Thermal water resources in Hungary, their utilisation and protection

THE PURPOSE OF THIS GUIDE

It is a well known fact that Hungary is one of the countries of favourable geothermal conditions, however there are a lot of erroneous ideas in this context. The possibilities originating from the geothermal conditions of the country are many times overestimated by the public opinion and professionals as well. It is not taken into consideration that the use of geothermal energy is not equal to the exploitation of thermal water. When discussing the geothermal potential of the country the environmental constraints of thermal water exploitation are not mentioned in the majority of the cases.

With a view to the quantitative protection of ground waters, overexploitation of thermal waters can reduce the amount of the water resources as constituents of a uniform hydraulic system to the extent which results in undesirable processes. Simultaneously the used thermal waters of high temperature and organic matter content conducted upon the ground surface into the rivers or lakes are increasing the heat and pollution load of surface waters and that of the geological formations. They are endangering the utilisability of the recipient, furthermore they are damaging the natural ecosystem through increasing the pollution and temperature of the recipient.

These environmental constraints the significance of which has been highlighted by the adverse trends of the past decades, do not mean that the utilisation of geothermal energy has no further perspectives.

The quantitative limits of the production of thermal waters are represented by the affordable decrease of pressures and water levels caused by the production in the geothermal reservoirs, from the aquifers of drinking water supply and from the shallow groundwater reservoirs. On the other hand, qualitative limits are indicated by the impacts of disposal of used thermal waters on the elements of the environment [geological formations (soil), surface and groundwaters] and by the affordable loads connected to limit values. Taking all the above into consideration the best solution seems to be the reinjection of the thermal water used in closed loop into the geothermal aquifers if it is demonstrated that the water is not polluted. However this is possible only in the case of energetic utilisation.

Therefore the utilisation of geothermal energy based on thermal water abstractions can develop in the future only after having been the technological problems of reinjection solved and if thus there will be no obstacle in the way of its everyday application. In this case the environmental problems are not significant and only the management with geothermal energy is concerned.

An other precondition of the development of the utilisation of geothermal energy combined with reinjection is economy, since such projects are costly. Recovery of the costs in a realistic time interval is an economic precondition even if the state makes these preconditions easier upon environmental considerations.

This guide covers the problems of reinjection and economy as well.

The purpose of this guide is to yield a realistic picture on the possibilities and obligations to everyone concerned, and to highlight those aspects of thermal water management according to which the competent authorities are conducting the licensing and controlling procedures.

It is hoped that this short booklet will be useful to everyone considering or realizing the possibilities of thermal water utilisation.