Just another WordPress weblog

There’s one major drawback to most proposed renewable-energy sources: their battery variability. The sun doesn’t shine at night, the wind doesn’t always blow, and tides, waves and currents fluctuate. That’s why many researchers have been pursuing ways of storing the power generated by these sources so that it can be used when it’s needed.

So far, those solutions have tended to be too expensive, limited to only certain areas, or difficult to scale up sufficiently to meet the demands. Many researchers are struggling to overcome these limitations, but MIT professor Donald Sadoway has come up with an innovative approach that has garnered significant interest — and some major funding.

The idea is to build an entirely new kind of battery, whose key components would be kept at high temperature so that they would stay entirely in liquid form. The experimental devices currently being tested in Sadoway’s lab work in a way that’s never been attempted in batteries before.

This month, the newly established federal agency ARPA-E (Advanced Research Projects Agency, Energy) announced its first 37 energy-research grants out of a pool of 3,600 applications, and Sadoway’s project to develop utility-scale batteries received one of the largest sums — almost $7 million over five years. And within a few days of the ARPA-E announcement, the French oil company Total — the world’s fifth-largest — announced a $4 million, five-year joint venture with MIT to develop a smaller-scale version of the same technology, suitable for use in individual homes or other buildings.

Because the technology is being patented and could lead to very large-scale commercialization, Sadoway will not discuss the details of the materials being used. But both Sadoway and ARPA-E say the sony vgp-bps11 battery is based on low-cost, domestically available liquid metals that have the potential to shatter the cost barrier to large-scale energy storage as part of the nation’s energy grid. In announcing its funding of Sadoway’s work, ARPA-E said the battery technology “could revolutionize the way electricity is used and produced on the grid, enabling round-the-clock power from America’s wind and solar power resources, increasing the stability of the grid, and making blackouts a thing of the past.”

Andrew Chung, a principal at Lightspeed Venture Partners in Menlo Park, Calif., which has no equity stake in Sadoway’s project at this point, says that “grid-scale storage is an area that’s set to explode in the next decade or so,” and is one that his company is following closely. The liquid battery concept Sadoway is developing “is an exciting approach to solving the problem,” he says.

Big is beautiful

Most battery research, Sadoway says, has been aimed at improving storage for portable or mobile systems such as cellphones, computers and cars. The requirements for such systems, including very low weight and high safety, are very different from the needs of a grid-scale, fixed-location sony vgp-bpl11 battery system. “What I did was completely ignore the conventional technology used for portable power,” he says. The different set of requirements for stationary systems “opens up a whole new range of possibilities.”

A large, utility-owned system “doesn’t have to be crash-worthy; it doesn’t have to be ‘idiot-proof’ because it won’t be in the hands of the consumer.” And while consumers are willing to pay high prices, pound-for-pound, for the small batteries used in high-value portable devices, the biggest constraint on utility-sized systems is cost. In order to compete with present fossil-fuel power systems, he says, “it has got to be cheap to build, cheap to maintain, last a long time with minimal maintenance, and store enormous amounts of energy.”

And so the new liquid batteries that Sadoway and his team, including graduate student David Bradwell, are designing use low-cost, abundant sony vgp-bps13 battery materials. The basic principle is to place three layers of liquid inside a container: Two different metal alloys, and one layer of a salt. The three materials are chosen so that they have different densities that allow them to separate naturally into three distinct layers, with the salt in the middle separating the two metal layers —like novelty drinks with different layers.

The energy is stored in the liquid metals that want to react with one another but can do so only by transferring ions — electrically charged atoms of one of the metals — across the electrolyte, which results in the flow of electric current out of the battery. When the battery is being charged, some ions migrate through the insulating salt layer to collect at one of the terminals. Then, when the power is being drained from the sony vgp-bps13/b battery, those ions migrate back through the salt and collect at the opposite terminal.

The whole device is kept at a high temperature, around 700 degrees Celsius, so that the layers remain molten. In the small devices being tested in the lab, maintaining this temperature requires an outside heater, but Sadoway says that in the full-scale version, the electrical current being pumped into, or out of, the battery will be sufficient to maintain that temperature without any outside heat source.

