The power grid is vulnerable to manipulation or sabotage, according to a study revealed this week.

Attackers could manipulate power-grid data by breaking into substations and intercepting communications between substations, grid operators, and electricity suppliers. This data is used by grid operators to set prices for electricity and to balance supply and demand, the researchers say. Grid hackers could make millions of dollars at the expense of electricity consumers by influencing electricity markets. They could also make the grid unstable, causing blackouts.

As utilities move over to open communications standards, as part of the migration to the “smart grid,” it could get even easier to intercept communications or hack into systems remotely.