HES-SO Valais-Wallis Page 1

Semi-autonomous DC-microgrid

for > 50% renewable energy

Conférencier: Christoph Ellert

Equipe: see next slide

HEI / System Engineering

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Equipe

Power electronics & regulation & drives H.-P. Biner, Florian Steiner, Rodolfo Horta, Philippe Barrade, Dominique Roggo, Carmine Arcudi, Pierre-Oliver Moix, Alain Germanier Ateliers Mech & Elec Alain Roduit, Steve Gallay, Olivier Walpen Gridlab Line Barras, Mohammed Öztürk, Didier Blatter, Thomas Ritler IT Thomas Sterren, Dominique Gabioud, Michael Clausen, Yann Maret HEIG-Vd (J-F Affolter), HES-Fr (Elena-Lavinia Niederhäuser), HEPIA, HEG-Sierre, EPFL-IMT (Ne) Partenaires entreprise ESR, FMV, Studer Innotec, Schaffner, Imperix

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Why? Motivation

Facts: • Today in Switzerland: PV provides 3% of total electric energy consumed • Strong 0…100% variations (regular for solar, irregular for wind) storage required • increase of renewable energies > 15 % Etot instability in distribution grid

Remedy: • Investment in grid infrastructure expensive • Smart grids complex communication & regulation task

• Energy storage short term (battery) ; unsolved: long term

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Why? Motivation

Facts: • Today in Switzerland: PV provides 3% of total electric energy consumed • Strong 0…100% variations (regular for solar, irregular for wind) storage required • increase of renewable energies > 15 % Etot instability in distribution grid Remedy: • Investment in grid infrastructure expensive • Smart grids complex communication & regulation task

• Energy storage short term (battery) ; unsolved: long term

Solution microgrid based grid topology

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1. > 50% integration of renewable energies into electricity grid

2. Stabilize distribution grid

3. Improve overall energy efficiency

Intelligent local integration of production, consumption & storage

Goals

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Installation of demonstrator: > 30 kW PV & > 50 kWh battery

1. Local power regulation & energy management

2. Forecast of solar production based on meteorological data

3. Predict power exchange to/from distribution grid, 48 h in advance

4. Reduce power losses caused by double conversion

5. Reality simulator of entire grid infrastructure

6. Economic evaluation of new grid topology

7. Integration of power2gas

Objectives

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DC/AC

DC-bus

Les 7 élements clefs …

PV

Short term storage Consumer

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Semi-autonomous DC-microgrid

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Semi-autonomous DC-microgrid

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Pmax ~ 6700 W

8. sept 2015

PV production: total power

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PV production: individual panels

10 panneaux

21. Juillet 2015

One tree covers individual panels at different times

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45 panneaux

14. Dec 2015

PV production: individual panels

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PV production: total power

16 april 2016 18 april 2016

Could be evaluated … Present power limit:

~ 10 kW

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Pmax ~ 3000 W

14. dec 2015

Charge

PV production – battery charge / discharge

Discharge

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… need to be considered in different categories:

Various features of our system Compared to different alternative solutions Semi-autonomous microgrid: + Compared to independent local grid: strongly reduced costs in batteries

+ Compared to non-local energy management:

• strongly reduced complexity of regulation task

• Fighting the basic law of quality: Q ~ qN

+ Compared to virtual combination of distributed smaller storage to one larger solution

Advantages - I

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DC-bus: + Increase of overall efficiency by suppression of double DC/AC conversion

+ Increased safety in case of fire – high DC-voltage of solar strings is switched off

+ Modular PV composition Easier planning, maintenance & upgrade of system

Advantages - II

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Communication infrastructure

Broker (cloude-IO)

DC-bus 700 Vdc

DC/AC

50kW

Local Meteo

Station

Weather

forecast

3x400Vac

Super-Grid

Xbee

RaspberryPie (toit):

Converter Supervision

Supergrid

operator

Variopower-

35

=

=

+ -

Xcom

Pb / Li-ion

=

=

Electrolysis

? =

=

Motor

variable

Coolstock

=

=

I

PV

RS232

?

Gateway

Pres(t)

Pres(t)

24h

Pusine(t)Pel(t)Pres(t) 24h

I=

~~~

PPV(t)

H2

Gateway

PBatt(t)

meteo

DB

H2-storage

Air

condition

Ethernet

GatewayRaspPie

history

DB

Process

DB

SCADAEnergy management & forecast

PV Production

forecastForecast

verific. 1%

48h Pres(t)

forecast

Pres(t)

consigne

GraphHum

MaInt

Reg.type

U / P

DC/

AC

DC-bus

Intelligence

Forecast

Communication

PV

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Communication infrastructure

Broker (cloude-IO)

DC-bus 700 Vdc

DC/AC

50kW

Local Meteo

Station

Weather

forecast

3x400Vac

Super-Grid

Xbee

RaspberryPie (toit):

Converter Supervision

Supergrid

operator

Variopower-

35

=

=

+ -

Xcom

Pb / Li-ion

=

=

Electrolysis

? =

=

Motor

variable

Coolstock

=

=

I

PV

RS232

?

Gateway

Pres(t)

Pres(t)

24h

Pusine(t)Pel(t)Pres(t) 24h

I=

~~~

PPV(t)

H2

Gateway

PBatt(t)

meteo

DB

H2-storage

Air

condition

Ethernet

GatewayRaspPie

history

DB

Process

DB

SCADAEnergy management & forecast

PV Production

forecastForecast

verific. 1%

48h Pres(t)

forecast

Pres(t)

consigne

GraphHum

MaInt

Reg.type

U / P

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Semi-autonomous DC-Microgrid provides: ≠ Local regulation

• Global high-level smartgrids: distribution grid owner regulates power

• Virtual storage solutions: linking of distributed storage facilities

≠ High percentage of autoconsumption of PV-energy

≠ High precision prediction (1%; 48 h in advance) of power exchange to/from

distribution grid

≠ reduces system & transfer losses

Distinguish to smartgrids

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Thanks for your attention