While some previous battery technologies have used one liquid-metal component, this is the first design for an all-liquid battery system, Sadoway says. “Solid components in batteries are speed bumps. When you want ultra-high current, sony vgp-bps13a/b battery,sony vgp-bps13b/b battery,compaq laptop battery you don’t want any solids.”

The U.S. Department of Energy on Tuesday announced that US$620 million in stimulus funding is going to 32 smart-grid programs, which will be coupled with another US$1 billion in private money. A total of US$770 million from government and industry sources in the next few years will go to energy storage, giving a number of storage technologies a dose of real-world experience.

Notable in the list is the prominence of compressed-air energy storage and flow batteries, two technologies rarely discussed just a few years ago. Also in the mix are flywheels and using batteries for distributed energy storage in communities.

It’s unlikely that all the DOE-aided projects will immediately prove to be commercially viable. But storage has clearly emerged as a key component in the vision of the smart grid. A number of start-ups are developing technologies they hope can address a specific storage application or undercut pumped hydro, considered the cheapest form of utility storage, on price. With pumped hydro, water is pumped uphill and released at peak times to run a generator. But its use is limited by geography.

Many of the 16 U.S. Energy Department power storage grants were focused on storing wind power, which is a variable source of energy. In California, for example, utility Pacific Gas & Electric plans to store the power generated by wind turbines at night, sony laptop battery ,when turbines are most productive in underground caverns. During the day, when grid demand is higher, the air is released and passed through a turbine to make electricity.

The advantage of underground compressed air storage is that it can be cheaper than batteries and can store many hours worth of energy. PG&E forecasts that its Kern County, Calif., project can deliver 300 megawatts of power for 10 hours, enough to supply tens of thousands of homes.

Another novel technique is using metal tanks to store compressed air, a technology being developed by a Dartmouth College spin-off SustainX. The compressed air is released to run a hydraulic sony vgp-bps10 battery motor that drives a generator to make electricity.

Flow batteries, meanwhile, use tanks of liquid electrolyte solutions. When the two liquids interact, there is a chemical reaction that creates a flow of electricity.

An advantage of this approach is that store large amounts of energy and discharge relatively quickly, according to the Electricity Storage Association. One project will use technology from Premium Power, which makes tractor trailer-size zinc flow sony vgp-bps10a battery to maintain a steady frequency on the grid and supply power during times of peak demand.

Different strokes
The variety of technologies points to the range of energy storage applications. Flywheels from award winner Beacon Power, for example, can absorb and discharge megawatts’ worth of power to the grid but only in 15-minute bursts. Still, flywheels are getting more attention because they are a nonpolluting replacement to the natural-gas plants now used to smooth out short-term fluctuations in grid frequency, according to the company.

Large batteries, too, will be further tested for grid storage. Duke Energy plans to use multiple sony vgp-bps10a/b battery types for 20 megawatts’ worth of power delivery at the Notrees Windpower project in Texas. The “hybrid” battery system is being designed for two tasks: to smooth out short-term grid fluctuations and to supply hours’ worth of power during the day, according to a Duke Energy representative.

Utility Portland General Electric in the next two years plans to install five batteries from auto battery supplier Ener1 to supply enough juice to power 400 homes for about an hour. Alternative chemistries, including lead carbon batteries from East Penn Manufacturing, will also be used.

One project will test the viability of used car batteries for grid storage. Lithium ion plug-in car sony vgp-bps10b battery from A123 Systems will be used to supply 25 kilowatts for two hours in 20 community energy storage projects. The performance of lithium ion batteries degrades after many years in a car, but there is still sufficient storage and power for grid applications, utility executives say.

Imagine if automakers got together and started measuring the gas mileage of new cars with a cool test of their own making—one in which the cars were rolling downhill with their engines idling. Suddenly you’d have some pretty amazing claims: Why, that three-ton SUV gets 300 miles per gallon! This subcompact gets 500! In tiny print at the bottom of the window sticker you’d find a disclaimer saying that, well, um, you know, your mileage may vary.

