MHI and SSE Partner to Bring Cargo Container Battery Storage to Orkney Islands Power Grid

Energy Storage System Will Have a Maximum Power Output Capacity of 2 MW

Vince Font, Contributing Editor
November 29, 2012 | 16 Comments

Mitsubishi Heavy Industries (MHI) has announced a partnership with SSE plc, an electric utility company located in Scotland, for an energy storage demonstration project that will use two 40-foot cargo containers full of thousands of lithium-ion rechargeable batteries to store as much as 800 kWh of generated clean energy, with a maximum power output capacity of 2 megawatts. The recipient of the joint effort will be Scottish Hydro Electric Power Distribution plc, the arm of the SSE that's responsible for distributing power in Scotland.

According to a press release issued by MHI, there will be a total of three cargo containers involved in the project: two of the containers will house roughly 2,000 units of lithium-ion batteries each, and a third will house the power conditioning system responsible for converting direct current (DC) to alternating current (AC).

The storage system is set to be installed at the Kirkwall Power Station in the UK’s Orkney Islands. Power will be transmitted to and from the mainland via a submarine cable anytime there’s a shortage or surplus of power. In theory, the storage system will store surplus power in the lithium-ion batteries whenever the supply exceeds demand, offering an increased level of reliability for later power delivery.

The issue of energy storage gets to the heart of one of the greatest perceived weaknesses of renewable energy technology: what happens when the wind’s not blowing, when the tide’s not turning, and when the sun’s not shining? According to Michael Goggin, Manager of Transmission Policy with the American Wind Energy Association (AWEA), energy storage systems like that being developed by MHI and the SSE may work well in certain situations, but in others it may actually be less cost-effective than alternative methods.

“On the mainland integrated power system, there are many existing sources of flexibility, so new energy storage resources are not needed to accommodate the very small amount of variability and uncertainty,” Goggin said. “Storage is one option for increasing the flexibility of a power system, and using it makes sense when it is cost-effective. However, other options, particularly making greater use of existing resources or building more transmission, are typically more cost-effective on large integrated power systems.”

According to the AWEA’s “Wind Power and Energy Storage” factsheet, flexibilities built into the existing power system enable operators to increase and decrease the output of generators. This makes it possible to easily and more cost-effectively accommodate for certain variabilities.

Goggin went on to say that he believes island power systems can benefit far better from energy storage systems. “They have no ties to the outside world and often have weak transmission systems and inflexible power plants,” he said, “so there tend to be more cases where storage can be economic.”

The joint MHI/SSE storage system is set to go online in early 2013.

Lead image: Wind turbine on Orkney Islands via Shutterstock

16 Comments

Lawrence Carroll
December 2, 2012

Annonymous, thank you for the link to http://hydrostor.ca/technology/

I have long been fascinated by the compressed-air-storage method.

While steel and aluminum tanks (such as in SCUBA and many other areas) do require maintenance/replacement periodically, the fact is that the costs and requirements for compressing/storing air are well known.

I suspect that such methods will eventually prove to be the simplest, quickest, and most cost efficient method of storing energy, whether in large scale grid situations such as that described on the "hydrostor" link that Anonymous left, or for hybrid vehicles and individual homes and businesses.

Naturally there are those who will repeat that such methods are inefficient compared to various battery technologies and hydrogen, but I suspect that they're not really looking at the costs involved in many cases. But not being an engineer or professional, I can only suspect this, but am unable to "prove" it . . . :)

jg williams
December 2, 2012

Hi,

The Orkneys have many lakes at different elevations and about 1.3m of rain per year. Pumped storage between lakes (lochs) at different elevations would be a far cheaper and more cost effective option than what must be an extremely costly lithum battery based system. The hydro-turbines could be reversed when there is surplus electricity being generated to pump water from a lower to a higher loch. When the grid falters or there is demand greater than what is being generated by the wind-turbines, the water hydro-electic turbines can be reversed to generate hydro-electricity, the only instantaneous and most responsive form of electricity generation enabling premium spot tariffs to be earned.

Dr. JAMES WOLTER
December 1, 2012

RHinLA All good questions ... not only do batteries have limited cycle life - they loose capacity steadily over their lives such that a common definition of "end of life" is when they decline to about 80% of their original capacity (when new for example).
the actual failure mechanisms are both chemical degradation and physical degradation and each "chemistry" suffers from its own modes of destruction.
If you were a serious fisherman (using deep cycle, lead acid trolling motor batteries and running them down to very low states of charge) you will replace batteries each season (300 deep-cycles kills them).
Modern secondary (rechargable) batteries such as Nickel Metal Hydride and numerous lithium-based versions have ten-times or more cycle lives as lead-acid batteries but they still have "wear mechanisms" (gradual oxidation of ionic receptor sites, abrasion of separator membranes from swelling and contraction of active battery materials (which leads to cell shorting), growth of crystalline dendrites lead to shorts etc. etc.

Whatever the chemistry - high-heat hurts - deep cycling hurts - allowing low states of charge hurts - high transient current loading hurts -- of all these, deep (vs shallow) cycling hurts the most. When GM tested prismatic NiMH batteries for their EV-1 project they got 250-300,000 cycles but their tests were for shallow depths of discharge (3% to 5% of the batteries capacity - then recharge etc.) The same batteries in the hands of private citizens were calculated to run the car about 60,000 miles before their battery capacity had declined to 80% -- then GM marketing was insisting on battery change-out.

So there you have it ... if you drive 15,000 miles per year - you could only get 4-years service from what arguably is a very competitive battery technology (using them in deep cycle mode).

