– a system-wide service Storage – a system-wide service

“Elon Musk hails 'crazy' response to Tesla battery launch” (Guardian, 6 May 2015)

Storage – what its not …. all about electricity and batteries …. an end in its own right …. something new

It’ called fire – it recycles wood!

Why is storage so topical again ? Decarbonisation - all agree on need to reduce carbon emissions … but carbon is major source of energy storage Oil (petrol and diesel) Coal Gas This provides system resilience and flexibility Unintended consequences of decarbonisation Intermittency/security of supply ‘Range anxiety’

Replacing carbon storage – questions What are we trying to achieve? How much are we willing to pay? What services are needed What role can it play in balancing supply and demand? Impact of electrification of heat and transport?

What are we trying to achieve? Time shift – across the day and the seasons Location shift – mobility Sector shift – heat, transport and electricity

What are we trying to achieve? – storage characteristics Energy (kWh) Power (kW) Duration (h) One or two-way Charging/Discharging rates Charging cycles Weight/volume

What are we trying to achieve? – Energy OR 1,000,000,000,000 Wh 1 Wh

How much are we willing to pay? OR £0.001 - £0.01/kWh £100 – £1,000/kWh

Storage technology characteristics

Managing variable production January December

Necessary storage capacity ~ 45 days January December

Balancing demand - the impact of heat

Seasonal gas storage

Current storage comparison System Transport (car tanks) Gas Coal Heat Electricity (Pumped storage) Storage (GWh) 10,000 60,000 30,000 65 27 Cost (£/MWh) 30 - 100 80 - 8,000 >60,000

Current electricity sector examples: Storage used for: Current market Grid services (eg fast reserve) £150m.pa (ca. £35/kW.pa) Capacity/Back-up Currently £19.40/kW.pa (limited to £75) Constraint avoidance £0.15/kWh (limited volume) Arbitrage Limited volume (£0.001 - £0.10/kWh) Grid services - a limited market (£100m’s) Capacity - large quantum, but must be low/competitive cost Constraint payments - naturally volume and time limited Arbitrage - naturally limited

Seasonal storage – probably the biggest challenge In the short to mid-term, natural gas can still provide capacity Other solutions must displace this (all year round), otherwise just an extra cost