Storage of Renewable Energy in the Natural Gas Grid “Power ... · -FAQ - ¾How is long-term ......

M. Specht1, U. Zuberbühler1, M. Sterner2, G. Waldstein3

1)

Centre for Solar Energy and Hydrogen Research (ZSW), Stuttgart2)

Fraunhofer

Institute for Wind Energy and Energy System Technology (IWES), Kassel 3)

SolarFuel

GmbH, Stuttgart

Storage of Renewable Energy in the Natural Gas Grid“Power-to-Gas –

Technology”

Speicherung Erneuerbarer Energie im Erdgasnetz

Deutsche Umwelthilfe, Congress “Energy Storage and Nature Conservation”,21.02.2011, Berlin

Agenda: Storage of Renewable Energy (RE) in the Natural Gas Grid

GoalSNG Production Routes from RE

Biogas SNG (Fermentative Route)Biomass Gasification SNG (Thermo-chemical Route)CO2 + Power SNG“Biogenic C”

+ Power SNG

Conversion EfficiencyEnvironmental Benefits of SNG from REConclusion / Next Steps

SNG: Substitute

Natural

Gas

Long Term Storage of Renewable Energy - FAQ -

How is long-term storage of energy realised today?

How much capacity do we need for RE storage?

What is the best way to collect and to store RE?

Can the existing infrastructure be used to store and to distribute RE?

What are the environmental impacts of storage technologies?

Land consumption of storage sites

Land consumption for power transmission

Other impacts like interference with landscape, electro smog, etc.

Energy Consumption and Storage Capacity in Germany (2008)

Electricity Natural gas Liquid fuels1)

Consumption [TWh/a] 615 930 707

Average power [GW] 70 1062) 81

Storage capacity [TWh] 0,043) 2174) 2505)

Calculated operating range of installed storage capacity6) [h] 0,6 2000 3100

1) Petrol, diesel, kerosene2) Seasonally fluctuating3) Pumped hydro storage4) 47 Underground gas storage facilities [Landesamt

für

Bergbau, Energie

und Geologie

(LBEG), Hannover]5) Provisioning of petrol, diesel, kerosene and heating oil6) Related to average power

Required storage capacity for electricity grid in DE: 20 -

40 TWh

!

Options for Long Term (Seasonal) Energy Storage: Chemical Energy Carriers

Hydrogen

Substitute Natural Gas (SNG)

Liquid Hydrocarbons

Renewable Energy Storage Systems: Capacity and Discharge Time

0,001

0,01

0,1

1

10

100

1000

10000

1 kWh 10 kWh 100 kWh 1 MWh 10 MWh 100 MWh 1 GWh 10 GWh 100 GWh

1 m

1 h

1 d

CAES

1 TWh 10 TWh 100 TWh

CAES

Fly

Wheels

Storage capacity of different storage types

Dis

char

ge ti

me

[h]

CAES Compressed

air

energy

storage

PHS Pumped

hydro

storage

SNG Substitute

natural

gas

Batteries

PHS

1 a

SNG

H2


Goal SNG Production Routes from RE


+ Power SNG


SNG: Substitute

Natural

Gas

(Digestive) Biomass SNG: State-of-the-Art - Technology

AnaerobicDigester

Plant

Gas Cleaning /Conditioning

Bio-Gas

50 - 70 vol.-%CH4

DigestiveBiomass

Compost

SNG

Separation of• CO2

• H2O• Impurities

(to Grid orFilling

Station)

(Digestive) Biomass SNG:Pressure Swing Adsorption (PSA) Gas Upgrading

Biogas

Vacuum pump

Off-gas(CO2)

Flushing gas

SNG

Water separator

Compressor

Des

ulph

uris

atio

n

Ads

orbe

r uni

t




+ Power SNG


SNG: Substitute

Natural

Gas

(Woody) Biomass SNG:“BtG” Biomass-to-Gas

CO, H2

, CO2

, CH4

Gasification

Biomass

Producer Gas

SNG(CH1.52

O0.65

)

(Synthesis Gas)

(Gas conditioning,stoichiometry

adjustment)

1st

Step 2nd

Step

Synthesis

1st

Step: (Woody) Biomass Producer Gas:Gas Composition of Different Biomass Gasifiers

0%

20%

40%

60%

80%

100%

RENUGAS (1)

Carbo-V

(2)

