Energy storage coming to a power grid near you

Someday, the electricity grid will operate with the equivalent of a giant hard drive. But in the short term, grid storage will look more like a PC's cache or RAM, able to serve up small bursts of power to keep things from crashing.

A panel of experts, organized by the New England Clean Energy Council, earlier this week said that the utility storage field has enormous potential. But rapid deployment of storage devices is held back by concerns over technology risk and financial complexity.

Technology optimists say that wide-scale energy storage will change the face of the transmission grid and make wind and solar power more compelling economically.

In this scenario, utilities store electricity made from renewable sources or produced during off-peak times. Then, when demand for electricity peaks in the middle of the day, they could draw from the stored-up charge.

This "peak shaving" practice avoids the need to build new power plants to meet growing demand. Utilities could also idle dirty and expensive "peaking plants," which are only turned on during times of high demand, such as very hot summer days when air conditioners max out the load.

But moving megawatts' worth of electricity around the grid like files on a computer is more theory than practice these days.

"Buying power at night and then selling it during the day--something like that will happen maybe in 30 or 40 years when storage technologies are one-tenth the costs they are today," said Ric Fulop, co-founder and vice president of business development at lithium-ion battery company A123 Systems.

But as utilities try out new technologies for different uses, Fulop and others predicted that storage will start to take hold in a variety of ways.

"I think we will see a lot of deployments in the next few years that will change how the grid works," Fulop said. "Then we'll see utilities jump on the bandwagon."

Two markets for energy storage
A123 Systems, which makes batteries for plug-in hybrids and power tools among other devices, is actively pushing into utility storage with more than 100 people dedicated to the market, said Fulop.

It's targeting what's called grid stabilization, or grid support, where warehouse-size installations of lead-acid batteries are the incumbent technology. That alone is a multimillion dollar market and will pave the way for different grid storage applications, he said.

With grid stabilization, kilowatts' or a couple of megawatts' worth of electricity are pumped onto the grid for a short amount of time, from a few seconds to under an hour. It's used to match grid demand and supply to make generators run more efficiently or to ensure a steady frequency.

Earlier this year, grid operators in Texas had to shut down power to its customers because the wind died down momentarily, effectively cutting off supply from its wind farms, noted Lawrence Gelbien, vice president of technology at utility NStar.

"If you could take the wind power, store it in batteries, and discharge when the wind starts again, then that's a fine application of storage," he said.

Gelbien said that storage units could be deployed in place of installing more "wires and poles" in a place that isn't served with enough electricity to meet demand for only a few days of the year. Because storage devices are movable, they could be redeployed in other places after a few years as the need arises.

Grid support is relatively mature at about $2.4 billion and growing at 3.3 percent per year, said Lux Research President Matthew Nordan.

Batteries with different chemistries as well as ultra-capacitors, such as the ones being developed by secretive start-up EEStor, serve this end of energy storage, Nordan said.

Flywheels are also a viable alternative. Flywheel maker Beacon Power earlier this month said it expects to have a megawatt-size machine, able to store 15 minutes of power, on the grid by the end of this year.

Dizzying array of technologies
At the opposite extreme are companies pursuing the "bulk storage" market where power is delivered for more than an hour.

This part of the market, where companies are developing a range of technologies, from so-called flow batteries to compressed air storage, represents the biggest business opportunity in grid storage.

The end game is to allow utilities to provide baseload power--meaning electricity during the middle of the day when demand is highest--with stored energy.

If only 10 percent of the installed wind power plants adopted large-scale energy storage, the market would hit $50 billion, according to Lux Research. That's because electricity costs more for utilities to purchase and deliver during peak times.

But utilities are risk-averse, and power plants take 5 to 10 years to construct. As a result, Lux Research pegs the market at $600 million in 2012, growing at about 25 percent per year.

One company tackling bulk storage head-on is General Compression, which is developing a wind turbine with an integrated air compressor.

Air is compressed and pumped underground into geological features like depleted gas wells or limestone caverns. There are currently two compressed air energy storage (CAES) plants in operation with a few others in development. But some utilities are seriously considering CAES.

