Archivio febbraio 2010
To select the 50 most innovative companies in the world, the editors of Technology Review looked for those that over the last year have demonstrated their superiority at inventing technology and using it both to grow as businesses and to transform how we live. We identified the companies that have the most promising technologies, whether they are giant corporations or fledgling startups with initial venture capital investments. Then we examined their business models, their strategies for deploying and scaling up their technologies, and the likelihood that they will succeed. The result is the first annual TR50.
Optical antennas could help solar cells produce more energy.
By Katherine Bourzac
Inexpensive thin-film solar cells aren’t as efficient as conventional solar cells, but a new coating that incorporates nanoscale metallic particles could help close the gap. Broadband Solar, a startup spun out of Stanford University late last year, is developing coatings that increase the amount of light these solar cells absorb.
Based on computer models and initial experiments, an amorphous silicon cell could jump from converting about 8 percent of the energy in light into electricity to converting around 12 percent. That would make such cells competitive with the leading thin-film solar cells produced today, such as those made by First Solar, headquartered in Tempe, AZ, says Cyrus Wadia, codirector of the Cleantech to Market Program in the Haas School of Business at the University of California, Berkeley. Amorphous silicon has the advantage of being much more abundant than the materials used by First Solar. The coatings could also be applied to other types of thin-film solar cells, including First Solar’s, to increase their efficiency.
Fonte: CRIT Research™
Il mercato europeo dei sistemi fotovoltaici integrati negli edifici (in inglese BIPV – Building Integrated PhotoVoltaics) è un settore di nicchia con un grande potenziale. Nonostante ricopra meno del 5% del mercato globale delle installazioni fotovoltaiche in Europa, esso riscuote notevole interesse a causa della progressiva crescita annuale e del sempre maggior numero di Paesi che intraprendono politiche incentivanti a supporto di questa tecnologia, come strumento per realizzare una crescita sostenibile del settore edile, sempre più focalizzata verso il risparmio energetico.
I sistemi BIPV sono prodotti in grado di equilibrare gli aspetti tecnici ed estetici dei componenti della tecnologia fotovoltaica con quelli dell’involucro edilizio, senza compromettere le caratteristiche funzionali di entrambi. Le caratteristiche fisiche del modulo fotovoltaico – forma, dimensione, colore, eventuale trasparenza – possono diventare elementi di caratterizzazione dello spazio architettonico, sia quando il modulo viene utilizzato come copertura, facciata o grande vetrata, sia quando esso diventa elemento di arredo urbano (chioschi, pensiline, fermate dell’autobus, lampioni, ecc.). Grazie ai sistemi BIPV, il pannello fotovoltaico viene interpretato e utilizzato come vero materiale edilizio, sostituendo un materiale da costruzione convenzionale, e diventando un componente attivo dell’edificio, in grado di contribuire positivamente alla sua performance energetica.
Nel 2007 al mercato europeo BIPV è stato attribuito un valore di 143 milioni di €, con una capacità totale installata di 25.7 MW, considerando complessivamente utenze commerciali, residenziali, industriali e pubbliche (Fonte: Frost & Sullivan). La maggior parte del fatturato attuale deriva dalle installazioni commerciali ed industriali, nonostante il mercato pubblico abbia avuto un ruolo importante nel diffondere la visibilità delle installazioni BIVP, grazie ad alcuni grandi progetti dimostrativi. Nonostante la diffusione dei sistemi BIPV rappresenti solo una minuscola fetta nel mercato del fotovoltaico, una maggiore penetrazione potrebbe essere conseguita attraverso una corretta implementazione delle politiche di sostegno, come è stato dimostrato nei mercati tedesco e lussemburghese, caratterizzati da una forte diffusione della tecnologia a partire dall’anno 2000. Prosegui la lettura »
A startup’s large-scale printing equipment could make high-performance OLED televisions more affordable.
By Katherine Bourzac
Organic light-emitting diode (OLED) displays are more energy-efficient and provide a better picture than liquid-crystal displays (LCDs), but they haven’t gained much of a market foothold because they’re far more expensive. A recently introduced OLED TV sold by LG in South Korea costs over $2,500, for example.
A startup in Menlo Park, CA, hopes to bring down the cost of these high-performance displays by making equipment for printing them on a large scale. Kateeva is testing a prototype large-area OLED printer that it will send to display manufacturers for testing next year. According to the company, its equipment can be used to print OLED displays for 60 percent of the cost of LCDs.
OLED displays are now found in a few products that take advantage of the picture quality, such as a high-end 11-inch flat-panel television made by Sony. Some portable electronics, including Google’s Nexus One phone, also use OLEDs because the relatively low-power screen extends battery life.
