Energy and economic profitability of the EMO conceptEscagues-GK-ENEA... · 1 €/Nm3 2 €/Nm3 3...

Energy and economic profitability of the EMOconceptA. RÉVEILLÈRE (GEOSTOCK), S. ESCAGÜES (ENEA)

November 8th, 2019

• Why does the cost structure matter ?

• Underground storage costs estimation

• Levelized cost of storage estimation

• Conclusion

| 08/11/2019 |Underground Energy Storage workshop 2

Why does the cost structure matter?


Simplified EMO storage equipment: « energy transformation »

or « storage »

Required equipments related to:

• the transformation capacity of the facility =

• the storage capacity of the facility = 3 salt caverns


ElectrolyserMethanation

reactorCH4 storage

O2 storage

Oxycombustion

turbine

CO2 storage

H2 CH4CH4

O2

CO2

O2

CO2

– Oxycombustion– MethanationElectrolysis

Simplified energy storage

technological competition


Technology CAPEX breakdown

« Transformation

equipments »

« Storage

equipments »

Techno 1 1000 €/kW 100 €/kWh

Techno 2 5000 €/kW 10 €/kWh

Storage demand

Power demand 1 MW 1 MW

Cycles 12h/12h

365 times

per year

6 months / 6

months

Once a year

→ Storage

capacity

demand

12 MWh 4 380 MWh

→ Total

CAPEX

involved

2.2 M€

5 M€

440 M€

50 M€

Reality is more complex


A comparison of competing storage solutions has to be done carefully. Many parameters

come into play:

• The investment and operation costs for « power equipment » • high for power-to-gas solutions, including EMO

• The investment and operation costs for « storage equipment »• low for salt caverns

• The cost & frequency of replacement• high for batteries

• The storage efficiency • 30% for H2 storage; 95% for Li-ion batteries

• The market(s) conditions• Currently, the « capacity market » pays more than the « energy markets »

• Last, projects can combine different techniques. • The HDF 140 MWh storage projet CEOG (Centrale Électrique de l’Ouest Guyanais) combines 20 MWh of

batteries and 120 MWh of H2 storage.

A usefull tool : Levelised Cost Of Storage (LCOS)

The breakeven selling price of the storage service

IEA, 2019

𝐿𝐶𝑂𝑆 =σ𝑛=1𝑁 𝐶𝑜𝑠𝑡 𝑛

1 +𝑊𝐴𝐶𝐶 𝑛

σ𝑛=1𝑁 𝑃𝑜𝑢𝑡 𝑛

1 +𝑊𝐴𝐶𝐶 𝑛

Lifetime of the

facility (years)

Weighted Average

Cost of Capital

𝐶𝐴𝑃𝐸𝑋 𝑛 + 𝑂𝑃𝐸𝑋𝑓𝑖𝑥𝑒𝑑+𝑂𝑃𝐸𝑋𝑣𝑎𝑟𝑖𝑎𝑏𝑙𝑒 × 𝑃𝑜𝑢𝑡 𝑛

MWh produced

during year n

𝐿𝐶𝑂𝑆,

Cost structures and competing technologies are driving the

cycles / storage range targetted by EMO storage

• Power to gas, including EMO storage, is in

competition with other techniques


What storage cycles should

EMO consider ?

Is this technology competitive ?

Moore & Shabani, 2015

• Underground storage cost

estimate

• « Energy transformation »,

or surface equipments cost

estimate

• → LCOS

• →Comparison with

competing techniques

• → Definition of cycles

Underground costs estimation


Nm3 per m3 : definition of an operating enveloppe and

consideration of the storage cavern thermodynamics


Cycles:

• Weekly

• Seasonal

Depth

Pressure

5 000 000

10 000 000

15 000 000

200 500 1 000 1 500

Wo

rkin

gga

s(N

m3)

Cavity depth (m)

CO2

O2

CH4

10 000 000

20 000 000

30 000 000

40 000 000

50 000 000

60 000 000

200 500 1 000 1 500

Wo

rkin

gga

s(N

m3 )

Cavity depth (m)

CO2

O2

CH4

€/m3 and per depth: Consideration of the well design, the number

of wells, and the leaching cost.


• Proposition of a

typical well

architecture

• Cost estimate for

various depths

• Adaptation of the

number of wells to

the acceptable flow

rates

0 €/Nm3

1 €/Nm3

2 €/Nm3

3 €/Nm3

4 €/Nm3

200 m 500 m 1 000 m 1 500 m

Underground storage costs for various depths

CH4 hebdo

CH4 saisonnier

→ Cost of 0.4 €/Nm3 or 2 €/Nm3 of

working gas for the weekly or

seasonal storage.

