Why Is Hydrogen Not Considered An Energy Resource?

Hydrogen is the most abundant chemical element in the universe. Here on Earth, hydrogen is most commonly found bonded with oxygen in water. Hydrogen is considered an energy carrier, which stores and delivers energy in a usable form. However, hydrogen itself is not considered an energy resource. This article will examine why hydrogen is not considered a primary energy resource, despite having properties that make it well-suited for energy storage and transportation.

Table of Contents

What is Hydrogen?

Hydrogen is the most abundant chemical element in the universe, making up about 75% of the universe’s elemental mass (Energy.gov, 2022). It is also the lightest element with an atomic weight of 1.008. On earth, hydrogen is rarely found in its pure form. It is usually combined with other elements like oxygen to form water (H2O) and hydrocarbons like methane (CH4) (National Grid, 2023).

Hydrogen has a high energy content by weight but low energy content by volume. This makes it challenging to store enough hydrogen onboard a vehicle to give it a similar range to gasoline vehicles. Hydrogen is colorless, odorless, tasteless, nontoxic, and highly combustible (EIA, 2022).

Key properties and uses of hydrogen include:

Clean burning – When burned or consumed in a fuel cell, hydrogen combines with oxygen to form water as the only byproduct.

Energy carrier – Hydrogen stores and delivers energy but is not a primary energy source itself.
Industrial uses – Hydrogen is used across many industries from refining to food production.
Potential transport fuel – With its high energy density by weight, hydrogen has potential as a zero-emission fuel for vehicles.

Primary Sources of Hydrogen

Hydrogen is mainly produced via two primary methods – electrolysis of water and steam reforming of natural gas. Electrolysis uses electricity to split water into hydrogen and oxygen. This process of producing hydrogen is considered renewable if the electricity used comes from renewable sources like solar or wind power. According to the U.S. Energy Information Administration, most of the hydrogen produced in the United States comes from natural gas via a process called steam-methane reforming. This involves reacting high-temperature steam with methane from natural gas to produce hydrogen gas.

Coal gasification is another way to produce hydrogen from fossil fuels. Coal is partially oxidized in a controlled environment to produce a synthesis gas mixture containing carbon monoxide and hydrogen. The carbon monoxide can then be converted to carbon dioxide while producing more hydrogen via the water-gas shift reaction. However coal-based hydrogen production results in double the greenhouse gas emissions compared to natural gas reforming and is not yet widely adopted.

While fossil fuel-based hydrogen production methods are more cost effective currently, water electrolysis offers a renewable pathway for producing hydrogen with zero-emissions when paired with renewable electricity sources. There is also ongoing research into biological and photobiological water splitting techniques using microbes and sunlight to produce hydrogen in a sustainable manner.

Energy Carrier vs Energy Source

An energy carrier is a substance that stores energy obtained from primary energy sources and can release that energy on demand to provide power or perform useful work (Energy carrier). In contrast, an energy source is a natural resource or phenomenon that can supply energy without requiring a conversion process. Examples of primary energy sources include fossil fuels like coal and oil, renewable sources like solar, wind and hydropower, and nuclear fuels like uranium.

While energy sources contain energy intrinsically, energy carriers require energy to be put into them before they can provide energy services. For instance, electricity and hydrogen act as energy carriers. Electricity is produced at power plants by converting energy from coal, natural gas, wind, etc. Hydrogen is produced by processes like steam methane reforming that require natural gas or electrolysis that requires electricity. The generated electricity and hydrogen then serve as portable and convenient means to transmit and deliver energy (IPCC).

In summary, energy carriers are not primary sources with inherent energy. They require external energy input to become energy-rich and enable the delivery of energy services.

Hydrogen is an Energy Carrier

Hydrogen acts as an energy carrier, not an energy source. This means that hydrogen is not freely available like fossil fuels, but instead must be produced using other energy sources (Energy.gov, 2021). Unlike fossil fuels which contain carbon and release energy when burned, hydrogen is an element that does not occur freely in nature. So it requires an initial input of energy to produce, store, and transport hydrogen before any useful energy can be released from it (EIA, 2021).

Hydrogen can be produced through various methods like electrolysis of water using electricity, steam reforming of natural gas, coal gasification, or even some biological processes. All these techniques require other primary energy sources like electricity, heat, or light. Thus, hydrogen is not a primary fuel itself, but rather acts as a portable carrier of energy produced elsewhere (Energy.gov, 2021). This is why hydrogen is considered an energy carrier, not an energy source.

Challenges with Hydrogen

Hydrogen faces several key challenges as a potential energy source.
First, hydrogen is difficult to store and transport efficiently. Compressing or liquefying hydrogen requires a significant amount of energy and specialized infrastructure that is not yet widely available (1).

