The realm of photobiocatalytic alkane biofuel synthesis has burgeoned recently; however, the current dearth of well-established and scalable production methodologies in this domain remains conspicuous. In this investigation, we engineered a modified form of membrane-associated fatty acid photodecarboxylase sourced from Micractinium conductrix (McFAP). This endeavour resulted in creating an innovative assembled photoenzyme-membrane (protein load 5 mg cm−2), subsequently integrated into an illuminated flow apparatus to achieve uninterrupted generation of alkane biofuels. Through batch experiments, the photoenzyme-membrane exhibited its prowess in converting fatty acids spanning varying chain lengths (C6–C18). Following this, the membrane-flow mesoscale reactor attained a maximum space-time yield of 1.2 mmol L−1 h−1 (C8) and demonstrated commendable catalytic proficiency across eight consecutive cycles, culminating in a cumulative runtime of eight hours. These findings collectively underscored the photoenzyme-membrane's capability to facilitate the biotransformation of diverse fatty acids, furnishing valuable benchmarks for the conversion of biomass via photobiocatalysis.@en

There is significant potential for reducing energy use and emissions from buildings through energy efficiency retrofits. However, a number of barriers, including long payback periods and uncertainties around business models and technologies, restrict large scale implementation. A recent joint project, piloting green energy schemes and low-carbon investments in public and commercial buildings in the Changning district of Shanghai, China, indicated opportunities to break through these barriers. This study conducted a cost benefit analysis to investigate how an innovative combination of financial and non-financial supported retrofits, and could serve as a model for other urban areas. In total, 44 retrofit sub-projects were carried out and achieved energy savings of 30,217 tons of coal equivalent. The average payback period was 2.43 years, and with subsidies was further reduced to 1.79 years. The Changning Low Carbon Office played a critical role in coordinating and supporting the uptake of retrofit measures but non-economic factors continue to restrict investment by financial institutions and the implementation of retrofits on a larger scale. Key policy insights Public and commercial building retrofits in Shanghai are found to generate commercially acceptable payback periods while having achieved significant energy and emissions reductions. Subsidies from the city and district governments significantly reduced the payback periods of energy efficiency retrofits, but may also crowd out investment by financial institutions. The Changning Low Carbon Office has coordinated energy efficiency retrofitting efforts, provided access to information, helped to connect investment funds with project opportunities and support project management. Achieving the deeper retrofits needed to achieve China’s climate targets may require more substantial financial incentives.@en

There is significant potential for reducing energy use and emissions from buildings through energy efficiency retrofits. However, a number of barriers, including long payback periods and uncertainties around business models and technologies, restrict large scale implementation. A recent joint project, piloting green energy schemes and low-carbon investments in public and commercial buildings in the Changning district of Shanghai, China, indicated opportunities to break through these barriers. This study conducted a cost benefit analysis to investigate how an innovative combination of financial and non-financial supported retrofits, and could serve as a model for other urban areas. In total, 44 retrofit sub-projects were carried out and achieved energy savings of 30,217 tons of coal equivalent. The average payback period was 2.43 years, and with subsidies was further reduced to 1.79 years. The Changning Low Carbon Office played a critical role in coordinating and supporting the uptake of retrofit measures but non-economic factors continue to restrict investment by financial institutions and the implementation of retrofits on a larger scale. Key policy insights Public and commercial building retrofits in Shanghai are found to generate commercially acceptable payback periods while having achieved significant energy and emissions reductions. Subsidies from the city and district governments significantly reduced the payback periods of energy efficiency retrofits, but may also crowd out investment by financial institutions. The Changning Low Carbon Office has coordinated energy efficiency retrofitting efforts, provided access to information, helped to connect investment funds with project opportunities and support project management. Achieving the deeper retrofits needed to achieve China’s climate targets may require more substantial financial incentives.@en

Improving the energy efficiency of existing buildings is a critical part of action on climate change. Retrofitting in particular provides benefits to the economy, the environment and society, as well as making significant reductions to operational greenhouse gas emissions. This policy brief looks in detail at the impact of retrofitting schemes adopted in Changning District, Shanghai, China, and highlights ways other cities can learn from Shanghai’s experience.@en