The advantage of this approach in the United States is that many states offer incentives to offset the cost of installation of a renewable energy system. In California, Massachusetts and several other U.S. states, a new approach to community energy supply called Community Choice Aggregation has provided communities with the means to solicit a competitive electricity supplier and use municipal revenue bonds to finance development of local green energy resources. Individuals are usually assured that the electricity they are using is actually produced from a green energy source that they control. Once the system is paid for, the owner of a renewable energy system will be producing their own renewable electricity for essentially no cost and can sell the excess to the local utility at a profit.
In rigid thin-film modules, the cell and the module are manufactured in the same production line. The cell is created on a glass substrate or superstrate, and the electrical connections are created in situ, a so-called “monolithic integration”. The substrate or superstrate is laminated with an encapsulant to a front or back sheet, usually another sheet of glass. The main cell technologies in this category are CdTe, or a-Si, or a-Si+uc-Si tandem, or CIGS (or variant). Amorphous silicon has a sunlight conversion rate of 6–12%
Even when aid agencies are well funded, they haven’t always delivered. Over the last decade, a strong critique of aid, ranging from William Easterly’s “The White Man’s Burden” to Dambisa Moyo’s “Dead Aid,” has laid much of the blame for Africa’s continued underdevelopment on the weaknesses of sweeping programs planned from afar. Still, aid agencies and global-development banks have a useful role to play in the energy transition. It will be years before it makes financial sense for solar companies to expand to the most remote and challenging regions of the continent. As new companies launch, they will need an infusion of what Helgesen calls “ultra-high-risk capital.” Private investors will supply it, he says, “but they want forty per cent of your company in return, which makes it hard to raise capital later on, because you’ve already sold off such a big chunk.” Some aid agencies have funded private ventures in the early stages, to help them get off the ground or reach new geographic areas. U.S.A.I.D. gave Off-Grid five million dollars toward its early costs, and, over the past few years, a Dutch development agency has given the company several hundred thousand euros as it has extended into the impoverished lakes region of Tanzania, where it otherwise wouldn’t have been profitable to go. Currency risks pose another problem: Poindexter told me that when she builds a Ghanaian microgrid she has invested in an asset with a twenty-year life span in a country where inflation is highly unpredictable. “We just had an election in the U.S. with huge consequences for policy,” she said. “But over here every election is potentially like that.” And, like anywhere in the world, national governments can make things easier by establishing clear policies. Rwanda’s leaders, for instance, specified the regions in which the rapidly developing country planned to extend its grid, thereby delineating where solar would be needed most.
The basis of producing solar panels revolves around the use of silicon cells. These silicon cells are typically 10-20% efficient at converting sunlight into electricity, with newer production models now exceeding 22%.
Solar power is arguably the cleanest, most reliable form of renewable energy available, and it can be used in several forms to help power your home or business. Solar-powered photovoltaic (PV) panels convert the sun’s rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. This electricity can then be used to supply renewable energy to your home or business.
Solar power is just as practical in populated areas connected to the local electrical power grid as it is in remote areas. “An average home has more than enough roof area to produce enough solar electricity to supply all of its power needs. With an inverter, which converts direct current (DC) power from the solar cells to alternating current (AC), which is what most home appliances run on, a solar home can look and operate very much like a home that is connected to a power line.”
Solar panels are used extensively in rural areas, where access to the grid is non-existent or inaccessible. These installations are called off grid (or independent, stand-alone) solar power systems, and require the use of batteries to store the energy for use at night or on long stretches of overcast weather. The energy stored in the batteries leaves the batteries as DC electricity which can power DC appliances (as in RV’s) or be converted to alternating current (AC) for use with conventional appliances. Much like running your own mini utility company, this method gives you full independence from the national grid.
First- and second-generation technologies have entered the markets, and third-generation technologies heavily depend on long term research and development commitments, where the public sector has a role to play.
Jan. 10, 2018 — A new design of algae-powered fuel cells that is five times more efficient than existing plant and algal models, as well as being potentially more cost-effective to produce and practical to use, has … read more
The New Zealand Parliamentary Commissioner for the Environment found that the solar PV would have little impact on the country’s greenhouse gas emissions. The country already generates 80 percent of its electricity from renewable resources (primarily hydroelectricity and geothermal) and national electricity usage peaks on winter evenings whereas solar generation peaks on summer afternoons, meaning a large uptake of solar PV would end up displacing other renewable generators before fossil-fueled power plants.
