Course outline
Module 1
Module 1: Introduction to the Hydrogen Economy
Introduction to the Hydrogen Economy
Knowledge check
Q1. What is the most abundant element in the universe, making it a foundational element of the hydrogen economy concept?
- A. Helium
- B. Hydrogen ✓
- C. Oxygen
- D. Carbon
Why: Hydrogen is the most abundant element in the universe, accounting for roughly 75% of normal matter by mass. Its abundance is one reason it is considered a candidate energy carrier, though on Earth it rarely exists freely and must be produced from compounds like water or natural gas.
Q2. Which term describes hydrogen produced from water using renewable electricity, with no direct carbon emissions?
- A. Grey hydrogen
- B. Blue hydrogen
- C. Green hydrogen ✓
- D. Brown hydrogen
Why: Green hydrogen is produced through electrolysis of water powered by renewable electricity such as wind or solar. Grey hydrogen comes from natural gas without carbon capture, blue hydrogen also uses natural gas but captures some emissions, and brown hydrogen is made from coal.
Q3. In the hydrogen economy, what role does hydrogen primarily play?
- A. A primary energy source found in large underground deposits
- B. An energy carrier that stores and transports energy ✓
- C. A fossil fuel replacement that is burned exclusively for heat
- D. A mineral extracted for use in construction materials
Why: Hydrogen is generally described as an energy carrier rather than a primary energy source, because it must be manufactured from other energy inputs. It can store energy produced at one time or place and deliver it later or elsewhere.
Q4. What is the primary byproduct when hydrogen is used in a fuel cell to generate electricity?
- A. Carbon dioxide
- B. Sulfur dioxide
- C. Water ✓
- D. Methane
Why: In a fuel cell, hydrogen reacts with oxygen to produce electricity, heat, and water. Because no carbon is present in the hydrogen fuel, no carbon dioxide is emitted at the point of use.
Q5. Which property makes hydrogen challenging to store and transport compared with conventional fuels?
- A. It is highly toxic to humans in small quantities
- B. It has a very low energy density by volume at ambient conditions ✓
- C. It is solid at room temperature
- D. It cannot be compressed under any conditions
Why: Hydrogen has high energy per unit mass but very low energy per unit volume at normal conditions, so it takes up a lot of space. Storage typically requires high-pressure tanks, cryogenic liquefaction, or chemical carriers to make it practical.
Module 2
Module 2: Hydrogen Production Methods
Hydrogen Production Methods
Knowledge check
Q1. Which hydrogen production method uses high-temperature steam to react with natural gas, producing hydrogen and carbon dioxide?
- A. Electrolysis
- B. Steam methane reforming ✓
- C. Photocatalysis
- D. Biomass gasification
Why: Steam methane reforming (SMR) reacts methane with steam at high temperature over a nickel catalyst, producing hydrogen and CO2. It is the most common industrial hydrogen production method today.
Q2. What is the main energy input required for water electrolysis to split water into hydrogen and oxygen?
- A. Chemical heat from combustion
- B. Mechanical pressure
- C. Electrical energy ✓
- D. Nuclear fission
Why: Electrolysis uses direct electrical current passed through water, with an electrolyte to aid conduction, to split H2O into hydrogen at the cathode and oxygen at the anode.
Q3. Which term describes hydrogen produced from renewable electricity via electrolysis, resulting in near-zero direct carbon emissions?
- A. Grey hydrogen
- B. Blue hydrogen
- C. Green hydrogen ✓
- D. Brown hydrogen
Why: Green hydrogen is produced by electrolysis powered by renewable sources such as solar or wind, so its production process emits essentially no CO2.
Q4. What distinguishes blue hydrogen from grey hydrogen?
- A. Blue hydrogen is made from water only
- B. Blue hydrogen captures and stores the CO2 emitted during production ✓
- C. Blue hydrogen uses nuclear power
- D. Blue hydrogen is produced at lower temperatures
Why: Grey hydrogen is made from natural gas with CO2 released to the atmosphere. Blue hydrogen uses the same process but adds carbon capture and storage to reduce emissions.
