There are numerous possible applications for hybrid power systems. The most common examples are (1) remote AC network, (2) distributed generation applications in a conventional utility network, and (3) isolated or special purpose electrical loads.

The classic example of the hybrid energy systems is the remote, diesel-powered AC network. The basic goal is to decrease the amount of fuel consumed by diesel generators and to decrease the number of hours that they operate. The first addition to ‘‘hybridize’’ the system is to add another type of generator, normally using a renewable source. (more…)

The term hybrid energy system refers to those applications in which multiple energy unit conversion devices are used together to supply an energy requirement. These systems are often used in isolated applications and normally include at least one renewable energy source in the configuration. Hybrid energy systems are used an alternative to more conventional systems, which typically are based on a single fossil fuel source. Hybrid energy systems may also be used as part of distributed generation application in conventional electricity grid. (more…)

Electric utility deregulation offers the great promise of market forces leading to lower electric rates, lower air pollution environment, greater energy (and economic) efficiency, and perhaps greater use of renewable energy sources. Ideally, deregulation involves the restructuring of a previously monopolized or nationalized electric utility into separate generation, transmission, distribution, and marketing companies, and allowing wholesale and retail choice of generation company or power marketer. Deregulation has occurred to varying degrees since 1989 in the United Kingdom, Norway, Australia, New Zealand, Chile, Argentina, and about 20 states in the United States. There have been promising results in a few countries and in some U.S. states in some respects, especially lower rates and lower air pollution problems. In most cases, competitive markets have yet to be realized and lower rates can be attributed to other causes, such as previously planned amortization or retirement of expensive power plants, unexpected surplus in natural gas, rate caps, etc. In addition, deregulation has had only a slight beneficial effect on the use of renewable electricity sources. The promise of electric utility deregulation is thus unfulfilled and deserves further study.

Geopolitical considerations have played a major role in many renewable energy policy decisions, e.g., in domestic debates over gasoline taxes, pipeline construction, radioactive waste disposal, and acid rain control legislation in the United States, and in petroleumrelated violence in Nigeria. The most prominent role for geopolitics in energy policy has probably involved international discussions on controlling greenhouse gas emissions, and in oil markets. In the cases of the Kyoto Protocol of 1997 and the 1992 Framework Convention on Climate Change, nations carefully considered their national economic interests, domestic politics, and international trade during the negotiations. European countries, with the lowest rates of population and economic growth along with strong domestic environmental lobbies, have pursued a greater rate of greenhouse gas reduction.

The United States, in contrast, has been stubbornly cautious and backed out of the treaty in 2001 (arguing it is not in its economic best interests), and the oil-rich nations of the Middle East have been least supportive of any emissions controls. In the case of oil markets, with the United States now dependent on imports for over half its supply, energy policy and trade strategy have played major roles in the pursuit of new oil discoveries in Alaska and in warfare in Kuwait, Iraq, and perhaps Afghanistan.

Scientists study Earth’s climate not just from observation but also from a theoretical perspective. Modern-day climate models successfully reproduce the key features of Earth’s climate, including the variations in wind patterns around the globe, the major ocean current systems such as the Gulf Stream, and the seasonal changes in temperature and rainfall associated with Earth’s annual revolution around the sun. The models also reproduce some of the more complex natural oscillations of the climate system. Just as the atmosphere displays random day-to-day variability that we term “weather,” the climate system produces its own random variations, on timescales of years. (more…)

air pollution problems created by coal combustion. Meanwhile, coal-fired power plants and industrial boilers spewed out tons of gaseous and particulate pollutants into the atmo- sphere. During combustion, the small amounts of sulfur and nitrogen in coal combine with oxygen to form sulfur dioxide (SO2), sulfur trioxide (SO3), and the oxides of nitrogen (NOx). (more…)

Fuel cell vehicles are being developed because they promise to meet the requirements expected of automobiles in a market increasingly constrained by environmental and resource limitations. Air pollution and oil dependence have been persistent challenges for vehicles powered by petroleum fuels (gasoline and diesel). Global warming presents a new challenge in the need to limit carbon dioxide (CO) emissions from fossil fuel combustion. (more…)

The spark-ignition and compression-ignition engine and internal combustion engines technologies that are currently employed in motor vehicles were developed more than 100 years ago. These conventional vehicle technologies are fueled by petroleum-derived gasoline and diesel fuels (the socalled conventional fuels). Over the past 100 years, the conventional technologies have been dramatically improved, reducing cost and increasing performance. (more…)

The leading automotive brands are being focused to produce electric vehicles because they believe they represent a harmony to the environment and climate change solution. (more…)

Do we have the resources? Rudolf Diesel developed the diesel engine which ran on biodiesel vegetable oil in the late 1800s. At the time, he speculated that his discovery seemed insignificant, but later could prove to be as important as mankind’s uncovering of future energy uses for petroleum and coal tar. Given the U.S.’ rapid expansion into biofuels, it would appear his vision was correct due to the drawbacks of biofuels. But widespread adoption of biomass-based fuels is not a foregone conclusion. Two questions haunt its progress. First, will it truly reduce U.S. reliance on fossil fuels? And second, is there enough farmland to accommodate widespread production, without jeopardizing food supplies? (more…)

Bioenergy produced from biomass is sometimes called a carbon-neutral energy source, because the same quantity of carbon released when the biomass is burned is sequestered again when the crop or forest is re-grown. Referring to bioenergy as carbon neutral or having zero net emissions may be misleading; there are emissions associated with producing biomass, such as from fossil fuel used in cultivation, harvest, processing and transport, and in manufacture and construction of fuel conversion technology. (more…)