11.   The drought forced its affiliates to use more-expensive thermal plants to generate power instead of hydroelectric plants.

12.   The drought has forced Endesa and Colbun to buy more expensive electricity from coal and oil-fired power stations to meet sales commitments, producing heavy losses.

13.   The drought has forced Endesa to buy more expensive electricity from coal and oil-fired power stations in order to meet its sales commitments.

14.   The drought has forced hydro-electricity generators to buy more expensive electricity from thermal generators to meet sales commitments.

15.   The drought has forced the company, a hydro-electricity generator, to buy more expensive electricity from thermal generators to meet its sales commitments.

16.   The drought is forcing the hydroelectric producers to buy more expensive electricity from thermal producers in order to meet their sales commitments.

17.   The drought forced the utilities to buy more expensive electricity from thermal power producers to meet their sales commitments.

18.   The drought had forced Endesa to buy more expensive electricity from coal and oil-fired producers in order to meet sales commitments.

19.   The drought is forcing hydroelectric utilities to buy more expensive electricity from thermal producers to meet sales commitments.

20.   The drought is forcing hydroelectric utilities to buy more expensive electricity from thermal-power producers to meet their sales commitments.