ENERGY HARVESTING IN MICROSYSTEMS

Energy Harvesting In Microsystems

Energy Harvesting in Microsystems

Introduction

The phrase Energy harvesting implies that these energy sources are alternatives to nuclear and traditional fossil fuels such as coal, petroleum, or natural gas. Energy harvesting, therefore, is a catchall category of energy sources that proponents argue can replace traditional fossil fuels in daily life, while causing less harm to the environment (Hendrick, 2007).

Energy Harvesting is the generation of power from nontraditional sources as opposed to sources such as coal and oil. The main sources of Energy Harvesting are hydropower, wind, solar, hydrogen, bioenergy, geothermal, and hybrid technology. Currently, the most prodigious source of Energy Harvesting is produced by large-scale hydroelectricity schemes, which account for 16 percent of the world supply of energy. By comparison, the other sources combined generate approximately 4 percent.

Energy harvesting is increasingly important for at least three reasons. First, fossil fuels are nonrenewable; eventually, they will be exhausted. The UK is already witnessing a decline in its petroleum production. In 1950, the UK was largely self-sufficient in fossil fuels, producing 32,562,667 billion Btus of energy. At the same time, Britishs consumed 31,631,956 billion Btus of fossil fuels. The UK therefore enjoyed a slight fossil fuel surplus. Now, fossil fuel consumption in the UK far outstrips production. In 2006, the UK produced 56,032,329 billion Btus of fossil fuels, but consumed 84,760,343 billion Btus (Martin, 2005). Advocates of energy harvesting argue that energy harvesting sources need to be developed now, so that when fossil fuels are gone, there will be other dependable energy resources.

Second, many advocates of energy harvesting argue that as oil production declines, Britishs and others around the world will become increasingly reliant on foreign sources of oil. This will require heavy investments in the military to ensure that fossil fuels continue to flow, especially from politically unstable regions of the world such as the Middle East (Daniel, 2001).

Third, energy harvesting has received increased attention because of a scientific consensus that the average temperature of the planet is rising. Scientists argue that a leading cause of global warming is the emission of so-called greenhouse gases such as carbon dioxide, methane, various nitrous oxides, hydrofluorocarbons, sulfur oxides, and particulate matter. These gases come from the combustion of fossil fuels in vehicles, in the production of electricity from coal or natural gas, and in many other processes (Daniel, 2001).

Carbon dioxide and other greenhouse gases are not inherently bad. In fact, these gases naturally occur in the atmosphere and help moderate the global climate to support living organisms, including humans. In this process, the Earth's surface is first warmed directly during the day by incoming solar radiation. At night, this energy is radiated back into the atmosphere as latent heat energy, some of which is absorbed by atmospheric gases such as carbon dioxide. The problem, say many scientists, is that the growing use of fossil fuels is increasing the concentrations of carbon dioxide, methane, and other gases, which, in turn, increase the capacity of the atmosphere to absorb latent heat energy ...