Sustainable Energy Storage: The DIFFER Solar Fuels program. Richard van de Sanden

Transcription

1 Sustainable Energy Storage: The DIFFER Solar Fuels program Richard van de Sanden DUTCH INSTITUTE FOR FUNDAMENTAL ENERGY RESEARCH, NIEUWEGEIN, THE NETHERLANDS DIFFER is part of and Toon Verhoeven, Big Science industriedag 2013, DARE!! Woerden, 16 oktober 2013 Toon Verhoeven, Big Science industriedag 2013, DARE!! Woerden, 16 oktober 2013 Relocation starts March

2 Motivation: the TeraWatt Challenge 1 Energy mix required to meet rising global energy demand Sustainable energy production to replace fossil fuels (CO 2 neutral!) - Solar panels - Wind turbines - Bio-based processes and chemicals - (Geo)thermal processes - Hydro-energy - - Nuclear fusion Match supply and demand Inhomogenous and intermittent character of sustainable sources - Smart grids - Electrical energy storage - (Geo-)thermal/geostatic storage - Chemical fuels (CO 2 -neutral!) - 1 M.I. Hoffert et al. Nature 385, 881 (1998) Motivation: CO 2 neutral (=Solar) fuels Closing the carbon cycle Excellent potential to harness solar energy Enables storage of sustainable energy in CO 2 -neutral chemical fuels Essential ingredient in the future sustainable energy infrastructure Essential to provide future carbon based chemical feedstock! 2

3 Motivation: Hydro-carbons? Ideal for energy storage High energy density per volume and per mass Use of existing hydro-carbon infrastructure Transport, distribution and use Motivation: Hydro-carbons? Ideal for energy storage High energy density per volume and per mass Use of existing hydro-carbon infrastructure Transport, distribution and use Coupling electricity and gas system: Power-to-Gas (P2G) Large storage capacity in gas grid (surplus RE electricity) NL gas grid ~ 552 TWh (one day EU electrical power ~ 10 TWh) 3

4 Challenge Shell Qatari plant Carbon containing fuels from CO 2, H 2 O and renewable energy Challenge Use-inspired research is focused on: H 2 generation from H 2 O CO generation from CO 2 The challenge: To find a cost-effective and energy efficient conversion process using robust and scalable materials and processes 4

5 Status & Potential (non-bio route) Direct conversion Capture direct air point source Thermochemical % CO 2 -neutral fuels H 2 CO Purification CH 4 CH 3 OH 1 See e.g. Steinfeld group (ETH Zurich), Science (2010) Thermochemical using CSP (direct) Concentrated solar power (CSP) CeO 2 + sunlight CeO 2-x +1/2x O 2 CO 2 + CeO 2-x CO + CeO 2 Or based on ZnO, Fe 3 O 4 Cyclic, solar to CO/H 2 efficiency: 2-3% Steinfeld group (ETH Zurich), Science (2010) 5

6 Status & Potential (non-bio route) Direct conversion Capture direct air point source Thermochemical % Photo-electrochemical % CO 2 -neutral fuels H 2 CO Purification CH 4 CH 3 OH 2 See e.g. Abdi et al. Nature Commun (2013) 1 See e.g. Steinfeld group (ETH Zurich), Science (2010) Photo-electrochemical conversion Three approaches with focus on H 2 generation: Van de Krol et al., J. Mater. Chem. 18 (2008) Van de Krol et al., Photoelectrochemical Hydrogen Production,

7 Challenges (direct conversion) Artificial Leaf approach photo-electrochemical conversion Direct Solar-to-chemical energy conversion Requires the development of novel materials (catalysts, semiconductors, etc.) and materials combinations which are robust (acid and basic solutions!) and abundantly available Requires the design of novel nano-structured device architectures, based on detailed kinetic and energetic understanding of light-tocharge and charge-to-chemical conversions Photoelectrochemical Solar Fuel Conversion Daniel Nocera Harvard/MIT Rene Janssen TU/e-DIFFER Nathan Lewis et al. JCAP. Abdi et al. Nature Commun (2013) 7

8 Photo-electrochemical conversion of CO 2? To tailor the catalyst to optimally use the solar spectrum for activating the catalyst TiO x tubes with Cu catalyst CO 2 + 2H 2 O CH 4 + 2O 2 Solar to methane efficiency η = % Roy, Varghese, Paulose, Grimes, ACSNano 4, 1260 (2010) Status & Potential (non-bio route) Capture direct air point source CO 2 -neutral fuels H 2 CO Purification Indirect conversion PV 25% Wind 30% Electrolysis % CH 4 CH 3 OH Overall energy efficiency: >15 25% 1 See e.g. R. de Levie, J. Electroanalytical Chemistry (1999) 8

9 Challenges (indirect conversion) Renewable electricity + Electrolysis Indirect Solar-to-chemical energy conversion Alkaline Electrolysis Liquid electrolyte, slow ramp up, robust, energy efficiency 67-82% Polymer Exchange Membrane Electrolysis Inverse fuel cell, membranes are costly, energy efficiency 67-93% Solid Oxide Electrolysis High temperature ( C), costly, energy efficiency 50-90% EASE/EERA report Electrical Energy Storage Technical maturity of various part of chemical storage options Joint EASA/EERA recommendations for a joint European Energy Storage Technology Roadmap towards