Q5. Which of the following is a feedstock commonly used in biomass gasification to produce hydrogen?
- A. Crude oil
- B. Agricultural residues such as wood chips ✓
- C. Liquid nitrogen
- D. Seawater
Why: Biomass gasification converts organic materials like wood chips, agricultural waste, and other biogenic residues into a syngas rich in hydrogen through heating with limited oxygen or steam.
Module 3
Module 3: Hydrogen Storage and Transport
Hydrogen Storage and Transport
Knowledge check
Q1. Why is hydrogen difficult to store at high density compared with many other fuels?
- A. Hydrogen is a solid at room temperature
- B. Hydrogen has a very low volumetric energy density at ambient conditions because its molecules are very light ✓
- C. Hydrogen reacts violently with all container materials
- D. Hydrogen cannot be compressed under any pressure
Why: Although hydrogen has a very high energy content per kilogram, its gas density is extremely low at ambient conditions, so a given volume holds little energy. This is why storage typically requires compression, liquefaction, or chemical carriers.
Q2. Which of the following is a common method for storing hydrogen as a compressed gas in vehicles?
- A. Storing it in pressurized tanks at around 350 to 700 bar ✓
- B. Dissolving it in water at room pressure
- C. Keeping it as a liquid at room temperature
- D. Storing it in open-air balloons
Why: Fuel cell vehicles commonly use Type III or Type IV composite tanks rated for 350 bar or 700 bar, which allow hydrogen to be stored at high pressure in a practical volume.
Q3. What is the approximate temperature required to store hydrogen as a liquid?
- A. About 250 K (-23 degrees C)
- B. About 20 K (-253 degrees C) ✓
- C. About 77 K (-196 degrees C)
- D. About 400 K (127 degrees C)
Why: Hydrogen liquefies at about 20 K, which is roughly -253 degrees Celsius. Keeping it this cold requires energy-intensive cryogenic systems and insulated tanks, and some hydrogen inevitably boils off over time.
Q4. Which of the following is an example of a chemical carrier used to store and transport hydrogen?
- A. Liquid ammonia ✓
- B. Liquid nitrogen
- C. Carbon dioxide
- D. Helium
Why: Ammonia can be synthesized from hydrogen and nitrogen and stored as a liquid under mild conditions, making it an effective hydrogen carrier. Hydrogen can later be released by cracking the ammonia. Liquid nitrogen, carbon dioxide, and helium do not chemically store hydrogen.
Q5. Why is pipeline transport of hydrogen considered challenging compared with natural gas pipelines?
- A. Hydrogen is too heavy to flow through pipes
- B. Hydrogen can cause embrittlement in some metals and has a lower energy density per unit volume ✓
- C. Hydrogen cannot be pressurized
- D. Pipelines cannot carry any gas with a low molecular weight
Why: Hydrogen can make certain steels brittle through a process called hydrogen embrittlement, so materials must be carefully selected. Its lower volumetric energy density also means pipelines must move larger volumes or operate at higher pressures to deliver equivalent energy.
Module 4
Module 4: Fuel Cell Technology
Fuel Cell Technology
Knowledge check
Q1. What is the primary function of a fuel cell?
- A. To store electrical energy for later use
- B. To convert the chemical energy of a fuel directly into electricity ✓
- C. To generate hydrogen gas through electrolysis
- D. To burn fuel and produce mechanical motion
Why: A fuel cell electrochemically converts the chemical energy stored in a fuel, such as hydrogen, directly into electricity, with water and heat as typical byproducts. Unlike batteries, it continues producing power as long as fuel is supplied.
Q2. Which two reactants are typically used in a hydrogen fuel cell?
- A. Hydrogen and carbon dioxide
- B. Hydrogen and oxygen ✓
- C. Methane and oxygen
- D. Nitrogen and hydrogen
Why: A hydrogen fuel cell combines hydrogen at the anode with oxygen (often from air) at the cathode. The reaction produces electricity, water, and heat.
Q3. What is the only significant byproduct of a hydrogen fuel cell when pure hydrogen is used?
