Beyond megawatts: scaling bankable solar and BESS in Asia-Pacific
The shift from clean energy to energy security
Across Asia-Pacific, the energy transition is no longer driven by climate ambitions alone. It is increasingly shaped by energy security, cost stability, and system reliability. Many countries continue to depend heavily on imported fossil fuels, while at the same time facing growing demand for electricity and the need to strengthen grid resilience.
Against this backdrop, falling battery costs and accelerating solar deployment are reshaping how energy systems are designed. As highlighted by Somesh Shah during his presentation at ACEF 2026, solar and battery energy storage systems (BESS) are no longer separate technologies. Together, they form the foundation of a more flexible and reliable power system.
Insights from Somesh Shah, Manager, International Solar Business, presented at ACEF 2026 at ADB headquarters in Manila. The views expressed in this article are those of the author and AFRY (with reference taken from globaly recoginsed public domain such as IEA, IRENA, etc.), and do not represent the views of the Asian Development Bank or ACEF.
Why solar and storage are becoming inseparable
Asia-Pacific has become the largest and fastest-growing renewable energy market globally, with solar capacity expanding at record levels and battery storage scaling rapidly alongside it.
This parallel growth reflects a structural shift. Solar provides low-cost generation at scale, but without storage it cannot fully support modern power systems. BESS enables energy to be shifted in time, stabilizes output and supports grid integration.
As a result, Solar + BESS is increasingly being developed as a combined solution. In many markets, this is no longer optional. Storage is becoming embedded in tender requirements, financing conditions and grid regulations, in many markets across the region. The key question is therefore no longer how much solar can be deployed, but how to ensure that it performs reliably and meets bankability requirements.
When models meet reality
A central message from the presentation is that project assumptions often fail to reflect real-world operating conditions, particularly in tropical Asia.
Standard modelling tools tend to underestimate the combined impact of climate and system constraints. In practice, higher levels of dust and biological soiling require more frequent cleaning. High humidity accelerates degradation in modules, while sustained high temperatures affect inverter performance.
Grid-related constraints further complicate the picture. In rapidly growing markets, curtailment can be significant as infrastructure struggles to keep pace with new generation capacity, yet these impacts are not always fully captured during feasibility stages.
The result is a persistent gap between modelled and actual performance. For investors and lenders, this translates into increased uncertainty around cash flow and debt service capability.
The underestimated impact of operations and maintenance
Operations and maintenance is one of the most important drivers of long-term project performance, yet it is often underestimated in early-stage planning.
In Southeast Asia, climate conditions significantly increase the complexity of O&M. High humidity, heat, and environmental exposure accelerate wear on equipment and amplify even small inefficiencies over time.
Another recurring issue is the use of inappropriate benchmarks. Cost and performance assumptions are still frequently based on data from other regions, leading to unrealistic projections. Over the lifetime of a project, these discrepancies can have a material impact on returns.
In addition, the rapid deployment of hybrid systems is creating a shortage of specialized skills, particularly in BESS operations. Combined with the logistical challenges of remote sites, this can increase downtime and operational costs.
Floating solar + BESS: a new frontier
As land constraints intensify across the region, floating solar is emerging as a viable solution for large-scale deployment. When combined with BESS, it opens up new opportunities but also introduces a new level of complexity.
Floating systems require specialized engineering to handle dynamic water conditions such as wind, waves and fluctuating levels. Materials must withstand continuous exposure to humidity and corrosion, and electrical systems face different operational stresses compared to land-based installations.
Integrating BESS adds further design trade-offs. Placing batteries onshore introduces transmission losses, while locating them on floating platforms raises challenges related to weight, safety, and fire protection.
Maintenance and safety also require new approaches, with water-based logistics and specialized procedures. At the same time, insurers and lenders are still developing frameworks to assess risk, given the limited historical data for floating energy assets.
As emphasized in the presentation, floating solar with storage is not simply an extension of ground-mounted systems; it represents a distinct category of infrastructure.
From ambition to execution
Asia-Pacific has the conditions needed to scale solar + BESS: strong demand, policy support, available capital and significant untapped potential, particularly on water.
The challenge now lies in execution. Bridging the gap between ambition and delivery requires more realistic modelling, stronger technical standards and closer alignment between developers, lenders and operators.
Ultimately, success will be defined not by installed capacity alone, but by the ability to deliver projects that perform reliably over time and meet the expectations of investors, regulators and end-users alike.
FAQ: Solar, BESS and floating solar in Asia-Pacific
- Why is Solar + BESS becoming the standard?
- What are the main risks in tropical solar projects?
- What should developers and lenders know before integrating BESS into a solar project?
- Why is O&M so important?
- What makes floating solar different?
- Why is Asia-Pacific leading this development?
Because solar generation is variable, storage is required to ensure reliability, manage peaks and enable integration into the grid. Increasingly, projects are designed with both technologies from the start.
Higher degradation, increased soiling, temperature-related losses and grid curtailment are all more significant than standard models often assume.
BESS integration involves a distinct set of technical, contractual and operational considerations that go beyond standard solar project requirements. These include performance verification in tropical climates, thermal management design and clear allocation of responsibilities between solar and BESS suppliers. With the right advisory support and due diligence framework in place from an early stage, these can be effectively managed — and doing so is what separates projects that reach financial close smoothly from those that face delays.
O&M has a direct impact on long-term performance and financial returns. In tropical environments, costs and complexity are significantly higher than in other regions.
Floating systems require different engineering, safety and operational approaches, as well as adapted financing frameworks due to limited historical data.
The region combines land constraints, available water bodies, supportive policy frameworks and access to financing, making it well suited for floating solar deployment.
