V4ES: Quirks, Curiosities and Conclusions

The view from 1 house in Burton-upon-Trent, UK

chris.rimmer@cenex.co.uk

About Cenex

222 April 2020

Firstly, some definitions…

Quirk

/kwəːk/

noun

a peculiar aspect of a person's character or behaviour

322 April 2020

Curiosity

/kjʊərɪˈɒsɪti/

noun

an unusual or interesting object or fact

The intelligent management of stationary energy storage and electric vehicles

(EVs) to provide services to the electricity system.

(And yes, it is a term that we have made up…)

Vehicle for Energy Services (V4ES)

• V4ES is based on technology-driven

solutions:

• Stationary storage. I.e. second-life EV

batteries

• On-site generation. I.e. solar pv

• EV charging and discharging. I.e.

Nissan Leaf

422 April 2020

• V4ES delivers benefits to multiple

players in the electricity system:

• Energy autonomy for the host

• Ancillary services for the distribution

grid

• Environmental benefits for the grid

• …

Cenex’s history with V4ES follows the Gartner Curve

522 April 2020

EFES /

SEEV4-city

Project kick-

off

Technology Trigger

Cenex’s history with V4ES

622 April 2020

EFES /

SEEV4-city

Project kick-

off

Technology Trigger

Peak of Inflated

Expectations

Cenex installs

UK’s first

domestic V2H

unit

Cenex’s history with V4ES

722 April 2020

EFES /

SEEV4-city

Project kick-

off

Technology Trigger

Cenex installs

UK’s first

domestic V2H

unit

Peak of Inflated

Expectations

Trough of Disillusionment

UK’s first domestic V2H

unit fails

Cenex’s history with V4ES

822 April 2020

EFES /

SEEV4-city

Project kick-

off

Technology Trigger

Trough of Disillusionment

UK’s first domestic V2H

unit fails

Slope of Enlightenment

New site selected

Cenex installs

UK’s first

domestic V2H

unit

Peak of Inflated

Expectations

Cenex’s history with V4ES

922 April 2020

Cenex installs

UK’s first

domestic V2H

unit

EFES /

SEEV4-city

Project kick-

off

Technology Trigger

Peak of Inflated

Expectations

Slope of Enlightenment

Plateau of Productivity

New site selected

Phase 2

Trough of Disillusionment

UK’s first domestic V2H

unit fails

Our phase 2 pilot has built on these experiences

1022 April 2020

2016 - 2018

• 4 kWp PV array

• 2 kWh stationary battery• 400W fixed input / output

• Control system by Moixa

• 2012 24kWh Nissan LEAF

• V2G unit from EFES• Never actually V2G-ed!

• First domestic V2G unit in the UK, very early technology which suffered from reliability problems

2019 - ….

• 3.86 kWp PV array

• 3 kWh stationary battery• 760 W variable input / output

• PV + battery control system by Moixa

• 2018 40 kWh Nissan LEAF

• V2G unit from Ovo Energy• 7.3 kW charge• 3.68 kW discharge

• Market-ready products, backed by commercial SLAs, guarantees and warranties

We’re still analysing but already we are seeing some quirks and curiosities

1. Networks are both a help and a hinderance

2. Equipment efficiency erodes effectiveness

3. V4ES increases consumption

4. Controls must communicate

1122 April 2020

Networks are both a help and a hindrance

• Networks are essential to the operation of the

electricity system

• They are bearing the brunt of the sustainable

energy and electric vehicle revolution:

• Peak loads increasing, electrical flow changing,

legislation evolving…

• They are a massive help for V4ES by

providing many interesting value pools

• But… their constraints also hinder V4ES

• Our Burton on Trent site export is limited to half

its potential due to network constraints

1222 April 2020

0

1000

2000

3000

4000

5000

6000

En

erg

y (

kW

h)

Imported Exported

But export limitation

prevents greater value

to be generated from

the home

Vehicle is charged to be

ready for the afternoon

peak

➢ Areas of the network most needing V4ES are most likely to require limitations on its operation

3.68 kW

export limit

Equipment efficiency erodes effectiveness

• The UK lockdown has allowed us to

explore the efficiency of the V4ES system

• Our EV has been very stationary storage!

• Electricity metered, then converted from

AC to DC to charge the EV

• The EV battery discharges, which is

converted to AC before being metered as it

is released into the home and/or grid

• We noticed that when there is no driving,

energy imported and exported correlate

• 78% efficiency observed

1322 April 2020

➢ Round-trip efficiency has a significant impact on the effectiveness of V4ES to deliver benefits

0

5

10

15

20

25

30

0 10 20 30 40

Ex

po

rte

d E

ne

rgy (

kW

h)

Imported Energy (kWh)

Non-driving days Driving Days

V4ES increases consumption

• The provision of V4ES means:

• Energy flows to and from assets

• Energy is imported to charge the EV

• Energy is exported to discharge

• Mean import increased 9% when V4ES was

switched on

• This replaces energy exported for services

• Supplier uses “export credits” to account for

this, but they are only valued at ¼ of import

• The net increase is small for a home (~£20

extra per year) but at scale could represent a

significant additional cost

1422 April 2020

➢ Any commercial V4ES solution will need to ensure the customer is not out of pocket

V4ES activeV4ES inactive

0

500

1000

1500

2000

2500

3000

3500

En

erg

y I

mp

ort

ed

(k

Wh

)

Controls must communicate

• The phase 2 pilot uses systems from 2

commercial suppliers

• These have different control strategies

informed by different data points

• PV + Battery + Energy Manager tracks

household energy balance

• V2G + Backend tracks grid services

• Thus far, this means they have not

conflicted but they also miss opportunities

to take advantage of a holistic view

• Well-exemplified by Monday 20th April

1522 April 2020

➢ The best V4ES systems will include a holistic view of all energy flows and coordinate all assets

Boost ends.V4ES initiates

export from EV.

Battery responds by charging

Vehicle

boosted for

a trip

Battery

discharges

-2000

0

2000

4000

6000

8000

06:00 08:00 10:00 12:00 14:00

Po

we

r (W

)

Household consumption Solar generation

Power flowing to battery

V4ES Quirks, Curiosities and Conclusions

1622 April 2020

Observation Insights

Networks are both a help and a

hinderance

Areas of the network most needing V4ES are most likely

to require limitations on its operation

Equipment efficiency erodes

effectiveness

Round-trip efficiency has a significant impact on the

effectiveness of V4ES to deliver benefits

V4ES increases consumptionAny commercial V4ES solution will need to ensure the

customer is not out of pocket

Controls must communicateThe best V4ES systems will include a holistic view of all

energy flows and coordinate all assets

Thank you for listening

Chris Rimmer

chris.rimmer@cenex.co.uk