LVDC grid based on PV energy sources and multiple electrochemical - PowerPoint PPT Presentation

LVDC grid based on PV energy sources and multiple electrochemical storage technologies Kolja NEUHAUS, Jeremy DULOUT, Corinne ALONSO Université Paul Sabatier LAAS-CNRS Toulouse

Summary ▪ Energy grids and their evolution to smart grids ▪ LVDC grid, NeoCampus context ▪ The ADREAM test platform - energy optimized building ▪ Cluster analysis of production and consumption ▪ Storage units adapted for energy optimized buildings ▪ Conclusion Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 2

Energy grids and their evolution to smart grids ▪ Vertical grid structure ◆ Main focus on security of supply (oil crisis 1973) ◆ Matching load to the production ◆ Unidirectional transport from producer to consumer Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 3

Energy grids and their evolution to smart grids ▪ Horizontal grid structure and smart grid ◆ Every element except grid operation is subject to competition since the years 2000’s. ◆ Free choice of energy provider and self-production/consumption made possible. ◆ Ability to integrate intermittent renewable and distributed production. ◆ Multidirectional transport based on energy flow mitigation with storage. Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 4

The ADREAM test platform - energy optimized building ▪ George Giralt building (ADREAM) • Total photovoltaic surface: 720 m² • Total peak power: 100 kWp • 4 different areas with different inclinations • Typical PV production data for an energy optimized building. Typical consumption data for a three phased AC micro-grid for energy optimized building. Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 5

The ADREAM test Platform - energy optimized building ▪ Solar radiation and PV production Solar irradiation sensors on their inclinable stand Pyranometer doted with a solar ring to measure diffuse and reflected irradiation ◆ Good knowledge of the producible means good knowledge of the production. ◆ Direct impact of solar intermittency on PV production and storage strategies. ◆ Solar radiation study is used as high precision comparison and verification of PV performance. Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 6

Cluster analysis of production and consumption ▪ Lots of data on photovoltaic energy production Daily production data with one sample per minute ▪ Lots of data of building energy consumption Daily consumption data with one sample per minute ▪ High intermittency is a determinant factor Solar radiation, building occupation and exterior conditions ▪ How to determinate simple and meaningful daily profiles from all this data ? Used to study storage strategies adapted to the intermittent production and consumption K-medoids Clustering Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 7

Cluster analysis of production and consumption The algorithm is initialized with the raw data. The number of desired clusters (K) is Raw Choice of K (number of clusters) 1 chosen by the user and one data vector is data + first medoids chosen as medoid for each cluster. The distance between each data point and Calculating distance between data point and 2 the medoids is calculated. medoids Each data is assigned to the closest medoid, Allocating data point to cluster based on 3 forming the clusters. minimal distance with medoid The new medoid of each cluster is selected. 4 Recalculating medoids for each cluster Medoids i == Medoids i-1 NO YES The algorithm stops when the K medoids 5 have not changed between two iterations. K clusters + K medoids Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 8

Cluster analysis of production and consumption Building consumption clustering results PV Production clustering results 2015 2015 104 10 4 6 1 Day type 1 5.5 Day type 2 0 Day type 3 5 (W) -1 4.5 W) Consumed Power ( 4 -2 PV Power 3.5 -3 3 2.5 -4 Low intermittent radiation 2 Low uniform radiation -5 High unifirm radiation High intermittent radiation 1.5 -6 1 00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12 21:36 00:00 00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12 21:36 00:00 Time ( hh:mm ) Time (hh:mm) Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 9

Storage units adapted for energy optimized buildings Important parameters for durable stationary energy projects : • Lifetime (depending on Depth Of Discharge per cycle) • Efficiency (ratio of charge/discharged energy per cycle) • Total environmental footprint • Price • Specific energy > Specific Power Selected technologies : Lithium supercapacitors Lithium iron phosphate Lead-Acid batteries and hybrids batteries ▪ Relatively low specific energy ▪ Good specific energy AND ▪ Good specific energy ▪ Lowest price power (good for intermittency) ▪ Medium price ▪ Jellified electrolyte (AGM, ▪ High price ▪ Close to no maintenance OPzV) for low maintenance ▪ Close to no maintenance ▪ 2500-3000 cycle lifetime ▪ 500-1500 cycle lifetime ▪ High cycle lifetime (>5000) ▪ Low environmental footprint ▪ Low self-discharge ▪ Low environmental footprint Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 10

Conclusion ▪ To conceive a local optimized energy grid based on photovoltaic sources, a good knowledge of the solar producible, its intermittence and its production is needed. ▪ Production and consumption must be studied in order to develop adequate energy and storage managing for optimal energy flow and minimize losses. ▪ Lead-acid AGM, OPzV and lithium iron phosphate batteries are particularly adapted to stationary renewable energy production structures. Electrochemical hybrid LIC has interesting technical specifications and seems promising. ▪ One key point in energy transfer optimization is a better knowledge of storage units. For this purpose, a model of state of charge (SOC) and state of health (SOH) in battery storage units is necessary and is in development stage for the next step of this work. Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 11

Thank you for your attention Laboratoire d’analyse et d’architecture des systèmes du CNRS Laboratoire d’analyse et d’architecture des systèmes du CNRS 12