Web Concepts

Posts Tagged ‘power grids’

The sun spewed three CMEs Earthward last week, sending solar particles hurtling toward the planet. The last two combined, resulting in a strong compression of the magnetosphere, NASA said. The double punch was expected to disturb power grids at high latitudes, NASA said.

2011 has already been a big year for solar flares, with a previous CME in February disrupting shortwave communications in China and ship-to-shore radios. That flare led to aurora borealis as far south as Great Britain. Then in June, a relatively smaller flare belched a billion tons of material away from the sun before it collapsed back to the surface.

The first CME already passed the Earth late last week, and the second two are affecting us right now, according to Reuters. The Space Weather Prediction Center at NOAA is forecasting a moderate to strong magnetic storm. The second two flares impacted an already compressed magnetosphere, so additional solar activity could exacerbate the disturbance — or do nothing at all, forecasters said.

It’s all part of the sun’s ramped-up cycle of activity, which is expected to peak sometime in 2013. Scientists have been beating the drum about solar activity preparations as the 11-year solar cycle continues, because a massive flare can disrupt satellites, power grids and telecommunications. Here’s hoping this triple threat is it for a while.

[Reuters]

Researchers at Georgia Tech scavenged sufficient microwatts to power a temperature sensor, using the ambient energy produced by a television station signal that was a third of a mile away.

More powerful systems that tap into multiple wireless bands could generate one milliwatt or more — enough to power small wireless sensors and microprocessors. Researchers hope that when it’s combined with advanced capacitor technology, the device could provide up to 50 milliwatts.

It’s not exactly the dream of wireless power envisioned by Nikola Tesla, who proposed vast tower networks transmitting electric fields. It’s more akin to siphoning juice from someone else’s battery. When the antenna receives a signal, the electromagnetic energy is converted from AC to DC.

“There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it,” Manos Tentzeris, a Georgia Tech electrical and computer engineering professor who is leading the research, said in a news release.

Tentzeris’ team has been using inkjet printers to print the devices on paper or plastic. An ink emulsion of silver nanoparticles are used to print radio-frequency sensors and circuits. The current prototype can scavenge power from frequencies ranging from FM radio to radar, from 100 megahertz (MHz) to 15 gigahertz (GHz) or higher, according to a Georgia Tech release.

In an upcoming experiment, Tentzeris’ team plans to activate a small microprocessor-based controller simply by holding it in the air.

The team believes these paper-based wireless scavengers, which are fairly cheap to make, will soon be widely available.

There are plenty of potential uses for them, from supplementary power generation for renewable sources to environmental sensors that scavenge energy from their surroundings. It could also serve as a backup power source, allowing an electronic device to emit a distress signal, according to the news release. They could be used to power RFID tags in anything from food to lumber; sniff for explosives or other chemicals at airports and other secure facilities; and even stress sensors on bridges and other infrastructure.

The researchers demonstrated the technology last week at an IEEE symposium in Spokane, Wash.

[via Georgia Tech Research News]

Once they’re programmed, electrically powered clocks tell time based on the rate of the electric current that feeds them, as an Associated Press story explains. Electrical utilities keep the current’s frequency stable in part to keep clocks precise, the AP says. But utilities could save energy and money by allowing for greater frequency variation, so the Federal Energy Regulatory Commission is considering allowing the change.

Joe McClelland, head of electric reliability for FERC, wondered whether anyone really uses the grid to tell time.

“Let’s see if anyone complains if we eliminate it,” he said.

Renewable energy is one primary reason FERC cares about frequency variation. Power sources like wind and solar energy will ramp up and drop off with great variability, inducing spikes and valleys in the energy flowing through the nation’s electrical grid. Adjusting for those differences is expensive, and can be wasteful, according to FERC. Forgetting about it would just be easier — unless all the nation’s clocks are suddenly off.

With a more variable current, wall clocks and appliance clocks, like the one that’s programmed to brew your coffee every morning, will become less accurate every second, a phenomenon that can get much worse over time. One trade group that has studied the potential effects says East Coast clocks could run 20 minutes fast over a year, and timepieces on the West Coast clocks would be off by about 8 minutes.

Officials from FERC said they are tentatively planning to test a more variable frequency in mid-July, AP said.

It’s a good thing we have ridiculously accurate atomic clocks to keep us all on track.

[Associated Press ]

SMES is, at its heart, a means to make a battery out of magnetic fields. The DOE is interested in the technology because it could be used to create huge facilities that would efficiently store massive amounts of electricity for use when renewable energy sources like wind and solar fail to meet grid demand. SMES devices work by storing electricity in huge magnetic fields generated by running direct current through superconducting wires. Their special geometry allows them to hold vast amounts of power while using very little energy to maintain the field.

