Ammonia Production

for Renewable Energy Storage

Shanwen Tao

University of Strathclyde

H2FC Supergen Hydrogen and Fuel Cell Hub meeting

13:35-14:00, Room: Crombie A, All-Energy, AECC, Aberdeen, 21st May 2013

Intermittence of renewable energy sources

2

http://integrating-renewables.org/grid-impacts/

Volumetric versus gravimetric energy density of

the most important energy carriers

A. Zuttel, A. Remhof, A. Borgschulte, O. Friedrichs, Philos Trans R Soc A-

Math Phys Eng Sci 368 (2010) 3329 - 3342.

Electrochemical Synthesis

H2O

CO2

N2

CO

H2

CxHy

NH3

Syngas Organic compounds

/polymers

5

Chemicals can be synthesised from CO2

Peter Skyring, Carbon capture and utilisation in the green economy, 2012

World renewable electricity production

6

http://en.wikipedia.org/wiki/List_of_countries_by_electricity_production_from_renewable_sources

CO2 emission from power generation

7

http://www.world-nuclear.org/education/comparativeco2.html

To convert 1000g CO2 into CO, at 2V, need 2.43 kWh energy

1kWh can convert 411g CO2 (at 100% Faraday efficiency)

World hydrogen production and consumption

http://www.eoearth.org/article/The_Hydrogen_Economy?topic¼60603.

In 2002

Comparison of different energy carriers

Rong Lan, John T.S. Irvine, Shanwen Tao*, Inter. J. Hydrogen Energy,

37 (2012) 1482-1494.

Biosynthesis

Haber - Bosch process

Natural gas

Coal

Nuclear

Wind

Solar

Wave Biomass

CO 2 - free e lectricity

Artificial

Photosynthesis

CO 2 scrubbing

Storage Delivery

Urea

Ammo nia

fuel cell Urea

fuel cell

Ammonia

Transportation

Nuclear H 2

) g ( NH 2 ) g ( H 3 ) g ( N 3 2 2

+ ) ( 3 ) ( 4 6 ) ( 2 2 3 2 2 g O g NH O H g N + +

Biosynthesis Artificial

Photosynthesis

Diagram of ‘Ammonia Economy’

Rong Lan, John T.S. Irvine, Shanwen Tao*, Inter. J. Hydrogen Energy,

37 (2012) 1482-1494.

To convert a normal car to NH3 car

http://www.nh3car.com/how.htm

Note: cost a couple of thousands US$ to convert; can run either petrol or NH3

Haber-Bosch NH3 Synthesis

http://www.greener-industry.org.uk/pages/ammonia/6AmmoniaPMHaber.htm

Global NH3 production and CO2

emission

http://www.fertilizer.org/ifa/HomePage/SUSTAINABILITY/Climate-

change/Emissions-from-production.html

245 million tons of CO2 released

World CO2 emission 2012: 35.6 billion tons

~ 0.7% CO2 is from ammonia industry

Consuming 1% of world energy generated

Norsk Hydro Rjukan

http://en.wikipedia.org/wiki/Norsk_Hydro_Rjukan

Norsk Hydro Rjukan is an industrial facility operated by Norsk Hydro at

Rjukan in Tinn, Norway, from 1911 to 1991. The plant manufactured

chemicals related to the production of fertilizer, including ammonia,

potassium nitrate, heavy water and hydrogen. The location was chosen for

its vicinity to hydroelectric power plants built in the Måna river.

30 million tonnes of products, equivalent of 1.5 million wagon loads, were

produced in Rjukan.

