Industrial application of SOFC systems in waste water treatment plants Business case Adam Hawkes Sara Giarola Gbemi Oluleye Imperial College London
SOFCs: pros and cons High electrical efficiency Low emissions Reduced energy security concerns and impact on use of natural resources (virtually zero if fuelled with a waste such as biogas) Flexibility of fuels High costs High frequency of stack replacement Low technology lifetime electricity biogas heat 2
Outline SOFC: current and projected costs The case study of Collegno (economic and technical feasibility) Market potential in WWTPs in Europe (estimate: optimisation and generalization) 3
Technological learning Roland Berger, 2015. Advancing Europe s energy systems: Stationary fuel cells in distributed generation. Cumulative production - As is 100 1,000 10,000 Capital cost Module [ /kw] 16,280 8,303 3,346 2,077 Maintenance [ /kw/y] 110 72 54 44 Module lifetime (stack ex.) y 10 20 20 20 Stack lifetime y 5 5 6 7-58 % capital cost reduction - 68% capital cost reduction 4
Technological learning Roland Berger, 2015. Advancing Europe s energy systems: Stationary fuel cells in distributed generation. Cumulative production - As is 100 1,000 10,000 Capital cost Module [ /kw] 16,280 8,303 3,346 2,077 Maintenance [ /kw/y] 110 72 54 44 Module lifetime (stack ex.) y 10 20 20 20 Stack lifetime y 5 5 6 7-58 % capital cost reduction - 68% capital cost reduction 5
Costs and performance SOFC vs state-of-the art technologies (reference size 50 kw) Variables SOFC MGT ICE Th. efficiency 27 % 43 % 60 % El. efficiency 54 % 27 % 28 % Module lifetime, y 20 20 20 Stack lifetime, y 5 20 20 Unit CAPEX, /kw 8,303 2,820 2,597 Replacement, /kw 1,223 N.A. N.A. Maintenance ( /kw/y) 72 124 165 Clean-up unit CAPEX, /kw/y 917 N.A. N.A. Clean-up unit OPEX, /kw 76 N.A. N.A. 6
Collegno WWTP: optimal SOFC dispatch Biogas composition, % CH 4 65 CO 2 33.1 H 2 O 1 O 2 0.2 N 2 0.7 min 3 SOFCs integrated into current energy system e,f,r,s,t f,t p c x + c y Biogas hourly profile Collegno WWTP, Turin Giarola et al. (2017). Accepted Manuscript in Applied Energy 7
LCOE, /kwh Technological learning Cost reduction needed to cut 68 % of CAPEX (~10 k modules) 0,15 0,1 0,05 SOFC SOFC-60 MGT ICE 0 CAPEX_8303 CAPEX_3346 CAPEX_2077 Giarola et al. (2017). Accepted Manuscript in Applied Energy 8
LCOE, /kwh High efficiency sludge handling (TSS 8 %) 0,15 0,1 0,05 0 SOFC SOFC-60 MGT ICE Giarola et al. (2017). Accepted Manuscript in Applied Energy 9
1. Market potential: eligibility General stats ~ 23,000 WWT plants in Europe 15,000 GWh/y energy need 27 Mt CO 2 -eq/y emissions 2.42 7.02 10 9 m 3 /y biogas Eligibility i. WWTP suitable for AD>20,000 P.E. ii. With secondary biological treatment 1072 819 758 583 608 402 230 DE ES UK IT FR PL NL 10
2. Market potential: assumptions a) Size WWTP size Persons Equivalent Electricity consumption, kwhe/pe XS 20,000 60,000 48 S 60,000 150,000 42.3 M 150,000 350,000 L 350,000 750,000 XL 750,000 > 1,100,000 37.6 b) Thermal load: Suspended Solids: 3 % Air and ground daily temperature Digester temperature (42 C) Sludge residence time (20 days) a) Biogas profile: Archetypal profiles - Collegno (XS,S,M), Castiglione (L,XL) 11
3. Market potential: energy costs WWTP size Natural gas, GJ/y XS 1,000 10,000 S M L XL 10,000 100,000 Electricity, MWh/y 500 2,000 2,000 20,000 20,000 70,000 WWTP size Natural gas, /kwh XS 0.044 S M L XL 0.00381 Electricity, /kwh 0.1453 0.1267 0.1087 12
Utilization Costs, k /y 4. Market potential: optimal cell number WWTP 150,000 350,000 PE 100% 80% 60% 40% 20% 0% 1 2 3 4 5 6 7 8 9 10 number of modules 1.400 1.200 1.000 800 600 400 200 0 Technology Utilization Biogas Utilization Total Costs, k /y Operating Costs, k /y 13
5. Market potential: SOFC capacity per size i. Average 2016 EU natural gas and electricity prices ii. iii. Average European temperature Specific Biogas production: 10 L/PE/day WWTP size SOFC unit capacity, kw Total SOFC installed capacity, kw Technology utilisation (%) Persons Equivalent Module number XS 20,000 10 3 30 80 % S 90,000 58.3 2 116.6 59 % M 210,000 58.3 3 4 233.2 72 % L 450,000 100 6 600 77 % XL 1,100,000 150 10 11 1,500 1,650 77 % 66 % 14
6. Market potential: sensitivity i. Natural gas and electricity prices (± 50%) ii. iii. Location (hottest and coldest European cities) Advanced sludge technologies (to increase TSS) The most influential parameter is the biogas availability 530 830 MWe SOFC capacity in current WWTP market ~ 9,000 14,000 modules of 58.3 kw If a specific biogas production of 20 L/PE/day is considered, the market potential could nearly double 15
Take-home message Current costs of SOFC do not quite compete with alternative technologies, but implementation of more efficient sludge handling technologies in WWTPs would make the investment more attractive in this application There is potential for up to 14,000 modules (58 kw units) in the WWTPs in Europe, considering the current AD technology The current market for SOFCs in WWTPs gives evidence to support the technology diffusion and favour technology cost reduction If the number of manufactured units reached 10,000 units the capital costs of SOFCs would fall by more than 60 % 16
Thank you for your attention s.giarola10@imperial.ac.uk