What is Hydropower?
'''Hydropower''' is the capture of the [[energy]] of [[movement|moving]] [[water]] for some useful purpose. In the 1830s, at the peak of the [[canal]]-building era, hydropower was used to transport [[barge]] traffic up and down steep hills using [[inclined plane]] [[railroad]]s. For direct [[Transmission (mechanics)|mechanical power transmission]] industries that used hydropower had to be near the waterfall. For example, during the last half of the 19th century, many [[gristmill|grist mills]] were built at [[Saint Anthony Falls]], to use the 50 foot (15 metre) drop in the [[Mississippi River]]. The mills were important for the growth of [[Minneapolis]]. Today the largest use of hydropower is for [[electric power]] generation. That allows low cost energy to be used at long distances from the watercourse. == Types of water power == There are many forms of water power: * [[Water wheel]]s, used for hundreds of years to power mills and machinery * [[Hydroelectricity|Hydroelectric]] energy, a term usually reserved for hydroelectric dams. * [[Tidal energy]], which captures energy from the tides in horizontal direction * [[Tidal stream power]], which does the same, but vertically * [[Wave power]], which uses the energy in waves === Hydroelectric power === {{main|Hydroelectricity}} [[Image:Water turbine.svg|thumb|[[Water turbine|Hydraulic turbine]] and [[electrical generator]].]] Hydroelectric power is a means of making electricity without burning [[fuel]]. Hydroelectric power supplies about 715,000 [[MW]]e or 19% of world electricity (16% in 2003). Large dams are still being designed. Apart from a few countries with plenty of it, hydro power is normally applied to peak load demand because it is readily stopped and started. Nevertheless, hydroelectric power is probably not a major option for future energy production in the developed nations, because most major sites within these nations are either already being exploited or are unavailable for other reasons, such as environmental considerations. Hydropower produces