SECTIE ENERGIE EN INDUSTRIE The crucial integration of power systems; Combining fossil and sustainable energy using fuel cells Kas Hemmes Lunchlezing 21 februari 2006 ; TU Delft SECTIE ENERGIE EN INDUSTRIE

Outline Introduction Classification of Energy systems MSMP Energy systems (Energy Hubs & Modeling and optimization methodology) Examples Conclusions Acknowledgements

SECTIE ENERGIE EN INDUSTRIE Introduction: Energy System YDTCT system boundary Φ i,in (x,t)Φ j,out (x,t) C S Φ loss (x,t)

SECTIE ENERGIE EN INDUSTRIE Introduction: Storage often necessary YDTCT S Yield & Demand Y(x,t) D(x,t)

SECTIE ENERGIE EN INDUSTRIE 1 Classification of energy system 2 3 Linear energy system Co-generation system Tri-generation system

SECTIE ENERGIE EN INDUSTRIE Linear energy system F R N E-net

SECTIE ENERGIE EN INDUSTRIE Input combinations of Fossil and Renewables Biomass Co-firing F R E-net Bio-ethanol Bio-diesel mix F R Transport

SECTIE ENERGIE EN INDUSTRIE Multisource-multiproduct MSMP-systems a b c Etc. d

SECTIE ENERGIE EN INDUSTRIE Example : simple CHP energy hub c

SECTIE ENERGIE EN INDUSTRIE energy hub

SECTIE ENERGIE EN INDUSTRIE Power Flow Coupling

SECTIE ENERGIE EN INDUSTRIE Relation between coupling matrix C and energy hub L = C. P

SECTIE ENERGIE EN INDUSTRIE Optimization How much of which input should be consumed in order to meet the load demand in an optimal manner ? (due to a certain optimality criterion, e.g. energy cost or emissions)

SECTIE ENERGIE EN INDUSTRIE Why new energy systems? What to optimize? Present systems suffer from “inefficiencies” 1.Conversion efficiency < 100% 2.Mismatch between Supply & Demand in time and space 3.Transport losses 4.Not 100% eXergy efficient (minimum entropy production) 5.Not used 100% of the time 6.Not 100% Renewable/sustainable 7.Not flexible, not 100% reliable 8.But also mixing entropy: N2 in Natural Gas; N2 in CO2 off-gas etc. 9.…and Institutional, Economic…

SECTIE ENERGIE EN INDUSTRIE Integration of Fuel Cells in a Nitrogen - Natural Gas mixing station IR-FCFCAir - SEP heat air N2N2 O2O2 NG NG/N 2 /(H 2 ) H2H2 E - power H2H2 Low T heat E - power

SECTIE ENERGIE EN INDUSTRIE Example: FC replacing N 2 /O 2 seperation unit in N 2 -NG mixing station IR-FCLow-T FC air N2N2 NG NG/N2/(H 2 ) H2H2 E - power N2N2 Low T heat The system is producing E-power instead of consuming it !!

SECTIE ENERGIE EN INDUSTRIE DOE goal for the 21 st century fuel cell (higher efficiencies) Thermodynamic efficiency, %  H std Chart source: NETL, Nov C+O 2 = CO 2 (DCC) CH x pyro +DCC Westinghouse tube SOFC Fuel-cell/turbine hybrid technologies Combined cycle Conventional Steam plants

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Precombustion solid-gas separation of Carbon in a MSMP system Thermal decomposition F (CxHy) R (Solar) or Nuclear C H2H2

SECTIE ENERGIE EN INDUSTRIE

Thermodynamic advantages of Direct Carbon Conversion Table 3 Order of magnitude comparison between the electrochemical conversion efficiencies of C, H 2 and CH 4 at 700 o C (Cooper, J. F. et al 2000) Fuel  fc  Nernst loss  irr  tot C H2H CH

SECTIE ENERGIE EN INDUSTRIE Electrochemical gasification in a Direct Carbon Fuel Cell 2C + O 2 ==> 2CO  S>0  H<0 DCFC C Q Power (Solar) Heat can be converted into power with an efficiency higher than the Carnot efficiency! Self regulating process Syngas