"There is an increasing gap between the growing demand for electricity and the availability of options," said Julianne Zimmerman, chief marketing officer for General Compression. "With increasing shareholder resistance to new fossil fuel and nuclear plants, there's a shrinking set of options."

Different types of batteries are competing for bulk storage as well.

So-called flow batteries, where liquid chemicals move between huge storage tanks to deliver a charge, are also being tested on the grid.

Start-up Deeya Energy says it is developing a flow battery for grid backup power or to integrate wind and solar power that will be far cheaper than lead-acid, lithium-ion, or nickel-metal hydride batteries and cheaper than fuel cells. Its products will be able to delivery between 2 kilowatts and 2 megawatts of electricity for 2 hours or up to 24 hours, it says.

Another flow battery maker, VRB Power, is currently testing systems, including a 5-kilowatt, four-hour prototype in Florida.

Pumped hydro, where water is pumped up a mountain and released as needed in a hydro plant, is also used, but its use is limited by the number of available sites.

The latest generation of concentrating solar power plants are being developed with integrated storage, in the form of hot water or even molten salt to deliver electricity after the sun goes down.

Challenges
But for all the promise of making the grid operate more like a hybrid car, there are serious challenges, panelists said.

Many of these technologies don't have a 15-year track record that utilities like to see, which makes them skeptical. Large-scale battery projects requires systems integration that involves batteries, electronics, software, and thermal management systems, said A123 Systems' Fulop.

They are also very capital intensive. To get around that problem, Beacon Power doesn't sell its flywheel. Instead, it bids on power generation contracts and sells the electricity to utilities.

Regulations for utilities are written around power generation units, but not energy storage, said Matt Lazarewicz, vice president and chief technology officer of Beacon Power.

"The market rules have to change to allow nongeneration assets to connect to the grid and get paid for it," he said. "And to make the grid look more like a Prius, utilities need to change their mindset to make more efficient use of the generation system."

Rising fossil fuel prices are an incentive to explore energy storage, as well as the rising costs of constructing new plants.

Ideally, a utility would be able to get money from a storage unit in multiple ways. One rural co-op installed a four-hour, 300-kilowatt storage system to offset peak electricity rates and to provide backup power to a nearby industrial company, said Matthew Johnson, director of business development at Gaia Power Technologies.

Utilities are showing interest in more options, but storage is still very much an emerging technology.

"There's a lot of technology development and new work. But one of the reasons we don't see more of it today is because the economics of this are actually quite complex," said Bruce Phillips, director at Northbridge Group.

[EurasiaUK]

In the UK the National Grid uses excess electricity in low demand times to pump water up into a massive reservoir in Wales.

This water is then used to produce Hydroelectric Power in peak times of use typically in the advertising breaks on mid evening television when all the kettles get switched on. It should not be to difficult for parts of the Grid in the USA to use a similar mechanism.

Certainly a couple of countries in Africa are considering such a system for night time generation from day time solar power.

[spothannah]

What about a large block of iron with channels cut throught it. You could heat it up with excess energy and then run water through the channels converting the water into steam to drive dynamos when sunlight or wind are not available? Just wondering.

[winchmeister]

The Danes and Israelis are planning on using mobile storage with electric and hybrid vehicles. The idea is to charge the vehicles during low demand and buy back excess at peak demand at differential rates that will benefit the vehicle owner. The owner will program a usage profile, so enough capacity will be available if additional driving is needed above a commute. Of course this means plugins at home, work, and perhaps in public parking areas. The design is to assist the variability of wind generated power. The Danes are currently supplied 40% of the world's wind generators.

[ittesi259]

This is done in some parts of California at least. The state does it and there is a planned project in a city in Southern California. However, seeing as how we Americans have a foolish notion that you must forever keep building and adding demand....its not enough. Oh yeah, and environmentalist activists always through the legal wrench into everything because its not "good enough".

[Neo Con]

What we could really use is some sort of substance that already has a bunch of energy stored in it, that we could just extract on-demand. I could envision two primary types of substances that might meet our demand and that would contain enough energy to actually do the job efficiently.

One would be a liquid (let's call it "oyl") and the other, a solid (let's call it "urayneeum"). If only we could find such substances right here on Earth and invent a way to extract the energy... Oh, well, a world can only dream, I guess...

