The spike in electricity prices this week has eased now that a couple of major power plants in Alberta are back online.

Spot prices topped $700 a megawatt over the past two days. In recent weeks, prices have typically been in the range of $35 to $50 a megawatt.

The Alberta Electric System Operator’s Mike Deising said the price spike was a surprise.

“We had three coal plants go out earlier this week, unplanned, as well our transmission line from British Columbia because of those outages and because of some other transmission issues is also out so we saw a little bit of a decrease in the generation capacity and because of that, you see momentary uptick in the pool price.”

Deising says although there was less electricity available earlier this week, at no point was there a lack of supply or any danger of a blackout in Alberta.

He says it's unlikely those few hours of higher prices will have much effect on the regulated rate that most home customers pay.

“You can't look at a hot day in July and say that it's 32 degrees and say, 'The weather in Alberta is always 32 degrees,' because it's not. Every day, every hour, it's going to change. It’s going to move and you need to look at the averages.”

Alberta's electricity watchdog, the Market Surveillance Administrator, is seeking answers on why the power plants were unexpectedly offline.

If it finds evidence of anti-competitive behaviour, a formal investigation could be launched.

With files from the CBC's Scott Dippel