A 12 MW Steam Heat Pump Replaces Fossil Boiler Duty at a Paper Mill
The unit delivers superheated steam at 3.4 bar and 150 to 180 °C from recovered waste heat, beat its guaranteed coefficient of performance by 10%, and avoids about 19,000 tonnes of CO2 a year.
Turboden, a Mitsubishi Heavy Industries group company, announced on 17 February 2026 the start-up of what it describes as the world's largest steam-producing heat pump in operation. The unit delivers 12 MW thermal of superheated steam at 3.4 bar absolute, lifting temperature to between 150 and 180 °C, at the specialty paper manufacturer delfort's site in Brescia, Italy.
The system combines a large heat pump with mechanical vapour recompression and recovers low-grade waste heat from the papermaking process using carbon-free electricity. Measured coefficient of performance came in 10% above the guaranteed value, and the installation is expected to avoid approximately 19,000 tonnes of Scope 1 CO2 emissions a year by displacing fossil-fired steam raising.
What is worth extracting is how differently this plant now behaves. A fired boiler is a demand-following device: steam demand rises, fuel valve opens, and the control problem is burner management. A heat pump raising steam from recovered waste heat is constrained on three axes at once — how much waste heat is actually available at any moment, what electricity costs at that moment, and where the compressor's operating envelope ends. Meeting a steam header setpoint under those constraints is an optimisation problem, not a combustion one.
That shifts the instrumentation. The waste-heat sources have to be measured properly rather than estimated, because their availability is now an input to a control decision. Compressor conditions need monitoring because the envelope is a real limit rather than a datasheet figure. And a coefficient of performance guaranteed contractually has to be verified continuously, which requires metering on both the thermal and electrical sides that is accurate enough to settle a commercial argument.
There is also a systems consequence. A plant whose steam comes from electricity is now a candidate for demand response and has a carbon accounting story that changes with the grid it draws from — both of which are data problems that did not exist when the answer was a gas burner.
Source: Turboden