Transmission Code Requirements for Domestic Solar PV

Singapore's Energy Market Authority (EMA) decided in its 26 August 2026 decision paper to modify the Transmission Code's technical requirements for domestic solar photovoltaic (PV) generation facilities. The modifications take effect on 9 September 2026 (EMA, decision paper dated 26 August 2026). In this decision, “domestic” means a solar PV facility installed in Singapore, not only a residential installation.

Connection threshold

For a consumer's installation connected to the transmission network, the Transmission Licensee must forward the proposed connection scheme to the Power System Operator when domestic solar PV generating units have an aggregated installed capacity of at least 1 MWac. The threshold is based on the aggregate nameplate AC capacity at the relevant connection point, rather than net or gross electricity-injection profiles; the approach covers front-of-meter and behind-the-meter configurations (EMA, Annex 1 and Annex 2).

New inverter and control requirements

From the effective date, a new grid-connected domestic solar PV generating unit must use a grid-forming inverter capable of operating from 0.9 leading to 0.9 lagging power factor, and the connected person must ensure and demonstrate compliance before energisation. EMA states that this requirement applies across system configurations, including low-voltage and front-of-meter or behind-the-meter installations, unless otherwise specified; the detailed grid-forming technical requirements may receive further guidance (EMA, clauses TC/2026/21 and 6.6.1 response).

The grid-forming-inverter requirement is for new units from 9 September 2026 and is not retrospective for existing systems, unless an existing system is recommissioned or materially modified, such as through a capacity change or inverter replacement (EMA, response on clause TC/2026/21). Domestic solar PV facilities need not provide automatic generation-control capabilities, but must still provide remote-terminal-unit or SCADA functions for remote monitoring of output and operating conditions (EMA, Annex 2).

Reserve and monitoring treatment

The modifications clarify that the Primary Reserve Requirement and the Spinning Reserve Requirements for Frequency Sensitive Plant do not apply to domestic solar PV generation facilities. They also exclude certain general generating-station measurement and remote-control information requirements where a facility's generation comprises solely domestic solar PV units (EMA, clauses TC/2026/23, TC/2026/24 and TC/2026/28). Solar-specific monitoring still includes gross active power and reactive power at the AC side, together with solar irradiance from a nearby sensor; the published minimum sensor specifications include a 0–2,000 W/m²-or-better range and a response time below 30 seconds (EMA, clause TC/2026/29).

These modifications focus on solar PV facilities installed in Singapore. EMA says it may introduce separate requirements or mechanisms later for energy-storage systems and hybrid facilities, taking account of their configuration, operating mode, technology and power-system needs (EMA, decision paper).