Climate considerations aside, damages wrought by ethanol made from corn were usually similar to, or even slightly worse, than damages from gasoline. That’s because of the extra energy needed to convert corn to biofuel.

Today, wind farms generate about 50,000 megawatts of clean, renewable energy -- the equivalent of the energy produced by 12 Hoover Dams.

Brief History of Tidal Power The energy stored in tides been known to people for many centuries. The earliest records of tidal mills are dated back to the 8th Century CE.7 The tidal mills were mainly used for grain grinding and were of similar design to the conventional water mills with the exception of the addition of a dam and reservoir. The industrial revolution increased demand for power but tidal energy never got off the ground, undercut by cheap fossil fuels and other developments which offered easier access to power generation. Existing tidal mills became as obsolescent as pre-industrial water-mills. The first large scale modern tidal electric plant started to operate in La Rance Estuary, St. Malo, France in the 1960s and has been operating ever since. In recent years the search for renewable, non-polluting energy sources and the increase in fossil fuel prices has encouraged renewed interest in tidal power.

Tidal power is a predictable source of energy unlike that of wind power and solar power because the tides follow the gravitational pull of the moon. The general production of tidal energy is similar to other forms of hydroelectric power where the force of water flow spins a turbine which generates energy.

he tidal stream generator uses the kinetic energy of the flowing tide to spin windmill like turbines. It is also often referred to as a tidal energy converter (TEC).

Tidal power is the production of electricity by the utilization of tidal energy.

Currently, numerous wave power plants (so called wave farms) have been implemented throughout the world. Many different organizations have designed various wave power systems that differ in size, cost, and effectiveness. A wave farm is a collection of wave power systems in order to create mass quantities of power. One example of a wave power plant is the Aguçadoura Wave Farm in Portugal from Pelamis Wave Power Ltd. It is the first wave farm ever established and produces 2.25 megawatts of power. It was completed in 2008. Other wave farms, with other companies involved, have been proposed.

solar panels are at least 20x better on the climate than coal, kWh for kWh.

Based on that study, solar PV works out to about 50g of CO2 per kWh compared to coal's 975g of CO2 per kWh, or about 20x "cleaner."

The steam from the water then increases in pressure, forcing a turbine to spin. The turbine is used to rotate a magnet encased in a generator a high speeds. As the magnet spins, electrons are produced, and they power the electricity grid.

As of 2009, fossil fuels supplied about 85 percent of the world's energy demands.

The biofuel industry takes the chemical energy contained in organic materials and converts this into useful energy sources. However, it is not necessarily a sustainable industry. Daniel Tan explains.