“I didn’t have any concerns for myself,” Helton said. “It didn’t even cross my mind that I, as a fixed rate customer with a big company, would get hit with any sort of ‘pass through charge.’ It was quite a shock to my system when I got the email.” In a Feb. 22 email, MidAmerican warned its 5,800 residential customers in Texas that the company expects “significant increases in ancillary charges,” also known as pass through charges, due to the disastrous effects of the storm. The provider has more than 1.6 million customers in states like Nebraska, Illinois and South Dakota. Between Feb. 13 and Feb. 21, MidAmerican’s ancillary service fee — the price of which is overseen by the Electric Reliability Council of Texas — was 100 times larger than an average monthly fee, said company spokesman TJ Page.