Fossil fuels – coal, oil, and natural gas – are currently the main sources of energy. These fuels have two main drawbacks: they are a limited resource and becoming increasingly expensive to produce, and fossil fuel combustion creates greenhouse gases such as CO2. Due to the fact that conventional fossil fuels are gradually being depleted, research is being conducted on new sources of energy – namely unconventional fossil fuels such as shale gas, tar sand oil and lignite; however, these sources involve an increasingly larger drain on our environment and do not solve the impeding energy crisis. The resulting greenhouse gases form an insulating blanket around the earth, causing increased atmospheric temperatures and sea-level rise. A third additional downside to electricity generation using fossil fuels is that only roughly half of the potential energy is converted to electricity; the other half is released as low-grade waste heat using cooling towers or heat exchangers (e.g. into lakes, rivers, and oceans). The heat is an additional strain on our environment and includes a number of negative ecological impacts.
RED has none of the previously described disadvantageous. As a matter of fact, RED is a completely renewable source of energy and will continue to be available as long as the sun continues to shine, because RED is, in essence, an indirect form of solar energy. The sun is the driving force behind the water cycle, in which water evaporates from the oceans, condenses to form clouds, falls as rain onto land, and finally collects into rivers and returns to the ocean along our coasts. The point at which a river empties into the ocean is a potential source of energy in the form of a salinity gradient, which is released when the two bodies of water mix. The only ‘byproduct’ of RED is brackish water due to the mixing of salt and fresh water. Brackish water can be found at the mouths of rivers emptying into the sea, thus brackish water isn’t actually an additional by product at all because it is naturally produced. Blue energy is then only extracting energy from a naturally occurring system found all over the world.