On the other hand - there are Toyota Prius cars in service with over 300,000 miles on their NiMH battery packs - but only 5-10% discharge cycles.

Dr. JAMES WOLTER
December 1, 2012

Robert Hall
December 1, 2012

So, you're saying that "rechargeable" batteries are only such for so long ("3000-4000 cycles")? Pardon my ignorance, please, but shouldn't those kinds of batteries be called "kinda-sorta rechargeable"? What is the something that eventually wears out in rechargeables? I guess we're looking for the perpetual motion machine where the excess energy generated is used to drive the process that stores excess energy.

Dr. JAMES WOLTER
December 1, 2012

What is not mentioned here is that the best case for cycle-life on any existing Li-based battery is from 3-4,000 cycles. This allows a likely use of only 8 to 10 years (theoretically) which does not match well with typical Utility infrastructure built for 30 to 40 years of trouble free service (and all this assumes the batteries are only cycled one time each day).
The second and perhaps more important issue is cost. Cost of cells themselves is now hovering between $800 to 1000 per kilowatt-hour (just for the component cells - no allowance for battery management systems) BUT recent quotes for Utility-Grade battery systems (including warranty for 10 years) are between $3500 to $4000 per KWH... Or $4 million per megawatt-hour. A "really good (Cat or Cummins) diesel gen-set costs about $400,000 per megawatt ... BATTERIES ARE NOT READY FOR "PRIME TIME" in any product market beyond consumer electronics! The Emporer is not wearing any cloths...

ANONYMOUS
December 1, 2012

A new system is available from a Canadian company called Hydrostor. When the wind is blowing and the electricity is not needed on the grid, the electricity is used to run an air pump that fills large bladders underwater. When the electricity is needed the air is released and the air pump becomes a generator. here is their website www.hydrostor.ca/

Christopher Lee
December 1, 2012

@RHinLA:

There is heat storage, for use as heat or as an add-on to concentrating solar. The latter would be an example of a combined solution: not the most thermodynamically efficient for spare wind energy, but not needing much investment if the solar furnace is already there; wind could keep it running at night. Not terribly interesting for an island to the North of Scotland!

A was thinking also of the newly proposed thermal system involving liquefying air.

Another one that has been proposed is that in places with hydroelectric facilities, you could pump water back into the reservoir.

Robert Hall
December 1, 2012

What are some "non-battery storage solutions"? Thanks.

Christopher Lee
December 1, 2012

I agree with the tenor of some of the remarks about whether batteries are appropriate. It would be as well to add that there should exist better battery solutions for static applications like this, where weight, volume and perhaps efficiency are not critical, but price and longevity are.

There exist non-battery solutions for storing energy, but it's legitimate to consider batteries as part of the mix, especially for sites like this one.

The thing that worries me, here and elsewhere, is that designers so often make what seem to be wrong choices, and are rarely able to combine different technologies.

Constantine Kritsonis
December 1, 2012

SHEC Energy claims baseload levelized cost of power at 12 cents per KW/hour in ideal solar radiance.

Penelope Gray
November 30, 2012

Amazing how little information is in this article. How much do these batteries cost and what is their "shelf life"? Having lived off grid for 28 years on solar power, I can say that the batteries are by far the most expensive component of the system and have an average ten year life span depending on how they are cycled. Can it be any less expensive for industrial wind? How much power will they provide the grid when fully charged, and for how long? Who is paying for these batteries? The rate payer?

Christina Nelson
November 30, 2012

Think thermal energy storage. The 40 foot container holds about 169,800 pounds of water. If that water is used to heat a building with a 20 degree F temperature drop, that is equal to 3,396,140 BTU which is equal to 995 KW. You can add to that domestic hot water too. And it will never wear out and need replacing. A 40 foot container can be purchased for about $4,000.

Stepan Tatulian
November 30, 2012

40-foot container dimensions are 12.2m by 2.4m by 2.6m, that makes the combined volume of two containers 152m3. The energy density of Lithium ion battery is believed to be between 250 and 730 watt hour/litre (http://en.wikipedia.org/wiki/Lithium-ion_battery) lets take the average of the two figures - 490 watt hour/litre. The energy density of this storage is 800/152=5.26 watt hour/ litre, a mere 1% of the lithium ion battery potential. Is there a mistake in figures?

Ed Sears
November 30, 2012

RHinLA

Not a bad idea, but it doesn't get around the fact that batteries are expensive (and polluting). The grid allows something like one third of the amount of power generation compared to everyone having their own off-grid sources (or batteries) as the power is used at different times e.g. shops and offices used during the day and houses used in the evening don't need separate power generation - you would end up with twice as much as you need. Those little batteries you are talking about are not a way to avoid the inherent problems with batteries - in fact they may well be more expensive per capacity than a larger battery.

Cheers
Ed

Robert Hall
November 30, 2012

I have a lamp on my desk that enables me to work during non-daylight hours. As an outside-the-box idea, instead of figuring out how to store excess energy on a grid scale, why not begin to manufacture power consuming products (like my lamp) similar to hybrid vehicles? Include a battery in my lamp (and in my printer, my refrigerator, etc.) so that I can run it when there is no power off the grid (or, when I don't want to consume grid power). The cost of the product may increase at point of sale, but the cost of the product over its lifetime will decrease based on reduced use of expensive grid power.

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Vince Font

Vince Font is a professional freelance writer specializing in the fields of renewable energy, high tech, travel, and entertainment. Read his blog at www.vincefont.com or follow him on Twitter @vincefont.