Electricity exists everywhere, from high voltage power lines to phones and computers. Understanding the basics of how it works remains essential to using it safely and efficiently.

When electricity travels from a positive lead to a negative lead in a circuit powered by a battery, it is considered direct current. This type of current powers electronics, LED lights, and cars. Alternating current is generated from rotation, usually by a generator. The direction of the current and the voltage flips as the generator completes a rotation. The faster the generator spins, the faster the flipping of current direction occurs. In North America, the typical frequency of AC power is 60hz or 60 alternations per second. The advantage of AC power is that the voltage can be stepped up easily by use of a transformer, which allows high voltage transmission. AC power is also useful for electric motors.

Specifically, power is a measure of energy usage over time. The standard unit of power is the watt and calculated as P (watts) = V (volts) x I (amps). Utility companies sell electricity in units of kW*h (kilowatt hours), which is simply one kilowatt of power delivered continuously over one hour.

Almost 2/3rd of Americans decorate there home with some sort of electric lights during the holiday season.  Over half require the use of some sort of extension cord and or power splitter during there holiday lighting decoration process.  The National Fire Protection Association (NFPA) Reports that Christmas tree fires alone cause on average an estimated $16.2 million in direct property damage, 16 injuries, and 6 deaths every year.  This statistic does not include injures or deaths due to outdoor lighting electric shock or fall injuries such as ladder work.

Hydroelectric power is a technology which produces electricity via hydropower, or the energy released by moving water, such as for instance water moving through the course of a river or falling downhill. In the United States today, most hydroelectric power is generated by water flowing downhill, and most of this downhill flow is achieved via the construction of artificial dams. The dams are constructed so as to engender sufficient water outflow volume by way of creating a significant “head” or, that is, the difference in height between the water’s source (or crest) and the water’s outflow.

A significant enough “head” is necessary to produce a sufficiently useful flow of energy from the hydroelectric power source. This is why dams constructed for the purpose of creating hydroelectric power are built as high as is feasible. Within these dams there are turbines which receive the force of the water’s flow, and the turning of the blades of the turbines generates the electrical current which is transferred to long-distance power lines and transformed into electricity for use in homes and offices.

In addition to the dams there are some tidal harnesses which have been constructed. These draw electrical power from the flow of the tide along a coastal area. In the United States, there is a heightened interest in creating many more small, unobtrusive tidal flow hydroelectric power generators in rivers and large streams which would be used just for generating local electricity. In Canada, there is so much electricity generated by hydroelectric facilities that they simply say “hydro” to refer to any public electricity utility, even nuclear power. Norway and Iceland also generate nearly all of their citizens’ needed electricity by way of hydroelectric power.

North America has the greatest hydroelectric power capacity. Canada is the world’s leading nation in that regard, and the United States is the world’s second leading nation.

Except in nations that have a proportionate abundance of the right natural resources (i.e. a lot of water), hydroelectric power is used to handle the supplying of electricity during high peak loads. Today’s greatest single interest in harnessing more hydroelectric power resides in the fact that it is a renewable source, or “alternative source”, of electricity, since obviously the planet will never run out of water and it doesn’t matter if the water utilized is potable or not.

The big concern about using more hydroelectric power is that it may disrupt ecosystems too much if more facilities (especially dams) are installed. A secondary concern is that water demand for hydroelectric facilities sometimes conflicts with irrigation demands.

The Greeks were using hydroelectric power to turn water-wheels for the grinding of grain over 2,000 years ago. Hydroelectric power was “rediscovered” in the 18th century in the U.S. and western Europe.

The first modern hydroelectric dam was completed in 1882 on the Fox River in Appleton, Wisconsin in the United States and could generate 12.5 kW of electrical power. It was based upon the ideas of American inventor Lester Allan Pelton, who invented a jet-free water turbine in 1880.