Taipei's Mandatory Green Coverage Ratio — a 40–70% Green Plot Ratio Rule for New Buildings

Taipei City's New Building Greening Implementation Rules require new construction projects to reach a Green Plot Ratio (GnPR) of 40-70%, with public buildings and schools held to the upper end of that range. The rule sits within Taiwan's wider EEWH green-building certification system, established in September 1999 as the world's second national green-building rating system after the United States' LEED.
As of January 2024, 12,585 buildings or projects across Taiwan had been certified or were candidates for certification as green buildings, with certified buildings projected to cut lifetime electricity use by roughly 20% and water use by roughly 30% over a 40-year building life.
A 2022 peer-reviewed hydrological study modelling the conversion of Taipei's grey roofs to green roofs found that, of the city's 26,855-hectare total area, only 304.5 hectares of grey roof were structurally suited to conversion. Where converted, green roofs cut stormwater runoff by up to 59% in the cold season, but only 14-28% during the rainy season, since substrate saturation limits performance in high-intensity storms — a limitation the researchers flagged explicitly.
Separate local studies on green-roof thermal effects found air-temperature reductions of roughly 4-6°C near vegetated roofs. Researchers note that thermal performance is the best-studied outcome locally, while stormwater and biodiversity effects remain comparatively under-monitored citywide despite the mandate's scale.

Read the full analysis: https://resourcehub.bakermckenzie.com/en/resources/global-sustainable-buildings-index/asia-pacific/taiwan/topics/green-certification