HTW (3

)DMT (4

)MTCI (5

)DM2 (

6)Batt

elle (

7)Wrig

ht/Malt

a (8)

Hynol

(9)FIC

FB (10)

AER (11)

Vol

. %

H2 CO CO2 CH4 Ethane+Ethylene

autothermal allothermal

2nd

Step: Producer Gas SNG:Methanation of COx

CO + 3 H2 CH4 + H2

O(g)

ΔH298K

= -

206.2 kJ/molCH4

CO2 + 4 H2

CH4

+ 2 H2

O(g)

ΔH298K

= -

165.5 kJ/molCH4

2 CO + 2 H2

CH4

+ CO2

ΔH298K

= -

246.8 kJ/molCH4

SNG Generation in Fixed Bed Molten Salt Cooled Reactor

SNG

Product Gas from AER-Process

Salt Loop C

atal

yst

Zone

IZo

ne II

Zone

III

Dec

reas

ing

Tem

pera

ture

Goal:SNG without downstream CO-shift

and without CO2

separation

due to in situ AER adjustment of Syngas

stoichiometry

Demo-plant: 100 kWSNG

Concept presented at ACHEMA Fair in May 2009 (cooperation ZSW with MAN-

DWE, Germany)

AER Producer

Gas SNGExperimental Results

Vol.%

H2

67,5

CO2

12,0

Methanation

H2

3,5

CO2

6,0

CH4

90,5

Vol.%

AER producer

gas CH4

-rich product

gas

Parameter of methanation:

T = 250 -

500 °C

pe

= 6,5 bar

SVwet

= 3000 1/h

CO

8,5

CH4

12,0




+ Power SNG


SNG: Substitute

Natural

Gas

Power-to-Gas (PtG) -

Concept: Basic Layout

CCPP / B-CHP

CO2

buffer

Grid Gas distribution system

Electrolysis /

H2

bufferMethanation

H2

CO2

CH4

POWER GENERATION

ELECTRICITY STORAGE

CO2

Gas

storage

Solar

Wind

H2

CO2

CCPP: Combined Cycle Power Plant; B-CHP: Block-type Combined Heat and Power Station

Power-to-Gas -

Concept: Interconnection with Mobility

EV:

Electric Vehicle

BEV: Battery Electric Vehicle

FCEV: Fuel Cell Electric Vehicle

CNG-V: Compressed Natural Gas Vehicle

Plug-In HEV: Plug-In Hybrid Electric Vehicle

(especial: Plug-In Electric Drive Motor Vehicles / Range-Extended Electric Vehicle)

CCPP Combined

Cycle

power plant

B-CHP Block-type combined heat and power station

Solar

WindCCPP / B-CHP

CO2

buffer

Electricitygrid

Gas distribution

system

Electrolysis

/

H2

bufferMethanation

H2

CO2

CH4

POWER GENERATION

ELECTRICITY STORAGE

CO2

Gas

underground

storage

Electricity H2 SNG

BEV FCEV CNG-V

Mobility

H2

CO2

Plug-In HEV Plug-In HEV

Power-to-Gas -

Technology: Technical Realisation for SolarFuel

Company

CH4

-Filling stationca. 15 kg, 200 bar

Electrolyser

CO2

-Recovery

CO2

+ Power SNGExperimental Results

Vol.%

H2

79,5

CO2

20,5

Methanation

H2

4,6

CO2

5,3

CH4

90,2

Vol.%

Synthetic educt

gas CH4

-rich product gas

Parameter of methanation:

T = 250 -

500°C

pe

= 6 bar

SVwet

= 4000 1/h



Biogas SNG (Fermentative Route)Biomass Gasification SNG (Thermo-chemical Route)CO2 + Power SNG“Biogenic C” + Power SNG


SNG: Substitute

Natural

Gas

Utilisation of Biogenic CO2

Resources for PtG-Process

C6

H12

O6

3 CH4

+ 3

CO2

Simplified overall reaction

C6

H12

O6

2 C2

H5OH + 2

CO2

Biogas production:

Ethanol production:

