renewable electricity storage with ammonia fuel: a … engineering research center renewable...

Resilience Engineering Research Center

Renewable Electricity Storage with Ammonia Fuel: A Case Study in Japan with Optimal Power Generation Mix Model

Ryoichi Komiyama, Yasumasa Fujii

The University of Tokyo

USAEE/IAEE 35th North American Conference, Concurrent Session 19, Royal Sonesta Hotel, Houston TX USA, November 14, 2017

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Contents

Introduction

Modelling Analysis for RE-based Ammonia Storage in Power Grid

Inter-Sectoral Analysis for RE-based Ammonia:• Electricity Sector & Chemical (Ammonia) Industrial Sector• RE-based Ammonia vs NG-based Ammonia

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Resilience Engineering Research Center 3

Background

RE-based hydrogen system has attracted keen attention for carbon reduction in Japan. e.g. Basic Energy Plan in Japan, 2014

RE-based hydrogen system, however, requires massive investment.

Ammonia is regarded as one of the candidates for H2 carrier and a possible fuel, due to key properties of energy density and logistics

• Well-established transport and storage infrastructure already in place• Availability like propane (LPG), transported easily at low pressures• Relatively higher energy density than H2

[Unit: MJ / liter]H2 (70MPa) 9, H2 (liquid) 10, NH3 (liquid) 15, Methanol 18, Ethanol 23, Propane (liquid) 29, Gasoline 36

• R&D progress for direct combustion tech.(e.g. SOFC) • Possible contribution for low-carbon chemical industry• Possible usage for energy storage for power grid

Objective: Energy modeling analysis is conducted for positioning ammonia in low-carbon power grid and energy system


Hydrogen‐Based Energy System

4(Source) Cabinet Office, Government of Japan, SIP ”Pioneering the Future: Japanese Science, Technology and Innovation 2015”

MCH (Methylcyclohexane) (C7H14⇔C7H8)• (Advantage) higher H2 density (500 times as much as gaseous H2), availability in existing gasoline infrastructure• (Disadvantage) dehydrogenation (400℃ steam, energy loss (30%)), Bulky, need of H2 refining for hydrogen station

Liquefied Hydrogen• (Advantage) higher H2 density (800 times as much as gaseous H2), no need of H2 refining for hydrogen station,

commercialized in power generation (dual fuel at H2 70%)• (Disadvantage) liquefaction(-253℃, energy loss (15%)), investment cost for infrastructure, boil-off (difficulty in long-

term storage)

Ammonia• (Advantage) higher H2 density (1200 times as much as gaseous H2(-33℃ or 8Pa)), availability in existing LPG

infrastructure, direct combustion in FC (fuel cell), cheap cost• (Disadvantage) toxicity, energy loss in dehydrogenation if needed, need of H2 refining for hydrogen station

* Demonstration stage

* Commercialized in small-scale project

* R&D stage, Demonstration stage


Chemical Industry & Ammonia Market

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Chemical industry e.g. fertilizers, steel, plastics etc. depends on hydrocarbons for raw materials and fossil fuel for the production. faces significant challenges: growing carbon emissions, security of supply for

both energy and raw materials. Carbon-free synthesis of chemicals by RE is possible option for the future.

Ammonia 2% of global fossil fuel is consumed in ammonia. 90% of ammonia production is

based on natural gas. 80% of ammonia is used in fertilizer industry. Fertilizer demand is growing at 3% per annum. World Ammonia Production (2012): 165 million ton

• China: 53 million ton, Europe: 17 million ton, North America: 16 million ton, India: 14 million ton, Japan: 1.3 million ton

Production today uses Haber-Bosch process, mainly on natural gas as feedstock.


