It is no secret that the sun can be harnessed to provide a source of energy for homes and businesses.

The sun is a powerful star. It supplies us with energy, through a process called nuclear fusion, and sustains life on our planet Earth. Solar energy, or energy from the sun, has existed since prehistoric times when men would magnify the sun’s energy in efforts to start fires.

The sun is a valuable resource that radiates enough energy on the United States in one day to meet the nation’s needs for one and a half years. Since it is a free, clean and renewable source of energy, it is an energy source that will play a vital role in our future.

Using the sun’s energy for our energy source seems like an easy solution to having an energy supply forever. Harnessing the suns energy is where the problem lies. The sun’s rays shine all over the world and not in just one spot. Although it takes only 8 minutes for sunlight to travel to the earth, trying to catch the rays over such a wide area can prove to be tricky. Also, the energy in any one given place will vary due to factors, such as, clouds and weather conditions.

The history of using solar energy began in 1890’s when solar water heaters were used in the United States. Solar water heating requires a storage collector and a storage tank. Flat plate solar collectors are mounted on rooftops. Pipes carrying water are pumped through these collectors. The tubes are painted black so they will get hot quicker. As the heat is collected the fluid in the tubes get heated. A storage tank holds the hot liquid. This helps with central heating and cutting fuel costs. Solar heaters became popular when natural gas was expensive and burning wood and coals were burdensome. It’s popularity diminished with the discovery of an abundance of natural gas and oil deposits. Now they are making a comeback to replace the depleting fossil fuels that had taken its place.

Solar energy can be in the form of heat energy or light energy. The technology of photovoltaic, or PV as it is commonly called, converts the suns energy into electric currents through the use of solar cells. These electric currents can be used instantaneously or stored for later use. The PV cells consist of pieces of silicon under a thin piece of glass. They have both a positive and negative charge. Simple examples of this are the solar powered calculators that are common today. More complex examples are solar panels placed on roofs. This consists of using thin film solar cells as rooftop shingles, roof tiles, and even glazing for skylights. Unfortunately, the cells generate only about one sixth of the sun’s energy into electricity. This means bigger arrays are needed and along with this come larger costs.

Solar thermal power plants use the sun to heat fluid, which in turn, is transferred into steam similar to fossil fuel burning plants. The steam is transformed into mechanical energy in a turbine and electrical energy from a generator. The downfall is solar plants cannot produce energy on cloudy days.

It is expected the next few years will see millions of households using solar energy. As research continues and processes improve, using our sun as a renewable energy source will produce efficiency and cost savings. So, let the sun shine in and take full advantage of this warm energy source where you live.

Smart energy will fulfill all your energy requirements at the lowest price. Smart energy master is a unique device which plays a vital role in meeting the energy needs of the new generation. The main features of the smart energy master are that it reduces the energy cost to a large extent. The device is easy to handle. This device reduces the carbon emission to a large extent and so it also a green energy equipment. Automatic monitoring is another major feature of this device. The maintenance cost of this device is very less compared to other similar devices. Free installation of the smart energy master is available. Smart energy master is a digital, intelligent central heating boiler management system which works on temperature and time, ensuring your boiler works at maximum efficiency. Smart energy master is compatible with almost all boilers.

Smart Energy UK – Dedicated To Helping Public

SmartEnergy uk offers some insight into why this rise is occurring: The wholesale price of gas has been one of the main factors in the sharp rise in prices, and as around a third of Britain’s electricity is provided by gas-fired power stations, the cost for all mainstream energy sources has been on the rise. Smart Energy also notes that the need to reduce carbon emissions has driven the price of coal up and it is, without a doubt, time to start thinking of alternative energy sources to save money and precious resources. smartenergy uk is dedicated to helping the public harness the power of the Sun to provide free energy for life.

Today, much emphasis is being placed on renewable energy, living green, and the environment, Never before has there been such a strong and growing grass roots movement toward renewable and sustainable energy and environmental responsibility. In truth, this movement is to a significant extent motivated by financial concerns of people who are desperate to cut utility bills by finding ways to conserve energy. However, the end result is the same; much more interest in and progress toward bringing renewable and sustainable energy technology such as wind power into the mainstream.

Wind power is a concept that, like solar power, has been around for a long time and sparsely used. In the last five years, this has changed dramatically. In the Midwest, one can see many examples of eclectic cooperatives purchasing land or at least leasing rights to construct huge farms of wind generators to augment their electricity generating capabilities and to bring down the cost of electricity to their customers. While this is a great development from an environmental aspect, the average customer sometimes does not see a great reduction in their monthly electric bill.