Hydroelectricity to NH3 synthesis

http://www.hydroworld.com/articles/hr/print/volume-28/issue-

7/articles/renewable-fuels-manufacturing.html

Wholesale NH3 price in the USA

http://www.hydroworld.com/articles/hr/print/volume-28/issue-

7/articles/renewable-fuels-manufacturing.html

Price of NH3 using different synthesis

methods

Cost of Ammonia Produced Using Haber-Bosch Synthesis Technology

Cost of Ammonia Produced Using Solid State (Electrochemical) Synthesis Technology

http://www.hydroworld.com/articles/hr/print/volume-28/issue-

7/articles/renewable-fuels-manufacturing.html

Electrochemical synthesis of ammonia

http://freedomfertilizer.com/

Principles of electrochemical synthesis

of ammonia

19

I.A. Amar, R. Lan, C. Petit and S.W. Tao, J. Solid State Electrochem. 15 (2011) 2845.

Summary of reported ammonia formation rates

20

Nitrogen fixation by legume crops

21

http://permaculturetokyo.blogspot.co.uk/2009_02_01_archive.html

http://www-naweb.iaea.org/nafa/swmn/topic-soil-fertility.html

Thermodynamic evaluation of ammonia

synthesis process

22

0 100 200 300 400 500 600 700 800 900 1000

-100

0

100

200

300

400

500

600

700

800

Gib

bs fre

e e

nerg

y c

hange (

kJ m

ol-1

)

Temperature (°C)

N2(g)+3H

2(g)=2NH

3(g)

N2(g)+3H

2O(g)=2NH

3(g)+3/2O

2(g)

N2(g)+3H

2O(l)=2NH

3(g)+3/2O

2(g)

(A)

0 100 200 300 400 500 600 700 800 900 1000

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Min

imum

required v

oltage (

V)

Temperature (°C)

N2(g)+3H

2(g)=2NH

3(g)

N2(g)+3H

2O(g)=2NH

3(g)+3/2O

2(g)

N2(g)+3H

2O(l)=2NH

3(g)+3/2O

2(g)

(B)

(A) The Gibbs free energy change for electrochemical synthesis of ammonia from N2 and H2, N2 and

H2O (gaseous or liquid) at pressure of 1 bar; (B) The minimum applied voltage required for

electrochemical synthesis of ammonia from N2 and H2 at pressure of 1 bar (the negative voltage at a

temperature below 200 C means spontaneously generated voltage), N2 and H2O (gaseous or liquid).

Synthesis of ammonia from H2 and N2

23

(A) Current density of a N2, Pt Nafion 211 Pt, H2 cell under different applied voltages. Cathode was supplied with

N2, anode was supplied with H2. (B) The ammonia formation rate at N2 and H2 sides, total ammonia formation rate

and Faday efficiency. (C) The relationship between formed NH3 and time of a N2, Pt Nafion 211 Pt, H2 cell under

different applied voltages. Cathode was supplied with N2, anode was supplied with H2

0 10 20 30 40 50 60 70

100

200

300

400

500

600

700

800

Curr

ent

density (

mA

/cm

2)

Time (min.)

applied 0.2V

applied 0.4V

applied 0.6V

applied 0.8V

applied 1.0V

(A)

0.0 0.2 0.4 0.6 0.8 1.0 1.2

0

1

2

3

4

NH

3 f

orm

atio

n r

ate

(x10

-5 m

ol m

-2 s

-1)

Applied voltage (V)

on air side

on H2 side

total

(B)

0.0

0.2

0.4

0.6

0.8

Farady efficiency

Fara

dy e

ffic

iency (

%)

0 60 120 180 240 3000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0

0.2

0.4

0.6

0.8

1.0

1.2

formed NH3

Fo

rme

d N

H3 (

x1

0-5 m

ol)

Time (min.)

(C)

Ap

plie

d v

olta

ge

(V

)

applied voltage

Synthesis of ammonia from H2 and air

24

0 10 20 30 40 50 60

0

100

200

300

400

500

600

applied 0.2V

applied 0.4V

applied 0.6V

applied 0.8V

applied 1.0V

applied 1.2V

Cu

rre

nt

de

nsity (

mA

cm

-2)

Time (min.)