Ammonia Production (Conventional Haber‐Bosch Process & RE‐based)

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N2+3H2→2NH3

Gas Preparation Ammonia Conversion and Separation

CH4+H2O→CO+3H2

2CH4+O2→2CO+4H2

Methane, Water(CH4, H2O)

Air (O2, N2)

H2, N2, CO

H2OH2, N2, CO2

H2O H2O, CO2

H2, N2 H2, N2, NH3

H2, N2Catalysor

SeparatorReactor Cooler

Ammonia(Fluid)

Conventional(HB, NG-based)

N2+3H2→2NH3

Gas Preparation Ammonia Conversion and Separation

H2, N2 H2, N2, NH3

H2, N2

Reactor Cooler

Ammonia(Fluid)

RE-based NH3(Electrolysis + HB)

Air Separation Unit

Hydrogen ElectrolyserH2

N2

H2O

Air

Renewable Electricity


Direct Ammonia SOFC (Solid Oxide Fuel Cell)

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4NH3+3O2→2N2+6H2O

Utilizes inexpensive base metal catalyst (Ni or Co)Operating temperature 800-1000°C, depending on electrolyte

Ammonia Oxidation (overall reaction for complete combustion of ammonia):

Utilizes inexpensive base metal catalyst (Ni or Co)Operating temperature 450-700°C, depending on catalyst

(F. Ishak et al, 2012)

SOFC is attractive fuel cell concepts, because of their ability to accommodate a range of fuels.SOFC conventionally runs at temperatures above 500 ℃ (typically 800-1000 ℃), and one of

the advantages of this is that the cracking process, necessary to free the hydrogen from the fuel, and the generation of electricity can be combined. Ammonia can be directly input into the SOFC without any pre-treatment.Conversion Efficiency: around 60%

Oxygen ion-conducting DA-SOFC Hydrogen proton-conducting DA-SOFC

NH3 → 3/2H2+1/2N2

O2-

H2OH2

O2

NH3N2, H2, H2O, NH3

AnodeElectrolyte

Cathode

O2, N2 O2, N2

V

NH3 → 3/2H2+1/2N2

H2O

H2

O2

NH3 N2, H2, NH3

AnodeElectrolyte

Cathode

O2, N2 O2, N2 ,H2O

VH+


Optimal Power Generation Mix Model (OPGM)

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Linear programming model. Single-year minimization of total electricity system cost Power grid topology: 135 nodes, 166 power lines (high-voltage) Time-resolution: 10-min hours on 365 days ⇒ 52,560 time segments per year

(=6×26×365)

(Power plants)• Construction cost• Capital recovery factor• Fuel cost• Life time (or legal durable years)• Conversion efficiency• Annual average availability• Seasonal peak availability• Load following capability• Ratio of DSS mode operation• Minimum output constraints• Schedule of plant maintenance• Fuel supply constraints• Existing power plant capacity• Constraints on newly built capacity

Electricity load curve

PV and wind power output

• Carbon regulation• Carbon tax

High Time-Resolution Optimal Power Generation Mix Model

(Calculated results)• Newly constructed capacity• Power generation• Power generation cost• Fuel consumption• CO2 emissions• Optimal power dispatch

(Energy storage technology)• kW､kWh construction cost• Cost of consumable parts• Life cycle• Round-trip efficiency• Self discharge loss• C-rate constraints• Maximum kWh ratio to kW• Usage ratio

The model evaluates the installable potential of RE-based ammonia storage system in the Japanese power grid.

Optimal Power Generation Mix Model (OPGM) Power Grid Topology and Demand in Japan

(Reference)• Komiyama, R., Fujii, Y., Energy Policy, Vol.101, pp.594–611 (2017)• Komiyama, R., Fujii, Y, Energy, Vol.81, pp.537–555 (2015)


Optimal Power Generation Mix Model (OPGM) ,combined with RE‐based Ammonia Storage

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• Wind• PV system

Electrolyzer

NH3 Synthesis (HB)

Fuel Cell (SOFC)

NH3

Suppression ControlRE‐based Ammonia Storage System

• Nuclear• Coal‐fired• LNG‐fired• Oil‐fired• Hydro• Geothermal

• NAS Battery• Li‐ion Battery• Pumped‐hydro

Electricity

Power Grid Electricity LoadElectricity Electricity

Electricity

Electricity Electricity

Power Generators

Energy Storage

N2 Separation

NH3 Liquefaction

NH3 TankO2 Production O2

N2

H2

NH3

RE‐based NH3 Supply

The model considers cost trade-off of ammonia with rechargeable battery, RE output curtailment and inter-node power transmission exchange.


