Monday, March 21, 2011
Affordable Energy Storage Key to Harnessing Wind and Solar Power
Future batteries used by the energy grid to store power from the wind and sun must be reliable, durable, and safe, but affordability is really the key to widespread deployment, according to a new report published March 4 in the journal Chemical Reviews. The report reviews electrochemical energy storage.
|PNNL researchers say future batteries used by the energy grid to store power from the wind and the sun must be reliable, durable, and safe, but affordability is key to widespread market deployment.
In the report, researchers from the Department of Energy's Pacific Northwest National Laboratory (PNNL) say that successful electrochemical energy storage, or EES, systems will need to evolve—in some cases, considerably—if they are going to compete financially with the cost of natural gas production. And besides technical improvements, the systems will need to be built to last, using materials that are safe and durable so that batteries could operate more than 15 years and require very little maintenance over their lifetime.
The report provides a review of four stationary storage systems—ones considered the most promising candidates for EES: vanadium redox flow, sodium-beta alumina membrane, lithium-ion, and lead-carbon batteries. In their study, the PNNL researchers note the potential of each technology but, more importantly, explain what advances must occur with each if they're ultimately to be deployed.
Researchers say continuing to improve battery technology is critical to bringing down the cost and increasing the reliability of batteries.
“By improving EES technologies, industry could tap into a near endless supply of wind and solar power and drastically reduce the dependence on fossil fuels to meet growing demand for electricity," said Z. Gary Yang, PNNL laboratory fellow and lead author of the paper.
Yang says with further research, the cost of these battery technologies could be reduced, the performance improved, and advances created in materials, chemistries, design, and system engineering.
Without advanced batteries, electricity from wind and solar power must be used the moment it's produced. Today, the most commonly used battery systems work by converting electricity to kinetic, or potential, energy and then discharging that energy back to the grid when it's needed. But these systems, such as flywheels and pumped hydro and compressed air systems, have limiting factors, such as lack of portability.
Electrochemical energy storage systems, on the other hand, can efficiently store electricity in chemicals and then release it upon demand. The electrochemical energy storage systems work similar to a traditional household battery, but at a much larger scale, and use a variety of materials, like carbon, aluminum, and even salt.
Like lead-acid batteries in a flashlight, batteries that store wind and solar power take in the electricity as it's produced and convert it to chemical energy, stored in the form of a liquid or solution. When the energy is needed from the battery, an electric charge starts the chemical conversion of energy back into electrons, which then move back into a power line on the electric grid.
Vanadium redox flow battery
Vanadium redox flow battery is a type of rechargeable battery that stores electrical energy in two tanks of electrolytes, or fluids that conduct electricity. Researchers conducting the study say redox-flow technology could be a good candidate for backup energy storage for durations of up to 12 hours, and could integrate wind and solar power in a residential neighborhood or at several large industrial sites.
When energy is needed, the liquid is pumped from one tank to another. During this slow and steady process, the chemical energy from the electrolyte is converted to electrical energy. When energy needs to be stored, the process is reversed. The amount of energy the battery can store is determined by the size of the tank and the amount of electrolyte it can hold. Researchers say this technology has potential if it can be made in a variety of sizes, portable, and affordable.
Sodium-beta alumina membrane battery
The sodium-beta alumina membrane battery is typically built in a tubular design, and uses elements such as sulfur combined with sodium to reversibly charge and discharge electricity using sodium ions layered in aluminum oxide within the battery's core. Researchers say the battery shows potential to store lots of energy in a small space and that its high energy density and rapid rate of charge and discharge make it a candidate for powering electric vehicles and for other applications that require short, potent bursts of energy.
However, materials are expensive and there are safety concerns with the high operating temperature of the battery. PNNL researchers say modifying the shape of the battery can improve efficiency, lower the operating temperature and cost. In fact, PNNL and company EaglePicher Technologies, LLC are studying these improvements as part of DOE's Advanced Research Projects Agency—Energy, or ARPA-E, program.
Lithium-ion, or Li-ion, batteries are most commonly found in household gadgets and now electric vehicles. Li-ion batteries store electrical energy in various compounds, composed of layers of different elements, such as lithium, manganese, and cobalt. High energy and power capacity has made Li-ion batteries a promising option for transportation applications like electric vehicles.
Researchers say bringing down materials cost sand improving safety could vastly improve Li-ion batteries and could help accelerate the penetration of electric vehicles, which themselves could serve as back-up storage on the grid.
In a traditional Li-ion battery cell, positively charged lithium ions migrate through a liquid electrolyte, while electrons flow through an external circuit, both moving back and forth from one side to the other. This movement creates and stores energy. Li-ion batteries have been a success for small, mobile electronics such as cell phones and laptop computers, but making them larger is difficult because they are expensive, are prone to overheating, and can lend themselves to electrical shorting. Scientists say while substantial progress has been made over past years to improve the technology, more work must be done to extend life, improve safety, and reduce materials cost for the stationary applications.
Lead-carbon batteries are an evolving technology born from the traditional lead-acid battery, commonly used for traditional automobiles and back-up generators. Scientists have found by adding a bit of carbon to traditional lead-acid batteries they can significantly increase the lifespan of the battery. Researchers say lead-carbon batteries could serve as a viable back-up source for wind and solar power because of their concentrated power.
