ABOUT THAT NEW ENERGY STORAGE

The challenge for green energy: how to store excess electricity; For years, the stumbling block for renewable energy has been how to store electricity for days when the sun isn't shining and the wind isn't blowing. But new technologies suggest this goal may be within reach...
Jon R. Luoma, 15 July 2009 (Yale Environment 360 via UK Guardian)

SUMMARY
People who have vested interests in the Old Energies just can’t seem to wrap their heads around the New Energies’ potential.

Case in point: Intermittency.

For many years, the charge against the New Energies that Old Energy advocates were quickest with was that New Energies were too expensive. As a result, the New Energies set off in pursuit of “grid parity” (where the cost of their generation is no greater than the cost of generation from traditional sources). Grid parity became the "Holy Grail" of New Energy. And guess what? Wind energy and geothermal energy have essentially achieved grid parity and most indications are that solar energy will achieve grid parity some time in the middle of the coming decade.

So Old Energy advocates became obsessed with intermittency, claiming New Energy could never be a true "baseload" power source until it could store the electricity it generates and provide it 24/7. So New Energy set out in search of large-scale, cost-effective storage. It became New Energy's new Holy Grail.

In a recent, widely read editorial, a former U.S. Secretary of Energy, who coincidentally sits on the board of one of the nation’s biggest coal companies, complained that wind power and solar energy could never make substantial contributions to the U.S. energy mix because the sun doesn’t shine 24/7 and the wind isn’t always blowing.

He and his co-author did not seem aware that pilot projects in solar power plant storage are already in place. (See STORING SOLAR ENERGY)

They also did not seem aware that new pilot projects in compressed air energy storage (CAES) for wind are being prepared. CAES was tested at sites in Germany and Alabama as long ago as the 1990s but judged too expensive and inefficient. Recent advances and the much higher cost of power generation now make CAES potentially practical. The idea is to use off-peak, otherwide unused wind power to push air into caverns, salt domes, and old natural gas wells, hold it under pressure and dispatch it on demand. Dispatchable wind may be used as a supplement to natural gas plants, reducing the need for gas by 70%. A consortium of Midwest utilities is now building the Iowa Stored Energy Park, a 268-megawatt CAES system, in conjuntion with the Sandia National Laboratory of the U.S. Department of Energy.

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The New Energy critics also seemed oblivious to the fact that there are batteries capable of storing energy in multi-megawatt quantities that can be positioned at wind and solar installations in large arrays.

They seemed uninterested in recent studies showing that wind installations in a 500- square mile region can be interlinked via regional transmission to bypass entirely local intermittencies.

And they seemed ignorant of the fact that even in the absence of 24/7 generation capability enormous supplies of wind, solar and other New Energies can be interconnected on the U.S. transmission grid to profoundly reduce the burden of greenhouse gas emissions-spewing fossil fuels.

Solar energy has, perhaps, been working at storage the longest because the electricity generated (voltaic) when light (photo) hits photovoltaic (PV) panels could not, for decades, be stored except in inefficient, cost-ineffective batteries. The grid system can now be used as a sort of gigantic battery while the volume of PV systems is low enough not to overwhelm it, but eventually something to hold the power for use during the hours when there is no sun will be necessary.

The most cutting-edge experiment in New Energy is still in the lab, but what an experiment!

Teams of researchers at the Massachusetts Institute of Technology (MIT), the California Institute of Technology (Cal Tech) and the University of California, Berkeley (Cal), have for several years been in pursuit of recreating photosynthesis with commonplace materials and using the energy generated to make hydrogen cheaply for storage.

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Hydrogen fuels cells have long been dreamed of as the ideal source of power, especially for vehicles, because the byproducts are only oxygen and water. The problem is that hydrogen is not found in nature and making it is so expensive that it becomes one of the most expensive ways to store and generate electricity.

Artificial photosynthesis is a theoretically cheap way of using the power of the sun to separate hydrogen from water. Except that last year Dr. Daniel Nocera’s MIT research team turned the theory into a reality. Nocera’s team found abundant and non-toxic materials, cobalt and phosphate, to drive the process of separating the water molecule into hydrogen and oxygen. When there is no sun, the process is allowed to reverse, liberating energy to generate electricity. Nocera quietly formed a startup company called Sun Catalytics in April.

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Cynics will apparently have to start looking for new reasons to doubt New Energy.

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COMMENTARY
The advent of better and better batteries using a lithium-ion formula or even more breakthrough chemical mixes has changed a lot of things.

Sodium sulfur batteries are being manufactured at 1-megawatt capacities and being delivered by fleets of flatbed trucks to back up remote wind installations in pilot projects.