They are also very, very expensive. Prohibitively expensive, that is.

But SMES technology does have a lot of potential if, perhaps, it can be scaled to the point of being cost competitive with lead-acid batteries and other means of storing up large amounts of power. ABB, Brookhaven National Lab, the University of Houston, and superconducting wire manufacturer SuperPower are collaborating with the ultimate goal of creating a one- or two-megawatt, grid-scale device that can compete with other energy storage schemes like batteries, pumped hydro (pumping water uphill to create potential energy for hydro plants) and compressed air (storing air in underground caverns at pressure).

Why bother with SMES if there are already cheaper ways to store energy? For one, SMES can be deployed anywhere unlike pumped hydro (which at the very least requires a hill) or compressed air (which requires an underground cavern). SMES devices can also be discharged rapidly and entirely, a critical quality for energy storage facilities that will be expected to quickly stabilize grids when wind or solar resources experience regular and sometimes precipitous plunges in output.

Many critics think SMES is unfeasible, as all that superconducting wire is really, really pricey. But what are organs like ARPA-E for if not for doing things others say are impossible (ARPA-E, for the uninitiated, is like the DOE’s DARPA)? If the collaboration can pull it off, SMES could become a critical component in those smart grids of the future that we hear so much about yet see so little of.

[Technology Review]

The new battery simply consists of tanks filled with three liquid layers kept at 1,292 degrees F (700 degrees C). Molten magnesium sits on top, and antimony sits on the bottom. The middle layer consists of a compound mixture of the two outer layers.

Charging the battery with electricity breaks down the middle layer, and thus enlarges the upper and lower layers, while discharging reverses the process, in a chemical reaction that releases electrons to provide power. Once running, the battery also creates enough self-sustaining heat to keep everything deliciously molten.

A battery as large as a shipping container could deliver a megawatt of electricity, or enough to power about 10,000 100-watt light bulbs for several hours. Its cheaper material costs compared to lithium make it a more cost-effective candidate for scaling up the power grid.

Some utility companies and cities have already turned to sodium sulfur batteries as backup power that can ease reliance on the aging transmission grid -- the Texas town of Presidio recently charged up the largest battery of this type in the U.S. But the molten metal battery technology could provide part of a newer energy infrastructure that supports a growing variety of renewable energy sources.

[via New Scientist]

The sodium sulfur battery is the largest of its type

The huge battery began charging up this week and can store up to four megawatts of power for up to eight hours. It represents the first NaS battery in Texas and the biggest in the U.S., and has already earned the local nickname of BOB (big-old battery).

Before BOB's arrival, the Texas town had an agreement with the Mexican government that allowed it to transfer the town's electrical load over to Mexico -- but that took time and left people without power for a certain period.

Similar room-sized sodium sulfur (NaS) batteries have already found growing use among U.S. utility companies that want to put off expensive upgrades for the power grid or building new transmission lines. USA Today notes that the batteries, built by NGK Insulators of Japan, store energy and can help ease blackouts for cities.

Electric Transmission Texas helped put the battery project together for around $25 million. But the utility has also agreed to build a second 60-mile transmission line to Presidio for about $44 million by 2012.

Such a battery could also serve as a test bed for utility companies to see how the devices can help with energy storage regarding renewable energy, such as wind power or solar power. That sounds good to us, as long as utility companies don't simply lean on the batteries as a technological crutch to avoid giving the power grid its much-needed makeover.

[via NPR]

Despite the grid’s numerous built-in safeguards, if enough transformers go down, they could take large chunks of the grid with them. The only way to get it running again would be to replace all the damaged gear. CMEs aren’t usually disastrous, but the two largest blasts on record, which took place in 1859 and 1921, could each knock out the Northeast power grid if they happened today. On the bright side, although CMEs have been known to put satellites out of commission, our atmosphere deflects most of the energy, so the radiation is too diffuse by the time it reaches your electronics to destroy them.

A man-made EMP poses a greater threat. If one goes off in your neighborhood, there’s a significant risk that the concentrated pulse will induce extra voltage in the circuit-board components, frying them for good. The best bet for protecting your electronics is to store them in a Faraday cage: a cube of interweaving metals, preferably copper and quarter-inch-thick steel, which together can act as an electromagnetic shield. Like in a lightning rod, the copper attracts electricity while the steel absorbs magnetic pulses. A cage big enough to hold all your favorite gadgets—your cellphone, TV, computer, and so on—runs in the neighborhood of $15,000. An EMP could also crash the power grid, so you might want to spring for an extra cage to protect your generator too.

Try to stump us. Send your questions to fyi@popsci.com