Flywheels spinning underground at Humboldt Industrial Park, supersized batteries in Montgomery County and two reservoirs proposed for Spring Mountain have the same purpose.
To store energy.
Storage systems like reservoirs that Grid Balance Hydropower of Pottsville hopes to build on Spring Mountain already play a key role in keeping the flow of power steady when demand changes by up to 40 percent between night and day or hot and cold spells.
Their importance will grow as the nation generates more electricity from solar panels and wind turbines, which only produce when the sun shines or wind blows but don’t emit carbon dioxide that contributes to climate change.
The Hazleton area became a trendsetter for storing electricity in 2013 when the flywheel plant went online. Except for a sister plant in Stephentown, New York, there is nothing like it in 13 states where the PJM Interconnection supplies power to 65 million people.
Grid Balance’s plan to generate electricity in Banks and Packer townships, Carbon County, by pumping water between reservoirs of different elevations is much more common.
Pumped hydropower provided 96 percent of the electrical storage capacity in the United States, the Union of Concerned Scientists reported four years ago, and most of those systems have been around for decades. Muddy Run Reservoir in Lancaster County, for example, started releasing water to a pond below Conowingo Dam on the Susquehanna River and making electricity in 1966.
The novelty of the Spring Mountain plan is that Grid Balance wants to use acid mine water from the Quakake Tunnel.
How to treat mine water so it won’t erode turbines or enter wells or public drinking supplies are among the questions that the company hopes to answer in a study. The study, which the company’s manager Paul DiRenzo Jr. said might last three years and cost $500,000 to $1 million, also would analyze the financial viability of building a pair of 110-acre reservoirs with 80-foot dams connected by a tunnel more than a mile long.
Storing saves money
Last month, the U.S. Senate Committee on Energy and Natural Resources held a hearing on adding large-scale storage facilities. The nation has 23 gigawatts of storage, but might gain 35 GW by 2025, according to a report by the Energy Storage Association.
Committee Chairwoman Lisa Murkowski, R-Alaska, said when opening the hearing on June 4 that plants save money and lower customers’ bills by storing power when prices are low and releasing it as prices rise. Storage also can help spare the need to build infrastructure to generate and transmit electricity, make the grid more resilient and help move from large, stable plants to decentralized, intermittent sources like sun and wind, she said.
Batteries, improved by the electric car industry, last up to four hours and cost about $200 per kilowatt hour, but George Crabtree of Argonne National Laboratory called for research to find still better technologies. He listed goals of cutting the price in half to make batteries “economically appealing” and to develop batteries for different needs such as electric car batteries that charge faster or storage batteries that last for days instead of hours because, he said, the sun might not shine for a week.
Kiran Kumaraswamy, vice president of Fluence, which owns batteries that store 2 MW in Norristown, Montgomery County, told the committee that utilities in California and Arizona decided to build battery storage sites as large as 100 MW instead of natural gas plants to meet peak demand. Batteries that Fluence installed helped keep the power grid working in the Dominican Republic after hurricanes in 2017, he said.
Mitchell Davidson, the chief executive officer of Brookfield Renewable, told the committee that equipment in hydroelectric plants can last 30 to 50 years and the plants themselves can remain for 100 years. The Energy Regulatory Commission can easily take more than five years to permit a facility, Davidson said.
Meeting peak needs
Grid Balance, when applying for a preliminary permit from the Federal Energy Regulatory Commission, said its proposed system could generate 400 MW as water in one reservoir atop Spring Mountain flows through turbines and settles into a reservoir at a lower altitude. At night when power is cheaper — and in less demand — the company would pump the water back up to the reservoir at higher elevation.
When listing public benefits in the application, Grid Balance said the project would help meet peak energy needs, store excess energy, “especially from intermittent renewable sources such as wind and solar,” help meet the PJM Interconnection’s goals for more storage and renewable energy, create jobs for builders and operators and help the local tax base.
In 2017, Pennsylvania got 4.5 percent of its energy from renewable sources, including solar and wind, but the state set a goal of deriving 18 percent of its electricity from renewables by 2021.
Murkowski said two projects in Alaska will be using batteries and flywheels to supplement wind power.
The flywheels in Humboldt, meanwhile, can store up to 20 MW, and are expected to last 30 to 50 years with proper maintenance, according to Convergent Energy and Power, which purchased the plant last year.
When demand for electricity is low, flywheels spin faster to absorb electricity.
As demand increases, the wheels slow and turn a generator to create electricity.
The system wastes little. The wheels are virtually frictionless because they spin in vacuum tubes, but they’re not cheap.
Beacon Power went into bankruptcy but still completed the Humboldt plant, which cost $53 million.
Contact the writer: kjackson@standardspeaker.com; 570-501-3587