transformative change grid scale energy storage · prudent energy 600-kw/3,600-kwh vrb-ess, ca, usa...

Professor Nigel Brandon OBE FREng

BG Chair in Sustainable Gas

Director, Sustainable Gas Institute

Imperial College London

Director: Hydrogen and Fuel Cell SUPERGEN Hub (www.h2fcsupergen.com)

PI: Energy Storage Research Network (www.esrn.co.uk)

[email protected]

Transformative change – grid scale energy storage

http://www.h2fcsupergen.com/

Thomas Edison in The Electrician (London) Feb.

17, 1883, p. 329

"The storage battery is, in my opinion, a

catchpenny, a sensation, a mechanism for

swindling the public by stock companies. The

storage battery is one of those peculiar things

which appeals to the imagination, and no more

perfect thing could be desired by stock swindlers

than that very selfsame thing. ... Just as soon as

a man gets working on the secondary battery it

brings out his latent capacity for lying.“

Content

• Why grid scale energy storage?

• Technology opportunities and trends

– Lithium batteries

– Sodium batteries

– Redox flow batteries

– Zinc air batteries

– Liquid air

– Pumped heat

– Power to gas

• Summary and way forward

Three Basic Questions

• What value does energy storage bring to the system?

• What cost does energy storage need to be?

• What characteristics do energy storage technologies need for

grid scale application?

Strategic Assessment of the Role and Value of Energy Storage Systems in the

UK Low Carbon Energy Future , Goran Strbac, Marko Aunedi, Danny Pudjianto,

Predrag Djapic, Fei Teng, Alexander Sturt, Dejvises Jackravut, Robert Sansom,

Vladimir Yufit, Nigel Brandon, Energy Futures Lab report for the Carbon Trust, June

2012 www.carbontrust.com/media/129310/energy-storage-systems-role-value-

strategic-assessment.pdf

The value of storage depends on the system

10 GW distributed storage

Strategic assessment of the role and value of energy storage systems in the UK Low Carbon Energy Future, Report for Carbon

Trust; G Strbac et al, (2012) Energy Futures Lab Imperial College London.

£300/kWyr ~ £3000/kW*

For a 6 hour store ~ £500/kWhr *Assuming 7.5% WACC and 25 yr life

What system savings can be generated if

energy storage is available?

2030 2050



Predicted duty cycles for grid scale application

Pattern of use for a distributed

storage system, with 6 hours of

storage capacity. This equates to

around 350 deep cycles per

annum.

Pattern of use for a bulk storage

system, with 48 hours of storage

capacity. This equates to around

250 shallow cycles per annum.



Energy vs Power

The value of storage added is not strongly

affected by increases in storage duration

beyond 6 hours (shown here is a 10 GW case in

base case scenario in 2030).

Low cost solutions are needed in both cases as

energy requirements increase.



Importance of round trip efficiency

Round trip efficiency does not have as significant impact an impact on the value of

storage as might be expected, but an increase in efficiency does open up a larger

market as more storage is deployed (shown here is the 2030 base case with 24 hour

capacity). It is therefore important to consider the overall costs, scaleability, and lifetime

of storage – round trip efficiency alone is not a good selection criteria



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2030 Bulk storage

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2030 Distributed storage

What do we learn from this?

• No one storage technology meets all the requirements – a portfolio of

storage technologies are therefore likely to be needed tailored to given

applications.

• It is the lowest cost of delivering the storage function that matters.

• Lifetime and technology risk are both important factors in determining the

effective cost of storage.

•An important issue where data is very limited is that of the lifetime of grid

scale storage technologies in practical applications, and how this relates to the

duty cycle and means of control. This increases the risk of investing in storage

technologies. For example, in automotive applications it is known that the

lifetime of Li-batteries can be increased by only operating them over a portion

of their full charge range, but this has implications for size and cost (e.g. 1000

cycles to 80% DOD, 1600 cycles to 50% DOD, 2670 cycles to 30% DOD

“Cost and performance of EV batteries”, element energy, 2012”).

