How giant batteries can help S'pore store excess solar energy

As Singapore seeks to harness as much sunshine as it can to maximise its limited renewable energy sources, it needs to improve technologies that can store excess solar energy from the day.

- Shabana Begum

One such technology is energy storage systems (ESS), which are essentially giant batteries packed in containers that store electricity for later use.

The Energy Market Authority (EMA) has awarded grants of $7.8 million to two companies to advance ESS technology from installing ESS underground to free up land, to exploring a different type of battery.

The Straits Times unpacks how ESS work, and why emerging technologies are crucial.

WHAT ARE ENERGY STORAGE SYSTEMS?

Commonly run on lithium ions, ESS store energy during sunny days when solar panels generate more electricity than consumed.

At night or when electricity demand peaks, ESS will discharge electricity for use.

The systems can also serve as a form of backup during power supply disruptions.

The International Energy Agency has projected that global battery storage capacity is expected to almost triple by 2030.

Dr Wesley Zheng, chief executive of Posh Electric, one of the two firms awarded grants, said that ESS are costly due to high upfront capital costs, including raw materials, technological complexity and requirements to integrate with the power grid.

A one megawatt hour (MWh) could cost between system $450,000 and $800,000, with a payback period of seven to 10 years, he added.

DOES SINGAPORE HAVE ESS?

Yes, there are ESS of various scales deployed here. The largest is on Jurong Island, with more than 800 large-scale battery units across 2ha of land installed by Sembcorp Industries in 2023.