For the last decade, government subsidies have played a crucial role in growth of the global solar market, with a 50 percent market growth rate for each of the last ten years. The European Union, led by Germany, has experienced the most growth in photovoltaic installations. In the EU, the solar industry has benefited from aggressive national feed-in-tariff (FIT) policies.
The United States does not have a national policy, but a mix of state and federal programs designed to support solar development -- from small residential systems to utility-scale power plants.However, except for China, the solar industry in the U.S. and other countries can no longer rely on the continued availability of generous government incentive programs.
The solar industry has entered a period of consolidation and maturation. With government incentives under scrutiny, it has become mission critical for solar manufacturers to invest in R&D and create technologies to drive the cost of solar low enough to make subsidies, or the lack thereof, a non-issue.
According to Stuart Wenham, chief technology officer Chinese solar module manufacturer Suntech Power Holdings, technologies that assimilate into existing manufacturing processes,and take advantage of existing supply sources, have a distinct advantage over innovations that require the industry to adapt. Bankrupt solar panel manufacturers like Evergreen Solar and SpectraWatt provide testaments to this failed business model.
The following advances in photovoltaic technology have the potential to move the industry into a new generation of solar cell and modules, which could drive the cost of solar power generation plants to grid parity with coal and beyond:
Solar Concentrator
California-based Hypersolar, Inc. has invented a product it calls “the world's first thin and flat solar concentrator for standard solar cells.” The concentrator installs over top of the solar cells. The technology, which consists of a thin, flat optical layer of material, enables solar cells to receive more sunlight and generate up to 400 times the power of conventional solar cells.
As a result, solar panel manufacturers require fewer solar cells to produce modules. Because solar cells make up a significant cost of materials in the solar module manufacturing process, this technology can significantly reduce the cost per watt of electricity.
Magnifying the sun's rays does not make for a novel approach; the concept has been around for centuries. However, the idea of a magnification overlay, which most solar panel manufacturers can employ in their existing process, represents an innovative and revolutionary low-cost concept. Hypersolar's technology, which the company believe provide innovative solutions for panel manufacturers:
1. Micro Concentrators- This product gathers the sun's ray from multiple angles without the use of a tracking apparatus.
2. Photonic Light Routing- Consist of a “solid-state” photonic system situated under the Micro Concentrators. The photonic network moves sunlight from the top of the concentrator to the bottom, which reduces the thickness of the material.
3. Photonic Light Separation - This technology divides the sunlight into various “spectrum ranges” and then distributes the sunlight to “output points” at the bottom to the different solar cells.
4. Photonic Thermal Management- Standard solar cells transform just a portion of the solar spectrum into electrical power. The remainder of the convert into heat and causes degradation of the solar cells performance. This technology, removes the part of the solar spectrum not converted to electricity, which prevents overheating.
The company plans to develop a variety of concentrators to fit different solar cells and functions.
Generating Solar Electricity at Night
Generally, solar modules provide energy only during daylight hours. Most PV systems, which provide energy after sundown, have some sort of energy storage system. The U.S. Department of Energy, Idaho National Laboratory, reports researchers have developed a thin film technology that allows for the generation of solar energy at night.
Traditional solar cell technology catches light from a single part of the spectrum. Nanoantenna captures sunlight from the infrared spectrum. According to the researchers, this method captures about 84 percent of the incoming protons under optimal settings.
The technology works by creating a flexible substrate that relies on nanoantennas in place of solar cells. The light-sensitive nanoantenna method relies on a variety of materials stacked in layers. Each material uses a distinct wavelength, which includes low and mid-energy wavelengths.
The project's lead researcher Steven Novack states almost 50 percent of the solar spectrum accessible energy lies in the infrared band. The material absorbs heat generated by the earth at night when the earth “reflects” heat. Novack claims the cells have an efficiency rating of 46%. Novack states the technology could be potentially groundbreaking they can find an inexpensive method of manufacturing the product.
Printable Solar Cells
Imagine printing solar cells on just a sheet of paper using an ink jet printer. Massachusetts Institute of Technology (MIT) researchers have created an innovated method for creating solar cells at a cost far less than current solar cell manufacturing.
Instead of employing the standard sputtering process, which deposits liquid-like semiconductor material onto a substrate, the process entails spraying a vapor consisting of multiple layers of special ink to form solar cells on various substrates, such as plastic, cloth, and paper. The cells capture light from the sun, or ambient lighting in the environment, to generate power.
Where silicon solar cells reflect light not directly converted to electricity, nanoantennas absorbs radiation from multiple angles
The potential of creating a flexible solar panel, simply by printing, presents the potential for far-reaching application, including panels, laptops, smartphones, and other electronic products. The researchers say the paper substrate is 1,000 times less expensive than glass. Forty percent of the cost of a solar module consists of glass. Researchers continue to work on improving the efficiency -- currently about one percent. They expect to bring a viable product within the next 24 months.
Quantum Dot Solar Cells
A report, published in a recent issue of Nature Materials, discusses progress made in the area of colloidal quantum dot solar cells. Quantum dot solar cells consist of minuscule spheres made of thousands of atoms. Concentrating these atoms in a very tiny space increases the level of interaction among electrons. Previously, researchers believed that one photon could only excite a single electron, which limits overall efficiency.
Based on the sunlight's color, this technology excites as many as three electrons, according to the scientists from the joint SLAC-Stanford PULSE Institute for Ultrafast Energy Science. This process, known as multiple exciton generation, improves solar cell efficiency up to 33 percent.
The quantum dot solar cell process paints or sprays the cells onto a substrate. The method requires an even diffusion of quantum dot solar cells within a material called colloid. Compared to silicone or CIGS solar cells, the product does not have as high an efficiency rating. However, researchers claim to be narrowing the efficiency gap.
Besides benefits for photovoltaic cells, quantum dot solar cells also have positive implications for lasers, high-speed electronics, light emitting diodes and other applications.
