The West Virginia Public Service Commission on June 24 cleared a battery storage project planned for a wind farm site in Greenbrier County, W.Va.
The commission concluded that the addition of an energy storage device at a wind generating facility is not a material modification of the Siting Certificate for the wind facility.
In 2006, the commission granted Beech Ridge Energy LLC (BRE I) a Siting Certificate for a 186-MW wind facility, to be located nine miles northeast of Rupert in Greenbrier County, and a 13.8-mile 138-kV transmission line to connect the generating facility to Allegheny Power‘s Grassy Falls substation near Nettie in Nicholas County, W.Va. Sixty-seven wind turbines capable of producing 100.5 MW were actually completed and placed into service in 2010.
In August 2012, Beech Ridge Energy II LLC (BE II) applied for a Siting Certificate to construct up to thirty-three turbines to generate between 53.5 and 85.5 MW, on land adjacent to the site where the sixty-seven BRE I turbines were installed. The commission granted BRE II a Siting Certificate in June 2013. As of February 2014, construction had not commenced on the BRE II turbines.
On Feb. 14, 2014, BRE I requested a waiver of the requirement to modify or amend its Siting Certificate in connection with the planned installation of an energy storage device at its wind farm. In the alternative, if the commission finds that the proposed modification is material, BRE I asked the commission to modify the Siting Certificate to allow construction of the $20m energy storage device.
The energy storage device, comprised of eighteen 1.8-MW modules of lithium-ion batteries, inverters, transformers and cooling systems (sometimes referred to as the battery yard), will have a combined nominal output of up to 32.4 MW. The lithium-ion batteries are the same kind of batteries used worldwide in a variety of applications. The batteries are grouped into battery packs that are loaded into trays, and the trays are mounted in floor-to-ceiling racks inside a standard shipping container that is about 40 feet long, 8 feet wide and 9.5 feet tall. Each 1.8-MW module includes one standard shipping container that houses four battery strings, four 450-kW inverters to convert power between direct current and alternating current, a chiller to cool the battery containers and a transformer for the inverter.
The energy storage device will produce 480-volt output that will be converted to 34.5 kV by pad-mount transformers inside the battery yard. The battery yard will be adjacent to the existing substation and connected to it by a short overhead line or an underground cable that will lead to a new 34.5-kV breaker and switches at the substation.
The energy storage device will regulate the wind farm’s ramp rate and provide automatic generation control. As to the ramp rate, the battery yard will be able to control the rate at which power is delivered from the wind farm to the grid. For example, the batteries can store energy generated by the wind turbines and release it when appropriate, like when power demand is high but wind generation is low. With automatic generation control, the wind farm will be able to increase or decrease its power output and thereby provide the ancillary service of regulation to PJM Interconnection. PJM matches generation levels with short-term changes in electricity use to maintain stable grid frequency at 60.0 Hz and selects resources each hour to provide regulation service. The wind farm will earn revenue through payments from the PJM regulation market.
BRE I plans to transfer the portion of the Siting Certificate that concerns the energy storage device to Beech Ridge Energy Storage LLC (BRES), which will be a wholly-owned subsidiary of BRE I. The transfer to BRES will enable the battery yard to be financed separately.