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.
6 Porto. World famous for its production of fine port wine, the busy city of Porto sprawls along the hills overlooking the Douro River in northern Portugal. At the heart of Porto is the charming pedestrian zone, the Ribeira, an atmospheric place on the river, buzzing in live music, cafes, restaurants and street vendors.