Lithium-ion batteries have made battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) a pending reality. But beyond powering the vehicle itself, the fleet of batteries coming with the new vehicles represents potential storage. Called Vehicle to Grid (V2G) technology, it takes advantage of the fact that most cars sit idle 90% of the time. Each battery has a 10-kilowatt capacity, enough to power something like 10 average houses. If a significant portion of the EV fleet is plugged into the grid throughout its idle time, intelligent meters can enable the cars' batteries to store winds that blow at night when demand is low or to store extra power generated by solar panels when the sun is most intense. That power could then be put to use when demand is high.

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EV batteries can also become a storehouse of potential after they have put in their 10 years of service and are taken OUT of the cars. By then, the batteries will only be able to hold an 80% charge. Inadequate for use in vehicles, they can be collected, warehoused and linked in huge arrays at a very low cost to provide further service as New Energy storage.

A more proven battery storage system has served the city of Fairbanks, Alaska, since 2003. Housed in a warehouse bigger than a football field, the nickel-cadmium battery holds up to 40 megawatts for a 7 minute period, a capacity adequate to have prevented 81 blackouts in its first 2 years or service.

7 minutes is a crucial backup supply for Alaskan winters when replacing grid power momentarily interrupted by severe weather or sudden demand might be a matter of life and death, but it is completely inadequate to the predictable hours-long part of the 24-hour cycle in which the sun does not shine or the regular and extended lulls of wind, especially at the scale of a utility’s needs, which could necessitate dozens or hundreds of such "Fairbanks" batteries.

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A pilot project in Japan places fuel cells in every home and uses them as “distributed storage.” Such storage, like the”distributed generation” of small wind and rooftop solar systems, require a larger-scale smart, interactive grid to be fully effective on a city, state or regional level, but plans for such a system are in the offing.

Another test project in Japan is with “flow” batteries, used to stabilize industrial power supplies. Such batteries use tanks of chemicals instead of structured cells. The liquid chemicals in the tanks are increased and re-circulated to extend the life and capacity of storage.

A 200 kilowatt flow battery has been used with a small wind installation on a limited scale since 2003 on King Island off the coast of Australia.

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Success with battery storage, or any storage really, hinges on cost. First, there is the cost of the battery. Adding the Fairbanks battery or the Japanese flow batteries would add a lot to the cost of a large energy system. Efficiency is also a cost. Batteries lose part of the power they store, and the longer the power is stored, the more power is lost.

The high hopes attached to lithium-ion batteries has to do with their balance of affordability and energy storage efficiency. Many of their flaws (like flammability) have been ironed out in laptop commuter applications and more will be ironed out when they are put to work powering PHEVs and BEVs. Experiments with lithium-ion battery for the grid have also started. GE-backed A123 Systems built a 2-megawatt battery for a California power plant. But lithium-ion technology is still expensive.

IBM is researching a lithium metal-air battery, which it says could handle 10 times the power of lithium-ion technology. PolyPlus says it has already developed such a battery. There is only one small problem, the air part of the lithium metal-air formulation. The battery separates out oxygen. Oxygen can highly flammable. (They’re working on it.)

Beyond batteries is the dream of the ultimate ultracapacitor. The deeply mysterious EEStor claims to be readying, and was awarded a patent for, an elaboration on the electronic capacitor with unprecedented efficiency and storage capacity. The patent is for a 281-pound device that can reportedly hold the same charge as a 1,000-pound Tesla lithium-ion battery pack. The EEStor product has yet to get to the marketplace so there is no way to be certain it can do what it says it can do cost-effectively. But Lockheed Martin and Zenn Motors have bought in. Zenn says it will have cars on the road using the EEStor ultracapcitor in 2010.

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QUOTES
- James Schlesinger, former U.S. Secretary of Energy, and Robert L. Hirsch: "Why are we ignoring things we know? We know that the sun doesn't always shine and that the wind doesn't always blow…[and because they produce intermittently] solar and wind will probably only provide a modest percentage of future U.S. power."
- From the article: “For decades, "grid parity" has been the Holy Grail for alternative energy. The rap from critics was that technologies like wind and solar could not compete, dollar-for-dollar, with conventional electricity sources, such as coal and nuclear, without large government tax breaks or direct subsidies. But suddenly, with rapid technological advances and growing economies of manufacturing scale, wind power is now nearly at grid parity…And the days when solar power attains grid parity may be only a half-decade away…[W]ith grid parity now looming, finding ways to store millions of watts of excess electricity for times when the wind doesn't blow and the sun doesn't shine is the new Holy Grail. And there are signs that this goal…might be within reach, as well.”

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- From the article: “In a world run mainly on fossil fuels, finding ways to store electricity was not a pressing concern: Power plants across a regional electrical grid could simply burn more fuel when demand was high. But large-scale electricity storage promises be an energy game-changer, unshackling alternative energy from the constraints of intermittence. It would mean that if a wind or solar farm were the cheapest and cleanest way to generate power, it wouldn't matter when the sun shone or the wind blew…”
- James Barber, scientist, Imperial College London: "[The MIT breakthrough in solar energy storage has] enormous implications for the future prosperity of humankind."