All the OLED displays on the market are manufactured using an expensive, small-scale technique called shadow-mask evaporation to lay down the light-emitting organic molecules that make up the pixels. Companies have looked into alternatives that are compatible with large-area manufacturing, such as ink-jet printing, but all the processes entail compromises on the performance and lifetime of the display. Kateeva’s technique combines features of shadow-mask printing and ink-jet printing to make high-quality OLED pixels over a large area. The company plans to sell printing equipment and OLED inks made of light-emitting small molecules.
IBM researchers have built efficient cells using abundant elements.
By Kevin Bullis
Researchers at IBM have increased the efficiency of a novel type of solar cell made largely from cheap and abundant materials by over 40 percent. According to an article published this week in the journal Advanced Materials, the new efficiency is 9.6 percent, up from the previous record of 6.7 percent for this type of solar cell, and near the level needed for commercial solar panels. The IBM solar cells also have the advantage of being made with an inexpensive ink-based process.
The new solar cells convert light into electricity using a semiconductor material made of copper, zinc, tin, and sulfur–all abundant elements–as well as the relatively rare element selenium (CZTS). Reaching near-commercial efficiency levels is a “breakthrough for this technology,” says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory, who was not involved with the work.
The IBM solar cells could be an alternative to existing “thin film” solar cells. Thin film solar cells use materials that are particularly good at absorbing light. The leading thin film manufacturer uses a material that includes the rare element tellurium. Daniel Kammen, director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley, says the presence of tellurium could limit the total electricity such cells could produce because of its rarity. While total worldwide electricity demand will likely reach dozens of terawatts (trillions of watts) in the coming decades, thin film solar cells will likely be limited to producing about 0.3 terawatts, according to a study he published last year. In contrast, the new cells from IBM could produce an order of magnitude more power.
The new cells could also have advantages compared to cells made of copper indium gallium and selenium (CIGS), which are just starting to come to market. That’s because the indium and gallium in these cells is expensive, and while the selenium used in the IBM cell is rarer than indium or gallium, its cost is a tenth of either.
Wireless optical networks could provide gigabit-per-second data transfer.
By Erica Jonietz
A wireless network that uses reflected infrared light instead of radio waves has transmitted data through the air at a speed of one gigabit per second–six to 14 times faster than the fastest Wi-Fi network. Such optical networks could provide faster, more secure communications and would be especially suitable for use in hospitals, aircraft, and factories, where radio-frequency transmission can interfere with navigation equipment, medical devices, or control systems. Another possible application is wireless networking for home theaters; a system that transmits data at 1.6 gigabits per second could broadcast two separate high-definition TV channels across a room, a capacity that exceeds the bandwidth of any existing radio system.
Penn State graduate student Jarir Fadlullah and Mohsen Kavehrad, professor of electrical engineering and director of the university’s Center for Information and Communications Technology Research, built and tested the experimental system. Their setup sent data across a room by modulating a beam of infrared light that was focused on the ceiling and picking up the reflections using a specially modified photodetector. The pair says that their measurements show the system could support data rates “well beyond” the one gigabit per second they are currently claiming.
Il punto di forza del nuovo dispositivo è il fatto di utilizzare un processore convenzionale che ne dovrebbe favorire la diffusione commerciale
Un sensore alimentato a energia solare di 9 millimetri cubi realizzato presso l’Università del Michigan ha guadagnato il primato di più piccolo dispositivo in grado di sfruttare l’energia ambientale mai costruito.
Processore, cella solare e batteria sono tutti contenuti in un involucro di 2,5×3,5×1 millimetri, quindi 1000 volte più piccolo di un analogo dispositivo disponibile sul mercato attualmente.
Utilizzabile per produrre impianti biomedicali e sistemi di monitoraggio ambientali, potrebbe migliorare l’efficienza delle reti di sensori riducendo al contempo i costi.
Uno dei punti di forza del dispositivo, come sottolineano i ricercatori che l’hanno presentato all’International Solid-State Circuits Conference di San Francisco, è il fatto di utilizzare un processore convenzionale, l’ARM Cortex-M3, con architettura a 32 bit, che dovrebbe favorire la sua diffusione commerciale. Esso è attualmente il microcontroller più parco nel consumo di energia elettrica disponibile sul mercato (il microcontrollore è un dispositivo alternativo al microprocessore, dotato di minore potenza ma anche capace di consumi nettamente inferiori).
Cells absorb sunlight concentrated 1,000 times without cooling.
By Katherine Bourzac
A startup company hopes to bring down the cost of generating power with concentrated sunlight by using microscale solar cells that can utilize twice as much light as other panels, without the need for expensive optics or cooling systems. Panels made from the tiny cells, which the Durham, NC-based company Semprius developed using a novel microprinting technology, also offer significant savings on materials costs. In late January, the company announced a joint agreement with Siemens to develop demonstration systems based on its technology. Semprius plans to begin volume production of the modules in 2013.
