How Do We Make Hydrogen, and How Much Does It Cost?

In the ongoing quest for a more sustainable energy, hydrogen has emerged as one of the promising alternatives to fossil fuels. Its potential as a versatile and environmentally friendly energy carrier has positioned it at the forefront of global efforts to combat climate change and reduce greenhouse gas emissions. This article will delve into the production methods and cost considerations surrounding hydrogen, explaining some of the obstacles and challenges of hydrogen economy.

Hydrogen Production Methods

Hydrogen production methods are diverse, offering their unique benefits and challenges. They can be broadly categorized into three primary types: Steam Methane Reforming, Electrolysis, and Thermochemical Process and Biomass

Steam Methane Reforming (SMR)

Steam Methane Reforming (SMR) is the most widely employed method of hydrogen production, and is major contributor to the global hydrogen supply. This process involves the catalytic reaction of methane (CH4) with high-temperature steam (H2O) in the presence of a metal catalyst, typically nickel. The primary chemical reactions that occur are as follows:

Methane Reforming: CH4 + H2O → CO + 3H2 Water-Gas Shift Reaction: CO + H2O → CO2 + H2

The end result is the generation of hydrogen (H2) and carbon dioxide (CO2). While SMR is prevalent due to its efficiency and high hydrogen yield, however it releases a significant amount of CO2 emissions, ranging from 7.5 to 12 tons of CO2 per ton of hydrogen produced.

Large-scale SMR plants can produce hydrogen at a rate of thousands to tens of thousands of normal cubic meters per hour (Nm³/hr). Some industrial SMR facilities can even produce hydrogen at rates exceeding 100,000 Nm³/hr*.

Electrolysis

Electrolysis stands as a more eco-friendly alternative, as it cleanly divides water (H2O) into hydrogen (H2) and oxygen (O2) by using an electric current. The process occurs in an electrolysis cell, where water is split into hydrogen at the cathode and oxygen at the anode. The main reactions involved are:

Hydrogen Formation 2H2O + 2e- → 2OH- + H2 Oxygen Formation 2H2O → O2 + 4H+ + 4e-

Electrolysis has the advantage of producing “green hydrogen” with virtually no carbon emissions when powered by renewable energy sources like wind, solar, hydropower, or nuclear. While electrolysis costs more than SMR, it is becoming increasingly competitive as renewable energy technologies progress and the processes becoming ever more efficient.

Large-scale electrolysis plants, designed for industrial applications and the production of green hydrogen, can have capacities exceeding 1,000 Nm³/hr* or even higher, but not even close to the output of SMRs.

Thermochemical Processes and Biomass

Thermochemical processes, such as gasification and pyrolysis, represent innovative approaches to hydrogen production. They utilize solid biomass materials and waste products, like agricultural residues, wood chips, or even municipal waste, to generate hydrogen. The process involves exposing these materials to high temperatures and controlled environments, resulting in the release of hydrogen gas.

Furthermore, anaerobic digestion of organic waste produces biogas, which contains a significant proportion of methane. This biogas can undergo a subsequent reforming process to extract hydrogen. The utilization of organic waste materials not only provides a sustainable source of hydrogen but also contributes to waste management and reduction in greenhouse gas emissions.

Hydrogen Production Costs

The cost of hydrogen production is a complex consideration. The biggest factors are the production method, energy source, operational scale, and location. Currently, hydrogen production costs exhibit substantial variability, but concerted efforts are underway to improve cost-competitiveness.

The cost of Hydrogen produced by SMR varies between $1.3 and $1.5 per kilogram in United States $1.7 to $2.4 In Europe. The cost of SMR hydrogen is influenced by the cost of natural gas and the use of carbon capture. Logically the more carbon capture in process the higher the cost.

A good comparative table and data is provided by the International Energy Agency:

Green Hydrogen Costs

Green hydrogen, produced through renewable-powered electrolysis, emerges as the most ecologically friendly option. Yet, it tends to be pricier than hydrogen originating from SMR or other conventional methods. The cost of green hydrogen closely ties to the cost of renewable energy sources. If renewable energy becomes more affordable, stable, and efficient, green hydrogen production costs would too decrease. This cost reduction will make green hydrogen more competitive in the overall energy landscape.

In United States and Europe, the cost of green hydrogen from electrolysis is typically in the range of $3 to $7.5 USD per kilogram. The cost vary with the availability of renewable energy (as much as people worship wind and solar these sources are not available 24/7), and is limited, compared to SMR, in the output volume.

A great cost comparison and data by energy source is again provided by the International Energy Agency:

Economies of Scale

The size of hydrogen production facilities plays a pivotal role in cost considerations. Larger facilities enjoy economies of scale, which translate to increased efficiency and the ability to distribute fixed costs across a more extensive volume of hydrogen production. In other words, the more hydrogen a facility produces, the lower the cost per unit of hydrogen becomes. This principle incentivizes the development of larger and more efficient production facilities, further driving down the cost of hydrogen.

Hydrogen production methods are pivotal in creating a (sustainable) hydrogen economy. As the world seeks cleaner and more environmentally friendly energy alternatives while striving to diminish greenhouse gas emissions, the path forward hinges on rendering hydrogen production cleaner and more cost-competitive. With evolving technology, hydrogen’s promise as a clean energy carrier continues to gather momentum, offering prospect of cleaner energy and an alternative to fossil fuels.

This article is one of a series of articles about the (potential) hydrogen economy. In the previous article, I outlined how a hydrogen economy could look, and in the next one, I will take a closer look at the combustion of hydrogen.

*The unit “Nm³/hr” stands for “Normal Cubic Meters per Hour.” It is a measure of the flow rate of gases, indicating the volume of a gas at standard or “normal” conditions that is being transported or processed in one hour. The standard conditions typically used for gas volume measurements are:

• Temperature: 0 degrees Celsius (0°C or 273.15 K)
• Pressure: 1 atmosphere (1 atm or 101.3 kPa)

In the case of Nm³/hr, it represents the volume of a gas, such as hydrogen, at these standard conditions per hour. This unit is commonly used in various industries, including the oil and gas sector, chemical manufacturing, and hydrogen production, to express the flow rate of gases through pipelines, processing plants, or other systems.