Energy Transitions: From Hydrocarbon to Hydrogen
The earliest discovered wood fire goes back to 75,000 years ago in a cave near Marseilles in France. From those days until close to 1800 AD, wood was the only carrier of energy. Then came coal, oil and gas, each appearing, ascending and declining. The transition from wood to Hydrogen happened in the past 200 years. Now we talk of an entire economy based on Hydrogen produced from water using solar electricity.
What distinguishes these fuels from each other is the energy density, which is the amount of energy ( usually Million Joules or MegaJoules) stored in a unit mass or volume. 1 MJ is the energy required to boil 3 litres of water. Wood has the lowest energy density demanding much more volume or weight of wood to generate a given amount of energy. This has an economic impact; you need more space to store low energy-density fuel.
Why there was no demand for an alternative to wood for thousands of years until the first industrial revolution in 1765? Wood was cheap and freely available, with no geographical monopoly. It can be stored in the backyards.
Two events ended the reign of wood as the preferred fuel. The first was the Industrial Revolution, the first of which, mostly confined to Britain, lasted from 1750 to about 1830. The Second Industrial Revolution lasted from 1850 until the early 20th century and happened in Britain, Europe, North America, and Japan. By 1660 Britain’s basic fuel supply, wood, began to fail. The reason for this was primarily the increase in consumption as the industry demanded wood to fuel its factories. Wood resources were depleting because of the limitation of the land area.
The second reason was the urbanization resulting from industrialization. Before 1600, most people lived in villages. The fraction of the city-living population did not reach 5%. Industrialization built factories which demanded workers. They began living in colonies near the factories. This is how cities formed and The concentration of urban people increased. By 1800, this fraction climbed to 7%; and by 1900 to 16%. Wood and hay, the prevalent energy sources at the start of the 19th century, take space and are inconvenient to transport and store. Wood gradually lost the competition to coal to fuel the multiplying urban centres.
The discovery of iron ore smelting using coke made in 1709 in Coalbrookedale, a small village in Shropshire, transformed the making of iron, with annual production in Britain growing from about 2,500 tonnes per annum in the 1700s to 180,000 in 1800 and 2.5 million by 1850, a jump in production never possible without coal (1).
The beginning of the coal age coincided with the beginning of the Industrial Revolution and the emergence of modern capitalism. Oil’s emergence saw the birth of multinational consortia like Standard Oil, Burmah Shell and Getty.
All fuels contain Carbon or Hydrogen. Both burn to release heat. Wood-based energy systems, composed of 50% carbon, 42% oxygen, 6% hydrogen, and 2% other elements rely heavily on carbon, burning bout 10 carbons for each hydrogen atom. Coal contains two C’s per H, while oil has the reverse ratio, and methane is a lean CH4.
By 1900, the advantages of fluid-fuel began to become clear. Energy density-wise, oil was superior to coal and had the advantage of piped flow. Though oil prevailed over coal by 1950 as the world’s leading energy source, its storage and distribution are still problematic. The preferred configuration for spatially extended distribution energy is a grid of pipes which allow fuel to be introduced/extracted continuously.
The European grid for Natural gas is a pervasive, and efficient system of pipes of 200,000 km length. It provides an excellent hierarchy of storage. The capacity of the European grid is such that it provides for 100 days of consumption without refill.
The demand for higher energy density drove decarbonization, the process of reducing the Carbon-Hydrogen ratio of fuels. This is at the heart of the evolution of the energy system and has been progressively happening. The natural end to this path is Hydrogen as fuel. Hydrogen, as the energy carrier, can address many aspects of the energy problem. Hydrogen can be used in fuel cells or chemical reactions.
The concentration of Carbon Dioxide in the atmosphere steadily increased since the usage of hydrocarbon fuels started with a correlated increase in the global temperature. The transition to Carbon-free nuclear, solar and Hydrogen is driven by the urgency of protecting the planet from excessive warming. Swedish physicist Svante Arrhenius created the first model of climate change when he showed that doubling the amount of CO2 in the atmosphere would raise the world’s temperature by 5 to 6 degrees Celsius (2).
The Inter-Governmental Panel on Climate Change (IPCC) recommends ambitious climate action now and through this decade to keep warming limited to 1.5 degrees Celsius. Their roadmap to realise the 1.5-degree limit is to have 40% of energy by renewables by 2030. By 2040, all power should be green. Complete decarbonisation ultimately depends on using pure hydrogen.
There are many ways of producing Hydrogen. In steam-methane reforming, high-temperature steam (700°C–1,000°C) reacts with Methane aided by a catalyst to produce hydrogen, carbon monoxide, and some carbon dioxide. This is called Grey Hydrogen. Further processes yield ‘Blue Hydrogen’. A competing alternative is to produce Green Hydrogen by electrolysis of water releases Hydrogen and Oxygen. This demands scarce materials such as platinum as catalysts. The cost of green Hydrogen is estimated at ~$4 to $6/kg.
Hydrogen storage for automobiles has to be very safe. New storage tanks Carbon Fibre composites lined with high-density polymer will be used for automobiles. Metal hydrides such as alanates allow high hydrogen storage density. Nanostructured materials may improve absorption volume and incorporated catalysts may improve release (3).
To produce electricity from Hydrogen, fuel cells are used. On contact with the anode, the Hydrogen atoms are ionized and electrons. The “ionized” hydrogen carries a positive electrical charge. The protons pass through the porous electrolyte membrane, while the electrons, going through a circuit generate an electric current. At the cathode, the protons, electrons, and oxygen recombine to form water molecules. With no moving parts, fuel cells are silent and reliable.
Hydrogen internal combustion engines (Hydrogen ICE) are nearly identical to their gas counterparts. Direct injection systems introduce the fuel into the cylinders. However, when hydrogen burns with air-fuel ratios that are near stoichiometric, a significant amount of NOx can be created, requiring an exhaust treatment system to remove this (4).
Hydrogen fuel cell vehicles like the Hyundai Nexo, can manage long distances and only take minutes to fill up, in contrast to the hours required to recharge an electric car. Hydrogen fuel cell cars will take time to enter the market because of the higher cost and the lack of fueling facilities.
The Solar-Hydrogen economy is a concept of an energy system based on hydrogen as a zero-carbon energy carrier produced using green electricity. 25 % of all industrial Carbon emissions come from Steel Manufacturing. Steel manufacturing has a carbon footprint of 1.4 tons per ton according to International Energy Agency. With close to 1800 Million tonnes of Steel production, 3.7 Billion tonnes of CO2 is emitted. New processes replace coal-powered blast furnaces with plants using hydrogen, helping to decarbonise steelmaking. The advantage of Hydrogen is that its flame gives a temperature of 2254 C as against 199 for a Methane Flame and 900 for a coal fire.
India has an ambitious plan to enter the Hydrogen economy. 5 Million metric tonnes of Hydrogen production is planned with plans to establish 60–100 GW of electrolysis capacity. The investment is in the range of 8 Lakh Crore. However, if the past transitions are any guide, the transition to a Solar-Hydrogen phase will take at least fifty years, though prodded on by climate change concerns. Our grandchildren shall inherit this future.
(1) https://www.economicsobservatory.com/what-can-we-learn-from-the-role-of-coal-in-the-industrial-revolution
(2) https://www.lenntech.com/greenhouse-effect/global-warming-history.htm
(3) https://present5.com/basic-research-needs-for-the-hydrogen-economy-presentation/
(4) https://www.electricalindia.in/titbits-of-hydrogen-engines/
