Photovoltaics is best known as a method for generating solar power by using solar cells packaged in photovoltaic modules, often electrically connected in multiples as solar photovoltaic arrays to convert energy from the sun into electricity. To explain the photovoltaic solar panel more simply, photons from sunlight knock electrons into a higher state of energy, creating electricity.
Photovoltaics can refer to the field of study relating to this technology, and the term photovoltaic denotes the unbiased operating mode of a photodiode in which current through the device is entirely due to the transduced light energy. Virtually all photovoltaic devices are some type of photodiode.
Solar cells produce direct current electricity from light, which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft and pocket calculators, but today the majority of photovoltaic modules are used for grid connected power generation. In this case an inverter is required to convert the DC to AC. There is a smaller market for off grid power for remote dwellings, roadside emergency telephones, remote sensing, and cathodic protection of pipelines.
Cells require protection from the environment and are packaged usually behind a glass sheet. When more power is required than a single cell can deliver, cells are electrically connected together to form photovoltaic modules, or solar panels. A single module is enough to power an emergency telephone, but for a house or a power plant the modules must be arranged in arrays. Although the selling price of modules is still too high to compete with grid electricity in most places, significant financial incentives in Japan and then Germany triggered a huge growth in demand, followed quickly by production. Although module prices rose and plateaued, it is expected that costs and prices will fall to ‘grid parity’ in many places around 2010.
Many corporations and institutions are currently developing ways to increase the practicality of solar power. While private companies conduct much of the research and development on solar energy, colleges and universities and institutes also work on solar-powered devices. Most research is being carried out in Germany, Japan, USA and Australia. Solar power has received less research funding than other sources, but is seen as the most likely largest source of electricity in 15 years in the United States.
The most important issue with solar panels is capital cost (installation and materials). Because of much increased demand, the price of silicon has risen and shortages occurred in 2005 and 2006. Newer alternatives to standard crystalline silicon modules including casting wafers instead of sawing , thin film (CdTe, CIGS, amorphous Si, microcrystalline Si), concentrator modules, ‘Sliver’ cells, and continuous printing processes. Due to economies of scale solar panels get less costly as people use and buy more — as manufacturers increase production to meet demand, the cost and price is expected to drop in the years to come. As of early 2006, the average cost per installed watt for a residential sized system was about USD 6.50 to USD 7.50, including panels, inverters, mounts, and electrical items. In 2007 investors began offering free solar panel installation in return for a 25 year contract to purchase electricity at a fixed price, normally set at or below current electric rates.
A new photovoltaic “thin film” technology being pioneered by Californian company Nanosolar allows cells to be mass produced by printing them on to aluminium film at a fraction of the cost of existing techniques. At December 2007 the company claims it can achieve costs of USD $0.99 a watt which would be comparable to coal produced electricity.
Commercial production of roll-to-roll thin film technology, commenced on 2007 in Cardiff Wales, by a company called “G24 Innovations”, owned in part by the Ecole Polytechnique Fédérale de Lausanne (EPFL), which is the source for some of its technology (Dye-sensitized solar cells). It claims that its products “…incorporate raw materials that are both inexpensive and effectively limitless…” and that it has a current production capability of 30MW.
A less common form of the technologies is thermophotovoltaics, in which the thermal radiation from some hot body other than the sun is utilized. Photovoltaic devices are also used to produce electricity in optical wireless power transmission.
New Solar Panels That Work At Night
Despite the enormous untapped potential of solar energy, one thing is for sure- photovoltaics super-thin solar film that would be cost-effective, imprinted on flexible materials, and would be able to harvest solar energy even after sunset! are only as good as the sun’s rays shining upon them. However, researchers at the Idaho National Laboratory are close to the production of a
The technique involves the embedding of square spirals of conducting metal onto a sheet of plastic, each of which, referred to as a “nanoantenna,” just 1/25 the diameter of a human hair. The nanoantennas absorb infrared energy, which is absorbed by the earth during the day and released even hours after the sun goes down. The nanoantennas are thus able to harvest energy both during daytime hours and into the early evening. Because they can take in energy from both sunlight and the earth’s heat, the nanoantennas have a much higher efficiency (and potential applicability) than conventional solar cells.The scientific principle isn’t a new one, but the manufacturing process that maximizes efficiency certainly is state-of-the-art. The innovation within nanotechnology is what has allowed the nanoantennas to be efficiently embedded to absorb energy in a flexible and inexpensive material. Just imagine the possibilities…
Solar and Wind Photovoltaic ''Leaves''
My friends at Ecolect, the go-to sustainable design and materials community, have launched a monthly spotlight on sustainable design called Limelight – and the first feature is tough act to follow. Teresita Cochran’s sustainable design group, SMIT (Sustainably Minded Interactive Technology) has a compelling new project called GROW that’s an innovative and aesthetically arresting solar and wind power solution. Combining the best of green tech and ecology, GROW draws inspiration from ivy growing on the side of a building – resulting in a hybrid energy delivery device of flexible, ivy-like fluttering solar leaves that provide power via both sun and wind.
After a serendipitous collaboration with her brother, Samuel Cochran, during his undergraduate studies at Pratt and her graduate studies at ITP/NYU, Teresita began working on Samuel’s Industrial Design thesis project, GROW, by cutting leaf-shaped solar panels. What eventually followed was GROW as SMIT’s first product offering, which now exists in 2 versions, GROW.1 (currently at the Museum of Modern Art until May 12th, 2008 in the exhibit Design and the Elastic Mind), and GROW.2, a residential application built on top of a stainless steel mesh system, allowing ivy and other crawlers to grow with it.
Using a series of flexible solar cells as leaves, GROW takes the shape of ivy growing on a building- the leaves are solar cells while the wind that causes them to flutter is harvested as viable energy using a series of piezoelectric generators on the underside of each leaf. SMIT hopes that the modular system will be readily available in stores such as the MoMA store or Design Within Reach in the coming 1-2 years, in addition to other retail methods allowing consumers to access the technology via multiple channels. GROW also integrates an energy monitoring system called WATTg for GROW’s users to visualize their energy consumption and generation. The leaves are made of 100% recyclable polyethylene, and are available in a variety of colors and opacities.
I love the simplicity of the idea, the natural inspiration, and the idea of bite-sized solar panels fluttering in the wind on the side of a house. Gorgeous and green equals a great idea!
