Weekend read: Singapore solar walks the talk

pv magazine: In recent years, Singapore has introduced both targets and tenders for solar deployments – have these helped to drive PV forward in the country?

Thomas Reindl, deputy CEO of the Solar Energy Research Institute of Singapore (SERIS): Yes. In 2017, the Singapore government had set the target of 350 MW installed PV capacity by 2020, and Singapore surpassed this goal in April 2020. This was strongly supported by the government “walking the talk” through large tenders for PV deployment on government-owned buildings such as residential housing blocks or schools. These tenders helped to train and build up the local workforce and helped to raise interest amongst lenders for project financing through demand aggregation. Singapore’s new goal is “at least 2 GW of PV by 2030,” and I am very confident that this will also be achieved.

To date, solar in Singapore has been driven almost equally by projects in the public and private sectors. Do you expect this balance to shift in the coming years?

The public sector will naturally play a strong role, as many buildings and most of the industrial land is owned by the government. The real estate (be it rooftops, land or water bodies) is typically leased out, so that the investment in fact comes from the private sector and the electricity is partly sold to the government agencies and partly fed back to the grid. In addition, PV investments on private commercial and industrial buildings will continue to thrive.

The SERIS PV roadmap for Singapore forecasts different scenarios for both 2030 and 2050. What are the main factors that will decide which comes to pass?

Installed PV capacity in Singapore will likely grow at a pace that follows the “Accelerated” scenario of the roadmap. The “Baseline” scenario will materialise if no additional measures are taken, whereby PV installations happen simply because it is the lowest-cost method to generate clean electricity. As we see signs that support from the government will continue, and more areas will be made available for PV deployment, the adoption will happen faster than predicted by the baseline scenario.

Several of these forecasts were recently updated from the original predictions made in 2014 – what have been the biggest changes?

One of the major changes was that for the update we had access to a high-resolution 3D model of Singapore, which allowed a much more detailed assessment of the available areas for PV deployment compared to the original roadmap published in 2014. We modelled 132,000 buildings and assessed their solar potential on both rooftops and facades, using a self-developed software process.

We also carried out a grid impact assessment, given the high variability of solar power generation in Singapore’s tropical climate, which is characterised by frequent changes in cloud cover. Solar is the only viable source of renewable energy in Singapore. Therefore, the update to the PV Roadmap tried to summarise technoeconomic developments and deployment options. It also derived research, development and deployment needs for Singapore, as well as policy and regulatory recommendations.

Singapore has already emerged as a leader in floating solar, with some large projects on the way. Do you expect further growth here?

Singapore already has a number of floating PV installations, and is now deploying a 60 MW system that will be operational in 2021. In addition, a 5 MW near-shore floating PV system has almost finished the construction phase.

Floating solar will continue to be an option for PV deployment in Singapore, both on water reservoirs and in near-shore areas, especially those which are often not usable for other activities, for example so-called ‘dead spaces’ behind a jetty.

And what about the rooftop and ground-mount solar segments?

Areas generally usable for PV deployment can broadly be categorised into: building-related installations (rooftops, facades), land-based PV (which for the case of Singapore likely will need to have the additional feature of being “mobile,” as the land use may change over time), floating PV, and infrastructure PV, which describes the dual use of areas by over-building them with PV, for example car parks, canals and possibly roads.

Are other upgrades or changes to grid infrastructure necessary for solar to keep growing as SERIS forecasts?

As part of the study, we employed the latest power system simulation techniques to assess the impact of the variable and highly distributed generation of solar power on the Singapore grid. The possible impacts could be aggravated by the tropical weather conditions in Singapore, with frequent fluctuations in cloud cover. The assessment covered four distinct areas: demand profile and ramp rate impact, distribution network impact, inertia and reserve requirements, and the protection system.

The assessment found that there were no critical concerns foreseen for the national power grid until 2030. However, for 2050, there was a need to further review and ensure grid resilience, particularly for strong reductions in solar power output during extreme weather events, like sudden island-wide thunderstorms. To overcome such a challenge, suitable mitigation measures such as solar forecasting, flexible conventional generation, energy storage systems and demand-side management should be considered.

For the specific case of energy storage, the government has already set a target, which is 200 MW beyond 2025. This was announced simultaneously with the new solar target of at least 2 GWp by 2030.

Last year also saw the announcement of the ‘Sun Cable’ initiative, which will connect Singapore to solar power plants in Australia via an undersea cable – what is your view on this project?

This is obviously a very ambitious project and an implementation timeframe of a decade is probably the minimum one would need to consider, given the hurdles in terms of technical feasibility studies, contractual agreements between parties across three nations, offtake agreements for 20+ years and obtaining financing, to name just a few.

The project aims to install 10 GW of solar power in northern Australia, which is certainly feasible during the timeframe. Also, this part of Australia has very high irradiance conditions, hence is very well suited for solar power generation. Like in many areas of Australia, the high solar and wind resources often do not correlate with the local load centres and urban settlements, hence having sparked the idea of “exporting renewable energies” to other parts of the world. Such exports could, for example, be in the form of renewable hydrogen, which a number of groups are already working on, or, as proposed by Sun Cable, via a physical cable connection.

For Singapore, while it sounds tempting to suddenly get parts of its electricity supply from renewable sources, it is always important to also look at the balancing of the electric power grid, i.e. what would happen if the supply gets interrupted, and what would be a fair electricity market model for local generators and local producers of solar electricity.