School of somethingFACULTY OF OTHER

School of Chem. and Proc. Eng.FACULTY OF ENGINEERING

Electricity Storage for Large Enterprises

Andrew Pimm

Centre for Integrated Energy Research

Energy storage workshop at University of Leeds

14 June 2016

Introduction

Energy storage of interest to businesses/universities/hospitals,

particularly those with on-site generation

Economics of storage to enterprises poorly understood

Many revenue streams exist

Lancaster University interested in installing electricity storage

Case Study on Lancaster

University

Carried out case study with Lancaster

University after presentation given there in

January 2016

13k students, 4.5k staff, 8 halls of residence

on campus

Annual elec. demand ≈ 22 GWh; spend ≈

£2m pa

MD ≈ 6 MW

2.35 MW wind turbine, 50 kW PV and 1.9

MWe CHP on-site

2 days w/o power in early Dec due to floods

Energy Manager (Jan Bastiaans) interested

in installing up to 4MW / 4MWh of mixed

storage devices

0

1

2

3

4

J F M A M J J A S O N DMo

nth

ly E

lec.

(G

Wh

)

Month

Import WT CHP

0

2

4

6

8

0

0.5

1

1.5

2

2.5

3

J F M A M J J A S O N D

Max

imu

m M

on

thly

Dem

and

(M

W)

Mo

nth

ly E

lec.

Imp

ort

(G

Wh

)

Month

2014 (import) 2015 (import)

2014 (MD) 2015 (MD)

2014

Electricity Prices

Price made up of commodity and non-commodity components

Non-commodity = DUoS + TNUoS + RO + FiT + BSUoS + BS

+ HDC

Commodity price set after forward purchase and trading by

broker (Inenco)

0% 20% 40% 60% 80% 100%

Red

Amber

Green

% of marginal price

DU

oS

Tim

e B

and

DUoS REO BS BSUoS HDC FiT Energy Cost (avg.)

Time periods

Red Time

Band

Amber Time

Band

Green Time

Band

Mon to Fri 16:00 – 19:0009:00 - 16:00 00:00 - 09:00

19:00 - 20:30 20:30 - 24:00

Sat and Sun 16:00 – 19:0000:00 - 16:00

19:00 - 24:00

DUoS charges for HV meters in north west region

Electricity Prices

Time-varying marginal price is of interest to storage operator

LU’s marginal price of electricity, 04/2015-04/2016

(Mean commodity price of ~£0.06/kWh used, not including

Triads)

Transmission Network Use of

System (TNUoS) Charges

HH metered customers charged for use of transmission

network according to consumption during “Triads”

Triads: 3 half-hours of highest GB system demand between

Nov-Feb (separated by at least 10 days)

Since 1990/91, >80% have

been 17:00-17:30

Triad alerts issued by electricity

suppliers and utility

management companies

Optimisation Algorithm

Modified arbitrage optimisation algorithm to take into account generation and

demand (excess generation effectively costs the storage 4.91 p/kWh)

Results below for no generation… currently trying to work out how to synthesise

total demand and so half-hourly export based on monthly export figures

Optimisation Algorithm

Modified arbitrage optimisation algorithm to take into account generation and

demand (excess generation effectively costs the storage 4.91 p/kWh)

Results below for no generation… currently trying to work out how to synthesise

total demand and so half-hourly export based on monthly export figures

Savings Breakdown

Breakdown of savings available to Lancaster University and required expenditure.

• 2015 demand data &

charges

• 85% round-trip efficiency

• tch ≤ 12.5 hrs

• tdch = 2 hrs

• Hitting all Triads

Total Savings

Total savings

Total annual savings available to Lancaster University = £27,000/MWh

• 2015 demand data &

charges

• 85% round-trip efficiency

• tch ≤ 12.5 hrs

• tdch = 2 hrs

• Hitting all Triads

0

5

10

15

20

25

0

10

20

30

40

50

60

DU

oS

Red

-G

reen

(p

/kW

h)

TNu

oS

Dem

and

(£

/kW

)

