Which energy storage alternative holds the most promise?

[Dr. Mitul Sarkar]

Will current accessible (to the US) lithium reserves be sufficient for manufacturing the vast numbers of batteries that will be required to store energy and power vehicles, or are other efficient batteries in the works?

[Ken Carlson]

In the March 2009 issue of ColoradoBiz a number a renewable energy initiative were mentioned and a key area is the storage of energy in batteries. Not that battery storage is the only form of storing energy but a lot of hope and effort has been focused around Lithium-ion batteries. The technology is coming but too slowly.
If we are going to fully harness such areas as Solar and Wind we need to accelerate the research to find the solution for when the sun doesn’t shine and the wind doesn’t blow.

[Matt Baker]

There are many opportunities to promote all types energy storage. We need to conduct R&D on the next generation of battery storage devices but we also need to utilize the technologies we have now to the extent possible. Ice storage for HVAC and cooling, flow batteries to meet critical peaks and more pumped storage to regulate intermittent renewables can be done at scale today. These technologies allow us to store wind and solar today. By going Big on Batteries with today’s technology, utilities, developers and manufacturers don’t have to wait for the future to get experience, justify R&D or build a market. In addition, the grid can handle more clean energy.

[Keith Howard]

Matt,
Your idea of improving battery storage has a double benefit, helping not only solar PV energy storage but the battery prices for electric and hybrid cars.
When I was working on electric car batteries I found that the cost of lithium batteries had decreased by about 8% per year over the past 10 years, driven by the high-volume laptop computer market. The cost of batteries strongly depends on volume - electric car battery packs costs are almost entirely due to the cost of batteries.

While I was consulting for a one of the largest U.S. battery suppliers for auto packs, I noticed they were also building battery ‘trailers’: 30-foot trailers filled with advanced lithium cells, intended for the energy market for energy leveling. This large volume of cells could drive down the costs not only for the energy industry, but also the electric vehicle costs (which could then be recharged by solar PV, yielding an even lower carbon cost for electric vehicles).

One potential overlap is that the electric vehicle market defines end-of-life for a battery when its capacity is 80% of original capacity; the loss of range due to lower capacity makes them ineffective for vehicles. However, the power industry could potentially use these ‘end-of-life’cells for solar PV storage. Due to the lower energy demand compared to vehicles, and with the newer Li-ion prismatic long-life cells now being used, these cells could last for another 10 years past the time when they no longer have value to the electric vehicle industry.
Essentially, electric storage for free.

[Probir Ghosh]

Keith and any energy storage experts out there:
Reusing the batteries for lower quality storage seems to be an excellent idea. The extended use can change the life cycle cost pretty dramatically, especially considering that the current batteries reach 80% storage retention by about 2000 charges (6 years?).

The question about finding a solution for low cost storage is key to solar and wind farms massive scaling. I’d like some feedback from anyone who has a good feel for what are the various viable mass scale storage options and the credible road maps that can show how the prices can go down dramatically while increasing quality.

For the automoible sector right now, my understanding is it costs roughly $1600/kWh of storage with Lithium batteries. So if a car averages 12.5miles/kWh, a 200 mile range will mean a 16kWh charge, that will cost about $25,600. If the balance of car cost $10,000, the car cost out the factory with about a 10% profit will be about $40K. (Tesla recently announced a lower cost version car with a 160 mile range for about $40K and a 300 mile range, no price announced), I have a feeling this is much lighter, bareboned and much lower powered car than the 1st gen Tesla.

If by 2015, if we can bring down the battery price to $800/kWh, the battery cost for a 300 miles range becomes $19,200 and if the balance of system remains the same, the car cost comes down to $32K despite having a longer range (that compares to gasoline vehicles). If it can reach $500/kWh by 2020 (mass production and scaling impact) the vehicle cost can come down to about $24,000 in today ’s prices. At that point I believe we will see a massive swap from gasoline engine cars to battery based cars. If we see a 50% swap in USA by 2025, that amounts to 140 million cars… and by 2030 we can hope to swap out 90% of the gasoline engine cars.

Maybe, hydrogen fuel cell cars will win the battle if battery technologies cannot bring the prices down rapidly. The mammoth crisis in US auto may be a boon in disguise, if we can use this event to make a massive shift. We have to infuse bilions anyway and maybe invest a little more now to make the shift.. in any case we have lost serious ground to Japan and Europe for gasoline based cars.

Just like any other technologies and the current total dominance of gasoline based cars, the world needs to decide on one energy system to invest in before investing in massive infrastructure needed to support the system.

For those who have read the Breakthrough Solar Energy Initiative, they may have noticed that the projections go up to 25-30% of the total energy production by 2030, which is 200% more than the total current electric generation in the US, a complete sacrilege under conventional thinking. But then new radical innovations and breakthroughs always challenge conventional thinking.
Any comments?

[Sol Shapiro]

If the objective is to move ahead with wind and pv beyond the range of 20% or so of grid capacity, bulk storage of energy becomes key. The storage medium must have the properties of cost effectiveness and capacity. Without having done major research in the area, I have been exposed to periodic discussion of the subject. Here is a recent paper I've looked at - with Robert Williams of Princeton as a principle author. http://www.princeton.edu/~cmi/research/ ... s/CAES.ppt
He is someone I truly respect. This economic analysis shows compressed air energy storage as the winner by a long shot. I've also been exposed to statements that there are plenty of natural underground storage places. While, I believe there is limited availability of places for pumped storage. I know there's a caes facility in Alabama and one in Germany.
Briefly, the caes system uses about 1/4 as much gas as a natural gas generator per unit of energy conversion.
The only other bulk technology to serve large scale generation that I believe has any serious level of capacity and economic competitively is thermal storage associated with solar thermal.
So that if we look at the electricity grid and today's technologies, I see as competitors for a role in the "backbone" as wind and caes (backed by gas), pv and caes (backed by gas), solar thermal with storage (backed by gas) and geothermal.
Local use could certainly work with ice storage - but this doesn't fit into a general grid supply as far as serving a broad range of uses.
And if we look downstream at a possible transportation fuel from renewables - such as hydrogen (though I personally think the infrastructure and on-board storage will be against this) or liquid fuel made from some approach such as air, water and energy, then the storage issue is moot for this application.

[drmsarkar]

IBM and GE are throwing their weight behind the development of efficient Li batteries
http://www.businessweek.com/technology/content/jun2009/tc20090622_116016.htm

but sticking with Lithium means US dependency on a foreign resource. Some discussions at
http://agmetalminer.com/2009/04/16/how-does-the-supply-market-look-for-lithium/
and
http://www.scitizen.com/stories/Future-Energies/2008/06/World-Lithium-Supplies-and-Electric-Vehicles-/