Dynamic allocations increase financial savings in energy communities


A global group of researchers has analyzed energy allocations at a real collective self-consumption (CSC) project in France, comparing static, default dynamic, and customized dynamic methods in terms of self-consumption rates and economic savings.

“The main contribution of the research study presented in this paper concerns the comparison of a real CSC application of the three possible energy-sharing types regulated in France,” said the researchers.

The study was demonstrated on three buildings at the Izarbel Technology Park in southwestern France. Buildings ESTIA1 and ESTIA2 mainly host student activity related to the engineering school of the ESTIA Institute of Technology. Building ESTIA4, is a business facility with a data center.

The EKATE research project will install 286 kW across three buildings. The study focuses on the first step of installing 149 kW on ESTIA1, which will supply energy to all three buildings.

“As the above-mentioned PV was not yet installed during the EKATE project, the existing 5.6 kW PV installation at ESTIA1 (installed in 2005) was used to emulate the 149 kW PV panels to be installed shortly,” the academics said. “The fact that the new PV panels will have the same location and orientation as those already installed is a solid guarantee of the quality of the emulation.”

The Internet of Things (IoT) architecture will control and manage energy allocation in the park, using sensors, meter readings, and weather data. The three buildings prioritize using PV-generated power based on energy allocation methods, selling surplus energy to the grid. Energy data is recorded in the blockchain and shared with the local French utility for billing.

The static energy allocation method maintained constant keys of repartition (KoR) at an unspecified rate. In the default dynamic case, KoRs are variable and automatically calculated by the French grid operator, Enedis, in proportion to the consumption of each building. The customized dynamic energy allocation method is based on maximizing economic benefits.

“In France, the building that is equipped with PV panels does not pay the CSPE (taxes that are not related to the grid) nor the TURPE (grid tariff). As the PV panels were installed in ESTIA 1, this building did not pay these taxes,” the researchers said.

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ESTIA 2 incurred TURPE charges for grid usage but not CSPE, due to shared ownership with ESTIA1. In contrast, ESTIA4 faced a tariff of €0.11 ($0.12)/kWh. ESTIA1 achieved a 66% boost in savings, attributed to tax benefits, while ESTIA2 saw a 38% increase. Consequently, dynamic energy allocation prioritized ESTIA1's consumption, using surplus for ESTIA2, and then ESTIA4. Any remaining surplus was fed back into the grid for sale to the French electricity generation company. Researchers compared the outcomes of these methods in four scenarios – with and without a data center, and for low and high solar radiation.

The researchers said that it is not clear whether the data center will be included in the final CSC, so both scenarios were checked.

The data center at ESTIA4 maintains consistent electricity consumption among its servers, guaranteeing a permanent usage of over 100 kW.

“Compared with the static type of sharing based on consumption, the self-consumption rate (SCR) of dynamic allocations was 3.86% higher in the first scenario (low solar radiation and no data center), 0.78% higher in the second scenario (high solar radiation and no data center), and 0% higher in the third and fourth scenarios (low solar radiation and data center and high solar radiation and data center),” the academics said. “The static sharing based on investment was the worst-performing allocation strategy in terms of SCR.”

As for the financial savings, the differences were more substantial. In the first scenario, the customized dynamic sharing increased savings by 4.84% over the consumption-based static allocation and 4.25% over the dynamic default. In the second scenario, an increase of 0.67% was obtained.

“In the third scenario, an increase of 41.50% was achieved compared with the static sharing and 36.65% compared with the dynamic sharing by default,” the researchers said. “Finally, in the fourth scenario, the dynamic sharing achieved 16.29% more savings compared with the static sharing and 13.26% compared with the default dynamic sharing.”

The researchers presented their findings in “Photovoltaic energy sharing: Implementation and tests on a real collective self-consumption system,” which was recently published in Heliyon. The academics come from Spain's University of the Basque Country, France's University of Bordeaux, and New Zealand's Auckland University of Technology.

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