Solid Oxide Electrolysis Hydrogen production

Transcription

1 Solid Oxide Electrolysis Hydrogen production Peter Vang Hendriksen Fuel Cells and Solid State Chemistry Division, Risø DTU

2 Outline Principle, what is electrolysis? SOEC Thermodynamics Economy Technology status Durability Upscale (Unit sizes, production capacity) Example of research activities Summary 2 Risø DTU, Danmarks Tekniske Universitet

3 Routes to hydrogen Today From Hydrocarbon sources (NG) via syn-gas (Electrolysis, industrial applications on site) In Future Fermentation, gasification Coal gasification (with CO 2 capture). Fossil Biomass Fossil CHEAP Electrolysis Alkaline PEM SOEC Thermochemical watersplitting Photolysis Sulphur-iodine cycle Electricity, Wind Heat, solar SUSTAINABLE 3 Risø DTU, Danmarks Tekniske Universitet

4 Electrolysis, principle of operation (SOEC) Electricity + Heat Chemical energy Anode: Katode: Oxygen electrode 2O 2- O 2 + 4e - Fuel electrode 2H 2 O + 4e - 2H 2 + 2O 2- O 2 2O 2-2CO 2 + 4e - 2CO + 2O 2-2H 2 O 2H 2 2CO 2 2CO + 4 e - Solid electrolyte Electrolyte Ox. electrode H 2 electrode Temp. Y 0.16 Zr 0.84 O 2 (La,Sr)MnO 3 Ni/Y 0.16 Zr 0.84 O o C 4 Risø DTU, Danmarks Tekniske Universitet

5 Ni-YSZ supported cell ( 2.0G ) Ni/YSZ support Ni/YSZ electrode LSM-YSZ electrode 10 µm Acc. voltage: 12 kv SE image Manufacturing techniques

6 Thermodynamics 300 H 2 O H 2 + ½O Energy demand (KJ/mol) Liquid Gas Total energy demand ( H f ) /(2 n F) Energy demand (Volt) E cell = E tn Temperature (ºC) 0.00 Energy ( volt ) = Energy (kj/mol)/2f E tn = H/2F i E cell - G/2F Price 1/i [A/cm 2 ], η = H/ G > 1, η = 100 % at E = E tn (no heat loss)

7 Hydrogen by electrolysis for transport sector Is this an interesting option? FC vehicle has twice (?) the efficiency of the ICE vehicle FC vehicles may have ranges like ICE vehicle Transport from sustainable resources Market: Many small plants. Good entry point 7 Risø DTU, Danmarks Tekniske Universitet

8 Economical analysis 10 Price of electricity Other assumptions SOEC system cost 0.15 /cm 2 200$/kW* Electricity price ( /kwh) DK Electricity Price in 2010 Average Price Heat Cell voltage (H 2 O) Cell voltage (CO 2 ) 0.23 /kwh 1.3 V (Vtn) 1.5 V (Vtn) Current density 1.5 A/cm 2 Expected life time Interest rate 5% 10 years Expected CO 2 cost 23 /ton Expected H 2 O cost 2.3 /ton Hours Source; S. H. Jensen, S. Ebbesen, K. V. Hansen, A. H. Pedersen # and M. Mogensen, Cost Estimation of H2 and CO Produced by Steam and CO2 Electrolysis, 2011, (Unpublished). 8 Risø DTU, Danmarks Tekniske Universitet *J. Thijssen, U.S. DOE/NETL 2007

9 Economical analysis H 2 production cost ( /kg) /cm /cm 2 Heat 1% Water2% Investment 12% Electricity 85% H 2 production cost ( /Nm 3 ) Equiv. crude oil ( /barrel) Electrolysis activity (hours) Source; S. H. Jensen, S. Ebbesen, K. V. Hansen, A. H. Pedersen # and M. Mogensen, Cost Estimation of H2 and CO Produced by Steam and CO2 Electrolysis, 2011, (Unpublished). Oil price today ~ 79 $/barrel Centralized methanol production, break even at ~ 110 $/barrel AEC, H 2 production cost 1.85 /kg Source; Final Report Green SynFuels, Risø DTU, Danmarks Tekniske Universitet EUDP Source; Project Report plansoec, ForskEL2010,

10 SOFC Technology status Large development projects, (Risø DTU, Haldor Topsøe A/S) Transfer of technology to TOFC History from 2002 to # 12x12 cm 2 cells produced Year Success rate for 12x12 (%) - line Risø DTU, Technical University of Denmark

