Posts Tagged ‘improve efficiency’
Wednesday, August 7, 2013 @ 04:08 PM gHale
Organic solar cells that convert light to electricity using carbon-based molecules have shown promise as a versatile energy source, but have not been able to match the efficiency of their silicon-based counterparts.
That may soon change as researchers found a synthetic, high-performance polymer that behaves differently from other tested materials and could make inexpensive, highly efficient organic solar panels a reality.
The polymer, created at the University of Washington (UW) and tested at the University of Cambridge in England, can improve efficiency by wringing electrical current from pathways that, in other materials, cause a loss of electrical charge.
“In most cases you are generating charge but you have to out-compete all the areas of loss that keep you from delivering the electricity from the cell to the device you are trying to power,” said Cody Schlenker, a postdoctoral researcher in the laboratory of David Ginger, a UW chemistry professor.
“These materials can be printed like newspaper and manufactured into rolls of film like plastic wrap, so they could have a significant manufacturing cost advantage over traditional materials like silicon,” Ginger said. Schlenker and Ginger are co-authors of a paper analyzing the new material.
Organic solar cells change color briefly as they convert light to electricity, similar to how some prescription glasses darken when exposed to sunlight and become clear indoors. The researchers used a technique called photo-induced absorption spectroscopy to measure the color changes as “fingerprints” to study pathways that devices use to convert sunlight to electricity.
The same technique also pinpoints “dead-end” pathways that do not produce electricity, which are present in most organic materials used for solar cells and limit power production. UW scientists found their polymer appeared to have few dead ends, but they needed more sensitive measurements to be sure.
Cambridge researchers had seen hints of the same kind of behavior in similar materials for organic solar cells.
“They were seeing some of the same features that we were seeing, features that everyone said you shouldn’t be able to see,” Schlenker said.
At a scientific meeting in Italy last year, the two groups began discussing the apparent surprising properties of the UW-created polymer, composed of carbon, hydrogen, sulfur and nitrogen atoms. The Cambridge researchers used lasers to probe the polymer and saw clear evidence of the behavior they found hints of in other materials they studied.
They found the apparent lack of electrical dead ends in the new polymer related to a quantum mechanical property of electrons called “spin.” Essentially, with certain spin configurations the material can “rescue” electrical charges from what otherwise would be energy-losing pathways.
Currently, organic solar cells can achieve as much as 12 percent efficiency in turning light into electricity, compared with 20 to 25 percent for silicon-based cells. Schlenker said design concepts based on the new material will help to significantly close the gap between these two types of solar cells.
Organic materials are semi-transparent and tunable to any color, and their flexibility and ease of production mean that achieving greater efficiency in changing light to electricity could make them cheaper and easier to deploy than the silicon-based cells.
The carbon-based molecules in the organic polymers are similar to molecules already found in car paints, some clothing dye and the pigment in plant chlorophyll. Organic dyes could incorporate into ink and end up printed on materials such as shingles, siding or window frames.
Current materials are relatively low cost and recyclable. Work to extend their lifespan beyond five to seven years and to find ways to replace them relatively easily could make them a feasible option for a home or business, Schlenker said.
Solar cells now provide less than 0.2 percent of power used in the United States, but improving efficiency and finding ways to incorporate them into building materials is one way to make them cost-effective.
“You have to go in the direction of adding no cost to the material you already are planning to deploy,” Schlenker said.
Wednesday, April 11, 2012 @ 07:04 PM gHale
By Gregory Hale
Smart meters may not be perfect right now, but they are here to stay and will continue to get a stronger security posture.
“Smart meters provide a net benefit for utilities and for users,” said Jacob Kitchel, senior manager of security and compliance for Industrial Defender. “No computer or software will be totally secure, but it is possible they will have enough security built in to force attackers to go elsewhere.”
Kitchel was responding to a report that talked about a series of hacks perpetrated against smart meter installations over the past several years may have cost an U.S. electric utility hundreds of millions of dollars annually.
That report came from a FBI cyber intelligence bulletin obtained by KrebsOnSecurity.
The goal of smart meters is to improve efficiency, reliability, and allow the electric utility to charge different rates for electricity at different times of day. Smart grid technology also holds the promise of improving a utility’s ability to remotely read meters to determine electric usage.
However, some meters are better than others being able to fend off hackers and block unauthorized modifications. The FBI said insiders and individuals with only a moderate level of computer knowledge are likely able to compromise meters with low-cost tools and software available on the Internet.
Sometime in 2009, an electric utility in Puerto Rico asked the FBI to help it investigate widespread incidents of power thefts it believed related to its smart meter deployment. In May 2010, the bureau distributed an intelligence alert about its findings to select industry personnel and law enforcement officials.
Citing confidential sources, the FBI said it believes former employees of the meter manufacturer and employees of the utility were altering the meters in exchange for cash and training others to do so. “These individuals are charging $300 to $1,000 to reprogram residential meters, and about $3,000 to reprogram commercial meters,” the alert said. The FBI believes thieves hacked into the smart meters using an optical converter device — such as an infrared light — connected to a laptop that allows the smart meter to communicate with the computer. After making that connection, the thieves changed the settings for recording power consumption using software you can download from the Internet.
“The optical converter used in this scheme can be obtained on the Internet for about $400,” the alert said. “The optical port on each meter is intended to allow technicians to diagnose problems in the field. This method does not require removal, alteration, or disassembly of the meter, and leaves the meter physically intact.”
“People have been getting by on utilities in the past, but what sets this apart from the historical ways is using the optical port,” Kitchel said. “There will always be theft from meters, but this allows criminal to modify the configuration from a software perspective. Dumb meters didn’t have that capability.”
Kitchel added there was other potential part that could also come out of this incident and that is the wireless component. “These meters also have methods of wireless communication. That will be something to look at.”
Meter vendors have taken steps to solve security issues, but right now implementation varies. The first round of smart meters came out, but shortly afterward vendors and utilities found out what the problems were and they ended up fixed, Kitchel said.
The beauty of smart meters, though, is the ability to remedy the security profile.
“Meters have some flexibility in the software, so there is some ability to adjust,” Kitchel said. “
Another method of attacking the meters involves placing a strong magnet on the devices, which causes it to stop measuring usage, while still providing electricity to the customer, the FBI said.
“This method is being used by some customers to disable the meter at night when air-conditioning units are operational. The magnets are removed during working hours when the customer is not home, and the meter might be inspected by a technician from the power company.”
“Each method causes the smart meter to report less than the actual amount of electricity used,” the FBI said. “The altered meter typically reduces a customer’s bill by 50 percent to 75 percent. Because the meter continues to report electricity usage, it appears be operating normally. Since the meter is read remotely, detection of the fraud is very difficult. A spot check of meters conducted by the utility found that approximately 10 percent of meters had been altered.”
The FBI estimated the Puerto Rican utility’s losses from the smart meter fraud could reach $400 million annually.