Solar Thermosyphon Energy Savings & GHG Reduction Assessment Methods
Report on energy-saving & GHG reduction methods along with current and future trends
June 2026 - PDF 0.61MB
Editor: Li Bojia, Li Haimeng

This report provides a comprehensive analysis of four primary methodologies for quantifying carbon emissions reduction in solar water heating (SWH) systems: the Clean Development Mechanism (CDM), Life Cycle Assessment (LCA), project-level technical specifications, and White Certification schemes. The CDM methodology, established under the Kyoto Protocol, offers a standardized framework for certifying emission reductions (CERs) through rigorous baseline scenario determination, project emission monitoring, and third-party verification. It has proven particularly effective in developing countries like China and India, where abundant solar resources and strong hot water demand create ideal conditions for SWH deployment. By displacing conventional energy sources (e.g., electricity, coal, or gas), CDM-compliant SWH projects demonstrate measurable GHG reductions, with transparency ensured through certified monitoring plans and UNFCCC-approved calculation formulas. For instance, baseline emissions are calculated using regional grid emission factors or IPCC fuel coefficients, while project emissions account for auxiliary energy consumption, ensuring accurate quantification of net carbon mitigation. This methodology not only supports global climate goals but also generates economic benefits through carbon credit trading, making it a cornerstone for international carbon mitigation projects.

The Emergence of PV Hot Water Systems
A Technology Brief
April 2025 - PDF 1.35MB
Editor: Robert A Taylor, Tony Day

As photovoltaic (PV) system costs dramatically reduce, they are becoming economically viable as a technology to replace gas, grid electricity, and even solar thermal collectors as an energy source for low-temperature heating applications. The pairing of PV electricity with domestic water heating represents an under-explored—but rapidly emerging—opportunity for innovation, self-sufficiency, and sustainable modernization. In some regions, the household domestic hot water demand is over 50% of total household energy consumption. Thus, at the residential scale, the road to a low-carbon future must include sustainable solutions for domestic hot water.