Revisiting Day-ahead Electricity Price: Simple Model Save Millions
Linian Wang, Jianghong Liu, Huibin Zhang, Leye Wang
TL;DR
This work tackles day-ahead electricity price forecasting, where traditional time-series models underutilize the price formation mechanism driven by supply and demand. It introduces CoPiLinear, a Correlation-based Piecewise Linear model that fits a short-term-stable supply curve and derives prices from the intersection with forecasted demand, aided by forecasted capacity inputs. Across Shanxi and ISO New England datasets, CoPiLinear outperforms state-of-the-art TSF and correlation-based baselines, achieving lower MAE and sMAPE and higher revenue alpha, thereby delivering meaningful welfare gains. The approach demonstrates the value of embedding economic priors and supply–demand correlations into forecasting pipelines, offering a practical path to more accurate price forecasts and potential savings for residents.
Abstract
Accurate day-ahead electricity price forecasting is essential for residential welfare, yet current methods often fall short in forecast accuracy. We observe that commonly used time series models struggle to utilize the prior correlation between price and demand-supply, which, we found, can contribute a lot to a reliable electricity price forecaster. Leveraging this prior, we propose a simple piecewise linear model that significantly enhances forecast accuracy by directly deriving prices from readily forecastable demand-supply values. Experiments in the day-ahead electricity markets of Shanxi province and ISO New England reveal that such forecasts could potentially save residents millions of dollars a year compared to existing methods. Our findings underscore the value of suitably integrating time series modeling with economic prior for enhanced electricity price forecasting accuracy.