Biogas plant, Foto: Krautkremer

EtOH

plant in Nebraska, USA

Power-to-Gas -

Concept: Option 1 –

Interconnection with Biogas Plant

CCPP / B-CHP

CO2

buffer


Electrolysis /

H2

bufferH2

CO2

CH4

POWER GENERATION

ELECTRICITY STORAGE

CO2

Gas

storageBiomass

Solar

Wind

H2

Biogas plant with

SNG production

CH4

Methanation

Heat


Power-to-Gas -


Interconnection with Biogas Plant

CCPP / B-CHP

CH4

/CO2

buffer


Electrolysis /

H2

bufferH2

Biogas

CH4

POWER GENERATION

ELECTRICITY STORAGE

Biogas

Gas

storageBiomass

Solar

Wind

H2

Biogas

plant

Methanation

HeatCH4

/CO2CH4

/CO2


Power-to-Gas -

Container: Operation at a Biogas Plant with Biogas and PSA Off-Gas

Power-to-Gas -

Container: Operation with PSA Off-Gas at a Biogas Plant

0

10

20

30

40

50

60

70

80

90

100

00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00

Dauer [hh:mm]

y_C

H4 [

Vol-%

]

0

10

20

30

40

50

60

70

80

90

100

y_C

O2,

y_H

2, y_

O2 [

Vol-%

]

CH4 H2 CO2 O2

Power-to-Gas -


Interconnection with Biomass Gasification

CCPP / B-CHP

H2

/CO/CO2

buffer


Electrolysis /

H2

bufferH2

Syngas

CH4

POWER GENERATION

ELECTRICITY STORAGE

Syngas

Gas

storageBiomass

Solar

Wind

H2

Gasifi-

cation

Methanation

H2

/CO/CO2 H2

/CO/CO2

O2





+ Power SNG


SNG: Substitute

Natural

Gas

Schematic

Diagram of a Wind-to-SNG

-

Plant for

IPSEpro Process

Simulation (Feed: CO2

/H2

and Biogas/H2

)

SettingsEnergy demand electrolysis:

4 kWhel

/mN3H2

System pressure:

7 barabsGrid pressure:

16 barabs

Energy Flow of a Wind-to-SNG -

Plant

Case

1: “CO2

/H2

-to-SNG"Case

2: "Biogas/H2

-to-SNG“

(50 / 50 [Vol.%CH4

/ Vol.%CO2

] in biogas)Case

3: "Biogas/H2

-to-SNG“

(70 / 30 [Vol.%CH4

/ Vol.%CO2

] in biogas)

Influence of Electrolysis Efficiency on Wind-to-SNG System Efficiency (CO2

/H2

-to-SNG)

40

45

50

55

60

65

70

3,5 3,7 3,9 4,1 4,3 4,5 4,7 4,9 5,1

Electrolysis power requirement [kWhel

/mN3H2

]

Sys

tem

effi

cien

cy [%

]

Comparison Storage Efficiency incl. Re-Conversion: H2

vs. SNG

SNG

100 60 ca. 35

ElectrolysisMethanisation

Gas/steampower plantη

= 58 %

H2

100 75 ca. 34

Electrolysis Gas engineη

= 45 %




+ Power SNG


SNG: Substitute

Natural

Gas

Land Consumption: Pumped Hydro Storage vs. Power-to-Gas Storage

Goldisthal Source: e.on

Hanse

Pumped hydro power

Water surface, Dam, Bank reinforcement

Land use: 2 -

44 kWhpot

/m2

ηturbine

=

88 %ηpump

= 85 %

Underground storage facilities / PtG

Well site: 40 m x 60 m; Over ground facility, gas compression station: 200 m x 200 m; Security area

Land use: ca. 100 000 kWhSNG

/m2

ηSNG electricity < 60 %ηelectricity SNG = 60 - 65 %

Landscape Impact of Electricity Transmission

Transmission power line

Land Consumption: SNG Transmission vs. Electricity Transmission

Sources: Wuppertal Institut

für

Klima, Umwelt

und Energie; P. Konstantin; G. Wossog; H. Brakelmann; OMV

Gas Electricity

Pressure Diameter Transmission power

Protection strip Voltage

Trans-

mission

power

Overhead line, Route width

Underground

cable,

Protect. strip

[bar] [DN] [GW] [m] [kV] [GW] [m] [m]

< 0,1 50-600 < 0,1 2 -

10 0,4 (low) 10 1

> 0,1-1 100-400 0,01 -

0,2 2 -

8 1-24 (medium) 20 4

> 1-16 300-600 0,8 -

3 6 -

10 50-170 (high) 0,3 44 7

> 16

900 9 -

12 8 -

10 220 (high) 0,5 55 9

1000 12 -

16 8 -

10 380 (high) 0,9 70

1400 21 -

28 8 -

10

Transmission power:

Gas pipeline < 70 GW Power line < 7 GW

Environmental Benefits: Emissions Reduction through CNG-Vehicles

-80% -80%

-20%

-40%

-10%

-60%

-90%

-10%

-80%

CO NMHC GHG OZONE CO NMHC NOx GHG OZONE

in relation to gasoline in relation to Diesel

Source: nach

Fachverband

der

Gas-

und Wärmeversorgungsunternehmen, Wien

1) 1)

1) Green house gas reduction by using natural gas;nearly 100 % reduction by using renewable SNG!

