Blue hydrogen refers to hydrogen production from natural gas through a process called steam methane reforming (SMR), coupled with carbon capture and storage (CCS) to reduce greenhouse gas emissions. While blue hydrogen does result in the release of carbon dioxide (CO2), the exact efficiency and emissions depend on various factors.
In the steam methane reforming process, natural gas (which is primarily methane, CH4) is reacted with steam to produce hydrogen gas (H2) and carbon dioxide (CO2). The CO2 generated can be captured and stored underground to minimize its impact on the environment. However, it is true that for every molecule of methane converted into hydrogen, one molecule of CO2 is produced.
The efficiency and environmental impact of blue hydrogen production depend on the efficiency of the SMR process and the effectiveness of carbon capture and storage. The efficiency of SMR can vary, but it typically ranges from 70% to 80%. This means that around 70% to 80% of the energy content in the natural gas is converted into hydrogen, while the rest is lost as heat.
Regarding the CO2 emissions, carbon capture and storage technologies aim to capture a significant portion of the CO2 produced during SMR and store it underground to prevent it from entering the atmosphere. The efficiency of carbon capture can vary, but it typically captures around 90% of the CO2 emissions. Therefore, not all of the CO2 needs to be pumped back underground, but a substantial portion is captured and stored.
It is worth noting that the costs associated with blue hydrogen are influenced by several factors, including the cost of natural gas, the cost of implementing carbon capture and storage infrastructure, and the economies of scale. As technology advances and more efficient carbon capture methods are developed, the costs associated with blue hydrogen production may decrease.
On the other hand, green hydrogen is produced through electrolysis, which uses electricity to split water molecules into hydrogen and oxygen. Green hydrogen does not produce CO2 emissions during production, as it relies on renewable energy sources. However, the availability and cost of renewable electricity are essential factors that affect the cost and scalability of green hydrogen production.
Both blue and green hydrogen have their advantages and challenges, and the choice between them depends on factors such as the availability of renewable energy, the existing natural gas infrastructure, and the specific goals of the hydrogen production project.