FORECASTING: FROM MINUTES TO MONTHS INTO THE FUTURE

The implementation of renewable energy technologies is accelerating in many regions around the world. As the penetration levels of renewable energy increases, the intermittent characteristics of weather-driven technologies becomes one of the greatest challenges to acceptance by power utilities and system operators.

Renewable energy forecasting increases reliability and maximizes efficiency by minimizing unnecessary operation of conventional plants and by optimizing storage. Improved operation of these projects, facilitated by accurate forecasting, ultimately leads to greater acceptance renewable energy technologies. Good-quality forecasts turn renewable technologies into viable energy alternatives.

Why Forecast

Forecasting is a crucial component of the operation of renewable energy systems, especially for utility-scale or large-scale systems. During real-time operations, power system operators need to have an idea of how much power the renewable energy sources will produce in the future (minutes or hours). The reasons are, first, to determine the amount of power to be produced from conventional power plants in order to meet the expected load (electricity demand), and, second, to estimate the needed reserve capacity from conventional generators to balance the intermittent output of the renewable sources, following reliability and frequency control requirements.

A forecast is also required to support economic decisions during the commercial operation of the renewable energy sources. For instance, in hydroelectric plants, knowing future inflows determines the best reservoir management decisions according to the market expectations. Storing water now may translate into a considerable income in the future.

Forecast Horizons

According to the timeframe and extent of the forecast, different methods are used.

Although the accuracy of the longer-term models is lower in comparison with the short-range models, the possibility of estimating weather-driven resource conditions months or years in the future can provide crucial value at the renewable energy project’s technical, economic and financial planning stage.