Inside one of the biggest office complexes in the Netherlands, hundreds of people are working to develop innovative energy technologies. Some 200 metres (over 650 feet) below ground, a natural energy system is also hard at work.
Specially constructed wells of hot and cold water stored in different geothermal layers deep underground provide renewable energy that helps keep the complex operating. Shell Technology Centre Amsterdam (STCA) houses more than 1,000 people and a large number of laboratories.
Yet the building – including its heating and air-conditioning – adds almost no carbon dioxide (CO2) to the atmosphere. In winter, a pump sucks up water from a hot well.
A heat exchanger extracts the heat from the well water, and transfers it to fresh water circulating in pipes in the floors of the building and in heating coils in the inlet ventilation system, warming the premises.
Once the heat has been extracted, the water is sent back to fill up the cold water well. In the warmer temperatures of spring and summer the system works in reverse.
Then the pump draws up the chilly water, and the process replaces heat with cold to provide an alternative to power-sapping air conditioning.
The electricity used to drive the pumps and run the office complex is offset by power that goes to the grid from the Egmond aan Zee wind farm off the Dutch coast, built by Shell and utility company Nuon, making the centre almost CO2 neutral.