Energy storage technologies deployed on grid (2010 - global)

28.4 GWh of Li-ion cells sold for consumer applications in 2010

Cost Pumped hydro (DOE), 1.3 GW, 11.7 GWh, $900-2000/kW, $103/kWh

Lithium ion batteries

• Current state of the art

designed for automotive

applications.

• Packs cost around $800 per

kWh. Li-ion pack cost may

reduce by 50% by 2020, and

70% by 2030, through

technology advances and

volume manufacturing for

transport applications.

• (Tesla claim they are at $300

kWh).

• High energy density, high rates of charge and discharge, but lifetime

currently a major concern for grid applications.

• Known resources of 33M tonnes Li will meet EV market requirements, but

may put pressure on Li supply for grid scale applications.

Sodium ion batteries

• Sodium is much more abundant than lithium, offering potentially lower

costs and less concerns over materials supply.

• Technology still at an early stage – lots of room for innovation.

• Builds on UK strengths in lithium ion technology.

• Materials system under development by Peter Bruce (Oxford), Clare Grey

(Cambridge) and others.

• Novel manufacturing which allows larger electrodes to be fabricated, and

routes to controlled microstructures to optimise performance and lifetime,

are being developed by Patrick Grant at Oxford – also for Lithium batteries

and supercapacitors.

• A battery technology designed for grid scale storage – not one adapted

from a storage technology where gravimetric energy density is a key factor.

Redox Flow Batteries (RFB)

Prudent Energy 600-

kW/3,600-kWh VRB-

ESS, CA, USA

• A flow battery stores energy in tanks, usually as a liquid oxidant and

reductant, then flows these through a fuel cell when power is needed. As

such RFBs decouple the cost of power and energy.

• The all vanadium flow battery is the most common, and is commercially

available with 2.4M Vanadium and a power density of 0.15 W cm-2, at

around $800 per kWh for a 200 kW - 700 kWh system, >13,000 cycles.

• Recent work in the USA has shown that 1.5 Wcm-2 can be achieved by

optimisation of the flow field and electrode. A x10 improvement.

• We are exploring novel chemistries which offer 24M (x10) of much lower

cost reactants, and use significantly cheaper membranes.

Zinc-air batteries

• Zinc-air batteries offer (potentially) up to three times the energy density of

Li-ion batteries, but with much lower cost and higher levels of intrinsic

safety.

• Technology is being developed commercially, but remains at a relatively

early stage, with cycle life (in particular dendrite formation) a key issue.

• But costs are encouraging, offering costs of $190 per kWh based on

developer (Eos) projections.

Liquid Air Energy Storage

Liquid air or nitrogen is generated when energy is available, which is heated

and expanded through a turbine when energy is needed. The process has

scale, and uses equipment already engineered for the cryogenic industry.

Round trip efficiency ~60%, access to low grade waste heat improves round

trip efficiency to 70%. The technology is applicable to the range 5MW/15

MWh to 50 MW/200 MWh. Current costs at $900/kWh for 15 MWh,

projected to be <$500/kWh at larger plant.

1 MWh of energy storage requires

around 10 tonnes of stored liquid

air.

LNG is stored in 25,000 tonne

tanks = 2500 MWh if equivalent

tanks were used for this purpose.

Being developed by Highview

Power Storage (UK).

Pumped Heat Energy Storage

Isentropic (UK) are developing a 1.5MW/6 MWh demonstration unit. The

storage system uses two large containers of mineral particulate. Electricity is

used to pump heat from one vessel to the other resulting in the first cooling

to around -160°C and the second warming to around 500°C. The heat pump

can then be operated in reverse to drive an electrical generator. The round

trip efficiency is 72-80% depending on size, and the technology can be

deployed at the MW/MWh scale.

