Shujia ZHANG , Qiancheng WANG, Linyi HU, Wenyan SHI, Minghang QU

1. Department of Building and Real Estate, The Hong Kong Polytechnic University, canaan.zhang@connect.polyu.hk A Feasibility Study on the Waste-to-Biogas SOFC-Based Multi-Generation with Energy Storage System for Building Applications in China Shujia ZHANG, Qiancheng WANG, Linyi HU, Wenyan SHI, Minghang QU

2. 1.Introduction • Building Sector Energy Consumption • Global: 32% of global energy use and 19% of energy-related GHG emission (IPCC, 2014) • China: 17.7% - 20.3% of total energy use between 2000 - 2014(Huo et al., 2018) Fig 1. China's building energy consumption from 2000 to 2014. (Huo et al., 2018) 1362

3. 1.Introduction • Municipal Solid Waste (MSW) Treatment • Groundwater Contamination: Average FI of groundwater near landfill sites was 6.78 (Han et al., 2016). • Heavy Metal Pollution: 36.08% of the soil heavy metal contamination originated from MSW incineration(Ma et al., 2018). Fig 2: Trend of MSW disposal and proportion of different treatments during 2003-2016 (Source: China Statistical Yearbook 2003-2017) 1362

4. 1.Introduction • Solid Oxide Fuel Cells System • Electrochemically generation technology • Higher efficiency than conventional energy conversion systems (Laguna-Bercero, 2012) • Higher operating temperature (i.e. 650°C-1000°C). Fig 3. Schematic diagram SOFCs with illustration of the working mechanism. 1362

5. 2.Aims and Objectives • Previous research: • Design of biogas-from-MSW SOFC system for electricity generation (Ni, 2013; Chen & Ni, 2014; de Arespacochaga et al., 2015) • Research Gap: • Fixed electricity output and dynamic energy demand • Waste thermal energy from SOFC exhaustedgas • Aim and Objectives: • Propose an SOFC multi-generation system with energy storage and utilize operation data from a typical airport in China to analyse the feasibilityof the system Fig 4. Process Flow Diagram of the biogas-powered SOFC (de Arespacochaga et al., 2015) 1362

6. 3. Proposed System Design • Energy Storage Plan Table 1. Main technical features of storage systems (Source: SBC Energy Institute) 1362

7. 3. Proposed System Design • Finalized Design • Biogas Purification MSW Energy Storage Iron Sorbent FA Iron Sorbent FB CO2 Compression and Liquefaction • Biogas Generation and Treatment • Distributed Energy Generation 1362

8. 4. Case Study: XG Airport • Background Information of XG Airport Table 2. Operation Data of XG Airport 1362

9. 4. Case Study: XG Airport • Detailed Design Plan 5 units of ES-5710 to provide 1,250kWelectricity 5 units of PUXIN 260m3digesters 3 units of 2,000m3 gas holders Iron Sorbent FA 2 units of screw presses Iron Sorbent FB Capacity of the SOFC servers 1MWh Efficiency of energy transformation Low cost of the energy storage Li-ion Battery (0.25-25MWh), Efficiency = 90% Low cost per kWh (Dunn et al., 2011) 1362

10. 4. Case Study: XG Airport • Economic Analysis – CAPEX & OPEX Table 3.Proposed system CAPEX and OPEX analysis 1362

11. 4. Case Study: XG Airport • Economic Analysis - Payback Period Table 4. Proposed system payback period analysis *Formula: * Interest Rate = 0.38% (HKMA, 2018) Operational Saving = $154,858 (Calculated) 1362

12. 4. Case Study: XG Airport *= Scrap Value, =15-year lifespan of the SOFC system, = 6.7% depreciation rate • Economic Analysis –Life Cycle Cost Table 5.Comparison of Life Cycle Cost 1362

13. 4. Case Study: XG Airport • Environmental Analysis Table 6. GHG Emission during Operation (15 Years) 1362

14. 5. Conclusion • Propose an eco-friendly SOFC-based building energy solution with an energy storage system to meet dynamic built environments. • Verify the economic feasibility of the proposed system. The annual financial savings of $154,858 gives it a short PP (i.e. less than 27 months) and satisfactory resistance to financial risks. • The system can also significantly reduce the GHG emission and demonstrate the environmental feasibility, compared with the other existing systems. 1362

15. 6. Reference • Chua K J and Chou S K 2010 Energy performance of residential buildings in Singapore Energy 35 667-78 • Jiang Z 2008 Reflections on energy issues in China J. Shanghai Jiaotong Univ. (Engl. Ed.) 13 257-74 • Ni M, Leung D Y and Leung M K 2009 Electrochemical modeling and parametric study of methane fed solid oxide fuel cells ‎Energy Convers. Manage. 50 268-78 • Laguna-Bercero M A 2012 Recent advances in high temperature electrolysis using solid oxide fuel cells: A review J. Power Sources 203 4-16 • Bonanos N 1992 Transport properties and conduction mechanism in high-temperature protonic conductors Solid State Ionics 53 967-74 • Colson C M and Nehrir M H 2011 Evaluating the benefits of a hybrid solid oxide fuel cell combined heat and power plant for energy sustainability and emissions avoidance. IEEE T. Energy Conver. 26 140-8 • Tucker D, Shelton M and Manivannan A 2009 The role of solid oxide fuel cells in advanced hybrid power systems of the future Electrochem. Soc. Interface 18 45 • Washington K 2000 Proc. of the Fuel Cell Seminar (Portland) • Onovwiona H I and Ugursal V I 2006 Residential cogeneration systems: review of the current technology Renew. Sust. Energy Rev. 10 389-431 • Curry N and Pillay P 2012 Biogas prediction and design of a food waste to energy system for the urban environment Renew. Energy 41 200-9 • Dunn B, Kamath H and Tarascon J M 2011 Electrical energy storage for the grid: a battery of choices Science 334 928-35 • Meyer F Compressed Air Energy Storage Power Plants (Bonn: FIZ Karlsruhe) • EPA U 2018 Emission factors for greenhouse gas inventories Stationary combustion emission factors 1362

16. Shujia ZHANG canaan.zhang@connect.polyu.hk 1362