ACEEE flags up emerging US trend – peak-time demand is starting later


The utility of the future may face a change in peak-time demand due to changing behaviours of consumers, said Steven Nadel, executive director of the American Council for an Energy Efficient Economy. 

In a blog posting released this week, Mr Nadel said a reduction of the traditional mid-afternoon peak and growth of an evening peak could have a large impact on many US utilities.

Change in customer habitsPeak-time demand changing home vehicle charging station

Nadel mentions that in many regions evening peaks are growing.

He attributes the change to more consumers using air conditioning in the evenings when they get home from work but two other factors are helping this trend.

Nadel said: “First and foremost is the growth in consumer-owned photovoltaic systems.

“These systems generate the most power on sunny afternoons, which is about when the traditional early afternoon peak occurs. But when the sun goes down, extra power is quickly needed to replace this solar power.

“Recent and projected data from Hawaii (where photovoltaic ownership is much higher than any other state) shows these effects. Even in 2012 photovoltaic systems likely depressed the afternoon peak in Hawaii.”

The other factor, which Nadel describes as less significant, is that with the increasing ownership of electric vehicles, consumers may routinely recharge their vehicles when they get home from work.

How to minimize impact of evening peak

Nadel lists the following ways to help utilities tackle the growing evening peak:

  • Energy efficiency household equipment such as lamps, water heaters, stoves and ovens.
  • Smart controllers on smart appliances that minimize energy use during the evening peak. For example, a smart refrigerator that is programmed to not turn on high-energy defrost cycle during this period.
  • Demand-response programs to lower the new peak.
  • Time-of-use tariffs that raise the price of power use during peak times.
  • Energy storage at a system, community, or end-user level.
  • Fast ramp-up generation to serve the evening peak and other times when renewable energy production plummets, for example when the wind dies down. Hydro is ideal, but fast ramp-up gas units are now entering the market.

The executive director of ACEEE concludes that the shift of the peak-time demand will be gradual in most areas, so “we have time to address it”.

“Rather than trying to stop this change by restricting photovoltaic systems,” said Nadel, ” we’ll be better off figuring out how to manage it, taking advantage of the time we have.”

(Pic credit: Chevrolet)