By Adrian Pang
The Sustainable Energy Association of Singapore (SEAS) hosted a recent webinar on the solar photovoltaic (PV) roadmap of Singapore. Dr. Thomas Reindle, CEO of the Solar Energy Research Institute of Singapore (SERIS) at the National University of Singapore (NUS) presented a holistic summary of SERIS’s report that charts Singapore’s roadmap based on reviews and updates of its 2014 roadmap. The roadmap highlights Singapore’s great potential in expanding its solar PV infrastructure and services. Some of the key areas of development are:
- Existing topics: space availability, space utilisation, increasing energy yield, levelised cost of electricity from solar PV (LCOE), possible scenarios for PV deployment, managing PV grid integration,
- New topics: end-of-life PV recycling, repowering, Renewable Energy Certificates (RECs), and importing of solar energy.
- Space availability: Solar PV deployment is part of sustainable urban planning and it embodies the clean and green ‘Garden City’ vision that Singapore values. Solar PVs benefit the environment and have public acceptance as it is perceived to be safe. Space availability for different types of PV deployment is assessed based on these values and their respective potentials. Despite being a small island nation, Singapore can deploy five types of solar PV:
- Rooftop (most common in Singapore)
- Facades (for building-added and building-integrated PV, BAPV/BIPV
- Mobile-/land-based PV (temporary land use)
- Floating PV (reservoirs, near-shore), and
- Infrastructure PV (e.g. over-arching land, canals, roads, or PV noise barriers).
- Space Utilisation: Solar PV deployment in land-scarce Singapore also entails the highest utilisation and efficiency of technologies employed. While ultra-high efficient modules have similar levelised cost of electricity (LCOE) as most standard modules, they have higher area efficiency, hence higher space utilisation. Put simply, more electricity generation in a given surface area. At present, ultra-high-efficiency technologies have higher market prices due to limited availability but higher production and demand will drive process and cost down for the benefit of Singapore’s solar landscape in the future. Aside from technologies, increasing area factor of PV systems and implementing novel PV applications (e.g. co-location of rooftop PV with greenery, improving BIPV areas, expanding floating PV, etc.) can maximise space utilisation of PV systems in Singapore too.
- Increasing energy yield: Solar technologies are also important to maximise PV system’s energy yield from its installed capacity. A well-designed system in Singapore has an initial “Performance Ratio” (PR) value of above 80% with a typical degradation rates of 0.8% per annum. The degradation is caused largely by Singapore’s high temperature climate conditions. Therefore, a PV system with good ventilation or technologies to regulate temperature (e.g. Floating PV) is beneficial in increasing energy yield. The “Floating PV testbed” at Tengeh Reservoir is found to have 5% to 15% higher energy yield. Next, the highly distributed nature of small individual systems in Singapore requires smart operation and maintenance, and fleet management to maintain effective energy yield and performance consistently. Approaches such as predictive and preventive maintenance based on big data, Artificial Intelligence, comprehensive diagnostics of issues, etc. are important to maintain a lean but efficient operation and maintenance of Singapore’s sprawling solar PV systems.
- Planning, management and development: Apart from physical infrastructure development, good strategic planning and actions are required to upscale solar PV systems in Singapore.
- Minimising the levelised cost of electricity from solar PV (LCOE): LCOE is a well-established method in energy finance and policy that calculates the generation cost at the point of connection to a load or power grid. In an energy market, sources that have lower LCOE are preferred and prioritised. Therefore, solar energy should strive to achieve lower LCOE through the continuous research and development.
- Possible scenarios for PV deployment: a scenario-based approach charts the potential development trajectories of solar PV deployments. In Singapore, there are two scenarios that are associated with different levels of adoption and technological advancements – “Baseline” (BAS) and “Accelerated” (ACC).
