That is what (diesel powered) locomotives do to get rid of electrical power created by using the wheel motors for braking.

New designs store the power in batteries, but most locomotives used in the US still have a compartment filled with fans and resistors instead.

Yes of course. My idea was a way for existing facilities to also function in this capacity so you didn't wind up with facilities reliant only on negative prices. I think that's important because those prices are a bandaid on the real problem that would be solved by sufficient power storage.

You can build this at a small scale pretty cheaply but the connection to sink meaningful amounts of power would quickly become a significant part of the expense.