Malaysian solar power forecasting requirements

22 April 2020

Malaysian keywords: In this post you’ll learn about:

  • ramalan solar
  • ramalan kuasa solar
  • ramalan kuasa PV
  • radiasi matahari
  • sinar matahar
  • ramalan irama solar

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You can find our latest solar radiation maps for Malaysia here.

Solar energy in Malaysia

Solar power capacity has been growing exponentially in Malaysia, and will reach 1GW of total capacity by the end of 2020. One of the fastest growing segments in solar capacity has been rooftop solar. Malaysia added “just 10 kW of rooftop solar in 2016, 2.33 MW in 2017 and 11.53 MW in 2018” before adding nearly 100MW in 2019. Source - PV Magazine

solar capacity Malaysia.png

Installed solar capacity is growing exponentially in Malaysia. Source: Statistica

Impacts of Solar on the Malaysian Power System

As a result, portions of the Malaysian power system has now integrated many tens of thousands of rooftop solar PV systems and a growing number of utility scale solar farm sites

TNB Chairman Tan Sri Leo Moggie recently said in an interview on the topic: ““Yes we enjoy a considerable amount of hot and sunny weather in Malaysia but we also have very low cloud cover. The other challenge is of course electricity generated must be used immediately. The technology to store the energy, which is produced from solar for example, is still not available”. Source

Challenges for Malaysia included is disparate, disconnected power system, potential grid congestion, frequency oscillation.

Malaysian Grid Code and Solar Power Forecasting

Malaysia’s grid operations have already provided clarity on how these challenges can be overcome - and solar power forecasting is a critical resource.

According to the Malaysia Grid Code, section VII - Scheduling and Dispatch

Malaysia follows a “Least Cost Generation Schedule” which controls which Generating Units may be dispatched in order to maintain control of system frequency control and interconnector power transfers. Source

This “generation schedule” requires matching of generation output with forecast demand across several time horizons, and must include reserve of generation to provide a safety margin. It is therefore very important that solar farm operators provide highly accurate solar forecasts through to TNB. Failure to do so will result in penalties being applied, according to the individual terms of your PPA.

gridcode_3.png Image Credit: TNB

Solar Radiation Resource in Malaysia

The available solar resource in Malaysia is excellent. Annual global horizontal irradiance (GHI) solar irradiation can exceed 1500 kWh per square metre in southern Malaysia while climbing to over 1900 kWh per square meter in the northern regions. Clouds are the dominant driver of solar production variability, and is mostly driven by convective clouds (i.e. thunderstorms).


Solar forecasting methods best suited for Malaysia

For solar asset owners and operators, there are two common approaches to establishing solar power forecasting.

The first is to subscribe to a solar power forecasting service completely made by a vendor. This approach works well provided that plant specifications are well described, and the power curves can be optimised via machine learning approaches (e.g. “Tuning” as carried out by Solcast).

The second approach is to subscribe to a solar radiation and weather forecasting service, and use internal capabilities to build the conversions from radiation to power. This approach can be successful, but requires strong internal capabilities, since the conversions from radiation to power are highly non-linear and the plant and weather condition impacts are numerous.

When considering the choice of solar forecasting technology, there are four solar forecasting horizons of importance for Malaysian solar farm operators, which are required by TNB, these are:

  • rolling 4 month ahead
  • 9-day ahead
  • day ahead
  • 1-hour ahead


Solcast allows you to create your own solar power forecast

Solcast allows asset owners or operators to add their own solar plants to our forecasting system using their web browser in our API Toolkit. This allows for users to instantly start using and evaluating forecasts. The process takes only a few minutes and requires no credit card.

Forecasts can be downloaded to CSV for analysis, and recent forecast accuracy over the site can be displayed on a graph. When the forecast goes into operations, a credit card is required for monthly subscription fees, and the Solcast API makes integration and submission of forecasts easy to automate.


The above is an example of a Malaysian utility scale solar farm setup for forecasting in the Solcast API Toolkit.

Solcast can also provide live and forecast solar irradiance and weather data as input to your own power forecasting methods Solcast also provides direct access to the forecasting data via API. Users can learn how to access these data using the API Toolkit, where they can download sample data and begin evaluating forecasts. Forecasts can be downloaded to CSV, JSON or XML for analysis.

Learn More:

Dr. Nick Engerer

Dr. Nick Engerer

Solcast Co-founder • 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