Wind power for the average private residence is possible. While technically possible to go off the grid with wind power, this is not as reliable or advisable compared to solar power. However, residential wind power generators do make sense in that they can significantly reduce one’s electric bill. Unlike the massive towers with gigantic propellers, that one sees the electric cooperatives using, residential wind generators are compact, relatively small and usually unobtrusive.

These residential wind generators can be free standing with their own tower, usually 20 to 30 feet tall, or they can be mounted on a tower which is in turn mounted on the roof of the house. The residential wind generator does face some challenges that solar power does not. The configuration of a wind generator generally requires that the propeller be at least 20 or 30 feet off the ground, especially in a dense residential area. Depending on the neighborhood, some will run into zoning restrictions that might prevent them from having a tall tower on or around their house. However this is the exception rather than the rule. Most homeowners will be able to install their wind generator with a minimum of trouble and expense.

Most wind generators are relatively affordable and can be paid for in the first two years with the savings in the monthly electric bill that they make possible. People are usually surprised by how little wind is necessary to generate a significant amount of wind power. This will vary according to region, but most places will have sufficient wind to generate at least some wind power every day.

Fuel Cell technology for buildings: Lowered Energy Costs, Increased Business Up-time and Reduced Emissions through CCHP (combined cooling, heating and power).

People have been aware that the sun’s energy can be harnessed to power various devices and machines for years, but it is not until recently that the technology and the motivation has pushed people to seriously consider solar energy as a viable power source.

With the current state of the economy and with the growing move toward a more environmentally responsible lifestyle, many people are considering various forms of renewable energy and “green living” principals. Solar power is usually at the top of the list when it comes to renewable energy sources. Solar power has been used for years by the government and various businesses, but it has only recently come into the mainstream for the everyday average household.

In almost any area of the country it is possible to dramatically cut one’s electric bill by installing and maintaining solar panels. Some people are even able to go entirely off the grid and power their homes completely independently of the traditional local electric company, all by solar power. While going off the grid may be an intimidating prospect for some, there is absolutely no reason why a household cannot install solar panels on the roof and greatly reduce the monthly electric bills.

Until recently, the cost to buy and install residential solar panels has been prohibitively high, and not everyone has the technical know how to do it themselves. However, with the shift toward renewable energy, many companies have seen this as an opportunity in an untapped industry and have started offering solar panels at much more competitive and affordable prices. The installation and upkeep of the solar panels is very easy and affordable. Many households find that they can pay for the solar panels in less than a year through the reduced electric bills they produce.

Obviously, once the panels are installed, the solar power is completely free and produces absolutely no harmful emissions, unlike traditional fossil fuels. As the technology becomes more mainstream, manufacturers and builders are constantly refining their techniques to make the solar panels more efficient, durable and innovative.

Recently, some builders have started to integrate solar power into their overall design by including solar panels as standard features on top of garages and in other unobtrusive places such as the roofs of gazebos, tops of pool houses, and on every available foot of roof space in general. Some pool decks are being built with embedded solar cells. As the renewable energy movement continues, more and more builders will find it necessary to integrate a solar power plan into their overall building plan in order to stay competitive with all the other builders who are doing the same.

Solar power is one of the easiest and best solutions to not only help the environment and climate, but to save significant amounts of money in electric bills as well. With solar power components being more affordable now than ever before, every homeowner should at least consider installing solar panels.

1. INTRODUCTION: FUTURE ENERGY NEEDS

Mankind has recently enhanced its living standard and its population in an explosive way. In fact, the human population quadrupled and primary power consumption increased 16-fold during the 20th century [1]. The consumption of energy, food, and material resources is predicted to increase 2.5 fold in the coming 50 years. As a result of our efforts for better life, we have come to face, in this 21st century, serious global issues threatening our safe life or even our existence itself on our mother planet earth. These are issues such as global warming, environmental degradation, declining nutrition on land and sea from rising CO2, and rapid decrease of fossil reservoir. Since the living standard and the population of developing countries are increasing continuously, the demand of energy will be several times larger than that of today’s requirement by the time of the half way of this century.

In 2000, the world had 6.1 billion human inhabitants. This number could rise to more

than 9 billions in the next 50 years as shown in Fig.-1. This future population increase is mostly due to very rapid increase in less developed countries although the number in more developed countries will be almost constant (about 1 billion) or rather decrease [2].

Fig.-1 World Population Prospects [2]

The explosive increase in the human population inevitably requires an exponential increase in the consumption of energy, food, and material resources. One primary power source at present comes from fossil fuels such as oil, coal and natural gas. However, the fossil fuels have two serious factors which prevent them from being used for a long term as primary power source. One is their limited amount that does not last long if used with the same or higher pace than that of today (Fig.-2). The other is their negative feature of emitting carbon dioxide, one of the green house gases, which causes the global warming.

