Seawater replaces coal

In the port of Esbjerg, the construction of a large seawater based heat pump station and a biomass boiler plant replacing the power stations share of district heating is begun with a deadline in the early spring of 2023.

We do not want to build one large unit we will be depending upon for the next 30 years. We only have a short deadline, and after April 2023, no more heat will be supplied from power station. The opportunities we had, time and legislation considered, we decided to build a 60 MW biomass heat only boiler and a seawater heat pump with 50 MW district heating power.

1.000 meters of pipe is supplying water

Even though the seawater heat pump location is in the port, it needs to get the water about 1.000 meters away. During the design phase, we became aware of the importance of placing seawater intake and outlet far apart – to avoid a short circuiting the seawater by sucking in cooled seawater into the intake. Pumps run 4,000 liters per second! By placing the seawater intake far away (about 1.000 meters) from the seawater outlet, we avoid seawater in the heat pump evaporator to form “slush ice” during winter.

The seawater heat pump system is electrically powered and produces district heating by cooling the seawater at a maximum of 4 oC locally at the outlet. It is planned to operate from September to May, provided the right electricity price and temperature conditions for running the seawater heat pump at the lowest possible production costs. In case of shut down of the local waste to energy plant, the heat pump can supply all the heat for district heating from June to August.