1. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 1 Dr Tim Fox Head of Energy and Environment Institution of Mechanical Engineers Cryogenics for Storing Air for Electricity Generation in a UK Policy Context

2. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 2 Fully engaged in public debate

3. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 3 Introduction Overview  Policy landscape and drivers  Energy storage  A novel cryogenic approach  Pilot plant project  Barriers  Policy needs  Conclusions

4. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 4 UK energy landscape Stable demand profile for past three decades Need to replace ageing plant and infrastructure North Sea gas depleting (by 2020, 80% of gas demand will need to be met through imports) Increasing global competition for limited primary energy resources, particularly oil and gas Decarbonisation aspirations and obligations (targets)

5. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 5 UK Energy policy Sustainability EU 20 / 20 /20 targets Climate Change Act 2008 Increased renewables Decarbonisation of electricity Decarbonisation of other sectors Increased use of electricity as a clean energy vector Energy conservation Energy efficiency Distributed generation Security of supply Licence conditions provide requirements for supply Ensure sufficient peak capacity (Winter) Maintain margin with adequate reserves Increase renewables and nuclear to reduce reliance on imported gas and other fuels Develop system flexibility and community level resilience Adopt smart grids Invest in storage Economy Open markets deliver competitive prices Interconnections link markets Avoid price uncertainty for consumers Political intervention and regulation to protect consumers Community and domestic stakeholder participation in ownership, production and trading Asset optimisation

6. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 6 Generation under ‘Gone Green’ scenario Source: National Grid Future generation mix

7. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 7 Renewables and power system  Large scale and small scale  Variability and location  Surplus and shortfall  Short and long term reserves  Markets/subsidies

8. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 8 UK power network Large scale competitive generation, regulated transmission and distribution Limited embedded generation (at distribution level) Wholesale market supplies retail customers Limited number of self suppliers System planned to meet peak demand plus reserves – spare (or under utilised assets) Low level of interconnections to other networks Regulated wires businesses Facing substantial change Significant shift from dispatchable generation to time variable generation Peaky demands from digital society, switch to heat pumps, uncertain effect of electric vehicles Distributed community and domestic level generation and trading Average and peak domestic demand likely to increase Balancing the system requires more flexibility Higher level on continental interconnection Today’s networkThe future

9. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 9 Tools for system balancing Flexible generation (reserve) Storage (absorbs and rejects power) Connectors (import or export) Demand response

10. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 10 Storage – enabling technology Flexibility of scale and location Intermittent renewable energy sources  Mix of storage technologies analogous to generation mix  Defers network investments and lowers system costs  Reduces SMART grid and interconnection risks Large base-load electricity generation  ‘Wrong time’ electricity generation – too much or too little  Optimises return on investment (ROI) in renewables plant  Reduces need for idle spare capacity (reduces investment costs in asset base) and avoids (volatile) fuel costs  Sweats assets for improved ROI – e.g nuclear and biomass

11. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 11 Enablers – electricity storage Pumped hydro Compressed-air Power to gas Flywheels Thermo processes Batteries and capacitors Fuels

12. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 12 Application scales and potential users Storage application matrix

13. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 13 Using cryogenic technology Principles  Use liquefied air or liquid nitrogen as storage medium  Mature technology from air separation industry  Proven ‘standard’ equipment in daily use with well established supply chains  Energy density of cryogen compares well with other medium

14. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 14 Highview Power Storage Ltd The Company Pilot Plant  Established 2005 to design and develop utility-scale energy storage and power systems  $18m equity investment plus $1.8m DECC capital grant  UK company based London with pilot plant in Slough  Working with UK Universities to develop technology further  300kW hosted by SSE at Slough Heat & Power  Operating since April 2010, fully integrated into local distribution network Tim Fox thanks the Directors of Highview Power for permission to present this work and the engineering staff for assistance in preparing this talk.

15. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 15 The storage cycle

16. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 16 The plant (1)  300 kW turbine output, 20° (68°) to 60°C (140°F) inlet temp  30 tonne/day liquefier, 2.5 MWhrs storage

17. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 17 The plant (2) Milestones  2005 – research begins University of Leeds  2008 – pilot plant project starts November  Power recovery and cold recovery ops Spring 2010  2010 – STOR service trials begins  Cold storage, recycle and liquefaction ops Spring 2011  2011 - Triad service trials  2012 – pilot successful – next step commercialisation Note: STOR = Short Term Operating Reserve – balancing duty

18. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 18 Value of cold recycle  Available enthalpy for cold cycle ~300kJ/kg of liquid product  Cycle simulation indicates near term target thermal storage efficiency of 80% would deliver >50% cycle efficiency Achieved on pilot plant Target cold recycle at full scale

19. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 19 TS diagram for power recovery Four Stage Expansion With re-heat between stages Compression of cryogenic liquid Heat addition at Constant pressure

20. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 20 The value of waste heat More work recovered with use of waste heat

21. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 21 Commercial service trials Summary of STOR trials  Over 2 week period achieved 94.6% availability.

22. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 22 Results - Power recovery Time (minutes) Power (kW)

23. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 23 Pilot outcome Overall  Highview have successfully demonstrated use of cryogenic technology for electricity storage at pilot plant scale  Viability of cold recycle to improve efficiency of cryogen manufacture  Use of waste heat for cycle efficiency improvements  Ability to deliver commercial reserve services

24. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 24 Possible next steps Commercial scale demonstration  10 MW output with >50% efficiency  Liquefier sized to suit market application  100’s MWs output with GWhs storage  Capital cost ~$900 to $1900/kW  Annual O&M cost ~2% capital cost  No geographical constraint and benign environmentally  70% efficient with waste heat at 239°F

25. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 25 Barriers and challenges Research, development and demonstration funding Classification of storage solutions Electricity market structure  Electricity “consumer” and electricity “generator”  Competitive generation market and highly regulated transmission and distribution provider  Need to be allowed to access multiple income streams  Lack of incentivisation  DECC Energy Storage Technology Demonstration  £0.5 million for 12 organisations – feasibility of ideas  DECC Storage Component Research & Feasibility Study  £1.5 million for 4 companies to improve materials and explore systems in UK electricity networks

26. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 26 Policy needs Separate classification for storage Recognise the value of storage Create competitive incentivised environment Support demonstration at commercial scale  Strongly dependent on network generating mix and local market rules  Recognise unique roll as both ‘consumer’ and ‘provider’  Needs to ensure inclusion and access to multiple streams

27. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 27 Conclusions Develop policy frameworks and mechanisms that reward value of electricity storage in UK power markets Create a shop-window for UK electricity storage technology so innovations can be seen and sold Encourage/support UK companies and research organisations that are developing and demonstrating storage technologies

28. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 28 Thank you @TimFox_IMechE

29. Improving the world through engineeringwww.imeche.orgImproving the world through engineering 29 Storage comparisons