- A. Carbon monoxide
- B. Water ✓
- C. Sulfur dioxide
- D. Nitrogen oxides
Why: When running on pure hydrogen and oxygen, the electrochemical reaction yields water and heat as its only products, with no direct carbon emissions at the point of use.
Q4. What is the role of the electrolyte in a proton exchange membrane (PEM) fuel cell?
- A. To supply the fuel to the anode
- B. To conduct protons from the anode to the cathode while blocking electrons ✓
- C. To collect the electrical current
- D. To cool the cell during operation
Why: The electrolyte membrane in a PEM fuel cell allows positively charged protons to pass through to the cathode. Electrons are forced to travel through an external circuit, which is what creates the usable electric current.
Q5. Why is a fuel cell often described as more efficient than an internal combustion engine?
- A. It does not need any fuel at all
- B. It avoids the intermediate step of combustion and heat-to-motion conversion, which is limited by the Carnot cycle ✓
- C. It operates at a higher temperature than engines
- D. It produces more energy per gram of fuel than any other source
Why: Fuel cells convert chemical energy directly into electricity, bypassing combustion. Heat engines are limited by Carnot efficiency, so fuel cells can achieve higher efficiencies, especially at partial loads.
Module 5
Module 5: Hydrogen Safety and Standards
Hydrogen Safety and Standards
Knowledge check
Q1. Which property of hydrogen makes it most prone to leaking through small gaps and seals compared with natural gas?
- A. Its high density
- B. Its very small molecular size ✓
- C. Its high boiling point
- D. Its strong odor
Why: Hydrogen is the smallest molecule, so it can escape through tiny gaps, seals, and some materials more readily than natural gas, which is why leak detection and sealing standards are critical.
Q2. What is the approximate flammability range of hydrogen in air by volume?
- A. 1% to 5%
- B. 4% to 75% ✓
- C. 15% to 30%
- D. 50% to 100%
Why: Hydrogen is flammable across a wide range of about 4% to 75% by volume in air, much broader than many fuels, so even modest leaks can create an ignitable mixture.
Q3. Why is hydrogen flame generally difficult to see in daylight?
- A. It burns at a very low temperature
- B. It produces little visible light in the flame ✓
- C. It is always blue-colored
- D. It only burns in the dark
Why: Pure hydrogen flames emit very little visible radiation, so they can be nearly invisible in daylight, which is a hazard that requires flame detectors using infrared or ultraviolet sensing.
Q4. Which safety practice is recommended for detecting hydrogen leaks in enclosed spaces?
- A. Relying on the smell of the gas
- B. Using dedicated hydrogen gas detectors that alarm at a fraction of the lower flammability limit ✓
- C. Waiting for visible smoke
- D. Checking the temperature of the room
Why: Hydrogen is odorless and colorless, so smell is unreliable. Dedicated detectors set to alarm well below the lower flammability limit (about 4%) are the standard safeguard.
Q5. Which standard body is a primary source of international codes and standards for hydrogen technologies?
- A. International Organization for Standardization (ISO) ✓
- B. World Health Organization (WHO)
- C. International Monetary Fund (IMF)
- D. World Trade Organization (WTO)
Why: ISO, through technical committee ISO/TC 197, develops international standards for hydrogen technologies covering production, storage, transport, and safety, alongside bodies such as IEC and national standards organizations.
Module 6
Module 6: Economics and Cost Analysis
Economics and Cost Analysis
Knowledge check
Q1. Which term describes hydrogen produced from natural gas using steam methane reforming without carbon capture?
- A. Green hydrogen
- B. Grey hydrogen ✓
- C. Blue hydrogen
- D. Pink hydrogen
Why: Grey hydrogen is produced from fossil fuels such as natural gas via steam methane reforming, and the resulting CO2 is released to the atmosphere without capture. Blue hydrogen uses the same process but adds carbon capture and storage.
Q2. What is the main factor that drives the cost of green hydrogen produced by electrolysis?
- A. The price of natural gas
- B. The cost of electricity used in the electrolyzer ✓
- C. The price of carbon credits
- D. The cost of hydrogen storage tanks
Why: Electricity typically accounts for the largest share of the levelized cost of green hydrogen from electrolysis, so the electricity price (especially from renewable sources) strongly determines overall production cost.
