Renewable energy is not a new concept. While it may appear to be a rather fashionable topic of conversation in certain circles, renewable energy initiatives have been with us since the dawn of man. There is some debate about the accepted definition of renewable energy, but it can be loosely defined as a form of energy that is essentially inexhaustible. Furthermore, the resource is continually replenished by various natural processes identifiable in the natural world. One key distinction to make when discussing the concept of renewable energy is that of sustainability. One could make the argument that, in the long term, fossil fuels are a renewable energy resource. While the logic stands on its own, this is a failed notion. The central difference between fossil fuels and other forms of renewable energy is that fossil fuels are being depleted at a rate faster than they can be replenished. For this reason, fossil fuels cannot be considered truly renewable. They are simply not sustainable, due to the accelerated rate of consumption. Some of the more popular renewable energy resources include sunshine, water, and wind. Solar energy refers to the energy that is collected from sunlight. This form of energy is captured using a photovoltaic array, more commonly known as a solar panel. The solar radiation is captured by the photovoltaic array and converted to direct current (DC) electricity. From there, the direct current electricity must be converted to alternating current (AC) for use in most applications. The converted electricity is then stored in a battery for use at a later date. There are also various forms of energy that exist in water. One of the most commonly acknowledged is that of hydroelectric energy, but there are a number of others including tidal power and ocean thermal energy conversion. Hydroelectric energy generally employs the use of a dam, wherein the energy of the water flow is captured and used to power a turbine. The turbine then generates a supplementary form of electricity. Tidal power attempts to make use of the natural energy potential of tidal activity in the oceans and seas. In simple terms, the high tide is captured and fed through a turbine to generate electricity. Ocean thermal energy conversion attempts to exploit the variances in water temperature, from the warmer surface water to the cooler deep water, resulting in a cyclic heat engine. Wind power is one of the oldest accepted forms of renewable energy. It has been used for centuries as a source of power, dating back to the creation of the sailboat. The innate potential of wind power was realized a number of years later in the form of a wind mill. In this instance, the kinetic energy of wind is used to drive a turbine which, in turn, generates electricity. Wind energy possesses immense potential for sustainable energy generation, and a number of large-scale development projects are currently underway throughout the world. One of the greatest challenges facing humanity is to discover a way to reduce our reliance on unsustainable resources, like fossil fuels. Most, if not all, modern industrial societies rely far too greatly on fossil fuels and increasingly, this is becoming an undeniable reality. Wars of conquest are being waged to secure what is left of the world's oil reserves. If only the resources of the powerful nations were channeled into developing sustainable energy alternatives, as opposed to driving a war machine bent on dominating the oil markets. Our modern way of life is going to undergo some difficult times in the very near future, if this reality continues to be ignored. Ask yourself what you can do to make a difference. You might be surprised at what you can accomplish.