Crazy, right? Yet that’s more or less what’s happening with laptop computers and their battery lives. Right now, I’m looking at a Best Buy flier touting a $599 Dell laptop that gets “up to 5 hours and 40 minutes of battery life.” Down in the fine print comes a disclaimer explaining that “battery life will vary” based on a bunch of factors. Translation: you ain’t gonna get five hours and 40 minutes, bub. Not ever. Not even close.

So how can Dell and Best Buy make that claim? These battery-life numbers are based on a benchmark test called MobileMark 2007 (MM07). The test was created by a consortium called BAPCo (Business Application Performance Corp.), whose members are—you guessed it—computer makers and other tech companies. AMD, the No. 2 maker of microprocessors, is a member of BAPCo, but now has become a whistle-blower. AMD says PC makers know full well that the new tests produce misleading numbers, but they are touting them anyway.

Laptops score big numbers because they’re tested with screens dimmed to 20 to 30 percent of full brightness, the Wi-Fi turned off and the main processor chip running at 7.5 percent of capacity—just like those cars idling downhill. Techies and industry insiders have long known that official battery-life claims are pretty much worthless. But regular folks don’t. As a result, some are getting pushed toward pricier machines by sales reps who tell them they’ll get an extra hour of battery life. Those customers may be paying a premium and getting nothing. “There’s only three endings to this story,” says Patrick Moorhead, a marketing vice president at AMD. “Either the industry regulates itself, or the FTC steps in and regulates us, or we get hit with a class-action lawsuit. I suggest the industry go with the first option.”

AMD is recommending computer makers adopt a new way of measuring battery life, using two states: “active time” and “resting time,” similar to the way cell-phone makers describe the “talk time” and “standby time” of a phone. A Dell executive says that approach makes sense, and that the company is considering providing customers with information beyond the MM07 scores. “Customers expect the advertised battery life to reflect the way they really use the product,” says Ketan Pandya, head of AMD-based products at Dell.

AMD isn’t leading this crusade out of a sense of altruism. Its real gripe is that MM07 gives Intel, its archrival, an unfair advantage. AMD claims MM07 was created in Intel’s labs and rigged so that Intel chips would outscore AMD chips, since AMD chips draw more battery power when idle. (AMD says that in real-life usage, laptops using its chips perform comparably to Intel’s.) AMD also points out that the president of BAPCo happens to be the head of performance benchmarking at Intel.

Intel says this is all hogwash. An Intel spokeswoman says that just because the consortium’s president is an Intel exec doesn’t mean Intel has special influence. Meanwhile, she can’t resist taking a crack at AMD: “You will often find that companies who are behind in performance sometimes challenge independent and standards-based benchmarks,” she says via e-mail.

Intel and AMD are the Bickersons of the computer industry, with AMD always complaining that Intel is cheating, and Intel always responding that AMD should quit being such a crybaby. But lately AMD has been landing some punches. In May, European antitrust regulators smacked Intel with a $1.45 billion fine, claiming Intel used unfair tactics to bully AMD.

Meanwhile, out in the marketplace, the crazy battery claims persist. Dell says its $2,000 Adamo notebook will run for more than five hours, but The Wall Street Journal got only two hours and 44 minutes. Apple claims eight hours of battery life for its $2,800 17-inch MacBook Pro, but CNET got only four hours and 14 minutes. This stuff is so pervasive that professional reviewers see company-generated battery-life claims as a joke. “The rule of thumb is that in real-world use you get about 50 percent of rated battery life,” says Mark Wilson, associate editor at Gizmodo. “It’s not that companies are lying, but they’re stacking the deck in their favor. [Their claims] are misleading to the general public.” That’s something to keep in mind next time you’re out shopping for a laptop.

In a 2002 survey by chipmaker Intel, 57% of laptop users said they wished their batteries lasted longer. And that is wishful thinking, according to Isidor Buchmann, president and founder of Cadex Electronics in Vancouver, B.C., Canada. He suggests that although batteries become about 10% more efficient every year, the average PC’s power needs also increase by about the same amount. Result: The average battery life is still painfully short (just three to four hours for most laptop models).

But you don’t have to end up sitting in a waiting area, staring at a darkened screen, like I was. Here are four tried-and-true tips to extend the life of your laptop battery. Why should you take advice from a guy who couldn’t keep his own unit charged? Read on if you want to hear my sad excuse.