Certain materials, generally metal oxides, can sustain the unassisted photo-electrolysis of water into H2 and O2. The energy contained in the photons that are absorbed by these materials can in many cases be efficiently converted into energy stored into the chemical fuels produced by the photo-electrolysis system. However, these materials have optical absorption thresholds (band gaps) that are too large to permit effective absorption of the visible and infrared portions of the solar spectrum, thereby wasting a large fraction of the incident solar energy and yielding overall energy conversion efficiencies of o 1%. Modification of metal oxide materials has been claimed to be much more promising, with a modified TiO 2 photo-anode yielding 8% efficiency in the photo-assisted splitting of water into H2 and O2 . (more…)
Several molecular systems have been constructed that mimic various aspects of photosynthesis. Two of these utilize molecular system ...
The basic processes that occur in such a system are well understood. The semiconductor electrode efficiently absorbs light, produci ...
The issues of hydrogen storage run through the hydrogen production, hydrogen transport, supply and demand for end use of hydrog ...
Hydrogen has many applications when it comes to fuel. It can be used both in internal combustion engines and hydrogen fuel cells. ...
All of today’s hydrogen conversion products, demonstration models, and prototypes possess some deficiencies; they cannot yet pr ...
Solar energy desalination is a method by which the sun’s energy is used to desalinate brackish or seawater to produce fresh drinkable water. There are two methods for using solar energy: directly by heating and evaporating the brackish or seawater in a solar still (this method is called solar distillation) and indirectly by capturing solar energy using one of the techniques that transform solar radiation into thermal or electrical energy to drive a conventional desalination method (the indirect method is called solar-assisted or solar-driven desalination). (more…)
Solar distillation is the process in which solar heat is used to purify water from an impure water source by evaporation and conden ...
Since the 1980s, no large-capacity solar distillation plants have been built, mainly for the following reasons: Large installation ...
Our homes collect large amounts of solar energy, our homes when built are often placed on our sections to get the best solar en ...
So you're finally tired of those exorbitant electricity bills, or, you're catching onto a "greener" way of life. Either way, solar ...
Nowadays, solar power have become more affordable. That makes it a viable alternative energy option for homeowners who would li ...
Solar dryers are special structures that enhance the drying power of the sun and protect the agricultural product from dust, dirt, and insects. Table below shows a block diagram of an active solar drying system, consisting of solar air collectors, a drying unit or chamber, and an air handling unit. An active solar drying system can accommodate the use of a backup heat source when there in not enough solar heat available. (more…)
Drying is one of the most important post harvest steps. It enhances the storage life of the crop products, minimizes losses during ...
Solar distillation is the process in which solar heat is used to purify water from an impure water source by evaporation and conden ...
Since the 1980s, no large-capacity solar distillation plants have been built, mainly for the following reasons: Large installation ...
Active solar hot water systems water are usable with air, liquid, vapor or liquid collector fluid or gas to liquid process. Hot ...
The U.S. Department of Energy has determined that about 80% of residential energy use is consumed in single-family homes, while 15% ...
In Europe, modern renewable energy sources technologies were explored thoroughly for the first time after the oil embargo/ price crisis of 1973. Notably, market introduction of renewable energy technology started in about 1985, but the renewable energy sources industry has become vital only during the past decade. Accordingly, relevant statistical renewable energy sources data have been systematically compiled only over the past decade, although reliable and consistent statistical renewable energy sources data, collected since 1989, exist for all 15 countries of the European Union and for Western Europe (defined here as the EU-15 plus Switzerland, Norway, and Iceland). (more…)
There are various and somewhat complementary reasons to foster the growth of renewable energy sources in Europe. A major incent ...
The development of the ‘‘new’’ wind and solar technologies is of great importance for the future contribution of RESs to energy sup ...
Although technology change (usually involving an improvement in energy efficiency) is not inherently a geographic process, it does ...
The energy that people use every day comes from many different sources. The resources are divided into two main groups: renewa ...
Renewable energy sources cannot run out and causes so little damage to the environment that its use does not need to be restric ...
The energy that people use every day comes from many different sources. The resources are divided into two main groups: renewable energy and nonrenewable energy. Renewable energy sources are those that can be used again and again. Renewable energy resources have unlimited supply. (more…)
In Europe, modern renewable energy sources technologies were explored thoroughly for the first time after the oil embargo/ price cr ...
During the US Presidential Election 2008 Campaign, the renewable portfolio standard was one of the main agendas for Presidentia ...
