Assessment of waterfront office redevelopment plan on optimal building energy demand and rooftop photovoltaics for urban decarbonization

TL;DR

This study evaluates how waterfront building designs and rooftop photovoltaics in Tokyo influence energy demand, self-sufficiency, and CO2 emissions, highlighting the economic and environmental benefits of integrating PV systems for urban decarbonization.

Contribution

It introduces a scenario-based analysis of waterfront redevelopment focusing on building form, PV integration, and their impacts on energy and emissions, providing policy-relevant insights.

Findings

Rooftop PV systems become increasingly economical from 2018 to 2030.

CO2 emissions can be reduced by 2-9% with rooftop PV adoption.

Payback periods for PV systems decrease from 14 to 6 years between 2018 and 2030.

Abstract

Designing waterfront redevelopment generally focuses on attractiveness, leisure, and beauty, resulting in various types of building and block shapes with limited considerations on environmental aspects. However, increasing climate change impacts necessitate these buildings to be sustainable, resilient, and zero CO2 emissions. By producing five scenarios (plus existing buildings) with constant floor areas, we investigated how building and district form with building integrated photovoltaics (BIPV) affect energy consumption and production, self-sufficiency, CO2 emission, and energy costs in the context of waterfront redevelopment in Tokyo. From estimated hourly electricity demands of the buildings, techno-economic analyses are conducted for rooftop PV systems for 2018 and 2030 with declining costs of rooftop PV systems. We found that environmental building designs with rooftop PV system are increasingly economical in Tokyo with CO2 emission reduction of 2-9% that depends on rooftop sizes. Payback periods drop from 14 years in 2018 to 6 years in 2030. Toward net-zero CO2 emissions by 2050, immediate actions are necessary to install rooftop PVs on existing and new buildings with energy efficiency improvements by construction industry and building owners. To facilitate such actions, national and local governments need to adopt appropriate policies.