11 New Topsoe Fuel Cell pilot plant Inaugurated spring 2009 Production for development, test and market introduction 5 MW per year capacity (for demos) Full scale plant in 3-5 years

12 From cells to stacks Each fuel cell gives a voltage of ~ 0.8 volt. To attain useful voltages several cells, e.g. 50, are stacked in series High energy density: Stack electric power density of 2.5 kw/liter demonstrated with by Topsoe - Risø DTU cell stacks Scalable technology: From kw to MW

13 SOEC, Cell performance, Process is reversible World record! S. H. Jensen et al., International Journal of Hydrogen Energy, Volume 32, Issue 15, 2007, P Risø DTU, Danmarks Tekniske Universitet

14 Technology status, SOEC Degradation of standard SOFC operated as electrolysis cells With Clean inlet gasses: No degradation at low current density (up to A/cm 2 at 850ºC) Cell voltage (mv) C, A/cm Electrolysis time (h) H 2 O electrolysis CO 2 electrolysis Co - electrolysis H 2 O + CO 2 S. Ebbesen et al; Journal of The Electrochemical Society, B1419-B

15 Status at stack level Few (~ 7) experiments only Standard TOFC stack (SOFC stack, 2.0G cells) operated as both H 2 O and coelectrolysis A/cm A/cm 2 Stack voltage (V) Electrolysis time (h) No degradation at low current density (up to A/cm 2 at 850ºC) The Danish National Advanced Technology Foundation s advanced technology platform Development of 2nd generation bioethanol process and technology,s. Ebbesen et al. Int. J. of Hydrogen Energy 36, 2011

16 New SOFC cell types tested for electrolysis durability A TOFC 10-cell stack with three classes of SOFC cells is being tested currently 800 C, A/cm 2, co-electrolysis (45%CO 2-45%H 2 O-10%H 2 ), 1000 hr. 2.5* G cells improved over 500 hr.!! 2.1 G cells and MTC-cells showed mild degradation 16 Source: M. Chen ForskEL2010, Energinet.dk

17 Electrolysis, Comparison of technologies Type Maturity Current density Other Advantages AEC Proven LT-PEM H 2 at pressure SOEC CO 2 /H 2 O electrolysis HT-PEM HT heat Documented lifetime 1/Price SOEC: Cheap materials, No noble metals, Low volume Winner :???? Determined by price per Nm 3 /hr over lifetime at right scale and time 17 Risø DTU, Danmarks Tekniske Universitet

18 Electrolysis, Comparison of technologies Type Largest system Commercial suppliers Danish companies tanks/day AEC 3.5 MW Norsk Hydro Hydrogenics Iht,. Green Hydrogen Siemens Corp. Tech. (DK) 500 LT-PEM 45 kw H-TEC systems Hydro, IRD SOEC 15 kw Haldor Topsøe A/S TOFC 2! HT-PEM W Tantaline 18 Risø DTU, Danmarks Tekniske Universitet Elektrolyse 5/

19 Status and Challenges Status 20 kw SOFC deomstrated Wartsila/TOFC 100 kw SOFC deomstrated (1996) Westinghouse 250 kw design projects stated in Europe and US TOFC production line 5 MW/year 65 tanks per day 20 units Scale relevant for early demonstration (?) Durability at 0.75 A/cm 2 looks promising (1000 hour test, SOFC hours) Economy (SOEC electrolysis) looks promising Challenges Fast scale up needed Large risk (FC Vehicle vs E-Vehicle vs synthetic sustainable fuels) Demonstrate reliability and lifetime Improve power density Demonstrate pressurized operation 19 Risø DTU, Danmarks Tekniske Universitet

20 Acknowledgement Sponsors Danish Energy Authority Energinet.dk EU Topsoe Fuel Cell A/S Danish Programme Committee for Energy and Environment Danish Programme Committee for Nano Science and Technology, Biotechnology and IT Colleagues: M. Mogensen, S. Ebbesen, A. Hauch, S. Højgaard Jensen, X. Sun, M. Chen, C. Graves, J. V. T. Høgh, K. Agersted Nielsen, Y. L. Liu, J. U. Nielsen + many many more

21 Status and Challenges Scale relevant for early demonstration (?) Durability at 0.75 A/cm 2 looks promising Economy (SOEC electrolysis) looks promising SOFC technology is a very good starting point for SOEC technology Challenges Fast scale up needed Large risk (FC Vehicle vs E Vehicle vs synthetic sustainable fuels) Demonstrate reliability and lifetime Improve power density Demonstrate pressurised operation Further information Report: Pre-Investigation of Water Electrolysis, PSO-F&U Report: plan SOEC ForskEL