The broad range of home solar energy systems are mostly known as Photovoltaic Systems (PV) or Thin Film Solar Technology. The s ...
The hydrogen can come from various sources including fossil fuels, wind, solar, biomass, nuclear, solar thermo-chemical reactio ...
Renewable energy sources cannot run out and causes so little damage to the environment that its use does not need to be restric ...
High-speed maglev technology offers four main advantages: non-contact operation; low-mass vehicles (on a per seat basis, maglev vehicles weigh approximately one-third to three-quarters as much as high speed trains); high speed; and wayside system control and self-propelled vehicles (each car contains its own secondary part of a linear synchronous motors).
Non-contact operation means that vehicle traction does not depend on adhesion between contact surfaces, e.g., wheels and rails. (more…)
A propulsion alternative is to transfer power to the vehicle and then have a magnetic structure on the vehicle that can create ...
Electrodynamic Suspension (EDS) can be viewed as an array of magnets moving over a conducting sheet and being pushed upwards by ...
Designers in China have launched the first wind turbine levitating in the world of permanent magnetic levitation (Maglev) in the Wi ...
All electromagnetic suspension-based systems employ some type of feedback control mechanism to maintain stable levitation. (An inte ...
Electromagnetic Suspension (EMS) system in which an array of magnets is attracted upwards to a steel rail. It is possible to de ...
Cost–benefit analysis (CBA), also known as benefit–cost analysis, is rooted in applied welfare economics. It is a way of organizing and analyzing data as an aid to thinking. It provides a set of procedures for comparing benefits and costs and is traditionally associated with government intervention and with the evaluation of government action and government projects. The underlying rationale for CBA is rational choice; that is, a rational agent will weigh the costs and benefits of any proposed activity and will only undertake the activity if the benefits exceed the costs. (more…)
The first step in categorizing potential benefits and costs is determining the relevant scope of the analysis. We have concluded th ...
Energy efficiency is defined here to mean energy services provided per unit of energy input (for example, gallons of water hea ...
ISO document 14040 identifies four areas for using life cycle analysis (LCA) results: (1) identifying opportunities to improve ...
Recently, attention to energy efficiency has been gaining momentum. The attention given by policy maker is mainly due to concer ...
The question has long been not whether or not to reduce air pollution, but by how much and by what means. Since the extent of t ...
In the mid-1880s, Charles Fritts built the first solar cell formed by selenium coated with a thin layer of gold and with an energy efficiency of 1%. However, it was not until 1954 that Bell Labs discovered accidentally that would be the first commercial solar cell, with silicon as the base. (more…)
So-called thin-film photovoltaic devices are usually based on mixtures of elements other than silicon — most notably copper ind ...
Today, photovoltaic cells only contribute a small proportion (approximately 0.04 percent) of total electricity in the United St ...
So you're finally tired of those exorbitant electricity bills, or, you're catching onto a "greener" way of life. Either way, solar ...
The broad range of home solar energy systems are mostly known as Photovoltaic Systems (PV) or Thin Film Solar Technology. The s ...
Some people may doubt about the ability of these alternative power sources - to much like science fiction they may say. But the ...
The convention aims not only at stabilizing CO2 emissions in developed countries but also at ultimately reducing man-made CO2 emissions globally so as to stabilize the global climate. Environmental degradation cannot be singled out as an independent matter among various global issues. (more…)
Biomass has been a main energy sources in the world since the beginning of civilization. It has been important in development p ...
Over the last decade, the number of countries researching the potential of biomass and bioenergy for energy services rose rapid ...
Renewable energy sources cannot run out and causes so little damage to the environment that its use does not need to be restric ...
Estimation of the future technical potential of biomass as an energy source is dependent on assumptions with respect to land av ...
Climate change caused by the enhanced greenhouse effect is one of the most significant global environmental issues. Increased emiss ...
The hydrogen can come from various sources including fossil fuels, wind, solar, biomass, nuclear, solar thermo-chemical reactions, and solar photolysis. (more…)
Researchers at the Institute of Chemical Technology have developed a new catalyst that allows to obtain, from bioethanol, hydrogen ...
Hydrogen has many applications when it comes to fuel. It can be used both in internal combustion engines and hydrogen fuel cells. ...
The issues of hydrogen storage run through the hydrogen production, hydrogen transport, supply and demand for end use of hydrog ...
Most production systems try to become first full-scale production begins as small toys and devices of concept. The Horizon hydr ...
With ethanol’s future uncertain, many commentators see the transportation debate evolving into a war between two other technologies ...