Hydropower, also known as hydroelectric power, is the use of water to produce power. Harnessing water to perform work has been going on for thousands of years. The Greeks used waterwheels for grinding wheat into flour more than 2000 years ago. Besides grinding flour, the power of the water was used to saw wood and to power textile mills and manufacturing plants. This article looks briefly at how hydropower plant began, why it is considered renewable energy technology, the parts of a hydropower plant, types of turbines and when they are used, and what research and development is occurring. (more…)
Up to around 1980, hydropower research and development (R&D) efforts focused mainly on improving turbine efficiency, reducing c ...
The water levels of most of the world’s rivers fluctuate with seasonal rains, melting snows, or droughts, and in the arid zones ...
The World Commission on Dams (WCD) was formed in 1998 by a joint initiative of the World Conservation Union (IUCN) and the Worl ...
The winners in hydropower and other large dam projects are those who gain electricity, domestic water supplies, sanitation, dro ...
The demand for electric energy by a community varies with the time of day and with the time of year. An electric power utility ...
Global energy consumption in the last half century has increased very rapidly and is expected to continue to grow over the next 50 years. However, we expect to see significant differences between the last 50 years and the next. The past increase was stimulated by relatively “cheap” fossil fuels and increased rates of industrialization in North America, Europe, and Japan; yet while energy consumption in these countries continues to increase, additional factors are making the picture for the next 50 years more complex. These additional complicating factors include the very rapid increase fuel economy in energy use in China and India (countries representing about a third of the world’s population); the expected depletion of oil resources in the not-too-distant future; and the effect of human activities on global climate change. (more…)
The relationship of gross national product per capita to energy consumption per capita for most countries of the world correlat ...
The long-term prospects for the U.K. economy are inevitably uncertain, and the most recent Department of Energy long-term proje ...
Transportation is another sector that has increased its relative share of primary energy use. This sector has serious concerns ...
The development of the ‘‘new’’ wind and solar technologies is of great importance for the future contribution of RESs to energy sup ...
To determine the effects of past climate trends on global energy consumption, the econometric equations providing the degree day el ...
Several molecular systems have been constructed that mimic various aspects of photosynthesis. Two of these utilize molecular systems that are derived from natural photosynthesis but that incorporate chemically based modifications to produce artificial photosynthetic devices. These devices use artificial photosynthetic pigments to drive chemical reactions across lipid bilayers or use noble metal catalysts to change the function of the photosynthetic process to produce hydrogen and oxygen instead of sugars ethanol and oxygen. Neither of these systems are sufficiently robust to be operated for extended periods of time as energy unit conversion devices, but they have shown that it is possible to produce artificial photosynthetic assemblies that function well in a laboratory setting. (more…)
The basic processes that occur in such a system are well understood. The semiconductor electrode efficiently absorbs light, produci ...
Certain materials, generally metal oxides, can sustain the unassisted photo-electrolysis of water into H2 and O2. The energy co ...
A fuel cell is an electrochemical device that combines hydrogen with oxygen to generate electricity, heat and water to produce. ...
A fuel cell is an electrochemical device that directly converts a fuel to electricity by means of reactions on the surfaces of ...
The fuel cell can trace its roots back to the 1800s when a Welsh-born, Oxford-educated barrister, Sir William Robert Grove, realize ...
Indoor air quality (IAQ) research deals with the presence, levels, health effects, and control of physical, chemical, and biological factors in indoor environments, including homes, workplaces, and vehicles. IAQ research in industrialized countries has examined hundreds of specific factors (e.g., temperature, various chemicals, and mold), sources of pollution environment (e.g., environmental tobacco smoke, occupational factors, consumer cleaning products, and moisture), and control technologies (e.g., ventilation). (more…)
Important research over the past few decades has illustrated that indoor air pollution and indoor smoke from solid fuel poses i ...
In terms of aggregate health effects, household solid fuel use is currently the most important source of indoor air pollution i ...
Exposure to air pollutants and air pollution problem are very high in indoor environments in developing countries. Smith has es ...
Reducing exposure to indoor air pollution from household energy use can be achieved through interventions in of the following a ...
Exposure to indoor air pollution from the combustion of solid fuels has been implicated, with varying degrees of evidence, as a ...
The formation of acidic deposition is largely from the combustion of fossil fuels and the smelting of sulfide ores. Minor natural sources exist such as the formation of hydrochloric and sulfuric acid from gaseous volcanic eruptions.