Environmental Benefits -

SNG Utilisation in CNG Cars: “Wind Energy for Mobility”

Opel Zafira

1.6 CNG ecoFLEX

Turbo, CNG cruising range: 370 km

85 000 CNG vehicles on the road875 filling stations

(Germany, 2009)

VW Passat

1.4 TSI EcoFuel,CNG cruising range: 480 km

Daimler B 180 NGT, CNG cruising range: 370 km


SNG Utilisation in CNG Trucks: Clean Fuel for Densely Populated Areas


SNG Utilisation in μ-CHP: Virtual Power Plant

SNG

100 65 ca. 60

ElectrolysisMethanisation

μ-CHPpower plantη

< 60 % (electric)

Today:Lichtblick-Conceptwith VW μ-CHP,ηel

= 33 % Tomorrow:BlueGEN

SOFC fromCeramic FuelCells Limited,

ηel

= 60 %

∆+




+ Power SNG


SNG: Substitute

Natural

Gas

Integration of Renewable Energy in Electricity and Gas Grid

Natural Gas (NG)

Load = Feed (at any time)

Load ≠

Feed (at the same time)

FEED LOAD

Electricity Grid

GRID

Conventional Power

Gas Grid

Gas Storage > 200 TWh

„Electricity“

Storage 0,04 TWh

Fluctuation Electricity from Renewables

Gas from Renewables

Backup Power

Production and Utilisation Flexibility of Renewable SNG

Upgraded biogas via anaerobic digestion

Bio-SNG via biomass

gasification

E-Gas via Power-to-

Gas-Process

Electricity generation (EEG)

Mobility

Heating market, Industry

Combined cycle power plant

Peak power (gas turbine)

GtL

plant (Aviation Fuel)

Production Utilisation

Pool renewable

SNG

H2

μ-CHP (virtual power plant)

Conclusion: Advantages of Renewable SNG / PtG

-

Technology

Inspired by nature: “PtG as artificial photosynthesis”

Increasing importance of (S)NG backup power for load balancing

SNG is an ideal chemical storage medium for RE

Storage of RE with “unlimited” storage capacity in the gas grid

Utilisation of existing underground gas storage facilities

Stabilization of electricity grid (positive and negative control power)

Merging of the energy sectors “electricity grid”, “gas grid”, and “mobility”

Conclusion: Combination Renewable Electricity and Bio-energy

Biomass contains renewable carbon and is therefore predestined for the generation of carbon-based fuels

The combination biomass/electricity from RE offers a 3 times higher output of carbon-based fuels compared to biomass alone

Biomass and renewable electricity are ideal partners !

Conclusion: Environmental Benefits

No environmental disadvantages of renewable SNG compared to other existing storage technologies for RELong term storage in the form of SNG enables a 100 % RE system (without coal and nuclear power plants)PtG-Technology without limitation of agricultural areaReduced land consumption for SNG transmission via pipelines compared to high voltage electricity transmissionReduced land consumption for the SNG storage facility compared to pumped hydro powerCO2-neutral Carbon-based fuel for mobility

Reduced traffic pollutant emissions (no particles, 90 % NOxreduction vs. Diesel engines, etc.)

Vision: Wind Energy for Mobility –

NOW!

SNG as CO2

- neutral fuel for

sustainable mobility

Timeline Commercialisation

Alpha-plant (25 KWel): Nov. 2009

Alpha-plus-plant (250 kWel): spring 2012

Beta-plant (6 MWel): 2013

Gamma-plant(> 6 MWel

, commercial product):

2015

Co-operation partners of ZSW:

An interesting discussion !

Thanks for your kind attention.

Storage of Renewable Energy in the Natural Gas Grid “Power ... · -FAQ - ¾How is long-term ......

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