Solar energy, radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The Sun is an extremely powerful energy source, and sunlight is by far the largest source of energy received by the Earth, but its intensity at the Earth’s surface is actually quite low. This is essentially because of the enormous radial spreading of radiation from the distant Sun. A relatively minor additional loss is due to the Earth’s atmosphere and clouds, which absorb or scatter as much as 54 percent of the incoming sunlight. Yet the total amount of solar energy incident on Earth is vastly in excess of the world’s current and anticipated energy requirements. If suitably harnessed, this highly diffused source has the potential to satisfy all future energy needs. In the 21st century solar energy is expected to become increasingly attractive as an energy source because of its inexhaustible supply and its nonpolluting character, in stark contrast to the finite fossil fuels coal, petroleum, and natural gas.
In February 2011, the U.S. Department of Energy (DOE) launched its SunShot initiative, a collaborative national effort to cut the total cost of photovoltaic solar energy systems by 75% by 2020. Reaching this goal would make unsubsidized solar energy cost-competitive with other forms of electricity and get grid parity . The SunShot initiative included a crowdsourced innovation program run in partnership with Topcoder, during which 17 different solar energy application solutions were developed in 60 days. In 2011, the price was $4/W, and the SunShot goal of $1/W by 2020 was reached in 2017.
Renewable energy sources are energy sources that are always being replenished. They can never be depleted. Some examples of renewable energy sources are solar energy, wind energy, hydropower, geothermal energy, and biomass energy. These types of energy sources are different from fossil fuels, such as coal, oil, and natural gas. These are nonrenewable energy sources, which means that if we use them all up, we can never get more during our lifetime.
In February 2010, the Rudd Government announced proposed that from 1 January 2011, the RET will include two parts – the Small-scale Renewable Energy Scheme (SRES) and the Large-scale Renewable Energy Target (LRET).
Chemicals such as Boron (p-type) are applied into the semiconductor crystal in order to create donor and acceptor energy levels substantially closer to the valence and conductor bands. In doing so, the addition of Boron impurity allows the activation energy to decrease 20 fold from 1.12 eV to 0.05 eV. Since the potential difference (EB) is so low, the Boron is able to thermally ionize at room temperatures. This allows for free energy carriers in the conduction and valence bands thereby allowing greater conversion of photons to electrons.
By lowering a building’s utility bills, these systems not only pay for themselves over time, they help reduce air pollution caused by utility companies. For example, solar power systems help increase something called “peak load generating capacity,” thereby saving the utility from turning on expensive and polluting supplemental systems during periods of peak demand. The more local-generating solar electric power systems that are installed in a given utility’s service area, the less capacity the utility needs to build, thus saving everyone from funding costly additional power generating sources. Contributing clean, green power from your own solar electric system helps create jobs and is a great way to mitigate the pollution and other problems produced by electricity derived from fossil fuel. Solar-powered electrical generating systems help you reduce your impact on the environment and save money at the same time!
Effect of orthotropy ratio of the shear web on the aero-elasticity and torque generation of a hybrid wind turbine bladeEffect of orthotropy ratio of the shear web on the aero-elasticity and torque generation of a hybrid wind turbine blade
A solar power tower system uses a large field of flat, sun-tracking mirrors called heliostats to reflect and concentrate sunlight onto a receiver on the top of a tower. Sunlight can be concentrated as much as 1,500 times. Some power towers use water as the heat-transfer fluid. Advanced designs are experimenting with molten nitrate salt because of its superior heat transfer and energy storage capabilities. The thermal energy-storage capability allows the system to produce electricity during cloudy weather or at night.
