Carbon Capture Could Cut Solar Power Waste and Battery Needs Across ASEAN

The Association of Southeast Asian Nations, or ASEAN, faces rising electricity demand alongside commitments to cut emissions, with the study projecting that the region’s electricity needs will roughly triple by 2050.

Solar panels can produce plenty of electricity at lunchtime, with little to offer after sunset, leaving countries with a difficult question about how to keep homes, factories, and businesses running without adding more carbon pollution. A study published in Scientific Reports, titled "Balancing renewables and carbon capture in emerging economies: a decarbonization pathway for ASEAN," explores how carbon capture could help meet that challenge.

Researchers from the Technical University of Munich and TUMCREATE modelled a future in which solar power works alongside fossil fuel plants fitted with equipment that captures much of their carbon dioxide before it reaches the atmosphere. The findings suggest this combination could sharply reduce wasted renewable electricity, shrink battery requirements, and make use of existing power stations during Southeast Asia's energy transition.

A growing appetite for electricity

The Association of Southeast Asian Nations, or ASEAN, faces rising electricity demand alongside commitments to cut emissions, with the study projecting that the region's electricity needs will roughly triple by 2050. Coal and natural gas supplied more than 70% of ASEAN's electricity in 2022, and renewable sources contributed 25.4%. Many fossil fuel plants have substantial operating lives remaining, making early closure a difficult financial decision.

The region has considerable renewable resources: the researchers estimated more than 25 terawatts of potential solar capacity and 622 gigawatts of wind capacity, alongside opportunities for hydropower, geothermal energy, and biomass. Turning those resources into reliable electricity requires planning for the hours when renewable output falls short.

Using an energy planning model called urbs, the team compared two pathways built from 2022 data. One allowed renewable expansion without carbon capture; the other permitted new plants with capture equipment and upgrades to existing coal and gas plants from 2030.

The model searched for the lowest-cost electricity system that could meet demand and progressively tighter emissions limits, examining hourly operation across six model years between 2025 and 2050. It included batteries and cross-border electricity connections, carrying investment decisions forward between model years.

Both pathways followed a regional target reaching a 90% reduction in direct power-sector carbon dioxide emissions by 2050. The target applied across ASEAN collectively, allowing individual countries to follow different paths and leaving some emissions in the system.

What happens when the sun goes down

In the model, solar panels supplied abundant daytime electricity, and plants with carbon capture increased their output as sunlight faded or weather reduced solar production. Having that dependable supply reduced the need to build very large amounts of solar capacity and batteries to cover gaps.

Building extra solar panels can create a glut of electricity during sunny hours, forcing operators to limit production that cannot be used or stored, a practice known as curtailment. Across ASEAN, annual curtailed electricity in 2050 fell from 433 terawatt-hours in the pathway without capture to 61 terawatt-hours with capture, a reduction of about 86%.

Vietnam's curtailed electricity dropped from approximately 240 to 25 terawatt-hours, Indonesia's from 86.5 to 12, and the Philippines' from almost 42 to roughly eight. These results reflect less surplus generating capacity and a better match between electricity production and demand.

Battery storage requirements fell sharply: the model needed more than 90% less battery energy capacity in Vietnam and around 70–75% less in Indonesia and the Philippines.

Solar remained a major part of both futures, with installed capacity reaching 1,944 gigawatts without capture and 723 gigawatts with it. The capture pathway needed fewer panels to meet the same emissions target because dependable generation reduced the need to compensate for gaps in solar output through extensive overbuilding.

Giving existing power plants a different job

Adding carbon capture equipment to an operating plant, known as retrofitting, offered a way to cut emissions without replacing the entire facility. The model treated these upgrades as cheaper investments than constructing new plants with capture equipment.

More than 90% of existing gas plants were retrofitted in most countries in the model, with substantial changes across Indonesia, Malaysia, Thailand, Vietnam, and Singapore. New gas plants with capture equipment helped meet growing electricity demand. By 2050, new and retrofitted gas plants with capture supplied roughly 38% of electricity in the capture pathway, and solar supplied 29%. Wind, hydropower, biomass, and geothermal energy remained part of the mix.

Countries with limited renewable resources depended heavily on electricity imports in the pathway without capture. Upgrading their gas fleets increased domestic generation, giving them another option for meeting demand alongside regional electricity trade. These benefits depend on investment costs and the practical suitability of individual power stations, since existing sites may lack the conditions needed for a capture retrofit.

The carbon still needs somewhere to go

The paper cites an estimated regional geological storage potential of about 170 billion tonnes, with promising formations in Indonesia, Malaysia, and Vietnam. Only part of that potential is expected to be technically and economically usable, and several countries need better information about their storage resources.

Delivering the modelled pathway would require geological surveys, detailed storage assessments, transport routes across borders, clear approval rules, and investment support. The researchers call for coordinated regional policies, retrofit guidance, and reliable incentives.

Carbon capture does not remove every emission: the model assumed a 90% capture rate and carbon dioxide transport and storage costs of US$10 per tonne. Changes in those assumptions, fuel prices, plant efficiency, or technology costs could change which electricity mix is cheapest; falling renewable costs could reduce the appeal of capture.

The study covered direct emissions from electricity generation and excluded nuclear power, direct air capture, and bioenergy with carbon capture and storage. Battery storage was the only storage technology modelled because suitable regional data for pumped hydropower were limited.

Demand forecasts and national policies can change, and the authors recommend further testing of uncertain costs and technical assumptions. Their results describe a possible route for expanding renewables with dependable backup, whose value will depend on affordable capture equipment, accessible carbon storage, and projects that work beyond a computer model.