The $3 Billion Plan to Turn Hoover Dam Into a Giant Battery

.. Now it is the focus of a distinctly 21st-century challenge: turning the dam into a vast reservoir of excess electricity, fed by the solar farms and wind turbines that represent the power sources of the future.

.. wants to equip it with a $3 billion pipeline and a pump station powered by solar and wind energy. The pump station, downstream, would help regulate the water flow through the dam’s generators, sending water back to the top to help manage electricity at times of peak demand.

The net result would be a kind of energy storage — performing much the same function as the giant lithium-ion batteries being developed to absorb and release power.

.. The Hoover Dam project may help answer a looming question for the energy industry: how to come up with affordable and efficient power storage
.. when solar and wind farms produce more electricity than consumers need, California utilities have had to find ways to get rid of it — including giving it away to other states — or risk overloading the electric grid and causing blackouts.
.. The target for completion is 2028, and some say the effort could inspire similar innovations at other dams.
.. Using Hoover Dam to help manage the electricity grid has been mentioned informally over the last 15 years. But no one pursued the idea seriously until about a year ago, as California began grappling with the need to better manage its soaring alternative-electricity production — part of weaning itself from coal-fired and nuclear power plants.
.. estimated that utility-scale lithium-ion batteries cost 26 cents a kilowatt-hour, compared with 15 cents for a pumped-storage hydroelectric project. The typical household pays about 12.5 cents a kilowatt-hour for electricity.
.. engineers propose building a pump station about 20 miles downstream from the main reservoir, Lake Mead
.. “Hoover Dam is ideal for this,” said Kelly Sanders, an assistant professor of civil and environmental engineering at the University of Southern California. “It’s a gigantic plant. We don’t have anything on the horizon as far as batteries of that magnitude.”
.. “With lithium-ion batteries, you have durability issues,” Mr. Narayan said. “If they last five to 10 years, that would be a stretch, especially because we expect to use these facilities at full capacity. It has to be 10 times more durable than it is today.”
.. its proposal would increase the productivity of the dam, which operates at just 20 percent of its potential, to avoid releasing too much water at once and flooding towns downstream.