→ 1000 m case. For all gases.

→ Suited to Manosque / Etrez /

Hauterives / Tersanne conditions

Storage service cost estimation

(LCOS)


The Levelized Cost of Storage (LCOS) accounts for the capital

and operating costs of each component of the EMO process


Electricity

Electricity

O2

H2

CO2

SNG

η = 74% η = 79% η = 52 %

Water

Water

200MW

Temp ( C)

Press.(Bar)

Flow (Nm3/h)

155 MW

482MW

35 C, 20 bar

35 C, 20 bar

35 C, 20 bar

20

35

56 500

Electrolysis Methanation Storage Combustion

20

35

14 075

20

35

83 731

20

35

28 460

20

35

14 519

20

35

86 561

20

35

166 977

H2 Compressor Methanation reactorPost methanation

drying unit

SNG

CompressorOxycombustion Turbine

CO2 CompressorPost oxycombustion

drying unit

O2 Compressor

O2 Cavity

SNG Cavity

Electrolyser

CO2 Cavity

O2

H2

CO2

SNG

0

100

200

300

400

500

600

700

800

EMO - interseasonal cyclingNominal assumptions

EMO - weekly cyclingNominal assumptions

LCO

S (€

/MW

he

l fe

d b

ack

into

th

e g

rid

)

Post oxycombustion drying unit

Oxycombustion turbine

Gas turbine

CO2 cavity storage

CO2 compression

O2 cavity storage

O2 compression

CH4 cavity storage

SNG compression

Post methanation drying unit

Methanation reactor

CO2 supply

Electrolysis

Power grid connection

Electricity conversion losses

Energylosses 20%

Charge43%

Storage16%

Discharge 21%

Energylosses 22%

Charge56%

Storage2%

Discharge 21%

Charging and discharging account for the majority of EMO’s

LCOS in both interseasonal and weekly cycling scenarios


738€/MWh

516€/MWh

For weekly storage, EMO competes against proven

technologies


ElectrolysisMethanation

Cavitystorage

Oxycombustion

Water pumping

Water storage in

dam

Water turbine

Air compression

Cavitystorage

Air decompression

EMOPumped Storage Power Stations

Compressed Air Energy Storage

CH4CO2O2

Air

EMO is not competitive against CAES and pumped storage

(PSPS)


0

50

100

150

200

250

300

350

400

450

EMO - weekly cyclingOptimistic assumptions

CAES PSPS

LCO

S (€

/MW

hel

fed

bac

k in

to t

he

grid

)

High LCOS

Low LCOS

Post oxycombustion dryingunitOxycombustion turbine

Gas turbine

CO2 cavity storage

CO2 compression

O2 cavity storage

O2 compression

CH4 cavity storage

SNG compression


Methanation reactor

CO2 supply

Electrolysis



424€/MWh

290€/MWh

90€/MWh

For interseasonal storage, EMO competes against other

power-to-gas-to-power technologies


EMOConventionalmethanation

Pure hydrogen withfuel cell


Cavitystorage

Oxycombustion

Cavitystorage

Fuel cell

CH4

CO2

O2

H2


Electrolysis

Cavitystorage

CH4

Conventionalcombustion

EMO falls within a similar cost range as other power-to-gas-to-

power technologies, with potential for further cost reductions


0

100

200

300

400

500

600

700

800

900

EMO Conventional methanation Pure H2 with FC

LCO

S (€

/MW

he

l fed

bac

k in

to th

e gr

id)

Potential fuel cell surplus cost

Fuel cell

Gas turbine

Post oxycombustion dryingunitOxycombustion turbine

H2 storage

H2 compression

CO2 cavity storage

CO2 compression

O2 cavity storage

O2 compression

CH4 cavity storage

SNG compression


Methanation reactor

CO2 supply

Electrolysis



738€/MWh

668€/MWh

856€/MWh

Storage 118€/MWh

Conclusions


Conclusions

Power-to-gas is adapted to interseasonal storage

• Power-to-gas cannot compete with PSPS for weekly storage demand

• Power-to-gas is costly, but it is the only suitable technology for interseasonal storage

EMO system must be able to undergo short times of discharge

• Charging assets and cavities must handle short to long charging periods (6 hours to 8 days)

• Discharging assets and cavities must handle very short to moderate periods (6 hours to 8 days)


Thank you for your attention !

Acknowledgments:We are thankful to the ANR FluidStory project for funding us in this work

We also thank Guillaume d’Herouville, whose final year internship

produced part of the comprehension presented (in the caverns costs section)


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Energy and economic profitability of the EMO conceptEscagues-GK-ENEA... · 1 €/Nm3 2 €/Nm3 3...

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