- Managing PV grid integration: As renewable energies are highly varied in nature, solar PV faces challenges from other renewable sources to be the preferred renewable energy source in Singapore. An all-encompassing and comprehensive approach that includes assessing global development trends in the renewables sphere, PV grid integration measures (supply and demand side management, energy storage system (ESS), grid upgradation, and new equipment), and grid impact assessment of PV (demand profile and ramp rate impact, distribution network impact, inertia and reserve requirements, and protection system) are required to solidify solar PV’s status as Singapore’s preferred renewable energy source.
Aside from the existing topics that require constant improvements, the updated project also identified new topics that are crucial for the development of solar PV deployment in Singapore.
- Re-powering: As PV systems age, power generation equipments require replacement with the latest technologies that have higher efficiencies, better performance and greater reliability. This is evident in the more mature wind industry where maximum power generation per tower and size of windmills have increased substantially. As the development of wind power project sites are usually time consuming, it is often more economical to upgrade existing systems.
- Recycling: As the solar industry grows exponentially, ageing PV modules are an upcoming waste issue that requires responsible management. A study by the International Renewable Energy Agency (IRENA) showed that PV waste was around 250 tonnes in 2016 and is expected to grow to 1.7-8 million tonnes by 2030. Ageing modules constitute hazardous waste if not managed properly. Therefore, recycling is crucial in the PV value chain. There is currently no PV recycling company in Singapore, as well as a lack of efficient and cost-effective PV management process locally due to the low volume of PV waste and a relatively young market. However, Singapore is projected to increase its solar capacity from the current 350 MWp to 2GWp by 2030. Coupled with the “re-powering” of old assets that accelerate the decommissioning of certain existing installations, “end-of-life” PV and system components require the formation of policy-based regulations and technological improvements to ensure safe and sustainable recycling.
- Renewable Energy Certificates (RECs): RECs are tradeable, non-tangible market instruments that represent proof that electricity was generated from a renewable energy (RE) source. There are two categories of RECs:
- Bundled RECs: instruments whereby the “green attribute” is coupled with the electricity that is generated. Bundle RECs are generated and retired in tandem with the actual supply and consumption of electricity, thereby bound by certain considerations such as geographic constraints.
- Unbundled RECs: instruments whereby the “green attribute” is decoupled from the electricity that is generated. Unbundled RECs do not provide physical delivery of electricity from a renewable source but rather its green attribute. Unbundled RECs allow for more flexibility as business can purchase them at different volumes and at any time based on internal business and sustainability goals and decisions.
- Importing of Solar Energy: Singapore can boost its share of renewable energy by importing from other countries in the forms of electricity or other energy carriers such as hydrogen (often referred as “solar fuels”). However, the premise of importing renewable energies also includes other renewable sources such as wind power, bioenergy, hydropower or geothermal. At present, these are the notable projects and developments:
- Trans-border cable connections
- PV system deployment in neighbouring countries (e.g. setting up Solar Farms in Malaysia and transporting energy generated across the Johor Strait)
- Pan-Asian power grid interconnection (transnational super grids that foster large scale utilisation of renewable energy sources beyond regional co-operation)
- Imports over greater distances
- Off-shore floating solar farms (e.g. Singapore building off-shore solar farms in international waters of the South China Sea, supplying solar electricity via subsea cables to Singapore)
- Long-distance cable connections
- Importing solar fuels (e.g. Australia’s national hydrogen strategy focuses on developing and expanding its hydrogen export markets)
- Trans-border cable connections
The webinar on the updated solar photovoltaic (PV) roadmap of Singapore concluded with the following priorities to increase solar power use in Singapore. First, there is a need for high to ultra-high efficiency solar technologies. Secondly, employing novel “urban solar” applications (cost-effective solutions with good deployment and no substantial substitutes type of potential developments). As for topics with increasing relevance for the solar PV sphere in Singapore, discussions around recycling and circular economy, urban heat island effect of PV in cities and bankability of PV in Singapore are gathering pace. Overall, Singapore possesses a high potential to make significant transitional steps to become a solar powered country.