Q3. What does LCOH stand for in hydrogen cost analysis?
- A. Liquefied Compressed Oxygen and Hydrogen
- B. Levelized Cost of Hydrogen ✓
- C. Low Carbon Operating Hydrogen
- D. Linear Cost of Heat
Why: LCOH stands for Levelized Cost of Hydrogen, which spreads all lifetime costs of a hydrogen production system, including capital, operating, and energy costs, over the total amount of hydrogen produced. It allows comparison across different production methods.
Q4. Roughly how many kilograms of hydrogen are contained in one kilogram of hydrogen gas measured by mass compared to its energy content relative to gasoline?
- A. Hydrogen has about three times the energy per kilogram of gasoline ✓
- B. Hydrogen has about the same energy per kilogram as gasoline
- C. Hydrogen has about one-third the energy per kilogram of gasoline
- D. Hydrogen has ten times the energy per kilogram of gasoline
Why: Hydrogen has a higher heating value of about 142 MJ per kilogram, roughly three times that of gasoline at about 46 MJ per kilogram. Its low volumetric energy density, however, makes storage and transport costly.
Q5. Which cost component is often the biggest challenge for hydrogen infrastructure such as pipelines and refueling stations?
- A. Capital investment in new infrastructure ✓
- B. Cost of hydrogen molecules
- C. Marketing expenses
- D. Insurance premiums on vehicles
Why: Building hydrogen pipelines, storage facilities, and refueling stations requires large upfront capital investment, which is a major economic barrier. Infrastructure costs must be recovered over many years of use, so low utilization early on raises unit costs.
Module 7
Module 7: Policy, Markets and Future Outlook
Policy, Markets and Future Outlook
Knowledge check
Q1. Which term is used to describe hydrogen produced from renewable electricity via water electrolysis?
- A. Grey hydrogen
- B. Green hydrogen ✓
- C. Blue hydrogen
- D. Brown hydrogen
Why: Green hydrogen is produced by splitting water using electricity generated from renewable sources such as wind or solar, resulting in very low lifecycle carbon emissions.
Q2. What is the main difference between grey hydrogen and blue hydrogen?
- A. Blue hydrogen uses renewable electricity while grey hydrogen does not
- B. Blue hydrogen captures and stores a large share of the CO2 emitted during production, while grey hydrogen releases it ✓
- C. Grey hydrogen is produced only from biomass, while blue hydrogen uses natural gas
- D. There is no practical difference; the terms are interchangeable
Why: Both grey and blue hydrogen are typically made from natural gas via steam methane reforming. Grey hydrogen vents the resulting CO2, while blue hydrogen pairs the process with carbon capture and storage (CCS).
Q3. Which policy instrument directly sets a price on carbon emissions to encourage cleaner hydrogen production?
- A. Renewable portfolio standard
- B. Carbon pricing, such as a carbon tax or emissions trading scheme ✓
- C. Feed-in tariff for natural gas
- D. Import quota on fossil fuels
Why: Carbon pricing makes emitting CO2 costly, which improves the relative competitiveness of low-carbon hydrogen compared with high-emission production routes.
Q4. What is a key reason hydrogen adoption faces market challenges today?
- A. Hydrogen has no industrial uses at all
- B. Green hydrogen is currently more expensive to produce than fossil-based hydrogen in most regions ✓
- C. Hydrogen cannot be stored or transported
- D. Electrolysers are too small to produce any meaningful volume
Why: Production costs for green hydrogen remain higher than for grey hydrogen in most markets, largely due to electricity costs and electrolyser capital expenditure, so policy support is often needed to close the gap.
Q5. Which sector is widely considered a strong early target market for hydrogen demand?
- A. Residential lighting
- B. Industrial uses such as ammonia, steel and refining, where hydrogen is already used or hard to decarbonise otherwise ✓
- C. Bottled drinking water
- D. Paper printing
Why: Industries like ammonia production, oil refining and steelmaking already consume large amounts of hydrogen or face few alternatives for deep decarbonisation, making them natural early markets.