10 Challenges (indirect conversion) Renewable electricity + Electrolysis Indirect Solar-to-chemical energy conversion Improve flexibility ( cold start ) and lifetime of electrodes Focused on cost efficient materials and materials synthesis e.g. polymer membranes for polymer membrane electrolysis Novel innovative operational concepts e.g. heat integration and co-electrolysis for high pressure solid oxide electrolysis Indirect Conversion of Solar Radiation > 6 /kg * Costs determining factors Useof scarcematerials Lifetime, durability Expensive (a.o. membranes) Power-to-gas Large scale deployment ongoing a.o. in Germany!! * H 2 generation from CH 4 steam reformation <1 /kg 10

11 Challenges (indirect conversion) Renewable electricity + Electrolysis Indirect Solar-to-chemical energy conversion Improve flexibility ( cold start ) and lifetime of electrodes Focused on cost efficient materials and materials synthesis e.g. polymer membranes for polymer membrane electrolysis Novel innovative operational concepts e.g. heat integration and co-electrolysis for high pressure solid oxide electrolysis Challenges (indirect conversion) Renewable electricity + Plasmolysis Indirect Solar-to-chemical energy conversion Improve flexibility ( cold start ) and lifetime of electrodes Focused on cost efficient materials and materials synthesis e.g. polymer membranes for polymer membrane electrolysis Novel innovative operational concepts e.g. heat integration and co-electrolysis for high pressure solid oxide electrolysis To overcome these challenges for electrolysis: alternative indirect approach based on the generation of a nonequilibrium CO 2 plasma using renewable electric energy (DIFFER) Efficency [%] CO 2 CO + ½O 2 Energy efficiency [%] Conversion efficiency [%] Power [W] Bongers et al. (2013) 11

12 DIFFER s Strategy Artificial Leaf Plasmolysis DIFFER in its research strategy will focus on: Fundamental research on direct conversion of solar energy by means of the artificial leaf approach Indirect conversion of renewable electricity by means of nonequilibrium plasma conversion Plasmolysis approach Thermodynamics Energy efficiency approx. 42% (@ 2500 K) 12

13 Plasmolysis approach Nonequilibrium Energy efficiency is essential!!! 1 Why plasma (benefits)? Higher energy density medium (>10MW/m 3 ) - Smaller footprint (?) Scalable technology - e.g. C 2 H 2 & carbon black process - use of earth abundant materials Can quickly react to changes of renewably energy supply - peak shaving Can relatively easily activate CO 2 Plasma-chemical Conversion 1 Benchmark is Electrolysis with its high effciciencies of >80% Plasmolysis approach Efficency [%] Energy efficiency [%] CO 2 CO + ½O 2 Conversion efficiency [%] 10 Bongers et al. (2013) Power [W] Potential Energy efficiency 1 >90% Why nonequilibrium plasma? Higher energy density medium (>10MW/m 3 ) - Smaller footprint (?) Scalable technology - e.g. C 2 H 2 & carbon black process - use of earth abundant materials Can quickly react to changes of renewably energy supply - peak shaving Can relatively easily activate CO low gas temperature 1 A. Fridman, Plasma Chemistry (Taylor&Francis. 2009) 13

14 Plasmolysis approach capture & release CO 2 activation & CO separation chemical synthesis to fuel separation & recycling Basic research topics in the CO 2 processing chain Materials that operate in conjunction with a plasma treatment Understanding and controlling the nonequilibrium kinetics in CO 2 containing plasmas Designing novel plasma excitation schemes for energy efficient CO 2 activation System integration for efficient gas stream separation and reactor up scaling aspects DIFFER s Strategy Artificial Leaf Plasmolysis DIFFER in its research strategy will focus on: Direct conversion of solar energy by means of the artificial leaf approach Indirect conversion of renewable electricity by means of nonequilibrium plasma conversion 14

15 The artificial leaf approach Research will be on fundamental mechanism: which limit the performance and processes (acid and basic) which govern materials degradation Strategies will include nanostructuring of materials to bypass limitations of bulk material properties Key in functioning of the artificial leaf is also the system integration, integration aspects are considered from the onset of the research Fundamental understanding of interfaces is key, e.g. the interface between a semi-conductor and catalysts and the gas/liquid/solid phases need to be understood Experiments and computer modeling are essential to address the processes at these interfaces down to the fundamental (atomic) scale level The artificial leaf approach (cont.) Basic research topics in artificial leaf approaches Novel nanoscale architectures to convert solar energy with high efficiency Improved absorber layers for more efficient solar-to-charge conversion, photon management and multi-junction solar cell architectures Developing improved electrocatalyst, which generate an optimal potential with little overpotential to split chemical bonds and which are robust to photodegradation Integration of the solar-to-fuel device 15

16 The DIFFER Solar Fuels program Artificial Leaf Plasmolysis DIFFER in its research strategy will focus on: Direct conversion of solar energy by means of the artificial leaf approach Indirect conversion of renewable electricity by means of nonequilibrium plasma conversion 16