TOU program catches on with fish farmers

While utilities across the country are considering ways to encourage peak reduction, use of advanced metering for demand response is gaining acceptance in some unexpected places.

In one case, a rural electric cooperative in Mississippi is implementing technology that will make current and future energy management more efficient. Natchez Trace Electric Power Association (NTEPA) is experimenting with its advanced metering system to administer a time-of-use (TOU) program for catfish farmers.

Mississippi leads the nation in the production of freshwater catfish, making it an important part of the state’s business sector. NTEPA serves about 16,000 members, including some aquaculture operations, in parts of seven counties in the northern part of the state.

James Pettit, superintendent of substations and metering at NTEPA, said the utility’s experience so far has been positive and adds value to the advanced metering system it began deploying in 2005. That system, the TS2 power line carrier-based system from Landis+Gyr, provides continuous two-way communication with each meter.

In the past, NTEPA had used TOU meters for aquaculture accounts that wanted an off peak rate. “Then one of the meters went bad and we lost all of its memory,” Pettit said. “That’s when we started implementing the TOU capabilities of our TS2 system.”

Unlike a traditional TOU meter, the TS2 system provides remote programming of TOU periods or data “buckets” from the utility office, allowing rate periods to be changed daily if desired. The TS2 module and data collector at the substation both provide redundant data storage, protecting billing data and minimizing the effects of power or transmission failure. Best of all, NTEPA was able to retrofit single phase meters with TS2 modules, providing a significant cost savings.

According to Pettit, the request for a TOU pricing program initially came from customers. Unlike other load control programs, TOU relies on customers controlling demand during peak periods and provides more flexibility.

In the case of aquaculture, the demand reduction focus isn’t on any one specific piece of equipment – such as aerators or grain feeders – but on the power used at the entire site during the peak period.

NTEPA purchases power from the Tennessee Valley Authority, and follows the TVA’s time-of-use rate schedule. The rate differential is about 3 or 4 cents a kilowatt hour between TOU off peak and regular commercial rates. Peak periods are also set by TVA. Typically, the peak period runs 12 hours per day, with a summer peak from 10 a.m. to 10 p.m. and a winter peak divided between 6 a.m. to 12 p.m. and 4 p.m. to 10 p.m.

The key to a successful TOU program, according to Pettit, is the mutual benefit of all parties. Not only do co-op members benefit by lower rates, the utility’s purchased power costs decrease as well.

“Our advanced metering system is proving to be a very efficient way to manage time-based rates,” Pettit said. “We believe we can stay out front of whatever TOU requirements come our way in the future.”