New Pricing Math Could Cut the Hidden Cost of Storing Clean Energy

Big batteries are now a major player on the electric grid, and they get paid through a constant auction: power plants and batteries offer electricity, utilities bid to buy it. Batteries are tricky, because using stored power now means you can't sell it later. Standard pricing — paying the going rate at each location, known as locational marginal pricing — doesn't fully capture that trade-off. So grid operators hand battery owners extra 'true-up' payments, called bid cost recovery. Those payments ultimately show up on your monthly bill.

The researchers, in a paper accepted to the IEEE Conference on Decision and Control, showed these extra payments are basically unavoidable whenever a seller's asking price is higher than a buyer's bid. More usefully, they pinpointed a single signal that flags exactly when the top-ups will appear: whether the battery is hitting its storage limits. Then they designed a pricing rule, nicknamed UP-BCR, that minimizes the extra payments instead of ignoring them.

In computer simulations that included uncertainty about how much wind and solar power would show up, their method cut both the extra top-up payments and the total amount customers paid, compared with today's standard approach. It also kept the market's books clean, with no hidden surplus piling up anywhere. That matters, because a pricing fix that quietly creates profits somewhere else isn't really a fix.

The catch is the test setup. The simulation used a 'copper-plate' model — imagine the grid as one perfect wire with no bottlenecks between regions. Real grids have congested lines and messier rules, so the savings would likely be smaller in practice. It's also a math paper, not a pilot project on a working grid. Still, it points at a real cost that grows as more batteries come online.