Assessment of The Water-Energy Nexus in The Municipal Water Sector: A Case Study of Eastern Province, Saudi Arabia

Abstract

When it comes to water and energy, it is hard to have one without the other. Water is required to produce energy and energy is necessary in water production and management. This water-energy interrelation ―Nexus‖ was investigated and discussed in Saudi Arabia using the Eastern Province as a case study. The Eastern Province water-energy nexus was assessed within the municipal sector focusing on the electric energy footprint in water value chain (groundwater, desalination and wastewater treatment ―WWT‖) and water footprint in electric energy generation (thermal power plants). The study aimed to shed light on the Eastern Province current nexus circumstances and conditions using the year of 2013. The study revealed that the Eastern Province is highly dependent on energy for water provision. Similarly, its energy dependency on fresh water resources is also major and evident although it decreases as we move closer to coastal areas. Thermal desalination is by far the most energy intensive stage among the entire Eastern Province water cycle. In 2013, it was estimated that desalination occupied 13% of the Eastern Province energy generation capacity and 5% of the Kingdom capacity. Substantial energy input in desalination in the Eastern Province is attributed to the provision and conveyance of water to the capital Riyadh (desalination; transmission). As for groundwater pumping it was estimated that 206.2 GWH was used for pumping (268 MCM) in 2013. WWT primary, secondary and tertiary energy requirement was revealed to be the least (2-108 GWH). On the other hand, water footprint in electricity generation was estimated to be at an average of 739307.5 m 3 in 2013 (0.125 m3 /kWh) and is relatively high compared with the norm of gas combustion turbine cooling water requirement around the world. Anthropogenic Greenhouse Gases (GHG) emission mainly in the form of CO2 was computed to be around 17 Million Ton of carbon dioxide equivalent (CO2e) for the entire water supply chain. Again, desalination had highest carbon footprint throughout the whole water cycle (16.9 MT of CO2e). Nevertheless, carbon emissions from electric energy generation through power plants had significantly exceeded the entire water supply chain’s carbon footprint. Finally, alternative mitigation options of management and technologies fixe were reviewed and suggested to reduce energy consumption in water cycle, minimize the water footprint in electric generation and mitigate associated GHG emission