Over 80% of Singapore's resident population lives in Housing and Development Board (HDB) flats. With more than 10,000 blocks spread across the island, HDB rooftops represent one of the largest contiguous surfaces available for solar panel deployment in a land-scarce country.
The SolarNova Programme Structure
SolarNova was launched in 2014 as a collaboration between the Economic Development Board (EDB) and HDB. Its function is to aggregate solar deployment demand from government agencies, enabling bulk procurement that drives down per-unit costs and supports the growth of Singapore's domestic solar industry.
The programme operates on a leasing model. Private solar companies bid for contracts to design, finance, install, and maintain rooftop PV systems on HDB blocks. Town Councils, which manage day-to-day operations of HDB estates, purchase electricity generated by the panels at rates not exceeding retail tariffs. This structure eliminates upfront capital expenditure for the public sector while ensuring long-term maintenance accountability from the private operator.
Deployment Scale as of 2026
By the third quarter of 2026, solar panels will have been installed on approximately 9,500 HDB blocks, following the latest tender covering an additional 1,075 blocks. HDB has stated its objective of installing panels on as many of its 10,000+ blocks as technically feasible.
The combined SolarNova programme targets 540 MWp of installed capacity by 2030, with annual clean energy generation projected at approximately 648 GWh. This represents a material contribution to Singapore's revised national target of 3 GWp by the same date.
How Rooftop Solar Powers Common Areas
Solar electricity generated on HDB rooftops is first used to power common area loads within the block. This includes lifts, corridor lighting, water pumps, and centralised cooling systems where installed. During daylight hours, solar generation typically exceeds common area demand, with the surplus exported to the national electrical grid.
According to HDB data, blocks with installed solar panels achieve net-zero energy consumption for common areas on average. This means the total solar energy generated over a year equals or exceeds the electricity consumed by shared facilities. The practical effect for residents is moderated Town Council operating costs, as common area electricity bills are partially or fully offset by solar credits.
Technical Characteristics of HDB Rooftop Installations
HDB blocks present specific constraints for solar deployment:
Roof Area and Orientation
Standard HDB blocks have flat roofs ranging from 200 to 500 square metres of usable area, depending on block type and the presence of rooftop structures (water tanks, lift motor rooms, antenna masts). Panels are mounted on fixed-tilt racking systems, typically at 5-10 degrees from horizontal, optimised for Singapore's 1.3 degrees North latitude where near-flat mounting maximises annual yield.
Module Selection
Most SolarNova installations use polycrystalline or monocrystalline silicon modules rated between 350-550 Wp per panel. Recent tenders have shifted toward higher-efficiency monocrystalline PERC (Passivated Emitter and Rear Cell) modules, which deliver better performance per square metre in high-temperature conditions.
Structural Loading
HDB roofs are designed to support live loads including maintenance access and equipment. Solar installations add approximately 15-20 kg/m2, which falls within the structural capacity of standard HDB roof designs. Pre-installation structural assessments are conducted for each block.
Maintenance and Cleaning
Tropical conditions bring high dust deposition from construction activity, pollen, and organic debris. Soiling losses in Singapore are estimated at 2-5% of annual output without cleaning. SolarNova contracts require operators to maintain panels and perform periodic cleaning, with performance guarantees that incentivise regular maintenance.
The Role of HDB Solar in the National Energy Mix
Singapore's electricity generation is overwhelmingly dependent on imported natural gas, which accounts for approximately 95% of supply. Solar PV represented about 4% of installed generation capacity by early 2026, with rooftop installations contributing the largest single share.
The Energy Market Authority classifies distributed solar (rooftop systems below 1 MWp) separately from centralised generation. HDB rooftop systems fall into this distributed category, where generation is consumed locally or exported through the low-voltage distribution network. This reduces transmission losses compared to centralised power plants and defers investment in high-voltage grid expansion.
HDB blocks in Singapore. Rooftop space across 10,000+ buildings represents a significant solar asset. Image: Wikimedia Commons / CC
Remaining Challenges
Not all HDB blocks are suitable for solar installation. Factors that exclude blocks include excessive rooftop shading from adjacent taller buildings, insufficient structural capacity in older designs, and ongoing roof maintenance requirements. HDB estimates that approximately 10-15% of blocks may not be viable for solar deployment.
Ageing of installed systems is another consideration. The oldest SolarNova installations are now approaching 10 years of operation, which is the point at which tropical degradation studies suggest measurable performance decline may accelerate. Long-term performance data from these early installations will be critical for planning replacement cycles and contract renewals.