v4es: quirks, curiosities and conclusions … · 22-04-2020 · v4es: quirks, curiosities and...
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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
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