Today is World Toilet Day, an opportunity to raise awareness about the global sanitation crisis. About 4.5 billion people around the world still lack access to safely managed sanitation and 80% of the world’s wastewater is released untreated.

Two of the targets under the Sustainable Development Goal dedicated to water (SDG 6) — providing sanitation for all (target 6.2) and halving the proportion of untreated wastewater (target 6.3) — seek to address these challenges. But meeting these targets could put significant upward pressure on energy demand.

The links between energy and water run deep, which explains why the IEA is looking at the issue. New analysis in this year’s World Energy Outlook (WEO) shows that today’s water sector, which includes the collection and treatment of wastewater, accounts for 4% of total global electricity consumption. Wastewater treatment alone represents roughly a quarter of the water sector’s electricity consumption. Additionally, some estimates have put the sector’s share of total greenhouse gas emissions at 3%. However, there are also significant opportunities to produce energy by harnessing the embedded energy in wastewater, as our analysis in 2016 emphasized.