During discharge in a traditional lead-acid battery, sulfuric acid reacts with the lead anode and cathode to create lead sulfate. The process reverses during charge. This conversion produces a short, powerful burst of energy, such as needed to jump-start a vehicle. But over time, a lead-acid battery can lose its charge because of the gradual crystallization and buildup of lead sulfate within the battery's core. The corrosive acid also can eat away at a battery's core.
Adding carbon to the battery seems to minimize or prevent this crystallization from occurring, improving the cycle life and overall lifespan of the battery. Researchers say this technology has potential for storing renewable energy but that more field work is needed to understand the limitations—and to find ways to bring down the cost. The capital cost of the technology remains at $500 per kilowatt hour and they believe it needs to be reduced to between $150 and $200 per kilowatt hour to be viable.
Source: Anne Hass, Pacific Northwest National Laboratory (PNNL)
|We thank you for your cooperation in improving the quality of our materials.
Please contact Bill Green at Communications@nema.org if you have any questions or suggestions related to eiXtra.
New Method Could Improve Economics of Sweetening Natural Gas
Natural gas extracted from the nation's coal beds and methane-rich geologic features must first be purged of hydrogen sulfide before it can be used as fuel. Until now, processing methods have often proved to be inefficient, requiring large amounts of heat.
IDEA Appoints Michael Wentz to Director, Sales and Marketing
IDEA, a business-to-business technology service provider owned by the electrical industry, announces the appointment of Michael Wentz to Director, Sales and Marketing. 03/02/11
ESFI Recognizes National Flood Safety Awareness Week
The Electrical Safety Foundation International (ESFI) is pleased support efforts by the National Oceanic and Atmospheric Administration (NOAA) to highlight the hazards associated with floods during National Flood Safety Awareness Week, observed March 14–18, 2011.
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
||On the Hill/Around the Nation
CPSC Launches Public Database: The U.S. Consumer Product Safety Commission (CPSC) officially launched its Publicly Available Consumer Product Safety Information Database on SaferProducts.gov on March 11. The database, which will allow consumers and other submitters to enter reports of harm (ROH) alleging injury, illness, or death (or risk of same) encountered when using products, has been much debated. Many industries remain concerned about the potential for misuse or abuse of the database, as well as potential inaccuracies that could be included. NEMA encourages its member companies to register through the Business Portal as soon as possible to guarantee timely notification of any ROHs identifying their products. The SaferProducts.gov website also contains useful FAQs and video tutorials to assist manufacturers in registration and submitting comments in response to ROHs. NEMA supports CPSC’s efforts to improve product safety but remains concerned about potential inaccuracies in the database. NEMA advises member companies to report any problems encountered with the database to NEMA staff for continued congressional and regulatory advocacy efforts.
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Opportunity to Participate in Secretary of Commerce Gary Locke's Trade Mission to the UAE, Qatar, Abu Dhabi and Dubai, June 4–9, 2011
During the ITAC plenary session held on March 1, Secretary of Commerce Gary Locke mentioned that he will be leading a senior executive trade mission for multi-modal transportation and infrastructure development products and services to Doha, Qatar, and Abu Dhabi and Dubai, United Arab Emirates (UAE), June 4–9, 2011. The mission is designed to contribute to President Obama's National Export Initiative to achieve the goal of doubling exports and job creation by increasing exports of product and services that contribute to these infrastructure development projects in these locations.
See the memorandum and flyer about the secretary's trade mission and how you can take advantage of this opportunity. Further information can also be found on the mission website or you can contact Larry Brill via email at: Lawrence.Brill@trade.gov.
Trade Winds Forum—the Americas
Date: April 6–12, 2011
City: Mexico City, Mexico
The Trade Winds Forum is your company’s connection to business opportunities in Mexico and the Americas. It is the first step to tap into this $238 billion regional export market. Participating companies will enjoy: admission to all conference sessions offering market intelligence and entry strategies; customized business-to-business meetings with pre-screened companies in Mexico’s most industrialized cities—Mexico City, Guadalajara, and Monterrey—or other major cities in the Americas; and pre-arranged consultations with Commercial Attachés from across North, Central, and South America.
Commerce Department Announces September Trade Mission to South Africa for T&D and Efficient Buildings Technologies
Manufacturers of efficient energy and building technologies and equipment should consider this U.S. government coordinated visit to Africa’s largest economy.
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Mergers & Acquisitions
- Philips Acquires Dameca
Dameca will further broaden Philips’s portfolio and provide opportunity for innovation in areas such as anesthesia-related clinical decision support. 03/14/11
[ Industry News Archives ]
[ NEMA News Archives ]
- NEMA's T5 Fluorescent Lamp Shipments Rebound During 2010
NEMA’s T5 lamp index increased for the third consecutive quarter, registering a reading of 164.5 during 4Q 2010. Shipments of T5 lamps showed robust growth for the calendar year by advancing nearly 31.0 percent over 2009. 03/11/11
- HID Lamp Indexes Decline During Fourth Quarter
NEMA’s shipment indexes for high intensity discharge (HID) lamps declined by 11.7, 17.1, and 0.9 percent on a year-over-year basis for sodium vapor, mercury vapor, and metal halide lamps, respectively. 03/10/11