Power to Gas (P2G) • Generation of hydrogen using fast response electrolysis and

its storage and/or injection into the gas network. 1MW 70%

efficient electrolyser available from ITM Power. 11 P2G systems

are currently operational in Germany. UK Natural Gas

consumption in 2012 was 833 TWh.

• Generation of hydrogen for combination with CO2 in chemical

or biological methanation reactions, and injection of methane

into the gas grid. Methanation reactors ~ 65% efficient.

Produced methane costs predicted to be 4.2 & 28.2 p/kWh for

biological & chemical methanation [ITM for DECC, 2013].

Management Board:

10 Academics from seven UK universities,

all leading a work package integrating a

range of disciplines

Advisory Board:

A range of Industrial partners sit on our

advisory board

Hydrogen and Fuel Cell SUPERGEN www.h2fcsupergen.com

Science Board: This Board comprises of around 80 UK-based

academics working in H2FC research

Associate Membership: Open to anyone working in H2FC research.

The Hub has 240 Associate Members.

Around 330 members of H2FC community

RCUK funded activities in grid scale

energy storage

• Grand challenge programme in grid scale energy storage:

• Energy Storage for Low carbon Grids, £5.5M 5 years from Oct 1st 2012. PI Goran

Strbac (Imperial). Co-I’s N Brandon & R Green (Imperial), P Taylor (Newcastle), J

Bialek (Durham), P Bruce & P Grant (Oxford), C Grey (Cambridge), D Rogers

(Cardiff), X Guo (UCL), Y Ding (Leeds), P Hall (Sheffield).

• Integrated, Market-fit and Affordable Grid-scale Energy Storage (IMAGES), £3M 5

years from Sep1st 2012. PI Jihong Wang (Warwick). Co-I’s P Mawby, R Critoph, M

Waterson, R MacKay (Warwick), D Evans, A Milodowski, J Busby (BGS), M

Thomson, P Eames (L’boro), S Garvey, M Giulietti (Nottingham),

• SUPERGEN Energy Storage Hub, £3.9M, 5years from July 2014, PI P Bruce (Oxford).

Co-I’s P Grant (Oxford), S Islam (Bath), N Brandon and G Strbac (Imperial), C Grey

(Cambridge), A Cruden (Southampton), P Jennings and J Wang (Warwick), Y Ding and J

Radcliffe (Birmingham).

• Energy Storage Research Network, £490k, 3 years starting Oct 1st 2012. PI N

Brandon, Co-I G Offer (Imperial).

Capital for Great Technologies£30 million EPSRC funding announced for grid-scale energy storage projects

£14.3 million - Centre for Energy Storage for Low Carbon Grids

£4.9 million - Grid Connected Energy Storage Research Demonstrator

£3.3million - Advanced Grid-scale Energy Storage R&D facilities

£5.9 million - Centre for Cryogenic Energy Storage

£1.7 million - ThermExS Lab: Thermal Energy Storage Lab

Summary

•Storage provides flexibility to energy systems.

•The value of storage depends on the system – it is likely that flexibility

will be more valued as we move to lower carbon energy systems with

greater penetration of renewables and nuclear.

•As an island, the UK may offer a great place to deploy energy storage

technologies, as national interconnections are more difficult,.

•We need to focus on developing storage technologies which are fit for

purpose for grid scale application, in terms of cost, safety and lifetime.

•There are some exciting grid scale storage technologies emerging, at

varying level of technology maturity.

•There remain regulatory barriers to storage deployment which also

need to be addressed, and we need to learn more about the key

processes that control critical factors such as lifetime, along with

improved low cost manufacturing for grid scale.

Bringing together the energy storage research community, inspiring future collaborations.

University of Warwick Midday Tuesday 25th - Midday 27th November 2014

http://ukenergystorage.co/

transformative change grid scale energy storage · prudent energy 600-kw/3,600-kwh vrb-ess, ca, usa...

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