SECTIE ENERGIE EN INDUSTRIE DOE goal for the 21 st century fuel cell (higher efficiencies) Thermodynamic efficiency, %  H std Chart source: NETL, Nov C+O 2 = CO 2 (DCC) CH x pyro +DCC Westinghouse tube SOFC Fuel-cell/turbine hybrid technologies Combined cycle Conventional Steam plants C+½ O2=CO

SECTIE ENERGIE EN INDUSTRIE A Fuel Cell that produces hydrogen and converts heat into power ? CO + H 2 O ==> H 2 + CO 2 DCFC C Q (solar) Power Syngas C+½O 2 = CO

SECTIE ENERGIE EN INDUSTRIE Looking for ways to use the full exergetic quality of solid fuel !! Solid fuels become increasingly more important (security of supply). Coal because it is cheap and abundant. Biomass because it is CO 2 neutral. Waste. Also liquids are ‘closer’ to solids than to gases in terms of their exergy value.

SECTIE ENERGIE EN INDUSTRIE Countries with large potential for Solar and Biomass can become the energy producing countries of the future. Fuel cell technology Solar Biomass

SECTIE ENERGIE EN INDUSTRIE Example of trigeneration: H 2 and power co-production using an internal reforming fuel cell. IR-FC NG E - power CO / H 2 heat

SECTIE ENERGIE EN INDUSTRIE MCFC - Hot Module

SECTIE ENERGIE EN INDUSTRIE MCFC Hot Module

SECTIE ENERGIE EN INDUSTRIE Co-production Co-production of hydrogen and power from NG in an Internally reforming fuel cell (IR FC) is worked out by flow sheet calculations on an Internal Reforming Solid Oxide Fuel Cell (IR-SOFC) system. It is shown that the system can operate in a wide range of fuel utilization values from 95% i.e. ‘normal’ fuel cell operation mode up to 60% and lower corresponding to hydrogen production mode.

SECTIE ENERGIE EN INDUSTRIE Internal Reforming - SOFC system flowsheet

SECTIE ENERGIE EN INDUSTRIE Mode 1 – High efficiency mode First we kept the input flow rate of NG constant. The fuel utilization is now decreased by decreasing the current density. 1 input (natural gas input is kept constant at 2000 kW) 3 outputs vs Fuel Utilization Electric Power H 2 & CO (Waste) heat Efficiency vs Fuel Utilization

SECTIE ENERGIE EN INDUSTRIE Mode 1 – High efficiency mode

SECTIE ENERGIE EN INDUSTRIE Fuel cell theory and modeling OCV = Open Cell Voltage  = 100 – 220 mV u f = fuel utilisation i = current density r = specific resistance

SECTIE ENERGIE EN INDUSTRIE Conventional Solution for dealing with fluctuating renewable energy sources essentially is a complex storage device in a linear energy system. E - power Storage

SECTIE ENERGIE EN INDUSTRIE Conventional Solution for dealing with fluctuating renewable energy sources Electrolyser E - power heat H 2 FC O2O2 H2OH2O H2OH2O E - power Storage

SECTIE ENERGIE EN INDUSTRIE Example: Integration of a H 2 - power co-production FC with fluctuating renewable energy sources. IR-FC air N2N2 NG Optional (NG/N 2 ) H2H2 E - power H 2 heat

SECTIE ENERGIE EN INDUSTRIE Energy hub model of previous example IR-FC NG E - power CO / H 2 heat E - power

SECTIE ENERGIE EN INDUSTRIE Remarks on ‘Gasgestookte windenergie’ No storage of H2 needed. Instead the storage capacity of NG is used North sea provides NG and Wind !!

SECTIE ENERGIE EN INDUSTRIE Conclusions System thinking!! Identify "inefficiencies" An integration between Fossil and Renewable is possible and may be crucial in meeting our needs without sacrificing those of future generations. New definitions of efficiency and green energy in MSMP systems needed

SECTIE ENERGIE EN INDUSTRIE Acknowledgments TU Delft : Anish Patil, Theo + Nico Woudstra (Cycle Tempo flowsheet calculations) ETH : Martin Geidle (MSMP concept & calculations)