Hydrogen is the lightest and most abundant element in the universe, yet on Earth, it is rarely found in its pure, gaseous form. To be used as a fuel, hydrogen must first be separated from other compounds, such as water or natural gas. The question of whether hydrogen is renewable or non-renewable cannot be answered with a simple single label. Hydrogen itself is not a primary source of energy like wind or coal; instead, its classification depends entirely on the energy source and the method used to manufacture it.
Hydrogen’s Role: Energy Carrier, Not Energy Source
Hydrogen functions primarily as an energy carrier, similar to how a battery stores electricity for later use. It transports energy in a usable form, rather than being a naturally harvested energy source. Because hydrogen does not occur in abundant reservoirs, it must be produced through chemical processes that require an input of energy. This requirement means hydrogen’s sustainability is determined by the source of that input. If the energy used comes from a finite resource, the resulting hydrogen is considered non-renewable, but if it comes from sources that can be naturally replenished, the hydrogen is classified as renewable.
Production Methods Based on Fossil Fuels (Non-Renewable)
The majority of hydrogen produced globally today relies on non-renewable fossil fuels, chiefly natural gas. This production is dominated by Steam Methane Reforming (SMR), which accounts for a substantial portion of the world’s supply. SMR involves reacting high-temperature steam with methane, the main component of natural gas, to produce hydrogen and carbon monoxide.
When the carbon dioxide (CO2) generated during SMR is released directly into the atmosphere, the product is known as Gray Hydrogen. This is the most common production method, but it is highly carbon-intensive and contributes significantly to global CO2 emissions. Gray Hydrogen is considered non-renewable because its production consumes finite natural gas resources.
A variation is Blue Hydrogen, which also uses SMR with natural gas, but incorporates Carbon Capture, Utilization, and Storage (CCUS) technology. CCUS captures a large fraction of the CO2 emissions before they are released. While Blue Hydrogen is a low-carbon option, it is still fundamentally non-renewable because its feedstock remains methane, a finite fossil fuel.
Production Methods Based on Clean Electricity (Renewable)
The path to truly renewable hydrogen centers on using clean electricity to split water, a process that avoids the use of fossil fuels entirely. This process is known as electrolysis, where an electric current is passed through water (H2O) to separate it into hydrogen (H2) and oxygen (O2).
The most sustainable form is Green Hydrogen, produced when the electricity used for electrolysis comes exclusively from renewable energy sources, such as solar, wind, or hydropower. Because the energy source is replenishable and the process releases no carbon emissions, Green Hydrogen represents a fully renewable path for production. Technologies like Polymer Electrolyte Membrane (PEM) electrolyzers are well-suited for Green Hydrogen, as they can quickly adjust to the fluctuating nature of wind and solar power generation.
Another low-carbon method is Pink Hydrogen, which utilizes electricity generated from nuclear power for electrolysis. Nuclear power is a non-fossil fuel, low-carbon source, making the resulting hydrogen a cleaner alternative, though it is not strictly renewable like solar or wind power. These methods leverage the abundance of water to create a carbon-free fuel.
The Current Landscape of Hydrogen Renewability
Despite the potential of renewable production methods, the vast majority of hydrogen consumed globally is non-renewable. Over 99% of dedicated hydrogen production today comes from fossil fuels, predominantly yielding Gray Hydrogen. This means that hydrogen is currently a significant source of industrial CO2 emissions.
Low-emissions hydrogen, including both Blue and Green types, accounts for less than 1% of the total global supply. The industry is in a transitional phase, with substantial investment aimed at rapidly scaling up Green Hydrogen production capabilities. The future classification of hydrogen as a mainstream renewable fuel hinges on the widespread shift toward clean, electricity-powered electrolysis.