Adding concentrating lenses to solar panels increases the amount of electricity they can produce. But photovoltaic concentrators add a great deal of expense to a solar installation. The optical systems themselves are expensive and bulky–the larger a cell, the larger its paired lens must be. More intense light also means that more performance-degrading heat must be dissipated using heat sinks or fans. Although the cost is partly offset by the efficiency of high-concentration photovoltaics, it limits the potential power of such concentrator systems. The two major suppliers of concentrated solar modules, Amonix and Emcore, both sell systems based on conventional-size cells that operate under 500 times concentration sunlight with costly cooling systems.
Semprius’s solar modules contain arrays of square cells that measure just 600 micrometers on each side. These cells have three semiconducting layers–each of which is based on gallium arsenide and absorbs a different band of sunlight–and they are made using a combination of chemical etching and printing, which means fewer raw materials are wasted. They can operate under sunlight concentrated 1,000 times using cheap optical systems. According to the National Renewable Energy Laboratories, the efficiency of the resulting modules ranges from 25 to 35 percent and they can provide electricity for about 10 cents a kilowatt hour. The company expects the final costs to be $2 to $3 per watt.
Last year, a study by researchers at Sandia National Laboratories in Albuquerque, NM, suggested that microscale solar cells might offer various cost and design advantages. “You reduce the amount of semiconductor you need, so there can be a big cost savings,” says Gregory Nielson, head scientist on the Sandia project. “And you can do things with the optics that you can’t do with larger cells.”
Smaller solar cells are more efficient at dissipating heat. “When the cells are below a millimeter, they reject the heat so efficiently they’ll be just as cool as a one-sun panel,” without the need for any cooling systems, says Nielson. This is because the tiny cells have a much greater percentage of total area given up to heat-diffusing edges.
Government incentives and lower solar prices are starting to pay off.
By Kevin Bullis
In a few years, the United States is likely to be the world’s largest market for solar power, eclipsing Germany, which has taken the lead as a result of strong government incentives in spite of the relative paucity of sunlight in that country. A number of factors could make growth possible in the United States–especially changes in legislation that give utilities incentives to create large solar farms.
Last year, the U.S. solar industry got off to a slow start, but sales rebounded in the second half of the year, largely because of a drop in the prices of solar panels of up to 40 percent, partly caused by an oversupply due to the recession. Revenues for many solar companies were likely flat, but the megawatts of solar installed in the United States overall grew by 25 to 40 percent last year, says Roger Efird, the chairman of the Solar Energy Industry Association and the managing director of Suntech America, a branch of Suntech Power, the largest maker of crystalline silicon solar panels in the world.
This year, Efird says, solar installations could double, reaching a gigawatt of capacity. “That’s a big number,” he says. “If you are in the solar business, you were talking watts 15 years ago, you were talking kilowatts 10 years ago, and you have trouble even talking megawatts today.”
The growth had several likely causes, including decreasing prices for solar panels and installation costs, as well as increasing state incentives, which can make solar far more attractive. According to Harry Fleming, the CEO of Acro Energy Technologies in Oakdale, CA, these changes mean that the cost of a typical five-kilowatt rooftop solar system has dropped from $22,000 after state incentives are applied ($40,000 without them) to $16,000 in the last 18 months. Prices are expected to fall to $13,000 by the end of the year ($25,000 without incentives). “This is going to make solar a middle-class product,” he says.
At the same time, it seems likely that projects funded through the federal stimulus package will get underway this year. The U.S. General Services Administration and the U.S. Department of Defense, for example, are both ready to start solar projects, Efird says. “A big kick for us in 2010 will be these stimulus funds we’ve been waiting for,” he says.
Another key could be solar projects undertaken by utilities. Efird says that a small change in the tax code has allowed utilities to take a tax credit for solar investment. After that, “we began to see, really for the first time, utilities starting to get interested in solar as a way of generating wholesale electricity that they could then resell.” His company has done demonstration projects in the past, he says, “but we’ve never looked at the utility sector and said that’s a market in itself.” About a third of the new installations next year could come from utilities.
Researchers from Imperial College London and their European partners, including Volvo Car Corporation, are developing a prototype material which can store and discharge electrical energy and which is also strong and lightweight enough to be used for car parts.
Ultimately, they expect that this material could be used in hybrid petrol/electric vehicles to make them lighter, more compact and more energy efficient, enabling drivers to travel for longer distances before needing to recharge their cars. In addition, the researchers believe the material, which has been patented by Imperial, could potentially be used for the casings of many everyday objects such as mobile phones and computers, so that they would not need a separate battery. This would make such devices smaller, more lightweight and more portable.