Case Setting

CO2 RegulationBase (No Regulation), ‐50%, ‐60%, ‐70%, ‐80%

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Cost of NH3 technology (electrolyzer, NH3 production and storage, SOFC) is assumed as -80% reduction from reference values.

Nuclear, thermal, hydro, pumped, electricity demand etc. are assumed on the basis of METI’s energy outlook in 2030.

PV and wind installations are endogenized (determined through the optimization)• Lower limit values: PV (64 GW), wind (10 GW) from METI’s energy outlook in 2030 • Upper limit values: PV (330 GW ), wind (260 GW) from potential survey by Ministry of Environment, Japan.


0

100

200

300

400

500

600

700

800

900

Base

(MET

I 203

0)

CO2

50%

Red

.

CO2

60%

Red

.

CO2

70%

Red

.

CO2

80%

Red

.

GW AmmoniastorageSOFC

NH3 plant (HB)

Electroyzer

Battery2

Battery1

Pumped

PV

Wind

Oil

LNG GCC

-400

-200

0

200

400

600

800

1000

1200

1400

Base

(MET

I 203

0)

CO2

50%

Red

.

CO2

60%

Red

.

CO2

70%

Red

.

CO2

80%

Red

.

TWh LossSuppressed PVSuppressed WindAmmonia(PV)Ammonia(wind)Ammonia(out)Battery2(out)Battery1(out)Pumped(ont)Ammonia(in)Battery2(in)Battery1(in)Pumped(in)PVWindElectrolyzerAmmonia(out) & SOFCOilLNG GCCLNG STCoalNuclearMarineBiomassGeothermalHydro

Power Generation Mix in Japan

• Strict CO2 regulation policy accelerates the installations of PV, wind and energy storage system, such as NAS battery and NH3 storage, which replace carbon-intensive thermal power plants.

• Power transmission loss increases, due to nation-wide power exchange caused by massive RE integration.• Installation of NH3 storage is smaller than that of NAS battery

CapacityPower Generation

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LNGCCCoal

WindPV

NAS

NH3(wind)

Nuclear

NASPower trans. loss

LNGCCCoal

Wind

PV

NAS

NH3 storage

Nuclear

NH3 storage


Optimal Installation of PV and WindCO2: ‐80% reduction case

PV

• PV tends to be installed in demand-intensive region such as Kanto, Kansai and Chubu which have enough power balancing resources.

• Wind turbine (onshore) is introduced in the resource rich regions such as Tohoku and Kyushu.

PV[GW] Wind[GW]

Wind

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Locational Marginal Price (LMP) of ElectricityAnnual Average, CO2: ‐80% reduction case

Nodal Price Range[yen per kWh]

• Electricity price is lower in northern part of Japan, due to the installation of renewable energy.

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Ammonia Storage[GWh]

Ammonia Storage Installation

CO2 regulation plays an important role to accelerate the introduction of RE‐based ammonia energy system.

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210,000 ton is equal to three units of LNG bulk storage tank.

Ammonia Storage CapacityAmmonia Storage Capacity in CO2 ‐80% Red. Case

(=37 [1,000 ton of LNG])

0

50

100

150

200

250

Base (METI2030)

CO2 50%Red.

CO2 60%Red.

CO2 70%Red.

CO2 80%Red.

