meter data is delivered to customers’ smartphones or tables via DEWA’s Smart App, allowing them to view billing information, graphs to check and compare consumption as well as set caps for both water and electricity consumption. Overall DEWA aims to have 1.2 million meters installed within 5 years. The installation of the smart meters will be in two stages:

  1. Smart meter installation: 200,000 smart meters will be installed all over Dubai which will be connected to a new advanced computerized system and software.
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  3. DEWA will install the remaining smart meters. Enhancements of the operating system will be performed in conjunction with increasing the number of installed meters.
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Case 2: Phnom Penh reducing its leakage rate

Phnom Penh’s Water Supply Authority has a non-revenue water (NRW) rate of around 7%, which is one of the lowest rates in the world. To reduce leakage, as well as energy required in treating water to potable standards – nearly 45% of the Authority’s operating cost is attributed to energy consumption – the Authority has installed a telemeter system that detects high leakages and illegal connections in different zones of the water supply system. To detect leakages more efficiently the city has been divided into 58 sub-zones each with its own local leak detection system. To ensure leaks are fixed rapidly the utility has leak repair teams on standby that operate 24/7, with the response time being two hours after a leak is detected. To ensure the utility is proactive in detecting leaks the Authority has established leak detection teams that are offered incentives to find leaks throughout the water supply system: to become more efficient in its operations incentives have become an important element of the Authority’s staff remuneration.  At the end of each year the utility’s NRW Committee reviews all leakage work and analyses each leak detection teams’ performance. The most efficient teams – based on the ratio of leaks at the start of the year with the end of the year – are rewarded monetarily, with some technicians having received rewards of up to 25% of their annual salaries.

With rapid urbanization increasing demand for water, and energy, cities around the world are exploring a variety of technological and management innovations to reduce urban water-energy nexus pressures. Do you know of such innovations that are taking place in your city? Please share in the comments below.

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