Overview of thermal energy storage technologies and applications by - PowerPoint PPT Presentation

Overview of thermal energy storage technologies and applications by Dr Peter Klein CSIR

Agenda 1. Why thermal energy storage 2. Description of thermal energy storage technologies 3. Identification of applications 4. Thermal storage testing laboratory 5. Conclusions 2 2

Importance of energy storage Increasing penetration of variable renewable energy generators requires flexibility Installed capacity Energy mix [GW] [TWh] 100 250 Solar PV Solar PV 20% 80 200 Wind Wind 21% 15% 60 150 16% 23% 18% 13% 40 100 19% 42% 13% 12% 36% 34% 7% 28% 8% 20 50 32% 29% 25% 29% 1% 3% 14% 13% 16% 17% 4% 3% 0 0 2020 2030 2030 2040 2040 2050 2050 2020 2030 2030 2040 2040 2050 2050 IRP1 IRP3 IRP1 IRP3 IRP1 IRP3 IRP1 IRP3 IRP1 IRP3 IRP1 IRP3 Percentages indicate fraction of total generation installed capacity and energy mix 1 Based on draft Integrated Resource Plan 2018 3

Future energy system will be built around variability of solar PV & wind Actual scaled RSA demand & simulated 15-minute solar PV/wind power supply for week from 15- 21 Aug ‘11 GW 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Monday Tuesday Wednesday Thursday Friday Saturday Sunday Excess Solar PV/Wind Day of the week Residual Load (flexible power) Useful Wind Electricity Demand Useful Solar PV 4 Sources: CSIR analysis

Value of a Flexible Energy System 0% load flexible In order of 15% of generated energy GW curtailed in models 30 25 Energy curtailed Excess 20 15 10 5 0 -5 Deficit -10 -15 Flexible Gas (CCGT) -20 Peaking Gas (OCGT) -25 -30 Monday Tuesday Wednesday Thursday Friday Saturday Sunday Day of the week 5

Value of a Flexible Energy System 25% load flexible – energy balanced intraday GW No Flexible Load 30 30 25 25 Excess 20 20 15 15 10 10 5 5 0 0 -5 -5 Deficit -10 -10 -15 -15 -20 -20 -25 -25 -30 -30 Monday Tuesday Wednesday Thursday Friday Saturday Sunday Day of the week 6

Value of an Integrated Energy System 25% load flexible – energy balanced intraweek GW No Flexible Load 30 30 25 25 Excess 20 20 15 15 10 10 5 5 0 0 -5 -5 Deficit -10 -10 -15 -15 -20 -20 -25 -25 -30 -30 Monday Tuesday Wednesday Thursday Friday Saturday Sunday Day of the week 7

So why use thermal energy storage for flexibility? Thermal energy is the dominant energy end-use Thermal Battery (TES) Power-to-Heat/Cold Energy End-Use Concept preferably requires thermal energy • Solar Thermal (CSP) for end-use • Waste Heat Recovery • Biomass • Heat/Cold from Ambient • Absorption Chillers Advantages of TES • Low cost • Low tech • Potential for seasonal storage and high energy storage densities (thermochemical) • High storage efficiencies • Scalable and modular • Wide operating conditions • Deployed at GWh scale or residential • Can size power and energy independently 8

So why use thermal energy storage for flexibility? Thermal energy is the dominant energy end-use =92% =77% =71% 22% Final Energy 6% Final Energy 37% Final Energy Consumption 2 Consumption 2 Consumption 2 1 Based on DoE calculations in draft Integrated Energy Plan 2016 9 2 Based on IEA Energy Balances for 2015

End-use of electricity in industry in South Africa Chemicals Non-ferrous metals Gold mining 13% 21% 33% 67% 79% 87% Iron and Steel Other manufacturing Platinum mining 21% 35% 46% 54% 65% 79% Thermal Non-Thermal 10 Based on DoE calculations in draft Integrated Energy Plan 2012

