Water and energy
Electricity allows for the pumping, treatment and distribution of water required for improved water supply, sanitation and hygiene (WASH) services. In 2021, almost 700 million people lack access to electricity, 80% of whom live in Sub-Saharan Africa. Many more have only access to a limited, intermittent or unreliable electricity service.
Water is extensively used for electricity generation: in hydropower, and for cooling thermal and nuclear power stations. Primary energy sources such coal, oil and gas (including fracking) and biofuels are also highly water intensive.
The most water-efficient sources of electricity are wind and solar-photovoltaic (PV). Significant progress has been achieved between 2011 and 2019, however, meeting SDG 7 will require a substantial increase in the share of renewable energy sources for electricity (in addition to transport and heat). Such progress would also directly help achieving SDG 6, especially in areas facing water scarcity or where competition over finite resources between water use sectors could undermine prosperity.
A major challenge for wind and solar power is their intermittent generation and the need for electricity storage (for when the sun is not shining or the wind not blowing). While pumped-storage hydropower shows much room for expansion, lithium-ion batteries are the fastest-growing storage technology. However, extraction and processing of lithium and other ‘critical minerals’ can be extremely water intensive and polluting.
Some approaches and technologies aimed at mitigating greenhouse gas emissions require large amounts of water. The water intensity for biofuels is orders of magnitude higher than for fossil fuels. Carbon capture and storage systems are both highly energy- and water-intensive, potentially increasing a power plant’s water withdrawal and consumption by as much as 90%.
Action example:
Solar canals: innovation in the energy–water nexus
Almost ten years ago, a pilot project in Gujarat (India) put solar panels over canals, saving valuable land. There were multiple benefits – evaporation was reduced by shading so that water was saved for other uses, the water cooled the panels and made them more efficient, and the shade reduced algal blooms. One estimate suggested that 2 to 3 MW could be generated per kilometre (Gupta, 2021). A study in California suggested that enough water could be saved for 2 million people if all the 6,400 km of open canals were covered with solar panels, which themselves would generate 13 GW of renewable power (Anderson and Hendricks, 2022). Floating solar panels covering reservoirs could yield similar benefits (Jin et al., 2023), which include hindering weed growth and minimizing land use for new solar installations.
Full chapter
Consult chapter 5 : Energy
