by Publitek European Editors:
Monitoring is the key to unlocking the energy production of the solar cell. It is easy to lose efficiency through the use of circuit architectures that assume constant energy production when the solar environment is constantly changing.
The change in current-voltage properties as a solar module heats up or receives more light can be an important source of efficiency losses in solar arrays. If the inverter that generates grid-compatible electricity is not tuned to the output voltage and current conditions, it will waste more of the electricity than it should. In response, electronics companies have produced ICs that perform the maximum power-point tracking (MPPT) needed to optimize energy conversion as well as bypass electronics to prevent temporarily unproductive modules from disrupting the output of active cells.
Maximizing the Output from Solar Modules - [Link]
Researchers Steve Dunn at Queen Mary University and James Durrant at Imperial College London have been experimenting with a new design of thin, flexible solar cell made from zinc oxide. Manufacturing costs of the new cells will be significantly lower than conventional silicon based technology. The only disadvantage is their poor efficiency; just 1.2 %, a fraction of that achievable with silicon.
The material also exhibits piezo-electric properties, nanoscale rods of the material generate electricity when they are subjected to mechanical stresses produced by sound wave pressure. Sound levels as low as 75dB, equivalent to that from an office printer, were shown to improve efficiency. Durrant said “The key for us was that certain frequencies increased the solar cell output, we tried our initial tests with various types of music including pop, rock and classical”. Rock and pop were found to be the most effective. Using a signal generator to produce sounds similar to ambient noise they saw a 50 % increase in efficiency, rising from 1.2 % without sound to 1.8 % with sound.
New Solar Cell Shows a Preference for AC/DC - [Link]
by Publitek European Editors:
Led by solar photovoltaics, the market for harvesting energy from renewable sources is booming. At the simplest level, a single residence is equipped with a PV system, generating electricity for its own use, and feeding the excess back to the national grid. At the highest level are utility-scale PV plants and solar farms, contributing to improved grid resiliency and helping governments meet global targets to reduce CO2 emissions.
Meanwhile, the smart grid concept is emerging as the way forward to provide a much-needed upgrade to national electrical infrastructures. The deployment of smart meters and off-peak tariffs will help utilities meet peak demands without excessively increasing overall capacity. Techniques such as ‘demand response’ and ‘transactive energy’ will help us exploit renewable energy generation effectively.
Taking the Measure of Photovoltaic System Output - [Link]
A team comprised of the Fraunhofer Institute for Solar Energy Systems, Soitec, CEA-Leti and the Helmholtz Center, Berlin has just unveiled the world’s most efficient solar cell! Boasting an efficiency of 44.7%, the cell breaks the record set by Sharp just three months ago by 0.3%. The four-junction photovoltaic cell is not only dramatically more efficient than the theoretical 33.7% efficiency limit of conventional silicon-based solar PV, but it puts the team well on the road to reaching their goal of 50% efficiency by 2015.
German-French Team Unveils World’s Most Efficient Solar Cell! - [Link]
An application note from Microchip: Practical guide to implementing Solar Panel MPPT Algorithms (PDF!)
This application note describes how to implement MPPT using the most popular switching power supply topologies. There are many published works on this topic, but only a tiny portion of them show how to actually implement the algorithms in hardware, as well as state common problems and pitfalls. Even when using the simplest MPPT algorithm with a well-designed synchronous switching power supply, it can be expected that at least 90% of the panel’s available power will end up in the battery, so the benefits are obvious.
Practical guide to implementing Solar Panel MPPT Algorithms - [Link]
The following is important because with flexible organic photovoltaic cells, we are nearing a new era of development for practical solar-based solutions can be implemented with clever usage of these devices. Efficiency needs to be higher, but technology is progressing in the right direction and a breakthrough is inevitable.
Heliatek announced a record breaking 12.0% cell efficiency for its organic solar cells. This world record, established in cooperation with the University of Ulm and TU Dresden, was measured by the accredited testing facility SGS. The measurement campaign at SGS also validated the superior low light and high temperature performances of organic photovoltaics (OPV) compared to traditional solar technologies.
New world record for organic solar technology with a cell efficiency of 12% - [Link]
MIT engineers have proposed a new way to improve solar cell performance by using special ‘funnels’ to capture photons. The funnels would be formed in a thin film of semiconductor material by pressure from microscopic needles, producing elastic strain in the funnel area. The strain causes the band gap of the material to vary over the surface of the funnel, which allows a broader spectrum of light to be converted into electricity. The electron/hole pairs produced by the photons in the incident light would also be guided toward the centre of each funnel by electrical forces, improving efficiency compared to the usual diffusion process.
The MIT team used computer modelling to determine the effects of elastic strain on a funnel depression in a thin sheet of molybdenum disulphide (MoS2), a natural semiconductor material that can form films just one molecule thick. The elastic strain, and the corresponding change in the potential energy of the electrons, varies with the distance from the centre of the funnel. The potential energy determines the wavelength of the photons that can be captured by the material, and thus the portion of the light spectrum that can be converted into electricity. The team hopes to carry out laboratory experiments in the future to confirm their theoretical findings. [via]
Energy Funnels Boost Solar Cell Performance - [Link]
Small photovoltaic modules of the SMH series will reliably solve the power sourcing of low-power devices.
With modern components, it´s no problem to design devices with power consumption in units of mA and less. That´s why already one small solar module combined with a backup battery or a supercapacitor often solves power sourcing of devices intended for usage in places without electric energy, or in places where a connection to electricity would be inadequately expensive.
SMH series belongs to a segment of small solar modules primarily intended to be built-in to target devices – measuring systems, sensors, communication devices, … High quality construction and a high reliability predestine for various industrial devices. Power in a range of 407-1023 mW is sufficient for many applications including various control units (for example with low-power bistable relays).
SMH3, SMH4 and SMH8 are made of monocrystalline silicon with a UV resistant encapsulation of the IP65 class, optimized for outdoor use (polyurethane, 1.8mm overall thickness of module). As already their name says, they consist of 3,4 or 8 cells, what results in an output voltage of 1.65V, 2.2V or 4.4V. Leads are constructed as soldering pads on a rear side of modules. All modules are 100% electrically and optically tested. Color of modules is dark blue (almost black).
Supply your devices even in the desert - [Link]
This document covers a few of the applications where lasers can be used during the fabrication of crystalline silicon
(c-Si) solar cells.
Manufacturing c-Si Solar Cells with Lasers - [Link]