Another major challenge is hydrogen leakage. When hydrogen escapes into the atmosphere before being used, it can actually trigger warming (2). Developing methods to prevent leakage during storage and transportation is an active area of research. There are also safety concerns, as hydrogen is highly flammable.

Additionally, producing low-carbon hydrogen is currently expensive. Most hydrogen today comes from natural gas, which defeats the purpose of using it as a clean fuel. Producing hydrogen from water via electrolysis requires large amounts of electricity, often from renewable sources (3). Widespread commercialization will require major cost reductions.

In summary, key barriers for hydrogen as an energy source include storage and transportation issues, leakage concerns, high production costs, and lack of infrastructure. While hydrogen holds promise, overcoming these challenges is critical in order to unlock its potential role in the energy transition.

Hydrogen is Not Renewable

Most hydrogen production currently comes from non-renewable fossil fuels like natural gas and coal. According to the U.S. Department of Energy, around 95% of the hydrogen produced in the United States is made by steam reforming of natural gas (Hydrogen Resources). The rest comes from coal gasification and other methods. While hydrogen can be produced from renewable resources like solar, wind, and biomass, less than 1% of global hydrogen production comes from these sources today.

Because the primary feedstocks for hydrogen are non-renewable fossil fuels, most of the hydrogen produced today cannot be considered a renewable resource. Hydrogen production from fossil fuels also generates carbon emissions, reducing some of its environmental benefits. Significant investment and innovation around renewable hydrogen production methods will be needed for hydrogen to be truly sustainable and renewable.

Hydrogen Offers Indirect Energy

Hydrogen is considered an indirect source of energy because it must be produced from another energy resource. Hydrogen does not naturally exist on Earth in its pure elemental form – it must be extracted from substances like water, natural gas, or biomass through a process that requires energy input [1]. This makes hydrogen an “energy carrier” rather than an “energy source.”

For example, hydrogen can be produced through a process called electrolysis that uses electricity to split water molecules into hydrogen and oxygen. The electricity used in electrolysis acts as the primary source of energy that is then carried in the form of hydrogen gas. Hydrogen fuel cells can then convert the hydrogen back into electricity, releasing heat and water as byproducts rather than CO2 emissions. So hydrogen provides an indirect way of storing and transporting energy from renewable sources like wind or solar [2].

Because an outside energy source is always needed to extract and produce hydrogen, it serves more as an energy carrier or storage medium, not a primary energy resource. Hydrogen’s value is in its potential to offer a zero-emission way to store and use energy from cleaner resources.

[1] https://www.sustainability.ppg.com/Environment/Energy
[2] https://ppgsustain20k12prd.azurewebsites.net/Environment/Energy

Potential Future Role

Hydrogen has the potential to play a major role in future renewable energy systems, despite not being a primary energy source itself. Many experts see hydrogen as an important energy carrier that can enable the transition to a net-zero carbon energy system (IEA).

One of the main advantages of hydrogen is that it can be produced from water using renewable electricity through a process called electrolysis. The hydrogen can then be stored and transported to end use applications like vehicles or electricity generation (MIT). This provides a method to store intermittent renewable energy like solar and wind.

Hydrogen can be used as a fuel for transportation including cars, trucks, trains, ships and airplanes. When used in fuel cells, it can produce electricity with only water as a byproduct. Hydrogen combustion also does not produce any carbon emissions. This makes it an attractive option for decarbonizing major transportation modes (Bosch).

Additionally, hydrogen can be blended with natural gas for use in electricity generation, building heating, and industrial processes. When combined with carbon capture, hydrogen production and use can be carbon negative. Hydrogen may play a key role in a renewable energy system, enabling greater energy storage capacity and decarbonization across the energy sector.

Conclusion

In summary, hydrogen is considered an energy carrier rather than an energy source because hydrogen is not found abundantly in nature and must be produced from other substances. Hydrogen has no naturally occurring deposits that can be readily extracted like fossil fuels. While hydrogen can store and deliver usable energy, it requires energy input to produce in the first place. Hydrogen acts like a battery, not a power plant. It must be manufactured by steam reforming natural gas, electrolyzing water with electricity, or other energy intensive processes. Once produced, hydrogen can deliver energy for transportation, electricity generation, or industrial applications. But the upstream energy required to make the hydrogen offsets the downstream energy it provides. Essentially, hydrogen allows energy from renewables like solar and wind to be stored, transported, and accessed on demand. This makes hydrogen an incredibly versatile energy carrier with many applications, but still not an actual energy source.