Wind-plus-CAES mega plan for LA

In early January 2015, four companies - Pathfinder Renewable Wind Energy, Magnum Energy, Dresser-Rand and Duke- American Transmission - are expected to formally submit an $8 billion wind-power-plus-compressed-air-energy-storage proposal to the Southern California Public Power Authority, in response to the agency's request for proposals to supply the Los Angeles area with renewable energy and electricity storage.

The four companies say their initiative that would bring large amounts of clean electricity to the Los Angeles area by 2023.

The project would require construction of one of America's largest wind farms, in Wyoming, one of the world's biggest energy storage facilities, in Utah (capable of delivering 1200 MWe), and a 525 mile electric transmission line connecting the two sites.

“This project would be the 21st century's Hoover Dam - a landmark of the clean energy revolution," said Jeff Meyer, managing partner of Pathfinder Renewable Wind Energy, one of the four companies involved.

The project, say its proposers, would generate more than twice the amount of electricity produced by the 1930s-era hydroelectric dam in Nevada - 9.2 million MWh per year vs 3.9 million MWh.

Linking the wind farm to the energy storage facility would "enable the wind farm to function largely like a traditional coal, nuclear or natural gas power plant - capable of reliably delivering large amounts of electricity whenever needed, based on customer demand", say the project proponents, who also point out that the energy storage facility would reduce the need for Los Angeles area utilities to build expensive back-up power plants and power lines to serve customers on days when there's no wind, at night when there's no sunlight, and during other periods when traditional wind and solar farms are unable to produce electricity.

Key components of the proposed project:

• Wind farm - Pathfinder Renewable Wind Energy would build, own and operate the $4-billion wind farm - near Chugwater, Wyoming, 40 miles north of Cheyenne - which would have a generating capacity of 2100 MWe.

• Energy storage facility - Pathfinder Renewable Wind Energy, Magnum Energy and Dresser-Rand would build the $1.5 billion compressed air energy storage system proposed for a site near Delta, Utah, 130 miles southwest of Salt Lake City. Four vertical caverns - carved out of an underground salt formation at the site - would be key components of the storage system. Each cavern would be about a quarter of a mile in height, 290 feet in diameter and 41 million cubic feet in volume. The four caverns combined would allow energy storage equivalent to 60 000 MWh of electricity, the project developers say. During periods of low customer demand, the storage facility would use excess electricity from the Pathfinder wind farm to compress and inject high pressure air into the caverns for storage. During periods of high customer demand, the facility would use the stored, high pressure compressed air, combined with a small amount of natural gas, to power eight generators.

• Electric transmission line - Duke-American Transmission proposes to build the $2.6-billion, 525 mile, high voltage transmission line that would transport the Wyoming wind farm's electricity to the Utah energy storage facility. The transmission line - a shorter alternative to Duke-American Transmission's previously proposed 850 mile Zephyr transmission project - would traverse Wyoming, Colorado and Utah, with a target in-service date of 2023. A separate, existing 490 mile line - crossing Utah, Nevada and California - would transport electricity from the Utah energy storage facility to the Los Angeles area.

Pathfinder Renewable Wind Energy would develop the proposed wind farm with financial backing from lead partner Sammons Power Development, and employ wind turbine technology from GE. Pathfinder, based in Alcova, Wyoming, operates the "environmentally focused" 700 000 acre Sweetwater River Conservancy at the company's Wyoming ranch.

Magnum Energy, developer of the underground energy storage facility, is owned by Magnum Development, a Haddington Ventures portfolio company. Participating investors in Haddington Ventures, which has been working on plans to develop compressed air storage facilities in Utah for many years, include insurance companies, public and private pension groups, commercial banks and high net worth individuals. Magnum Energy is based in Salt Lake City.

Duke-American Transmission Co is a transmission developer equally owned by Duke Energy, the largest electric power holding company in the USA, and American Transmission Co, the USA's first multi-state transmission-only utility.

• Meanwhile, there are also big potential plans for storage in Texas. According to a study by Brattle for Oncor Electric Delivery Company (Texas transmission & distribution service provider), deploying large batteries on distribution systems across Texas "could provide substantial net benefits to the state". The study estimates that up to 5000 MW (15 000 MWh, assuming a three-to-one ratio of storage to discharge capability) of grid-integrated, distributed electricity storage would be "cost effective from an ERCOT system- wide societal perspective" based on a forecast of installed cost of storage of approximately $350/kWh. This installed cost projection is based on Oncor's discussions with vendors and is consistent with industry sources, says Brattle. Morgan Stanley predicts that battery- only costs may reach $125- $150/kWh in the near future, down from the $500/kWh currently, and "if battery costs are capable of reaching the low costs projected by Tesla Motors Inc., this would imply a battery-only cost of only $110/kWh", Brattle notes.

“Due to recent developments, electricity storage appears to be on the verge of becoming quite economically attractive," says the Brattle report, noting that several battery storage manufacturers have indicated that their costs will decrease substantially over the next few years. Forecasts are now suggesting cost declines from the current $700-$3000 per kWh of installed electricity storage in 2014 to less than half of that over the next three years, with analyst projections and vendor quotes pointing to further substantial cost reductions beyond that. "At these much lower system costs, many innovative applications of electricity storage could be cost effective", says Brattle.

(Originally published in MPS January 2015)