Microgrid in Remote Communities-Technical Challenges

Mostafa Farokhabadi, Ph.D. CandidateUniversity of Waterloo

Ehsan Nasr, Ph.D.

Canadian Solar Inc.

1

Canadian Solar Inc. (CSI)

• Background

2

Top 3 PV module supplier in the world

Proven project development track record and

8.5GW project pipeline

Founded in Ontario, 2001

Listed on NASDAQ (CSIQ) in 2006

Over 7,000 employees globally

Global footprint in 90 countries

PV module supplier

PV project development

Energy storage and Microgridsolutions

Canadian Solar Global Network

More than 7,000 employees in 18 countries

CSI Microgrid Solutions

4

Microgrid Project Experience (Remote Communities)

5

Deer Lake

North Spirit Lake McDowell Lake

Keewaywin

Deer Lake

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----What did we do?

Proposed a phased-in solar capacity development plan

Phase I - Install a 152kWdc/120kWac solar rooftop system connected into the diesel generating system.

Gained confidence of community and utility that renewables would not have a negative impact.

----What will we do?

Phase II – Implement a full microgrid system with 1MW solar system and energy storage.

----What did we learn?

Installation in these

remote areas with

extreme weather is

very challenging.

Logistics via winter roads

can experience delays

and unexpected

complications.

Important to triple check

and cross check bills of

material.

Ability to adapt to

unexpected situations.

Hydro One Remotes and

most Independent Power

Authorities now see the

benefit of renewable and

are eager to do more.

----How did it start?

High dependency on

diesel generation.

Existing generation

capacity could not

meet the rising energy

demands of their

growing communities .

7 homes unconnected.

Keewaytinook

Okimakanak (KO)

approached Canadian

Solar for a solution.

Deer Lake

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System Topology: 1000kW Diesel Generation, 500kW Hydro Turbines, 152kWp/120kWac Solar PV

System Performance: 121.45kWh 794kWh/kWp

Deer Lake

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Pack Everything!

Bring your own food →

Work can be Cold!

↓

Fort Severn

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----What did we do?

Proposed a phased-in solar capacity development plan

Phase I - Installed a grid connected 24kWdc/20kWac solar rooftop system.

Gained confidence of community and utility that renewables would not have a negative impact.

Phase II – To implement a pilot microgrid including 300kW solar, 10kW wind and 200kW battery to study the impact on the grid with diesel as primary.

Phase III – To implement a full microgrid including 600kW solar, 500kW wind and 750kW battery allowing for diesel-off operation.

----What did we learned?

Logistics in remote

locations is

unpredictable.

Shipping BOS

materials was another

challenge

Important to triple check

and cross check bills of

material.

Necessity of working

with the situations as

they arrive and adapting

to a change on the fly.

----How did it start?

Most remote

community in Ontario.

Highest cost of

electricity generation

due to transport cost of

diesel fuel.

Planned community

growth.

Prior – failed –

experience with wind

energy.

Fort Severn

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Fort Severn

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Technical Challenges

• Ground mount PV installation in permafrost

– Ballasted racking system

• Renewable penetration levels

– Power

– Energy

• Energy storage system sizing

• Frequency stability

• Grid forming capability of Power Conversion System (PCS)

• Ride through capability of PV and battery inverter (UL 1741, IEEE 1547)

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Battery Sizing (Dynamic Simulation)

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Battery Requirement #1 for 300 kW PV shading

Input Output

Battery Characteristics Minimum Frequency f < 57 duration (s)

Droop rate (kW/Hz) 30

57.09 0Output Level (kW) 90

Power rate (kW/S) 210

Battery Requirement #2 for 300 kW PV disconnection

Input Output

Battery Characteristics Minimum Frequency f < 57 duration (s)

Droop rate (kW/Hz) 60

57.24 0Output Level (kW) 160

Power rate (kW/S) 580

ValidationModeling

ValidationModeling

Software Simulation – Dynamic Modeling

0 2 4 6 8 100

50

100

150

200

250

300

350

Time (s)

PV o

utpu

t (kW

)

0 2 4 6 8 1056

57

58

59

60

61

Time (s)

Freq

uenc

y (H

z)

Configuration/input Simulation output

Software Simulation – Dynamic Analysis

Frequency Stability

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0 1 2 3 4 5 6 7 8 9 1055

56

57

58

59

60

61

62

X: 4.927

Y: 60.5

t(s)

Freq

uenc

y(H

z)

X: 6.256

Y: 60.5

X: 4.082

Y: 57

X: 2.784

Y: 57

300 kW PV shading

0 1 2 3 4 5 6 7 8 9 1056

57

58

59

60

61

62

X: 4.971

Y: 60.5

t(s)

Freq

uenc

y(H

z)

X: 6.187

Y: 60.5

X: 3.936

Y: 57

X: 2.907

Y: 57

250 kW PV shading

0 1 2 3 4 5 6 7 8 9 1056.5

57

57.5

58

58.5

59

59.5

60

60.5

61

X: 5.042

Y: 60.5

t(s)

Freq

uenc

y(Hz

)

X: 6.064

Y: 60.5

X: 3.575

Y: 57

X: 3.26

Y: 57

200 kW PV shading

0 1 2 3 4 5 6 7 8 9 1057

57.5

58

58.5

59

59.5

60

60.5

61

X: 5.165

Y: 60.5

t(s)

Freq

uenc

y(Hz

)

X: 5.856

Y: 60.5

150 kW PV shading

• System With PV Without Battery Energy Storage System (BESS)

Frequency Stability

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• Short term (high resolution data) for a PV and BESS active power

output

Grid forming vs grid following PCS

• Virtual Synchronous generator

• Frequency/voltage droop control-voltage source inverter

• Current source inverter

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Not every supplier in the market has grid forming capability for

Battery PCS.

Standard/ Requirement

• Hydro one interconnection requirement

• IEEE 1547/ UL 1741

• May need to expand the frequency range

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Frequency Range (Hz) Clearing Times (s)

> 60.5 0.16

< (59.5 – 57.0) 300 (adjustable)

< 57.0 0.16

Ref: Hydro One Distributed Generation Interconnection Requirements

Conclusion

• Challenges in remote communities to

implement microgrids are different than other

microgrid applications.

• Frequency stability is of main concerns for off

grid system.

• Standard/ requirements for these applications

may need to be revisited.

• Battery energy storage system and control

system in microgrid application are not “plug and

play”, and close attention should be paid for

system stability concerns.

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Thank You