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Concentration of CO2 in the Atmosphere

A Big Wind Project

Photo by David Jolley, found at Wikimedia Commons.

Photo by David Jolley, found at Wikimedia Commons.

By George Harvey

We just got news of a renewable power project in the West that is intended to supply enough power for about 1.2 million households. The project is budgeted at nearly $8 billion for a project with major sites in Wyoming and Utah, to deliver power in the Los Angeles area.

The developers include Pathfinder Renewable Wind Energy, which will build, own, and operate a wind facility in Wyoming; Magnum Energy and Dresser-Rand, which will take part in a power storage facility in Utah; and Duke-American Transmission, who will have a proposal before the Southern California Public Power Authority in early 2015 and hope to finish the project within ten years.

If things go as planned, the Wyoming wind farm will have a 2100 megawatt (MW) capacity. It will be located in PlatteCounty, about 40 miles from Cheyenne. The facility is expected to cost about $4 billion. Please note that this is not the same as another project that appeared in the news recently, with a wind farm of slightly greater capacity, which is intended to deliver its power through a transmission line to the San Diego area, and which is currently under development.

As planned, the newly announced wind farm will deliver its power through a new transmission line, 525 miles long, to the storage facility in Utah. There, it can be used to compress air to be stored in four huge caverns in a salt dome. The air can be used to drive generators with an output of 1200 MW. The total storage at the site will be 60,000 megawatt hours (MWh). The cost of the storage facility is projected to be $1.5 billion.

In Utah, the power, whether generated at the site’s storage facility or just passed through it from the wind farm, will be put onto existing transmission lines. These lines ultimately go to the Los Angeles area, for which the power is intended.

While this is all rather far from New England, it does have some points that may be of interest in the local area. We may not have a place for a wind farm of a size even remotely close to 2100 MW, and we may not have a handy salt dome full of caverns. Nevertheless, the vision of energy storage and transmission can be applied here.

Those who make economic projections on electric power backup systems have ideas about the cost at which a technology can become disruptively competitive with old grid technologies. If the price of a battery gets low enough, the cost of it and the renewable resources necessary to charge it become sufficiently low that they compete successfully with grid power, forcing changes in how the grid operates. At such a point, renewable resources have the advantage of needing no fuel and, if they are small, can be installed by consumers. The price most quoted for such a highly-competitive battery system seems to be about $200 per kilowatt hour (kWh).

Please remember, we are not considering the price of electricity here, for which 15¢ per kWh might be a little high. We are considering the price of the equipment to store it. An automotive starter battery might cost $80 per kWh, but it is not of sufficient quality to be charged and discharged repeatedly as needed for grid power.

What we are seeing in the new proposal, however, includes a storage facility that is said to cost $1.5 billion for 60,000 MWh. This is $25 per kWh, or about an eighth of the price the pundits say is disruptive. (In shock over the price, I have recalculated it three times. I keep coming up with the same figure. Someone, please correct me, if I am wrong.)

The fact is that you do not need a salt cavern to store massive amounts of air under intense pressure. A bit over a year ago, a slightly different technology was put into use in the UK for a grid-tied power storage pilot program. In that system, heavy-duty pumps compress air, which is then fed into a heat exchanger, where the heat of compression is removed and retained to be used elsewhere. This causes the compressed nitrogen in the gas to condense into a liquid, which is stored in a large steel tank. The oxygen-and-argon mixture left as gas is released. The liquid nitrogen is allowed to boil as needed, driving an electric generator. When this happens, it absorbs heat, and its cooling action is used in refrigeration equipment. We will doubtless hear more about this when the report on the pilot project is released. Also, we should keep in mind that there are many, many storage technologies under development.

We can do things similar to what is being done out west right here in New England – and perhaps even do them better here. We can use so-called intermittent power to keep our lights on “24/7,” as they say. And that new paradigm may be coming soon, delivering round-the-clock electricity from a compressor near you.

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