Different ways of producing H2

1. GREEN HYDROGEN
Dr. S. R. Moharir,Azeem Inamdar ,Arya Mahajan, Bhavna Pillai.

2. CONTENTS
INTRODUCTION
GREEN HYDROGEN
SHADES OF HYDROGEN
METHODS TO PRODUCE HYDROGEN
PROCESS OF MANUFACTURING GREEN HYDROGEN
USES
BARRIERS
MERITS
DEMERITS
CONCLUSION

3. INTRODUCTION
Hydrogen is the most abundant element in the universe.
Until now renewable sources like fossil fuels have been used , but they result in emission on
CO2 and other harmful gases.
Hydrogen is clean fuel which on consumption produces only water
Hydrogen even though available in large quantities has never been materialized.
Currently more than 95% of Hydrogen used is produced from fossil fuels which result in release
of CO2 gas.

4. GREEN HYDROGEN
Hydrogen made without the use of fossil fuels
Cleaner than other types of hydrogen
Electrolysis of water results in emission of hydrogen and oxygen.
Electricity used in obtained from renewable sources.

5. SHADES OF HYDROGEN
Hydrogen is classified into Eight types based on the way it is produced:-
i. Brown / Black Hydrogen
ii. Grey Hydrogen
iii. Blue Hydrogen
iv. Yellow Hydrogen
v. White Hydrogen
vi. Turquoise Hydrogen
vii. Pink Hydrogen
viii. Green Hydrogen

7. METHODS USED TO PRODUCE
HYDROGEN
Hydrogen is produced by the following methods:-
i. Thermal
ii. Electrolysis
iii. Biological
iv. Solar Driven
a. Photobiological
b. Photochemical
c. Solar Thermochemical
d. Photocatalytic Water Splitting

9. PROCESS OF MANUFACTURING
Green hydrogen which is produced with zero net carbon emission is mainly manufactured by four
processes:-
I. Biomass
II. Alkaline water electrolysis (AWE)
III. PEM Electrolysis
IV. Solid Oxide Electrolysis

10. Specification Unit Alkaline PEM SOE
Technology maturity State of the art Demonstration R &D
Cell temperature oC 60-80 50-80 900-1000
Cell pressure Bar <30 <30 <30
Current density A/cm2 0.2-0.4 0.6-2.0 0.3-1.0
Cell voltage V 1.8-2.4 1.8-2.2 0.95 -1.3
Voltage efficiency % 62-82 67-82 81-86
Specific energy
consumption
kWh/Nm3 4.5-7.0 4.5-7.5 2.5-3.5
Life time, stack hr. <90000 <20000 <40000
Cold start up time Min. 15 <15 >60

11. .
Green hydrogen is produced mainly by electrolysis of water , while the electricity used comes from
renewable sources.
Water is split into H2 and O2
Hydrogen gas is given out at cathode while oxygen is given out at anode
CATHODIC REACTION
4H ++4e - ➔ 2H 2
ANODIC REACTION
2H 2O ➔ O 2+4H ++4e

13. USES
Generate electricity
Produce heat
Alternative to conventional fuels
Fuel cell hydrogen cars
Container ship powered by liquid ammonia made from H2
Green steel refineries , use hydrogen over coal
Electrical turbines
Substitute for natural gas for domestic purposes

14. HYDROGEN FUEL CELL
Hydrogen fuel cell is used in Fuel cell Electrical Vehicles.
It uses hydrogen gas as fuel , and converts it into electricity.
H2is fed at the anode while air is fed into the cathode chamber.
Hydrogen fuel cell gives no by-products other than H2O and heat.

16. BARRIERS
Cost of water
Cost of infrastructure
Limitations of suitable Place
Energy losses
Lack of skilled workers

17. MERITS
Green hydrogen does not emit any greenhouse gases.
Green hydrogen is versatile, it can used in variety of sectors.
Green hydrogen is produced from renewable sources.
Green hydrogen is cleaner than other gases , zero carbon emission.
Green hydrogen gives higher energy production per pound in hydrogen fuel cell.
The only product of Green hydrogen is water.

18. DEMERITS
Hydrogen has 4 times the volume of natural gas.
Hydrogen is highly flammable and 20 times more explosive than petrol.
Hydrogen under pressure is small enough to slip through solid steel.
Cost of storage is high.
Cost of production of Green hydrogen is 2 times the price of brown hydrogen.
Appliances currently in use need to be replaced to match for hydrogen.

19. CONCLUSION
Green hydrogen is a key pillar in the global decarbonization of transportation, chemical and
industrial sectors.
Green Hydrogen being a clean fuel ,emit no greenhouse gases and carbon footprint
Even though green hydrogen is clean , currently less than 1 % of the world’s hydrogen is
produced by this method.
Though its advantages in decarbonization many sectors, green hydrogen faces many economic
and technical issues due to huge amount of required water and its pretreatment and purification,
and energy losses during generation, transportation and storing of hydrogen.

20. If green hydrogen is able to replace the hydrogen produced from fossil fuels , it will help in
reducing 10 – 12 tonnes of CO2 being produced behind every ton of hydrogen .
By 2030 the cost of production of green hydrogen is predicted to become half of its current value
due to the drop in the prices of electrolyzers.

21. THANK YOU…