内布拉斯加州公共电力公司（The Nebraska Public Power District（NPPD））正在着手在3000英尺的地下建设一个压缩空气储能项目。
NPPD的董事会上周五经过谈判达成了一致意见：将要租用位于德尔郡（Deual Country）Big Spring附近的达科塔砂岩层（Dakota Sandstone）存储压缩空气。该压缩空气储能电站将用来稳定风电场的输出。
Matheson估计，这个项目成本将是1200-1300美元/kW，但是，Matheson也表示，这个数字式非常初步的估计。
Matheson表示，目前压缩空气储能项目不符合减少温室气体排放的联邦贷款政策，但是在未来有肯能会得到这项贷款。
目前，世界上只有两座运行的大型压缩空气储能项目：1978年建成的德国Huntorf电站以及1991年建成的阿拉巴马州的电站。两个电站都采用的是采盐形成的地下洞穴。
The Nebraska Public Power District is going underground in a big way.
The state's largest electric utility is embarking on an innovative energy project to store compressed air in a geological formation 3,000 feet below ground and use the same pressurized air later to turn a turbine to produce power.
There are only two other Compressed Air Energy Storage facilities in the world, one built in Huntorf, Germany, in 1978, and the other built in 1991 in McIntosh, Ala., NPPD said. Both use underground caverns that were formed from salt mining operations.
NPPD's board of directors Friday directed management to negotiate an agreement to buy the rights to store compressed air in the Dakota Sandstone formation near Big Springs in Deuel County.
Dakota Sandstone covers parts of Kansas, Nebraska, Iowa, Minnesota and Wisconsin. Outcroppings can be seen in Lincoln along Antelope Creek near the zoo and in Pioneers Park.
Mike Matheson, a senior generator strategies engineer, said NPPD is not buying any land, only the rights to store compressed air in an existing natural gas storage facility that covers more than 40,000 acres.
The existing storage facility is owned by Kebrh Operating, an individual natural gas producer with addresses in Chappell and Merino, Colo., he said.
Matheson declined to say how much NPPD will pay for the storage rights, saying the parties still are in negotiations.
The Dakota Sandstone formation in Deuel County was mined for natural gas during the 1950s and '60s until supplies were exhausted, said John Swanson, generation strategies manager for NPPD.
"Since that time, various companies have used it to store natural gas," he said.
Once NPPD signs an agreement, it plans to develop a testing plan, which will involve creating computer models to build the storage facility, Matheson said. Testing will not begin for three to five years.
Here's how the compressed air storage facility will work:
* Compressed air is created by a compressor that works on the same principle as those found in gas stations. NPPD said power for the compressor will come from coal, nuclear, wind and other resources.
* The air then is pumped into the geological formation through injection wells and can be stored for weeks and even months.
Matheson said there is no danger of explosion. He said the utility will store the compressed air at the same pressures used to store natural gas.
He said energy storage projects are important as renewable energy generation increases in Nebraska, citing wind turbines as an example.
Sometimes there's not enough wind to turn the blades, he said, and as power generation fluctuates, an energy storage device helps stabilize a utility's power generation system.
"It allows your existing generation to run at a constant level where it is most efficient to operate," Matheson said.
Matheson estimated that a compressed-air facility would cost NPPD $1,200 to $1,300 per kilowatt, but he said those figures are very preliminary.
Matheson said compressed-air facilities do not qualify for federal credits for reducing greenhouse gases, but they may in the future.