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In order to provide sustainable clean energy for the growing demand of electrical power in off-grid districts in Asia Pacific and South-East Asia through renewable energy sources (RESs) integration, ENGIE and Schneider Electric have made a partnership to join the Renewable Energy Integration Demonstration-Singapore (REIDS) initiative, the world largest microgrid demonstrator in the tropical area, to demonstrate state-of-the-art multi-fluid microgrid solution. Currently being constructed on Semakau Island, South of Singapore, the demonstration platform will enable ENGIE and Schneider Electric to integrate and test their solution that will provide a package of services including electricity, mobility, and clean cooking. Key innovations of the project include: The scalability and ability to start from both greenfield system (electrification of remote districts) and brownfield system (with existing equipment); A multi-fluid optimization module to enhance synergies between different technologies (renewable production, consumption, flexible loads, storage, H2 chain, and biogas chain) to provide cheap and reliable electricity with low environmental impact; A power control module allowing up to 100% intermittent RESs penetration in the power thanks to the cutting edge technology of virtual synchronous generator; The integration of an H2 chain for energy storage and mobility purposes; The integration of biogas technology for waste treatment and clean cooking. Promising results have already been observed in both companies’ research centers on different technology bricks. These different bricks are currently being integrated into this microgrid for the first time to be verified for the feasibility and stability of the complete solution. Different use cases for both technical and commercial purposes have been designed and will be tested in the microgrid. Different tests and reports on this multi-fluid microgrid on Semakau Island will enable us to optimize the solution to be suitable for the tropical conditions of South-East Asia, thus promoting the integration of renewable energy for all.

Soil heat flux is an important component of the energy balance at the land surface. Heat flux plates have been used widely to measure soil heat flux, but suffer from errors such as heat flow distortion and soil–plate contact resistance. The Philip correction and self-calibrating heat flux plates have been applied to minimize measurement errors. The objectives of this study were to evaluate the effectiveness of heat flux plate correction methods and to introduce improved approaches for applying these methods under field conditions. Soil heat flux at a depth ( z ) below the surface ( G z ) was measured with conventional and self-calibrating plates buried at 2, 6, and 10 cm in a bare soil. Adjacent to the soil heat flux plates, soil thermal conductivity ( λ s ) and temperature gradients were measured simultaneously with heat-pulse sensors, allowing G z to be determined with the gradient method. The gradient method values were used as a standard to evaluate the performance of the heat flux plates. Temporal λ s values were also estimated from soil sand content, bulk density and water content using a thermal conductivity model. At the 6- and 10-cm depths, the conventional plates underestimated G z by 4.3–10.2 W m −2 due to heat flow distortion errors resulting from a mismatch between λ s and plate thermal conductivity ( λ p ). When the Philip correction was applied, both the measured and modeled λ s values improved the accuracy of conventional heat flux plates. However, the modeling approach simplified the procedure for obtaining λ s . The self-calibrating plate effectively corrected G z errors associated with heat flow distortion (accurate to within 6.4 W m −2 ) at the 6 cm and 10 cm depths. At the 2 cm depth, both types of plates produced erroneous G z data, which were attributed to alterations in the thermal field and heat flux pattern around the plates due to blocking convective heat and water transfer. We also demonstrated that the heating process of the self-calibrating plate could bias G z data by disturbing the heat flow field around the plate. Voltage signals during and shortly after self-calibration should be discarded from data analysis. With these corrections, heat flux plates can provide an effective method for measuring soil heat flux.