Fig.- 2 Pattern of Global Energy Dependence [3]

Fig.-3 Atmospheric carbon dioxide monthly mean mixing ratios. Data prior to May 1974 are from the Scripps Institution of Oceanography (SIO, blue), date since May 1974 are from the National Oceanic and Atmospheric Administration (NOAA, red). A long term trend curve is fitted to the monthly mean values [4]

Atmospheric CO2 has increased from 275 parts per million (ppm) before the industrial era begun to 379 ppm in March 2004 as shown in Fig.-3. Some scientists suggest that it will pass 550 ppm this century. Climate models and paleoclimate data indicate that 550 ppm, if sustained, could eventually produce global warming comparable in magnitude but opposite in sign to the global cooling of the last Ice Age [5].

Global energy demand continues to grow along with worldwide concerns over fossil fuel pollution, the safety of nuclear power and waste, and the impact of carbon-burning fuels on global warming. As a result sustainable energy sources like solar, wind, hydropower, biomass, geothermal, hydrogen, ocean thermal, tidal power etc are drawing prime attention, out of which solar power is the most promising one. Terrestrial solar power has too many limitations like atmospheric attenuation, daily and seasonal variation, and affects by climate conditions etc. To overcome these limitations concept of Solar Power from Space is getting momentum, which was first proposed by Czech-American engineer Peter Glaser as a solution to the oil crises of the 1970s [6]. Solar Power from Space is a proposed concept to place a gigantic solar power station in space orbiting around the earth that uses microwave power transmission to beam solar power to a very large antenna on earth where it can be used in place of conventional power sources.

2. SPACE SOLAR POWER (SSP) vs TERRESTRIAL SOLAR POWER (TSP)                   

The SSP concept arose because space has several major advantages over earth for the collection of solar power. Space is free from day-night cycle, atmosphere, clouds, dust, rain, fog and other climatic changes, so it would receive 30% more intense and at least eight times more sunlight than that of at ground constantly and continuously unaffected by the weather. In geosynchronous orbit it would receive sunlight almost 24 hours a day hence avoiding the expensive storage facilities necessary for earth-based solar power systems.  Since earth’s axis is tilted, it would be in earth’s shadow only for 70 minutes maximum at late night when power demands are at their lowest, during 42 days near the equinoxes [7] as shown in Fig.-5.

Fig.-5 Daily duration of eclipses as a function of the date [7]

3. SSP: SYSTEM DESIGN AND TECHNOLOGIES

The SSP system is composed of a space segment and a ground power receiving site (Fig.-6). Space segment consists of mainly three parts; solar energy collector to convert the solar energy into DC (Direct Current) electricity, DC-to-microwave converter, and large antenna array to beam down the microwave power to the ground. Ground power receiving site uses a device called rectenna (rectifying antenna) to receive and rectify the microwave power beam. The rectenna system converts the microwave power back to DC power which is then converted to conventional AC (Alternating Current), and is connected to existing electric power networks.

Assuming typical values for efficiencies like 15% for solar panels to convert solar energy into DC, 70% conversion rate in the space segment from DC to microwave, 90% beam (power) collection efficiency, and 80% conversion rate for rectenna from microwave to DC in ground segment, the estimated over-all efficiency is approximately 7.5 %. With such efficiency a SSP space segment would be of size of about 50 km2 (5 km x 10 km) to generate 5 GW DC power on earth (Fig.-6).

Fig.-6 : Reference Model: 5 GW GEO based Space Solar Power Station Designed by US Department of Energy (DOE) and NASA in 1979 [8]

3.1 -SOLAR CELL: EFFICIENT STRUCTURES

In the very near future, breakthroughs in nanotechnologies promise significant increase in solar cell efficiencies from current 15% values to over 50% levels. That might decrease required size of space segment by about 3 fold. Author proposes Metal-Metal junction cavity solar cell which theoretically promises to increase solar-electric conversion efficiency many folds.

A cavity of metal m2 (work function W2) with thin polish of metal m1 (work function W1, W1 <W2 , Fig.-7) on inner surface, with a pin hole is kept at the focus of the solar concentrator coinciding the pinhole and focus. Pinhole is covered with transparent glass to protect inner polish of cavity from atmospheric reaction. Such cavity behaves as metal-metal junction solar cell (termed as M-M cavity solar cell) with various features (described below) leading to enhancement of solar-electric conversion efficiency.

·  The major loss in usual structures is the reflection loss (about 30%) but in M-M cavity solar cell once ray enters in cavity, undergoes multiple inner reflecti