Solar Power Forecasting for Energy Markets

Solcast day-ahead irradiance and power forecasts are now improved by 15% to 35%

17 October 2019

The impacts of solar forecasting on energy markets

When it comes to energy markets, Solcast has a wealth of experience in delivering solar power forecasts for utility scale and behind the meter solar applications. We've become intimately familiar with how behind the meter solar can drastically impact demand forecasts, particularly in South Australia (>50% Rooftop Solar Penetrations). We've deployed operational solar forecasting systems for energy market participants who are operating utility scale solar farm sites. We've even built the world's first sky-imager with with satellite imagery and solar farm power output data integration.

Here are three examples of how solar forecasting and energy markets are linked.

Solar ramping events for behind the meter solar


In the above image, we can see the impact of convective cloud cover on the 1GW+ of rooftop solar installed in New South Wales, Australia. The sudden development of these thunderstorms covers the coastal region where most Aussies live (and where there is the most rooftop solar). In this example, nearly 450MW of rooftop solar disappears off the energy market, leading to an observable jump in demand, which brings us to our next example

Rooftop Solar PV Impacts on Demand Forecasts

In the below image, we have a prime example of how an event like the first one (fast moving, fast changing cloud cover) can impact not only the overall rooftop solar PV output in a given geographic region, but also the actual demand on the energy market. The bottom left graph compares the forecast demand (every energy market operator makes these every day!) versus the observed demand - and a large error is apparent.

At bottom right, you can see an in-house solar forecasting system based on numerical weather model data (updating once per day), compared with a 2-hour ahead, rapid-updating (every ten minutes) forecast from Solcast. It is quite important to forecast these events quite accurately once solar penetrations rise above ~1-2% in an energy market. This is our specialty!


Self-forecasting for Energy Market Participants

Solcast also has plenty of experience producing solar forecasts for individual utility scale solar farms for their participation in the local energy market. With better overall forecasts in the energy market, the whole market operates more efficiently (and at lower cost). We have a 'Super Rapid Update' forecasting system for this purpose which helps to dispatch solar farms into their energy market by producing 5-minute ahead, highly precise forecasts with real-time SCADA data and sky-imagers deployed on onsite!


Read more on that here!

To learn more about solar power forecasting for energy markets...

To learn more, you can listen to our CTO describe some of the above slides in the YouTube video below!

Why are solar power forecasting technologies important for energy markets?

Here are three reasons why solar power forecasting technologies are 'must haves' for modern energy market operations:

  1. As soon as the total installed solar in an energy market reaches 1-2% of peak demand (approximately), solar forecasts are needed
  2. Without incorporating a prediction of, load (demand) forecasts for a given time of day will experience errors (core business impacted!)
  3. Errors create inefficiencies in the market operations, and can require reserves to be activated (exact mechanisms of this will vary by energy market)
Dr. Nick Engerer

Dr. Nick Engerer

Solcast CTO • Author

Nick is an expert in the field of solar radiation and distributed solar PV modelling, and has co-founded Solcast out of a sincere desire to enable others to build the solar-powered future.

Read more about Dr. Engerer's scientific papers

Solar Power Forecasting