Data from Hawaiian Electric's time-of use-pilot program suggests that there are still some kinks that need to be worked out before the rate structure rolls out to more customers.
Time-of-use rates are meant to incentivize customers to shift their energy consumption to daylight hours. Rates are cheaper during the day when solar energy is abundant, and more expensive during the evening and night.
HECO put a trial group of residential and commercial customers on Oʻahu and Hawaiʻi Island on time-of-use rates at the beginning of 2024.
The first six months of data from Jan-June showed no statistically significant change in customers' energy usage.
Michael Angelo, the head of the Division of Consumer Advocacy said people may not be taking advantage of the cheaper daylight rates because they lack flexibility in when they use energy.
"It's very hard for a business to change its operations significantly to realize those bill savings," he said. "And then on the residential side, we essentially use electricity when we're home because we rely on it for so many of our needs."
The full report on HECO's time-of-use pilot program states that there is "some room for improvement in meeting customer satisfaction and value objectives."
Only 54% of residential customers said that they were satisfied with the program overall. Forty-five percent of customers were dissatisfied with the effort required to save on energy under the time-of-use rate scheme, and 47% were dissatisfied with the actual savings they saw on their energy bills.
Commercial customers were even less satisfied with the program, with just 49% of participants reporting a positive impression of time-of-use rates. A quarter of commercial customers reported that their energy bills went up during the program.
According to HECO, 14% of participants opted out of the program entirely, which can be done at any time.
The report recommends that HECO employ a comprehensive educational campaign to help customers change their energy habits to take advantage of time-of-use rates.
But Angelo cautioned that more awareness of the program might not result in changes if customers' energy choices are limited by their schedules.
"It's hard for customers to really change their usage behavior," he said. "I think we want to think about what we want to accomplish with the program itself."
Angelo suggested that time-of-use rates may be more effective if applied to large industrial customers who use significant amounts of electricity, rather than individual households.
HECO is now collecting data from the second phase of its pilot program. During the first phase of the program, any increases in participants' bills were capped at $10. That bill protection was removed in July.
"This interim report hasn't captured the impacts of taking bill protection out of the picture," Angelo said. "So we'll be looking to see what the next phase looks like after bill protection is removed, and whether customers are more responsive."