(A)

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

0

1

2

3

4

NH

3 f

orm

atio

n r

ate

(x1

0-5 m

ol m

-2 s

-1)

Applied voltage (V)

at N2 side

at H2 side

Total

0.0

0.5

1.0

1.5

2.0

2.5

Farady efficiency

Fa

rad

y e

ffic

ien

cy (

%)

(B)

0 60 120 180 240 300 3600.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

formed NH3

Fo

rme

d N

H3 (

x1

0-5 m

ol)

Time (min.)

(C)

Ap

plie

d v

olta

ge

(V

)

applied voltage

(A) Current density of an Air Pt Nafion 211 Pt, H2 cell under different applied voltages. Cathode was supplied with

air, anode was supplied with H2. (B) The ammonia formation rate at air and H2 sides, total ammonia formation rate

and Farady efficiency. (C) The relationship between formed NH3 and time of an Air, Pt Nafion 211 Pt, H2 cell under

different applied voltages. Cathode was supplied with air, anode was supplied with H2.

Synthesis of ammonia from H2O and air

25

(A) Current density of an Air, Pt Nafion 211 Pt, H2O cell under different applied voltages. Cathode was supplied

with air, anode was supplied with H2O. (B) The ammonia formation rate at air and H2O sides, total ammonia

formation rate and Farady efficiency. (C) The relationship between formed NH3 and time of an Air, Pt Nafion 211

Pt, H2O cell under different applied voltages. Cathode was supplied with air, anode was supplied with H2O.

0 10 20 30 40 50 60 70

40

50

60

70

80

90

Cu

rre

nt

den

sity (

mA

cm

-2)

Time (min.)

applied 1.2V

applied 1.3V

applied 1.4V

applied 1.5V

applied 1.6V

(A)

1.1 1.2 1.3 1.4 1.5 1.6 1.7

0.0

0.2

0.4

0.6

0.8

1.0

1.2

NH

3 f

orm

atio

n r

ate

(x10

-5 m

ol m

-2 s

-1)

Applied voltage (V)

on air side

on H2O side

total

(B)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Farady efficiency

Fara

dy e

ffic

iency (

%)

0 60 120 180 240 3000.0

0.3

0.6

0.9

1.2

1.5

1.1

1.2

1.3

1.4

1.5

1.6

1.7

formed NH3

Fo

rme

d N

H3 (

x1

0-5 m

ol)

Time (min.)

(C)

Ap

plie

d v

olta

ge

(V

)

applied voltage

Synthesis of ammonia from air and water

26 Rong Lan, John T.S. Irvine, Shanwen Tao, Scientific Reports (Nature Publishing Group), 3 (2013) 1145.

NH3 formation rate and Faraday efficiency

when low cost catalysts were used

1.2 1.3 1.4 1.5 1.6 1.70.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

NH3 formation rate

NH

3 form

atio

n r

ate

(x1

0-4 m

ol m

-2 s

-1)

Applied voltage (V)

0

1

2

3

4

5

6

Faraday efficiency

Fara

day e

ffic

iency (

%)

Note: NH3 formation rates are over 10 times higher than those

when Pt/C was used as catalysts.

Stability of a electrochemical cell using

low cost catalysts at both electrodes

28

0 10 20 30 40 50 60 70

0

25

50

75

100

125

150

175

200

225

250

Curr

ent (m

A)

Time (hour)

Current at 1.3V

Summary

29

• It has been demonstrated that ammonia can be

synthesised directly from air and water at ambient

temperature and pressure.

• Ammonia is an important energy carrier for energy storage.

• Ammonia has been produced from renewable electricity.

• Price of ammonia produced from renewable electricity

depends on the price of electricity, will be competitive.

• Unlike extra cost for CO2 capture, storage and

transportation for synthesis of hydrocarbons, ammonia can

be on site synthesised directly from air and water.

Acknowledgements

Professor John T.S. Irvine at University of St Andrews

Dr Rong Lan

Mr Ibrahim Amar

Other RAs and students in my group