Carbon Footprint of Grid-scale Battery Technologies

[Stoaty]

http://www.eurekalert.org/pub_releases/2013-03/su-ssc030813.php" onclick="window.open(this.href);return false;

"After determining the embodied energy required to build each storage technology, Barnhart's next step was to calculate the energetic cost of maintaining the technology over a 30-year timescale. "Ideally, an energy storage technology should last several decades," he said. "Otherwise, you'll have to acquire more materials, rebuild the technology and transport it. All of those things cost energy. So the longer it lasts, the less energy it will consume over time as a cost to society."

To quantify the long-term energetic costs, Barnhart and Benson came up with a new mathematical formula they dubbed ESOI, or energy stored on investment. "ESOI is the amount of energy that can be stored by a technology, divided by the amount of energy required to build that technology," Barnhart said. "The higher the ESOI value, the better the storage technology is energetically."

When Barnhart crunched the numbers, the results were clear. "We determined that a pumped hydro facility has an ESOI value of 210," he said. "That means it can store 210 times more energy over its lifetime than the amount of energy that was required to build it."

The five battery technologies fared much worse. Lithium-ion batteries were the best performers, with an ESOI value of 10. Lead-acid batteries had an ESOI value of 2, the lowest in the study. "That means a conventional lead-acid battery can only store twice as much energy as was needed to build it," Barnhart said. "So using the kind of lead-acid batteries available today to provide storage for the worldwide power grid is impractical."

The study also assessed a promising technology called CAES, or compressed air energy storage. CAES works by pumping air at very high pressure into a massive cavern or aquifer, then releasing the compressed air through a turbine to generate electricity on demand. The Stanford team discovered that CAES has the fewest material constraints of all the technologies studied, as well as the highest ESOI value: 240. Two CAES facilities are operating today in Alabama and Germany.

 

[surfingslovak]

This is great, Stoaty. Thanks for sharing!

 

[Stoaty]

It appears the CAES isn't very efficient, about 50%:

http://energyinformative.org/compressed-air-energy-storage-caes/" onclick="window.open(this.href);return false;

although there is a more advanced concept that may be up to 70% efficient:

http://www.rwe.com/web/cms/en/183732/rwe/innovation/projects-technologies/energy-storage/compressed-air-energy-storage/" onclick="window.open(this.href);return false;

This compares with 70-80% for pumped hydro storage:

http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity" onclick="window.open(this.href);return false;

 

[AndyH]

At less than 60% efficiency, I wonder how Audi's sun to fuel process rates on the new ESOI scale?


[youtube]http://www.youtube.com/watch?v=hOn1FkwPjMA[/youtube]

http://www.technologyreview.com/news/510066/audi-to-make-fuel-using-solar-power/

SolarFuel’s process uses excess renewable energy generated as a result of Germany’s push to reduce greenhouse-gas emissions. There’s now so much renewable energy in Germany that supply sometimes exceeds demand—such as when the wind is blowing late at night. That power could be cheap enough to make methane from water and carbon dioxide, even though the process for doing so is inefficient.

 

[DaveinOlyWA]

It appears the CAES isn't very efficient, about 50%:

http://energyinformative.org/compressed-air-energy-storage-caes/" onclick="window.open(this.href);return false;

although there is a more advanced concept that may be up to 70% efficient:

http://www.rwe.com/web/cms/en/183732/rwe/innovation/projects-technologies/energy-storage/compressed-air-energy-storage/" onclick="window.open(this.href);return false;

This compares with 70-80% for pumped hydro storage:

http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity" onclick="window.open(this.href);return false;

pumped hydro has improved a lot. I remember reading about storing water for crops in Eastern/Central WA and how much electricity it required but i see problems with both as a storage for the electrical grid.

both underground caverns suitable for storage or very large areas suitable for storing water are not extremely common and having them located near the wind/solar source is another hurdle.

batteries can be put anywhere and yes, a 10-1 ratio is not the best especially when hydro is 210 but i think its still a worthy option. what the study does not say is how many times the batteries had to be replaced in the 30 year time frame discussed? once, twice?

keep in mind that that 10-1 ratio will only go higher. i say if hydro/compressed air is viable anywhere then do it, for all other areas (I am guessing there will be many) lets do batteries.

there is a place in TX that started experimenting with battery back with a small 24 MW? system. not much but should give us some valuable data to look at