(1,000 LNG‐ton)


-8

-6

-4

-2

0

2

4

6

8

10

12

14Po

wer

Sys

tem

Ope

ratio

n [G

W]

LossInter ChangeSuppressed PVSuppressed WindAmmonia(PV)Ammonia(wind)Battery2(out)Battery1(out)Pumped(ont)Ammonia(in)Battery2(in)Battery1(in)Pumped(in)PVWindAmmonia(out) & SOFCOilLNG GCCLNG STCoalNuclearMarineBiomassGeothermalHydroLoad

-40

-20

0

20

40

60

80

Pow

er S

yste

m O

pera

tion

[GW

]


-60

-40

-20

0

20

40

60

80

100

Pow

er S

yste

m O

pera

tion

[GW

]


-20

-10

0

10

20

30

40

Pow

er S

yste

m O

pera

tion

[GW

]


Power Dispatch in May

15

Aug.1

Hokkaido

Tohoku

Tokyo

Kyushu NH3(PV)NH3(wind)

Wind

NH3 storage

NH3(out) & SOFC

NH3(wind)

NH3(wind)

Power Interchange

Suppressed Wind

Wind

NAS

NH3 storage NAS

NH3(out) & SOFC

NH3 storage

Suppressed PV

Suppressed PVSuppressed Wind

Power Interchange

NAS

NAS

Pumped(in)

Pumped(out)

Suppressed Wind

Power Interchange

NAS

NAS

NH3(wind)

Wind

PV

LNGCC

LNGCC

Suppressed PV

CO2: -80% reduction case


0

500

1000

1500

2000

2500

1‐Jan

1‐Feb

1‐Mar

1‐Apr

1‐May

1‐Jun

1‐Jul

1‐Aug

1‐Sep

1‐Oct

1‐Nov

1‐Dec

31‐Dec

Stored

Electricity

[GWh]

Pumped

NaS

Li‐ion

Ammonia

Annual SOC of Electricity Storage in Japan

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Round‐trip efficiency of NH3 storage is not good, and it is not suitable for a daily cycle.

Charge and discharge cycle of NH3 storage tank shows a monthly or seasonal cycle, while that of NAS battery exhibits a daily cycle .

Since a storage loss of NH3 tank is very low, the model selects a long‐term NH3storage of surplus RE output as an optimal solution under strict CO2 regulation.

Ammonia is a suitable option for a long-term storage of RE energy.

SOC of NH3 storage tank and battery

NH3

NAS Battery

Jan.,1 Feb.,1 Mar.,1 Apr.1 May,1 Jun.,1 Jul.,1 Aug.,1 Sep.,1 Oct.,1 Nov.,1 Dec.,1 Dec.,31

CO2: -80% reduction case


Inter‐Sectoral Analysis for RE‐based Ammonia(Electricity Sector & Chemical Industrial Sector)

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• Wind• PV system

Electrolyzer

NH3 Synthesis (HB)

Fuel Cell (SOFC)

NH3

Suppression ControlAmmonia Storage System integrated with VRs

• Nuclear• Coal‐fired• LNG‐fired• Oil‐fired• Hydro• Geothermal

• NAS Battery• Li‐ion Battery• Pumped‐hydro

Electricity

Power Grid Electricity LoadElectricity Electricity

Electricity

Electricity Electricity

Power Generators

Energy Storage

N2 Separation

NH3 Liquefaction

NH3 TankO2 Production O2

N2

H2

NH3 NH3 Demand

Haber‐Bosch (HB)Process

RE‐based NH3 Supply

NH3

NH3

Electricity SectorChemical Industrial Sector

(Ammonia)

NH3 Demand:1.3 mil. ton

CO2 Coefficient of NH3: 1.6 t/t-NH3NH3 Price: 570 $/t-NH3

Optimal Power Generation Mix Model, combined with RE-based Ammonia and Conventional (NG-based) Ammonia Supply

Conventional NH3 Supply

CH4

Natural Gas


RE‐based & Conventional (NG‐based) Ammonia

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CO2 Regulation for Total Emissions of both Electricity & Chemical Sectors BAU (No Regulation), ‐10%, ‐20%, ‐30%, ‐40%, ‐50%, ‐60%, ‐70%, ‐80%

Ammonia Sales Composition

0

200

400

600

800

1000

1200

1400

BAU 10%red.

