Renewable energy is becoming more important than ever in today's society. As electricity markets are deregulated, non-utility companies are building large solar farms. Solar power is a renewable energy that is relatively straightforward to implement. However, forecasting the amount of electricity generated by the sun poses a challenge due to the weather-dependent nature of the sun's radiation. As the return on investment in solar is more critically assessed, one company is offering a service to forecast solar power generation. Japan Weather Association (JWA) uses historical and real-time weather data to provide solar radiation forecasts. Here is what we learned from our interview with the company.
It used to take time to produce a solar radiation forecast after the latest weather data was loaded into the model. The model mesh element size was often between 5 to 20 km. The mesh size defines the grid resolution of the prediction model calculation. It had been difficult to accurately know solar radiation levels of areas smaller than 5 to 20 km using weather prediction models. To solve these problems, JWC developed a new solar forecasting method based on high-freqency, high-resolution observaton data of weather satellites, and the service is now available.
In response to growing attention to solar energy, JWA also enhanced their solar forecasting during sunrise, for two reasons. One, major electric utilities adjust the proportions of energy provided by solar, thermal and hydro. For this, they need to know precise amount of solar radiation, which is closely tied to solar energy. Two, it is desirable to determine what the peak demands would be. This requires accurate forecasting of solar radiation. The early morning forecasts were made possible by using infrared images that can be taken at night, rather than the conventional visible light images from weather satellites. As solar power becomes more widely deployed and self-generation gains momentum, the number of companies using JWC's service has increased sharply since its launch.
Concepts of energy management are more widely understood today. Examples include virtual power plants (VPP) that manage multiple power systems and facilities as a single system; or ZEH where electricity is generated on site by solar, while minimizing energy consumption to create a net surplus of energy. These are more popularly adopted among businesses, communities and individual households today. In addition, studies have begun to utilize the finer mesh satellite imagery to predict solar power generation for low output solar panels installed in homes.
We are entering an era in which electricity is generated at the site of consumption rather than being purchased. JWC believes their solar forecasting service will become more widely utilized to fulfill the need for accurate power generation forecasting.
Solar radiation forecasting services using weather satellite imagery will increasingly provide an important foundation for energy management for the new era.