Several birds with one stone

The Netherlands is the world leader in the storage of heat and cold in shallow (up to 300 m deep) aquifers (water-bearing layers in underground sand deposits). This year, the number of UTES installations will probably exceed a thousand. Up to now, it has primarily been a question of individual projects, with a UTES system being constructed for each office, hospital, residential area or campus.

Regional coordination prevents conflicts over the use of the available aquifers. It also improves efficiency, because the needs of the different types of users for heating and/or cooling (homes, offices, shopping centres) can be efficiently matched with each other and with the supply. Potential providers of heat include the chemical industry and greenhouse horticulture.

A preliminary survey, however, indicates that regional coordination offers many more possibilities. Companies that are still discharging heat to surface water would also be able to store it underground. This would therefore avoid the thermal loading of the surface water - which is a major problem, especially in hot summers.

UTES, the underground storage of thermal energy from the summer months,

can be combined very effectively with in-situ soil remediation and ground-

water management. Together with other parties, Deltares is conducting a

programme combining basic research and practical considerations.

20 Innovations collected

Another potential application, made more likely by regional coordination is soil and groundwater remediation. Despite every effort, the Netherlands still has more than half a million places where soil and/or groundwater have been polluted. Instead of excavating and cleaning the soil, the authorities are increasingly opting for in-situ remediation with the aid of soil micro organisms. The disadvantage of bioremediation, however, is that often a very long time is needed before the soil is clean. Storing heat in the soil can help, since the biodegradation processes occur more quickly at higher temperatures.

To maximise the potential of UTES, research, policy and implementation must all be well coordinated. Deltares has therefore formulated a programme to enable the results of scientific and technical research to be implemented as quickly and as effectively as possible in the practice of both the public and private sectors. In addition to the initial parties (Wageningen University and Research Centre, IF Technology and BioClear), provincial and municipal authorities and energy and water companies have now also become involved in the efforts to benefit from the opportunities that UTES offers and to minimise the risks.

Innovations collected 21