20%red

30%red.

40%red.

50%red.

60%red.

70%red.

80%red.

Ammon

ia Produ

ction [100

0 ton]

CO2 Regulation Scenario

RE‐based NH3

Conventional NH3

Which is economically affordable option under carbon regulation ? Carbon regulation, around after CO2 40% reduction case,

encourages RE-based NH3 supply

Conventional(NG‐based)

RE‐based


CO2 Price (Shadow Price)

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0

200

400

600

800

1000

1200

1400

1600

1800

10%red.

20%red

30%red.

40%red.

50%red.

60%red.

70%red.

80%red.

CO2 Marginal Price [$/t]

CO2 Regulation Scenario

Carbon price shows accelerative increase as severe carbon regulations are assigned.e.g.

Carbon Price: 200 [$/t] → LNG Price: +11 [$/MMBtu]LNG Price in Japan (2015): 9.3 [$/MMBtu] → 20 [$/MMBtu] Carbon Price: 1600 [$/t] → LNG Price: +89 [$/MMBtu]LNG Price in Japan (2015): 9.3 [$/MMBtu] → 98 [$/MMBtu]

CO2 Price (CO2 Shadow Price)


Summary

CO2 regulation are prerequisite for promoting RE‐based ammonia

Severe carbon regulation potentially replaces conventional ammonia supply with RE‐based ammonia

Ammonia is a suitable option for a long‐term storage of RE energy, such as in a seasonal or monthly cycle.

RE‐based ammonia is not dominant even under severe carbon regulation, due to its competition with rechargeable battery and other measures such as internode power exchange.

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Thanks for your kind attention.

Ryoichi KomiyamaAssociate Professor

The University of Tokyo

AcknowledgmentThis work was supported by JSPS KAKENHI Grant Number JP17H03531, JP15H01785,and by the Environment Research and Technology Development Fund 2‐1704 of the

Environmental Restoration and Conservation Agency .

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PV [GW]Wind [GW]

PV and Wind Potential in Japanestimated by Ministry of Environment, Japan

PV Wind

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Upper limit of PV and wind in each node is set by using those potential estimations by Ministry of Environment, Japan


0

20

40

60

80

100

120

Hokkaido Tohoku Kanto Chubu Hokuriku Kansai Shikoku Chugoku Kyushu

TWh

Suppressed Wind

Ammonia(wind)

Wind

0

20

40

60

80

100

Hokkaido Tohoku Kanto Chubu Hokuriku Kansai Shikoku Chugoku Kyushu

TWh

Suppressed PV

Ammonia(PV)

PV

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Wind (Japan)

PV (Japan)

PV, Wind and NH3 Production

In CO2 80% reduction case, 10% of wind output is utilized NH3 production. Wind-based NH3 is observed in Tohoku, Kyushu and Hokkaido. NH3 is not so much produced from PV output. In Kyushu, however, 30% of PV output is utilized for NH3 production.

Wind (by region, CO2 -80%)

PV (by region, CO2 -80%)

0

50

100

150

200

250

300

350

Base

(MET

I 203

0)

CO2

50%

Red

.

CO2

60%

Red

.

CO2

70%

Red

.

CO2

80%

Red

.

TWh

Suppressed Wind

Ammonia(wind)

Wind

0

50

100

150

200

250

300

Base

(MET

I 203

0)

CO2

50%

Red

.

CO2

60%

Red

.

CO2

70%

Red

.

CO2

80%

Red

.

TWh

Suppressed PV

Ammonia(PV)

PV

NH3

NH3

NH3NH3NH3

NH3

renewable electricity storage with ammonia fuel: a … engineering research center renewable...

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