Off gas by 2027

"We want to be part of the solution, not the problem. The hospital runs 24 hours a day and requires a lot of energy. We have already taken many steps to become more sustainable and reduce our energy consumption. But part of it still comes from natural gas. We want to change that. In 2027 we will no longer use fossil fuels and will no longer emit CO₂ for energy. This way we care not only for our patients and staff, but also for a sustainable world."

Energy security

"The PowerStove gives us energy security and makes us agile in a challenging energy market. This thermal battery delivers steam via a steam generator to our existing infrastructure. As a result, the gas-fired steam boilers will no longer be needed. They will only remain on standby for emergencies, running on biodiesel. This offers many advantages and is the final step for Nij Smellinghe to go fully off gas."

What makes the PowerStove unique

• First application at this scale in an existing hospital operating 24/7
• Stores energy for extended periods, from days to weeks
• Energy available when needed
• Heat storage up to 360 °C
• Compatible with existing infrastructure (steam, hot water, cooling, hot air)
• Fire-safe, circular, proven technology, lifespan of at least 30 years
• Made from sustainable, circular materials of European origin. Fully recyclable without harmful emissions
• Savings for Nij Smellinghe of 285,000 m³ gas per year — equivalent to the annual consumption of approximately 275 households

How the PowerStove works

The PowerStove is a thermal battery that converts locally and sustainably generated energy into heat and stores it for extended periods. Green electricity heats thermal oil, which transfers heat via heat exchangers to magnetite (iron ore) in a well-insulated container. This allows the battery to retain heat up to 360 degrees Celsius for days to weeks. Matched to the consumption and needs of Nij Smellinghe, the heat is stored for an average of three days. When the hospital needs steam — for example for sterilisation, pharmacy, kitchen or air humidification — this heat is used to produce steam and distributed via the existing infrastructure. This provides energy security, even when there is little sun or wind or the energy grid is overloaded.

Why steam in a hospital

Hospitals use steam for processes requiring temperatures above 100 °C. Such as sterilisation departments, the kitchen, the laboratory and for air humidification. Steam kills bacteria and pathogens on medical instruments, making them free of harmful micro-organisms. This is a safe alternative to chemical agents. Steam is also essential in the kitchen for preparing meals and cleaning crockery. The PowerStove converts renewable energy into heat and via the steam generator into steam. The steam can be used at any desired moment via the existing infrastructure.

Sustainability and energy reduction

Nij Smellinghe has already done a lot to make its energy consumption more sustainable and reduce it. Solar panels on roofs and solar carports generate 3 million kWh of energy annually — comparable to the consumption of about 1,200 households. The hospital has two Aquifer Thermal Energy Storage systems (ATES), insulated facades, a lithium battery and a smart Energy Management System (EMS) that automatically adjusts system usage. The final step to go off gas is with the thermal battery. The PowerStove replaces the gas-fired steam boilers, meaning Nij Smellinghe will use no more gas in 2027.

Partnership and future

Heatwacht is the developer of the PowerStove and Nij Smellinghe's partner in this project.