One of the key issues in solar capture and conversion is how to separate charge efficiently over macroscopic distances without using expensive, highly pure, semiconductor materials. This effort requires the development of new chemical and materials methods to make polycrystalline and nanocrystalline semiconductors perform as if they were expensive single crystals. Numerous research approaches are being pursued (13). Materials consisting of a network of interpenetrating regions can facilitate effective charge separation and collection, thus relaxing the usual constraint in which the photogenerated carriers must exist long enough to traverse the entire distance of the cell. Present photon conversion devices based on a single-bandgap absorber, including semiconductor PV, have a theoretical thermodynamic conversion efficiency of 32% in unconcentrated sunlight. However, the conversion efficiency can be increased, in principle, to 45–65% if carrier thermalization can be prevented (by overcoming the so-called Shockley–Queisser limit). Multiple-bandgap absorbers in a cascaded junction configuration can result in high photoconversion efficiencies, particularly when cells are designed to sustain the operating conditions (e.g., elevated temperatures) associated with highly concentrated sunlight. It is expected that mature high-concentration PV systems can provide 10–20% more energy than standard PV systems with the same installed power rating.
In addition, a ground-breaking study by the US Department of Energy’s National Renewable Energy Laboratory (NREL) explored the feasibility of generating 80 percent of the country’s electricity from renewable sources by 2050. They found that renewable energy could help reduce the electricity sector’s emissions by approximately 81 percent .
^ Artificial photosynthesis as a frontier technology for energy sustainability. Thomas Faunce, Stenbjorn Styring, Michael R. Wasielewski, Gary W. Brudvig, A. William Rutherford, Johannes Messinger, renewable energy F. Lee, Craig L. Hill, Huub deGroot, Marc Fontecave, Doug R. MacFarlane, Ben Hankamer, Daniel G. Nocera, David M. Tiede, Holger Dau, Warwick Hillier, Lianzhou Wang and Rose Amal. Energy Environ. Sci., 2013, Advance Article doi:10.1039/C3EE40534F
Power purchase agreements (PPAs) are very similar to how people pay their electric bills today — the equipment is owned by a third party, and customers are only charged for the kilowatt-hours of solar power that they use. In fact, some companies will simplify your solar and electric billing so you just receive one bill, to save on transaction costs. But overall, the lack of an up-front installation cost makes PPAs a very attractive proposition for solar-seeking homeowners. In fact, says Kimbis, overall, the majority of solar customers enter leases and PPAs instead of buying their own equipment outright.
Reports like these have been used to promote clean-energy production throughout the US and the rest of the world since the 1970s. However, it wasn’t until 2002 that California codified the practice. But despite being in effect for only 15 years, California’s mandatory reporting has become a potent tool in fighting greenhouse-gas emissions throughout the state.
It’s one of the most exciting renewable technologies around – and yet, do you really know how solar energy is captured, stored and converted? Get up to speed on photovoltaics and solar thermal with this short explainer video.
The panels, which will be installed on hundreds of rooftops across the city, are capable of producing up to 60 megawatts of solar power, the companies said. Work has started on the project, and it will be up and running by the end of the year.
…of chlorophyll pigment, which uses solar energy to produce carbohydrates out of water and carbon dioxide. The overall efficiency of this critical process is somewhat low, and its mechanics are extremely complex. It is related to light intensity, wavelength, temperature, carbon dioxide concentration in the air, and the respiration rate…
In 2007, the US Congress directed the Department of Energy to report on ways to reduce water consumption by CSP. The subsequent report noted that dry cooling technology was available that, although more expensive to build and operate, could reduce water consumption by CSP by 91 to 95 percent. A hybrid wet/dry cooling system could reduce water consumption by 32 to 58 percent. A 2015 report by NREL noted that of the 24 operating CSP power plants in the US, 4 used dry cooling systems. The four dry-cooled systems were the three power plants at the Ivanpah Solar Power Facility near Barstow, California, and the Genesis Solar Energy Project in Riverside County, California. Of 15 CSP projects under construction or development in the US as of March 2015, 6 were wet systems, 7 were dry systems, 1 hybrid, and 1 unspecified.
Thermoelectric, or “thermovoltaic” devices convert a temperature difference between dissimilar materials into an electric current. Solar cells use only the high frequency part of the radiation, while the low frequency heat energy is wasted. Several patents about the use of thermoelectric devices in tandem with solar cells have been filed. The idea is to increase the efficiency of the combined solar/thermoelectric system to convert the solar radiation into useful electricity.
A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building. As the chimney warms, the air inside is heated causing an updraft that pulls air through the building. Performance can be improved by using glazing and thermal mass materials in a way that mimics greenhouses.
Although some regions may produce excess RPS-qualifying generation, others may produce just enough to meet the requirement or may need to import electricity from adjoining regions to meet state targets.