[open-mind]

I think the flywheel approach has a lot of merit. Very simple and seems like it would be cheap. And if you made it strong enough (with carbon fiber or fiber glass?) and heavy enough( with lead?) it should be able to capture a lot of kinetic energy. Just need some reliable low-drag bearings.

[stlwest]

Well as long as that doesn't create a battery shortage for hybrids. A123 own Hymotion that can upgrade a hybrid to a plug in hybrid adding additional battery capacity. The government should subsidize and provide low interest loans for people who want to do the conversion. I'll be damned if Congress isn't sitting on thier hands, if you're for alternative energy renew the damn tax credits and stop putting a stupid per manufacturer cap on the credits. If congress would do its job and make it easy for Americans to take action to help ourselves, we might actually get something done.

If they didn't put stupid caps in on this we'd have more hybrids on the road right now that people could convert to plug in hybrids.

[dheurt1]

Excel Energy has been using such a system in Colorado for over 30 years.

[AdrianAkau]

I think more can be said for pumped hydro. I believe that in areas with dams and good wind, the water could be recycled back from the base ot the dam to the top using wind power. This practice would be especially good during times of drought for maintaining high water levels.

adrianakau2aol.com

[akvish]

We have invented a way of storing energy mechanically during peak times, be it Hydro, Solar, Wind or any form of energy generated. The energy can be utilized as needed
optimally. We hope to put together a demonstration model. Also, there is no need to
transmit generated energy immediately. We hope to make future of hybrids more robust
with this invention.

[popa pineapple]

I'm very curious as to why the most efficient method of storage, superconducting magnetic energy storage (SMES), is not even mentioned in this article. SMES has many advantages over previous technologies. The time delay of a SMES during charge and discharge is quite short. Power is available almost instantaneously and very high power output can be provided for a brief period of time. Other energy storage methods, such as pumped hydro or compressed air have a substantial time delay associated with the energy conversion of stored mechanical energy back into electricity. SMES would seem to be ideal because the loss of power is less than other storage methods since electric currents encounter almost no resistance. Also, since SMES has few moving parts, it is extremely reliable. Small SMES units (1MW) are presently being used for this purpose commercially and there are large SMES test beds currently on line to meet future needs so there's very little technical risk.

So why are we talking batteries and flywheels?

[benjaminstraight]

What a cool story.

[TMR_SystemsEngineer]

One thing to understand is that each of the technologies mentioned may play different roles in Energy storage. The main types that I can think of are:
1) Loap peak leveling (helps to level out the daily fluctuations)

2) Spinning/non-spinning reserve replacements (as a time limited backup to other, hopefully renewable, generation means; like in the case of a line outage)

3) Regulation service - balancing the real-time load/generation demands (on a short time scale)

For example, the CAES might be well suited to level out the slow fluctuations in the availability of wind power where flywheels may be better at providing the service of Regulation.

Remember, there are always trade-off in design and the real trick will be integrating these storage technologies with appropriate renewable resources such that we can make our grid reliable and clean.

[TMR_SystemsEngineer]

@ poppa pineapple: what are the cooling loads required to lower the superconducters down to the appropriate temperature? I would venture to guess that when these cooling loads are incorperated into the efficiency calculations of a SMES that the numbers less impressive. But I don't know. If you have those numbers, I would be interested in seeing them. Also the noted time delays for CAES and pumped hydro are real but not necessarily a problem unless they are providing Regulation. Flywheels are ideal for this application in that they can responds faster than the ISO can send signals (once every 4 seconds).

[mmiocev]

I'm no energy expert by any means but wouldn't it be simple enough to take all that unused energy and create hydrogen from it and then store the hydrogen. Then use the hydrogen to power generators in peak times? Is this an over simplified idea?

[bfarmer36]

We don't need to build dams to create the water pressure required to push hydro-turbines!
All the pressure we will ever need is straight down! Floating hydro-power plants, built down from off shore oil rig type platforms (400ft) The water at that depth will find the path of least resistance, toward the surface
pushing a SERIES of turbines on its way! The deeper we go, the more pressure we get, the more power we can generate for the grid w/zero emissions! (Forcing Water Displacement)