A 30-month study in South Africa’s Western Cape province has found that smart water heater management systems can play a major role in reducing energy use, smoothing power demand throughout the day, and facilitating the broader shift towards renewable energy.
Under the project, 500 electric water heaters in Cape Town and the Hessequa Local Municipality were equipped with devices developed by energy technology company Plentify.
The devices, called HotBots, use artificial intelligence to automatically turn water heaters on and off at the most optimal times, with the aim of shifting electricity use away from morning and evening peaks, capitalising on periods of strong solar output, and reducing overall power demand.
The study compared 19 months of baseline measurements against nearly 12 months worth of data following the installation of the HotBots.
It found that:
- The devices reduced each water heater’s electricity use during peak periods by up to 80%, without affecting the supply of hot water to the participating households.
- They improved each water heater’s overall energy efficiency by up to 24% by switching them off when they did not need to be consuming electricity.
- By coordinating the devices in such a way that each geyser drew power at a slightly different time, maximum demand at any point in time across the entire fleet of water heaters was slashed by up to 60%.
“This pilot project demonstrated that water heater management systems can be a powerful tool for cities looking to fight blackouts and adapt to an energy system transitioning to renewables, while also ensuring that households have hot water when they need it and can benefit from lower energy bills,” Plentify CEO Jon Kornik said in a statement.
Richard Larmour, researcher and measurement and verification specialist at the University of Cape Town, said: “This piece of work … is a welcome addition to an area which is grossly understudied.”
The project was a partnership between the two participating municipalities, German development agency GIZ, clean energy financing facility EEP Africa, Plentify, and others. It was overseen and advised by the University of Cape Town’s Inspection Body.