Ian Draisey

Managing Director, BayWa r.e. Solar Systems

NSC - 29th January 2015

National Solar Centre: Smart Solar Energy

Storage: The Commercial Implications for Distribution

Page 1

UK Market Deployment

Page 2

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2013 2014 2015 2016 2017

% of revenue

Modules Inverters Mounting BOS Storage

Page 3

German Experience

• Largest Market for Storage – Subsidy in place

• Emphasis is on self consumption

• 99% of the market is <10kWp

• Market doubled from 2013 – 2014

• 65,000 PV systems installed in 2014 (all sizes)

• 15,000 Storage systems

• 20% price reduction in a typical system in 2014 vs 2013.

• Bank led subsidy from 1st May, 2013

• Amortization grant of up to 660 €/Wp

Page 4

German Experience (2)

• Systems vary from €3K to €15K

• Both lead acid and lithium systems are being installed

• Due to car/EV development Lithium (or similar) will win

• High cost of electricity accelerates parity

• 50% of the systems sold don’t use the subsidy

• Few large commercial systems, Bern 5MWp – wind balancing

• 5MWp battery (fast) replaces 50MWp conventional (slow)

Page 5

Insights

• No silver bullet! Storage will balance Government/policy uncertainty

• 10% of Distribution by 2017

• Not a commodity! – yet! Needs knowledge, expertise and education

• Huge potential for domestic, 3 phase not far behind!

Export Limiting Systems –

Keeping the grid healthy and

reducing connection costs

Introduction

• Increasing penetration of Solar PV onto the grid presents

opportunities and challenges

• Self-Co su ptio is o a i porta t topi of dis ussio

• Commercial buildings already have high self-consumption, and

want to limit what is exported onto the grid to reduce impact

on grid

• Domestic customers have low self-consumption, and want to

increase it in order to save more electricity

• The majority of electricity generated by the PV system is consumed on site, a d does t e port onto the grid

• HOWEVER the DNO has to assume that at some point a PV system is going to export the full power onto the grid

• For example weekends and bank-holidays

• They will need to charge, sometimes a lot of money, to upgrade the lines and transformers

Commercial Load Profile

Export Limitation

• In Germany it is a requirement that no more than 70% of PV

capacity can now be exported onto the grid

• Renewable Energy Sources Act (EEG) ensures regulation

occurs within 10 minute average value

• In the UK however, Export Limitation can be set to any value

between 0-100%, which for example could be pre-arranged

with DNO

• ie) Client and DNO agree to a system that can only export 16 A

per phase, even though system has potential to generate

more than that

Example

• DNO wants to charge £300k to upgrade network for

250 kW system, because grid capacity is currently

only 50 kW

• Site is a factory with very high self consumption (100

kW base load)

• Export Restriction unit is fitted, and export is

restricted to 50 kW

• The system only turns down the inverters on sunny

da s he the u it is t orki g

Summer

Energy Imported

Energy Exported

PV Self Consumed

Winter

Real Life Example – 50 kW

restricted to 12 kW

Zero Export • Driven by conditions in Australia.

• Some electricity generators have exclusivity contracts,

meaning solar generators can not export onto the grid

• Zero restriction devices mean businesses can generate

their o ele tri it o site, ut do t iolate Australia exclusivity contracts

UK Example • 50 kW system, zero export allowed

Types of Export Limiting

Architectures • Export Limiting G59 panels

• Reverse current protection relays measure current,

• If current exceeds the pre-determined limit, the contactor is

tripped, and system disconnects

• So e s ste s ill load di ert

• Inverter control

• Smart meters measure current

• If current exceeds limit, the output of the inverter is turned down

• System does not disconnect

Advantages of Limited or Zero

Export Systems • When self-consumption is very high, not a lot of electricity is

exported onto the grid anyway

• Exception is bank holidays and weekends – exactly the

moments when the grid does NOT need lots of additional

energy

• With export restriction there are advantages for

• Client, not needing to pay such high upgrade costs

• DNO, not having to take into account nuisance power and voltage

increases on the grid off peak days

Issues DNOs have raised

• Failsafe operation of the system

• Reaction time of the system

• How to perform a witness test

Experience in Australia

• An export restriction system can be self-certified up to 30 kVA

Requirements

• Schematic submitted to Network Operator, approved by

certified designer

• Sealed terminals of CT clamps and lockable cabinet, plus

password protected relay management system

• Failsafe mode (system limits to most restricted amount when

communication is disrupted)

• Engineering Assessment required for systems above 30 kVA

Questions in the UK

• What is acceptable now?

• Should there always be a witness test, or can there be a limit

under which units are self-certified?

• What should be the standard test procedure?

• What installations guidelines must installer follow in order to

e sure the s ste is safe a d a t e ta pered ith?

Discussion