Integrating thermal storage into industry 11

Overview of Thermal Energy Storage Technologies Thermal Energy Storage Thermal Chemical Sensible Solid-Gas Liquid-Gas Gas-Gas Latent Heat Heat Reactions Reactions Reactions Liquids Solids Solid-Liquid Liquid-Gas Solid-Solid 12

Comparison of sensible and latent heat storage technologies Energy Stored Discharge Temperature Charging PCM Energy stored if no phase Sensible heat TES change Latent heat TES Discharging 13

Sensible heat storage overview L. Heller, Literature Review on Heat Transfer Fluids, STERG Report, 2013. 14 W. B. Stine and M. Geyer, “Power from the sun. Retrieved April 15, 2011, from http://www.powerfromthesun.net/book.html,” 2001 .

Latent heat storage overview 15 Hoshi, Akira, et al. "Screening of high melting point phase change materials (PCM) in solar thermal concentrating technology based on CLFR." Solar Energy 79.3 (2005): 332-339.

Latent heat storage: Ice storage for HVAC Southern California Edison – 25.6MW of peak ice storage capacity 1800 behind the meter ice batteries, as part of 250 MW energy storage requirement 16 https://www.energy-storage.news

Alignment between Solar supply, load and temperature as measured in summer at CSIR campus GHI and Temperature Load and Temperature GHI [W/m2] Temp. [C] Load [kW] Temp. [C] 1 200 40 6 000 40 35 35 1 000 5 000 30 30 800 4 000 25 25 600 20 3 000 20 15 15 400 2 000 10 10 200 1 000 5 5 0 0 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 0 0 2 2 4 4 6 6 8 10 12 14 16 18 20 22 24 8 10 12 14 16 18 20 22 24 17

Thermochemical heat storage overview Charging (endothermic) Discharging (exothermic) 18

Example of adsorption storage system 19

Comparison of Thermal Energy Storage Energy Densities 20

CSIR Energy Centre Thermal Storage Research Key roles identified for Thermal Storage Utilise low cost thermal storage to shift thermal loads in time Concentrating Solar Waste Heat Recovery Power-to-Heat Passive Applications Power 21 Based on US DOE, Energy Storage Database (2017)

Key roles identified for Thermal Storage Waste heat recovery Waste Heat Recovery Power-to-Heat H E Electricity Heat • Couple electricity and heat sectors • Smooth loads • Primarily from PV and wind • Batch-wise processes Thermal Storage • Utilise low cost TES to add • Increase efficiency flexibility • Increase capacity factor • Many existing loads can be • Supply for peak loads made flexible at low cost • Improve industrial efficiency 22

Waste Heat Recovery Pilot Project (WHR) under YREF grant How can thermal storage be integrated into WHR systems + SMME development Waste heat from high temperature kilns >1000 o C Drying moulds at 60 o C Partnership with NCPC combining energy audit with research and development for non standard WHR solutions 23

Waste Heat Recovery Boosted by TES Addition of TES adds 33% to average power Slide from Romagnoli , A. “Waste heat recovery in industrial processes via thermal energy storage” National Energy Efficiency Conference 2015 24

Key roles identified for Thermal Storage Concentrating Solar Passive Applications Power • • Typically 2 tank molten salt Provide passive cooling in buildings HVAC • • Generate electricity Integrate thermal storage into building envelope • • Commercially mature (1.1GWh) Eliminate need for active cooling • Opportunities for cost reductions with low cost materials (e.g. rocks) • Cost competitive issue with PV+battery 25

Thermal Storage Laboratory: Excellent integration opportunity between Energy Materials and Energy Storage Low technology solutions Short time to market B. Zalba, J. M. Marin, L. F. Cabeza and H. Mehling , “Review on thermal energy storage with change: materials, heat 26 transfer analysis and applications,” Applied Thermal Engineering, vol. 23, pp. 251 -283, 2003

Conclusions 1. Thermal energy is the largest end-use of energy in South Africa 2. A range of TES technologies exist which can be incorporated to add grid flexibility at low cost 3. In the near term TES for waste heat recovery presents an interesting opportunity 4. CSIR Energy Centre is looking to develop new materials and heat exchange designs for TES 27

Thank you 28