Kilowatt-Hour per Unit of Fuel. The energy value of a unit of fuel depends on its mass, carbon and hydrogen content, and the ratio of carbon to hydrogen. In general, hydrogen generates approximately 62,000 BTU per pound and carbon generates around 14,500 BTUs per pound.
Quick Answer. The three largest rivers in Portugal are the Tagus River, the Douro River and the Guadiana River. All three rivers also flow through Spain. The largest river in Portugal is the Tagus River; it is 645 miles long. Continue Reading.
Danube River. Danube River, German Donau, Slovak Dunaj, Hungarian Duna, Serbo-Croatian and Bulgarian Dunav, Romanian DunÄrea, Ukrainian Dunay , river, the second longest in Europe after the Volga. It rises in the Black Forest mountains of western Germany and flows for some 1,770 miles (2,850 km) to its mouth on the Black Sea.