Renewable energy storage and clean dispatchable power

Transcription

1 Renewable energy storage and clean dispatchable power Prof. dr Fokko Mulder Delft University of Technology Faculty of Applied Sciences 1

2 Energy use now Dutch energy use: 2.8 MW/km 2 (excluding sea EEZ) German 1.2 MW/km 2,, EU MW/km 2 World 33 kw/km 2 (entire globe) Source: 75% fossil energy EU energy in figures

3 Where do we plan to go from here? EU roadmap: 80-95% less CO 2 by 2050 No more fossil power Saudi Oil Minister Ali Al-Naimi: "In Saudi Arabia, we recognize that we are not going to need fossil fuels, I don't know when, in 2040, so we have embarked on a program to develop solar energy," 3 21/5/2015

4 Which scenario will we follow? Global Energy Assessment EJ 525 EJ 525 EJ = 525x10 18 J = 86 billion barrels of oil equivalent 4

5 Global Technical Potentials IPCC Renewable Energy Sources and Climate Change Mitigation 2012 Special Report of the Intergovernmental Panel on Climate Change 5

6 A scenario that tries to make Germany CO 2 neutral: Umwelt Bundesamt 6 Large energy use reductions

7 Note: - renewable electricity as main/only source - most electricity converted to chemical fuels for easier transport and storage 7

8 Main forms of renewable energy worldwide: Future: Now: - Solar power - Biomass - Wind power - Hydropower - Biomass - Wind power - Hydropower - Solar power 8

9 Solar Power - Photovoltaic devices ( solar cells ) for electricity generation - solar thermal energy 9

10 Wind power, a mature technology 10

11 Renewables Light switch on continents! (day/night and summer/winter) DESERTEC plan 0 o 11

12 Large area still shows large wind power fluctuations Internet source 12

13 Seasonal variations Sun Daily variations Sun v 3 [m 3 /s 3 ] March equinox June solstice Wind Sept.equinox Dec. solstice J F M A M J J A S O N D Month Wind Zhang, J. Appl. Meteorol. 43 (2004)

14 Varying output of renewables on an extended grid. Here: 70% PV, 30% wind EJ/day avg. EJ/day avg Time [days] Time [days] 14

15 primary energy demand minus electricity electricity demand sun + wind ~30% renewable EJ/day J F M A M J J A S O N D 21 st of month Mulder, J. Renewable and Sustainable Energy 2014

16 How 3 to use varying electricity? - use electricity for more applications (EV, heating, ) - match supply & demand by long/short term storage EJ/day sun + wind supply 2030 electricity sun + demand wind II electricity short storage long storage 0 J F M A M J J A S O N D 21 st st of month 2050: EU: 80-95% CO 2 reduction Short term: NL ~ 132 kwh/house ~ 2 Tesla batteries Long term: NL ~ 20 MWh/house ~ 1850 m 3 natural gas 16

17 With storage one can replace fossil powered capacity Wind Sun Wind, Sun & Storage Sun, Wind & Storage Fossil fuels Fossil fuels Fossil fuels Note EU Roadmap: -80% CO 2 in

18 Available storage technologies may determine the dispatchable power source A. Zuttel et al. Phil. Trans. R. Soc. A (2010) 368,

19 Solutions for large EJ scale energy storage? capacity efficiency Long term Short term EJ scale e - e - Hydropower Compressed air Batteries Hydrogen underground storage NH 3 (l) C n H m O p / x x CO 2 from air? 19

20 Storage options for large scales: to be developed (!) - batteries - H 2 - For the short term only (low J/ ) - Requires long life, cheap batteries - Requires large scale storage method itself - Requires cost reduction - C k H n O m - NH 3 - heat - Synthetic (conventional) fuels - Requires a carbon source (CO 2 from air) - Is already produced & stored at large scale, but not from renewables. - In industrial environment only (poisonous, safety). - Low efficiency, requires new synthesis routes - Conversion losses may be recovered as heat, CHP; this increases cycle efficiency 20

21 Hydrogen fuel - Electrolysis of water using renewable electricity sources: Needs cost reduction to compete with fossil derived hydrogen Pressurized hydrogen storage The target that industry has is a 700 Bar cylinder with a gravimetric storage density of 6 wt% and a volumetric storage density of 30 kgm

22 Materials solutions for hydrogen storage in metal hydrides hydrogen can be more concentrated than in liquid H 2 22

23 From hydrogen back to electricity: Fuel cell principle Zero emission Hybrid car Limited commercial releases Hyundai ix35 FCEV (2013) Toyota Mirai (2014) Demonstration or concept vehicles Toyota FCHV-adv (2008) Honda FCX Clarity (2008) Audi A7 h-tron quattro-fcev (2014) Honda FCV Concept (2014) Mercedes-Benz F-Cell (2009) Mercedes-Benz-F800-(2010) Nissan TeRRA FCV SUV (2012) Roewe 950 Fuel Cell (2014) VW Golf Hymotion (2014) 23

24 Battery storage: lithium ion batteries Li-ion Battery e - e - Li + Li + Li + Voltage: 3.5 V 24

25 Power density (dis-)charge rate Storing electricity fast is difficult! Charging 40kWh battery in 10 minutes means a power input of: 6x40kW = 240kW = 600A x 400V Charge in 3 hours: 14kW 25

26 Ionic diffusion in solids is slow even at atomic level Between neighboring sites µs-ms Mulder et al. PRL 2002 Between phases and nano crystallites ms-s 2D exchange NMR The slow diffusion makes that a Li ion takes an hour or more to travel only 10 μm! Mulder et al. Nature

27 Thin film layout of batteries Mostly dictated by the power handling requirements! 27

28 Energy density of batteries for electrical transport 500 km Electrical car range Energy density (Wh/kg) Cost (euros/kwh) 50 km km > km > km > km >160 < km <350 > 500 Objective Lead Ni-Cd Ni-MH Li-ion Li-ion Next Li-S Li-Air Available Being developed +R&D R&D 28

29 Lithium - Sulfur 29

30 Conclusions - Renewables are growing fast - Solar and wind power are expected to become dominant - The grid can facilitate transport and trade of electricity but it can not (yet) provide storage on sufficient scale - Electricity storage in batteries and fuels will become essential upon increasing renewables implementation - The choice of storage technology will guide which dispatchable Zero emission power sources become available 30

31 Ammonia NH 3 for large scale energy storage Production Storage Use based on abundant elements N, H, and cheap catalysts can be produced using abundant renewable electricity energy density NH 3 : 22.5 MJ/kg (HHV) liquid at 10 Bar, 20 o C current containers can contain ton NH 3 ~ 375 GWh. clean use in fuel cell, combustion engine, gas turbine fertilizer industry as launching customer Acceptance poisonous, but 100+ yr industrial know-how current NH 3 production costs >1.5 % of world energy use >5 EJ/yr (all methane based) Bio degradable (fertilizer) Air H 2 O N % NH 3 l X15 NH 3 jet engine Fe e - many TWh NH 3 Hybrid Toyota GT86 R 31

32 Biofuels can be stored Sugarcane Soybeans Poplar trees Rapeseed Elephant Grass flaxseed Palm oil Algae 32

33 Total energy use [in oil]/ Total earth surface Total yields of crops / m 2 farm To fulfil energy needs by biofuel alone one needs: 28.8/412 = 7% of the earths surface (which is impossible) See: Mulder 33