Distribution Area

TNUoS DUoS R-G

DUoS charges for HV HH metered customers

effective from 1st Apr 2017 & TNUoS demand

charges effective from 1st Apr 2016

Area ID Area

DUoS for HV HH Metered (p/kWh) TNUoS Demand (£/kW)Red Amber Green

10 Eastern 6.384 0.020 0.004 46.543113

11 East Mids 7.391 0.121 0.021 44.724594

12 London 1.921 0.017 0.000 51.870233

13 Manweb 10.508 0.348 0.180 42.678395

14 West Mids 7.156 0.392 0.007 45.738925

15 North East 7.556 0.364 0.036 42.927953

16 North West 6.265 0.463 0.057 42.828015

17 Scots Hydro 4.044 1.393 0.313 40.966038

18 Scots Power 7.856 0.470 0.017 40.244453

19 South East 7.632 0.097 0.008 49.204313

20 Southern 6.572 0.210 0.044 50.078028

21 South Wales 9.942 1.155 0.055 42.306722

22 South West 19.170 0.117 0.046 48.580421

23 Yorks 6.253 0.476 0.033 42.493827

36.60 38.11

27.97

44.7638.17

34.20 33.52

20.46

31.28

41.09 38.8043.67

69.83

33.82

0

10

20

30

40

50

60

70

80

Val

ue

of

Sto

rage

(£

k/M

Wh

.yr)

Distribution Area

Value of storage to HV HH metered customers in 2017

On-Site Generation

In 2015, Lancaster Uni exported 241

MWh (~1% of demand)

Could potentially have reduced spend in

2015 by £17,500

Detailed analysis not possible due to

lack of dataStephenson Halliday

Payback Period & NPV of

Tesla Powerpack

Tesla Powerpack (May 2016)

Technology Li-Ion

Storage capacity per module 100 kWh

Peak discharge power per module 50 kW

AC-AC efficiency (2 hour system) 82%

AC-AC efficiency (4 hour system) 83%

DC-DC efficiency (2 hour system) 91%

DC-DC efficiency (4 hour system) 93%

Cost per module $47,000

Cost per bi-directional 250 kW inverter $65,000

Cost of cabling & other hardware $2,000+$500/module

Powerpack costs equate to £417,000 for a 1 MWh, 500 kW system

Regular annual savings of £26,000/MWh & 5% discount rate give 33 year

discounted payback period in north-west (but 15 year projected life!)

In the south-west in 2017, annual savings of £65,000/MWh give 8 year

discounted payback period. After 15 years, NPV is £258,000/MWh, giving

13% annual rate of return

EOS Aurora advertised at £138,000/MWh,

but 75% round-trip efficiency

Incentive schemes in US give >£1.6m/MW

for electricity storage (up to 50% of project

cost)

Near-Delivery Electricity

Trading

Investigated value of purchasing on day ahead market,

assuming 2 hr discharge at 16:30-18:30 weekdays Nov-Feb,

optimal schedule elsewhere…

Up to £40,000/MWh.yr in north-west, an increase of

£13,000/MWh.yr over a flat commodity price

Other Revenue Streams

Several other revenue streams exist for small-/medium-scale

storage:

Service Response

Time

Max. Duration Min. Power Trigger

Enhanced Frequency

Response

1 s 9 s 3 MW Static frequency point

Firm Frequency Response

(Primary)

2-10 s 1-2 m 10 MW Static or dynamic frequency

Firm Frequency Response

(Secondary)

30 s 30 m 10 MW Static frequency point

Fast Reserve 2 m 15 m 50 MW NG request

Short Term Operating Reserve 4 h 2 h 3 MW NG request

Curtis M. Overview of the UK Demand Response Market. EPFL Workshop, 11 Sep 2015, University of Reading

Other Revenue Streams

Market size and returns (Curtis, 2015):

Service Overall

Capacity Per

Year (MW)

DR Capacity

Per Year

(MW)

Procurement

Method

Returns Per Year, Per MW

Enhanced Frequency

Response

200 ?? ??? Tender ???

Firm Frequency Response

(Primary)

200-700 ??? Tender £15,000 - £20,000

Firm Frequency Response

(Secondary)

700-1400 ??? Tender £30,000 - £40,000

Fast Reserve ??? ??? Tender ???

Short Term Operating Reserve 2500-3500 200-700 Tender £20,000 - £30,000

EFR aimed specifically at storage

FFR runs 24/7

STOR has 2 daily availability windows (~07:00-14:00 & ~16:00-20:00)

Returns based on availability payment & utilisation payment

Conclusions

• Savings from reducing network charges: £20 - £70/kWh.yr

• South-west highest, north Scotland lowest

• Value increased by on-site generation, up to £17.5/kWh.yr extra at

Lancaster Uni with 2.35 MW WT & 1.9 MWe CHP, 6 MW max. demand

• Additional revenue from near-delivery trading: up to £13/kWh.yr

• Payback period with Tesla Powerpack: 8 yrs in south-west; 33 years in

north-west

School of somethingFACULTY OF OTHER

Electricity Storage for Large

Enterprises

Thank you

Dr Andrew J. Pimm

a.j.pimm@leeds.ac.uk