There are well over 100 gaseous and aqueous phase reactions that can lead to acid formation and more than fifty oxidizing agents and catalysts may be involved. However, in the simplest terms sulfur in fuels is oxidized to SO2 , and SO2 in the atmosphere is further oxidized and hydrolyzed to sulfuric acid. Most nitric acid is formed by the fixation of atmospheric nitrogen gas (N2) to NOx (NO and NO2) during high temperature combustion emissions, followed by further oxidation and hydrolysis that produces nitric acid in the atmosphere. (more…)
Acid deposition and the associated particulate nitrates and sulfates are implicated in the deterioration of certain sensitive e ...
The increased use of fossil energy since the industrial revolution, and especially since 1950, has been the major cause of incr ...
Although underground coal mines operations are not as visible as surface mining, their overall environmental impact can be greater ...
Historically, mining companies have extracted the earth’s resources wherever economics made it feasible, secure in their knowledge ...
Federal Excise Taxes placed on specific energy sources tend to reduce energy demand for these energy sources in both the short and the long run. The federal government imposes excise taxes on almost all petroleum products (including petroleum additives) and coal (see Table 1). The federal government also imposes federal excise taxes on many transportation uses of methanol, ethanol, natural gas, and propane and imposes a fee on electricity produced from nuclear power plants and nuclear power electricity. (more…)
Economists have overwhelmingly favored fuel taxes over fuel economy standards as a means to reduce fuel or gasoline consumption ...
Taxation of energy in the United States, the federal government does not impose an energy tax or a general sales tax that is br ...
Analysis of future light-duty transportation energy use require estimates of the impact of fuel prices on travel and fleet fuel ...
Various provisions in the federal income tax treat energy producers more or less favorably than other businesses. By changing t ...
A number of countries have vehicle tax incentives programs designed to reward purchasers and owners of alternative fuel-efficient v ...
Exposure to air pollutants and air pollution problem are very high in indoor environments in developing countries. Smith has estimated that at the aggregate level (i.e., without accounting for particle size, chemical composition, and source), approximately 80% of total global exposure to airborne particulate matter occurs indoors in developing nations. Details of exposure for various household members, and the roles of both pollution and behavior (e.g., location with respect to stove and activities), have been studied and evaluated using new tools and technology. (more…)
Important research over the past few decades has illustrated that indoor air pollution and indoor smoke from solid fuel poses i ...
Exposure to indoor air pollution from the combustion of solid fuels has been implicated, with varying degrees of evidence, as a ...
Smoke from biomass and coal combustion contains a large number of pollutants with known health hazards, including particulate matte ...
Indoor air quality (IAQ) research deals with the presence, levels, health effects, and control of physical, chemical, and biologica ...
Reducing exposure to indoor air pollution from household energy use can be achieved through interventions in of the following a ...
The word “laser” is an acronym for “light amplification by the stimulated emission of radiation.” Lasers of all kinds consist of several basic components: an active medium, an outside energy source, and an optical cavity with carefully designed mirrors on both ends. One of the mirrors is 100 percent reflective while the other is somewhat less reflective, so a beam can be emitted. The active medium is inside the optical cavity and is excited with an external energy source (typically electricity). For the cavity to emit laser radiation, the active medium has to achieve an unusual energy state called “population inversion.” (more…)
The first known laser was made by Theodore Maiman at Hughes Research Laboratories in Malibu, California, in 1960, but the seeds ...
Different lasers use different materials as the active medium. The medium can be either solid, liquid, or gas, and there are ad ...
There are literally thousands of uses for lasers. One of the largest applications is telecommunications—sending a signal throug ...
It is known that laser printers print faster, but swallow a large amount of energy, even if the printer is in the energy saving ...
Fabrication techniques developed for integrated circuit (IC) production have been refined to the extent of supporting a multi-b ...
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 t ...
The characteristics and components of a hybrid system depend greatly on the application. The most important consideration is wh ...
Renewable energy generators are devices that convert energy from its original form in the renewable energy source into electric ...
The primary electric drivetrain components for fuel cell vehicles are the same as those for any electric vehicle: traction motors, ...
Drying is one of the most important post harvest steps. It enhances the storage life of the crop products, minimizes losses during storage, and saves shipping costs. The drying process is the removal of water from the wet surface of the food. In this process, heat is transferred by convection and radiation to the surface of the produce. This heat raises the temperatures heat and evaporates the moisture from the exterior of the agricultural products, diffusing the interior moisture to the surface and replenishing the evaporated surface moisture. (more…)
Solar dryers are special structures that enhance the drying power of the sun and protect the agricultural product from dust, dirt, ...
The moisture content of the feedstock affects the gas composition and the energy balance of the process since gasification is an en ...
Biomass Storage Biomass storage is required to ensure the continuous operation of the facility. To limit the space required for ...
As a result of high and rising costs of fossil fuels and fossil fuels affect global environment concern , and by the reduction ...
Solar distillation is the process in which solar heat is used to purify water from an impure water source by evaporation and conden ...