| Abstract |
Geothermal water in Bulgaria has only direct applications. Major types of direct utilization include balneology, space heating and air-conditioning, geothermal heat pumps, direct thermal water supply, greenhouses, and bottling of potable water and soft drinks. Electricity generation from geothermal water is not currently available in the country. About 72% of the total discovered flow rate of the state-owned reservoirs has a temperature up to 50oC. Flow rate varies within 1-20 l/s for about 75% of these reservoirs. The most prospective regions for geothermal application are located in the eastern part of Moesian plate (North Bulgaria, stratified horizons) and in Rila-Rhodopes massif (South Bulgaria, fractured intrusive and metamorphic rocks). The highest temperature (98oC) is measured in Sapareva banja (South Bulgaria). Thermal water use is dependent predominantly on water chemical content. TDS varies between 0.1 and 1.0 g/l in most of the reservoirs in South Bulgaria, while in North Bulgaria it is much higher: from 0.1 g/l up to 150 g/l. For this reason, thermal water application is more diverse and mainly concentrated in the territory of South Bulgaria. Most of the hydrothermal sites are developed as mountainous and sea resorts, and currently, leading applications are for balneology, direct thermal water supply for domestic needs, and space heating. Geothermal heat pumps also mark significant progress but no official summary for their use is available at present. The focus of this analysis is on the quantity and type of thermal water use in the hydrothermal regions in Bulgaria in terms of temperature, flow rate, and application. A comparison between the quantity and type of water use in North and South Bulgaria is also made. Five leading regions are considered in more detail with respect to application. The major barriers for geothermal development are briefly presented. |