In early February, a polar vortex hit the east coast resulting in record low temperatures in many communities across Atlantic Canada. The cold weather created a challenge for utilities to maintain reliability with the increase in electricity demand, known as Peak Demand. Residents rose to the challenge to help out. 

What is peak demand? 

The demand for electricity varies throughout the day as well as by season, which creates peaks and valleys for power generation. During the morning, demand increases as homeowners wake up, heat their breakfast and take a hot shower. During the day, demand evens out but rises again in the evening as we make supper and operate dishwashers other household appliances, for example (see NB Power’s 2-Peak Challenge). Electricity demand is also much higher in the winter in order to heat homes and businesses than in the summer, roughly twice as high in New Brunswick. 

Utilities reach peak demand typically in the mornings of the coldest days, as was the case in early February. 

“Today we also supplied more than ever – the majority from renewable electricity in Churchill Falls, Muskrat Falls, Bay d’Espoir, and Exploits, and 450MW across the LIL.”

– Newfoundland and Labrador Hydro

How do utilities meet peak demand? 

Depending on the province, demand peaks create three challenges: maintaining reliability, increased emissions and higher costs.  

Utilities work hard to maintain reliable electricity supply and typically balance load by relying on expensive fossil fuel-fired electricity generation. These ‘peaker’ facilities are often not relied on during much of the year when demand can be met using clean energy sources such as wind, hydro or nuclear generation, among other sources.   


For example, a spokesperson from Saint John Energy noted in 2021 that “during the peak, we tend to see almost double the CO2 emissions due to the fact that we have to use fossil fuels to be able to produce enough energy for the peak.” 

How do customers help lower demand peaks? 

Fortunately, residents can help utilities reduce demand peaks to help lower costs and emissions with behavioural changes. Temporarily lowering the temperature of your electric home heating and wearing warmer clothes is an important step. Delaying the time you shower, dry clothes or wash dishes can also help. Other easy steps include unplugging unnecessary appliances or lights or charging your vehicle in the middle of the day (if you have an EV or hybrid). 

NL Hydro - energy efficiency tips

Source: @NLHydro

How the polar vortex impacted utilities 

Utilities across Atlantic Canada asked customers to take action to help lower demand peaks in early February. These actions resulted in direct savings, fewer emissions and helped maintain reliability. 

  • Saint John Energy:  

Thanks everyone who joined us to #shavethepeak Saturday morning. We hit our peak at 9:54am Saturday at 253MW – our highest in 10 years. SJE’s actions combined with your help lowering your energy use meant we were able to shave over 14,000kw – an estimated savings of $215K. It was a cold morning, and our demand charge will still hit a record high for February, BUT thanks to our community we made a difference, and we could not be prouder of the help our customers always provide in #shavethepeak events.”  

  • Maritime Electric: 

Prince Edward Island reached record electrical demand (load), which peaked at 393MW.  

The Utility relied on diesel-fired generators to manage the peak, which are located in Charlottetown and Borden. These generators added 90MW of capacity.

The system held up well. It performed like it was designed to do.” – Jason Roberts, CEO, Maritime Electric

  • NB Power:  

“NB Power hit an all-time system peak at over 3,400 MW early this morning. We rely on all our system assets and our diverse fleet to meet a peak like this. Cold days like this make us more aware of the importance of balancing our fleet with the right mix of generation, now and into the future. Today has been interesting – the wind was too strong this morning to play a part in meeting our load. The right mix of assets in the future is very important to meet the energy needs of our customers.” 

  • Nova Scotia Power:  

During the cold weather, Nova Scotia Power had very strong performance from thermal units, hydro, transmission interconnections, and renewables. These sources were all required to serve this level of demand. 

We’ve been experiencing extremely cold temperatures & high winds across NS today which has caused outages. We understand how challenging this is on such a cold day.” 

Over 300 staff were in the field working to safely restore power for those that lost it during the storm. 

  • NL Hydro: 

The Island peak today was ~1730 MW. The previous record in 2019 was ~1720 MW.  A big thank you to our skilled & committed teams who have been working behind the scenes ensuring reliable delivery of electricity on this record cold day.