Survey of Energy Resources 2007
Hydropower Country Notes
The Bulgarian WEC Member Committee reports a gross theoretical capability of about 26.5 TWh/yr, of which the technically exploitable capability is just over 15 TWh/yr; no economically exploitable level is quoted, but Hydropower & Dams World Atlas 2006 provides an estimate of about 12 TWh/yr. Hydro-electric output in 2005 is given as 3 387 GWh. This level of generation implies that nearly 30% of Bulgaria's economic hydro potential has so far been utilised. It also implies a low capacity factor, in the region of 15%. As indicated by the Member Committee for the 2004 Survey, there are several reasons for the low capacity factors of the hydropower plants:
the design water quantities were overestimated;
the plants are used predominantly for regulation purposes;
great quantities of water are diverted to supply households, agriculture and industry;
the equipment is in poor condition owing to the low priority given to maintenance.
At the end of 2005 there was 207 MW of generating capacity at small-scale hydro plants (<10MW). For the present Survey the Member Committee has reported that, pursuant to an ordinance under Article 36, Paragraph 3 of the Energy Act, the public provider and public suppliers will be obliged to purchase at preferential prices electricity generated in plants using renewable energy sources, including hydro-electric plants, with total installed capacity up to 10 MW.