Reaping what we Sow The ever-increasing need for energy storage

Andy WestSenior Chemist

• Introduction• Energy Challenges• Hydrogen• The Ammonia Economy• Chemical Storage• Thermal Storage• Other Techniques• Outlook

Introduction• ‘Novel’ energy generation research is well supported

Energy Challenges• Generation is easy, storage is not...• At small scale...• At large scale...

Llyn Stwlan

Hydrogen• ‘Darling’ of energy storage, but… • 1Kg of H2 = 3.5Kg of petrol, petrol = 4l, H2 = 11m3!• Even at 300 atm, fuel tank would be x10 size • H2 attacks storage tanks

• Liquefied H2 is -253°C, Antarctica is -89°C• 40% of energy is used to liquefy• Storage maintenance uses more energy

The Ammonia Economy• Ammonia can be a hydrogen carrier, ICE and FC fuel• Storage under moderate pressure is easy (8 atm)• Fuel tanks would be 3x volume, 2x weight vs petrol• Ammonia production undertaken for >100 years• Unlike methane/methanol/ethanol, no C emissions

The Ammonia Refinery

Water hydrolysis

N2 purification

Energy

NH3 Synth

Hydrogen

Nitrogen Heat

Chemical Storage• Flow cells

Chemical Storage• Vanadium, V/bromide and polysulphide/ bromide• Size is theoretically limitless• No ‘charge memory’, storage decay• Charged by electricity / replacement of electrolyte• Used for power smoothing, wind / solar storage

Sodium-ion Battery• Lithium is expensive and becoming rarer• Sodium-ion batteries are significantly cheaper• Higher theoretical energy storage than lead/acid• Suitable for large and small energy storage apps• Cutting edge – no. of cycles is major hurdle

Thermal Storage• Solar thermal technology advancing• 1GW in 2012, 14GW by 2016• Only works in the day!• Energy storage as heat is highly efficient (night ops)• Need thermally stable heat transfer fluids

Thermal Storage• Current salts are stable up to 500°C• Heat can be stored for a week• Torresol (ES, 2011) 1st CSPS 24h continuous power gen• 20MW plant, larger planned

Other Techniques• Supercapacitors / ultracapacitors• Superconducting magnetic energy storage• Flywheel energy storage• Ice storage• Solar ponds• Biofuels

Outlook• E storage research more important than E generation• Lots of technologies with potential• Key factors are efficiency and E storage density• Large scale and small scale solutions will differ

Impact For Your Business• Improved ROI on renewables• No change at all!

Vanadium Oxide