New climate norms for forecasting electricity demand

In Quebec, many homes and businesses are heated and cooled by electricity, and outdoor temperatures are a major factor behind electricity demand. Hydro-Québec’s Distribution division, in collaboration with Ouranos, has carried out an in-depth study of the impact of temperature on electricity demand and implemented ways to incorporate recent temperature changes into the forecast of average and peak demand. It has been determined that demand forecasting can be improved by incorporating temperature trends. In addition, adapting the demand forecast is simple and efficient. Finally, long-term collaboration with climate experts ensures that information is continuously updated and improves the level of confidence in climate model data.

Understanding and Assessing Impacts

Nearly three-quarters of Quebec homes are heated with electricity, and managing peak demand during Canada’s cold winters is a major challenge for Hydro-Québec. It was necessary to show that temperature normals will continue to increase and that climate is no longer static and to link this with demand and sales forecasts. Temperature normals have increased over the past few decades, and observed data from weather stations no longer provide the best statistical basis for demand forecasts. As a result, Hydro-Québec has developed methods to improve demand forecasts by incorporating climate change trends.

Identifying Actions

Studying extreme events, which are rare by definition, is not easy. The process requires sophisticated statistical and mathematical skills. A multiple of the annual temperature increase due to the long-term trend has been added to the annual value of historical temperature data. The age of the data, expressed in years, determines the number of times the multiple is added so that data from colder past years is increased to reflect today’s warmer climate. In 2012, Hydro-Québec requested an update of the climate assessment of its database based on 137 climate simulations.

Implementation

Hydro-Québec now takes into account the increase in extreme events in its peak forecast. Its experts expect the model to improve the accuracy of their winter forecasts, just as the model based on projected warming trends has improved their forecasts for the rest of the year. After 2012, Hydro-Québec overhauled its entire forecasting system and implemented an econometric approach that integrates normal temperatures and reflects their changes over time.

Outcomes and Monitoring Progress

Climate trends are updated regularly to adjust the adapted forecasting approach. The provincial electricity regulator took this information into account and recommended that forecasters from another Quebec utility consult Hydro-Québec to learn more about its forecasting approach.

Next Steps

Hydro-Québec continues to update climate normals to better reflect the impacts of a changing climate on demand forecasting. Climate prediction models are constantly being refined.

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