The Tamil Nadu Green Energy Corporation Limited has invited bids to set up 20 megawatt (MW) of grid-connected rooftop solar projects on government office buildings in Chennai, Tiruvallur, Kancheepuram and Chengalpattu under the renewable energy service company (RESCO) model. The deadline for submitting the bids is April seven. The move is aimed at expanding renewable energy capacity on public assets and lowering electricity expenditure for state departments. This is not the first tender, as the corporation had floated bids in November last year for a combined capacity of 15 MW but received no offers. The selected developers will be responsible for site survey, design, supply, installation, testing, commissioning and operation and maintenance of the rooftop systems and will be required to maintain a minimum annual Capacity Utilisation Factor (CUF) of 17 per cent. Teams have inspected hundreds of government office buildings in the four districts and prepared feasibility reports for panel installation. Officials noted that several government departments have pending electricity dues and that the power distribution utility must collect tens of million (mn) Rs from them, which is seen as an additional rationale for on site generation. Authorities expect that rooftop generation will reduce long term electricity expenses for public offices and promote wider uptake of renewable energy across administrative buildings. Practical challenges were cited as a reason for limited bidder interest in earlier exercises. Sources explained that the projects will involve installations in hundreds of smaller units with capacities ranging from 10 kilowatt (kW) to 100 kilowatt (kW), and that managing a dispersed portfolio of systems for up to 25 years could be complex for developers. The dispersed nature of the assets and the operational demands of long term maintenance have reduced commercial attractiveness for some firms. The corporation has set technical and commercial conditions in the tender to try to address these concerns and attract viable bids.