What is our assessment?

Based on our analysis, blue hydrogen is ready to deploy and feasible, but there is mixed consensus and limited data on its effectiveness in reducing emissions. Its climate impact has the potential to be high, but only if the technology is adopted aggressively and there are technological improvements around methane leaks, hydrogen leaks, and CCS. Therefore, this potential climate solution is “Worth Watching.”

What is it?

Hydrogen is a fuel that can be used in place of fossil fuels in industrial, transportation, and energy systems. To deploy hydrogen (H₂) as an energy source or feedstock, it first needs to be extracted from other compounds. Each “color” is an informal term specifying hydrogen produced through a unique H₂ production path, each with a different associated supply chain, process, and energy GHG emissions. Grey hydrogen, which uses natural gas as the source of hydrogen atoms and electricity, is the most produced and has high production emissions, estimated at 10–12 t CO₂-eq/t H₂ on a 100-yr basis. One way to reduce emissions is by switching to blue hydrogen, which still uses fossil fuels but also uses carbon capture and storage (CCS) technologies to prevent the release of some of the CO₂ generated during production. Blue hydrogen has the potential to be a lower-emission source of energy relative to grey hydrogen or direct fossil fuel combustion.

Does it work?

Blue hydrogen is a plausible way to reduce emissions from grey hydrogen production. However, expert opinions are mixed on the magnitude of emissions that can be abated by producing blue hydrogen in place of grey hydrogen. The effectiveness of emissions reduction hinges on two main factors: upstream methane leakage rates and carbon capture rates, both of which are challenging to predict on a global scale. There is uncertainty around these performance metrics and the ability to effectively store and transport CO₂ at scale. Due to low current adoption, there is little real-world data to answer these questions. As of 2023, blue hydrogen comprised <1% of worldwide hydrogen production. While adding carbon capture to grey hydrogen production should help prevent emissions, there is limited evidence for both effectiveness and the ability to scale of this technology.

Why are we excited?

Compared to other types of low-carbon hydrogen, including green hydrogen produced from electrolysis powered by renewable energy, blue hydrogen is a technologically developed and lower-cost option. This makes it a near-term option to facilitate the transition to a global hydrogen economy. Expert estimates of cost per emissions avoided range widely, but the IEA estimates US$60–85/t CO₂ for lower carbon capture rates (55–70%) and US$85–110/t CO₂ for higher carbon capture rates (>90%). However, these costs are uncertain: with lower estimates of effectiveness, the cost could increase to ~US$260/t CO₂, including the cost to transport and store CO₂. If implemented with low GHG fugitive emissions and high CCS efficiencies, blue hydrogen can reduce emissions by more than 60% relative to current grey hydrogen production on a 100-yr CO₂‑eq basis. In this case, the climate impact of scaling blue hydrogen could be high. Estimates and targets for blue hydrogen production by 2050 range from ~30–85 Mt H₂. At that scale, even modest emissions savings relative to grey hydrogen (3 t CO₂‑eq/t H₂, 20-yr basis) would have a climate impact above 0.09 Gt CO₂-eq/yr by 2050. However, these adoption and effectiveness values are uncertain and depend on the quality of the infrastructure and rate of technology scaling, both of which are unproven.

Why are we concerned?

While it has some advantages, blue hydrogen is still a less effective solution than green hydrogen, while costing more than grey hydrogen. Though it could be useful for near-term energy decarbonization, this risks taking resources away from renewable energy and green hydrogen development. The infrastructure required to scale hydrogen-based energy is expensive and will require technical advances and policy incentives to be competitive with fossil fuels. There are mixed expert opinions about the realistic level of avoided emissions that blue hydrogen may reach. The theoretical worst-performing blue hydrogen plants (low capture rates, high methane leaks, high-emission electricity sources) have been predicted to lead to more emissions on a near-term basis than direct natural gas combustion. Additionally, there is uncertainty around whether CCS can meet its technical potential at a reasonable cost. While experts predict >95% carbon capture rates are possible, facilities currently in operation capture less than this target, some less than 60% of all emitted carbon. For blue hydrogen to be feasible and scalable, CO₂ transport and storage need to be low-emitting, stable, and available. Only ~8% of CO₂ currently captured from blue hydrogen production is injected in dedicated storage, with the rest used in industry, enhanced oil recovery, and other applications. Finally, an understudied risk is hydrogen leaks. Hydrogen transport and storage require larger volumes than fossil fuels, increasing the risk of leaks. Hydrogen has an indirect planet-warming effect by increasing the levels of other atmospheric GHGs. At scale, the IEA estimates that high H₂ leakage rates could contribute 0.1 Gt CO₂-eq/yr in additional emissions, potentially canceling out any positive climate impacts.

What is our assessment?

Based on our analysis, the widespread use of bioplastics is challenged by their potential ecological risks and currently high costs. While bioplastics offer some environmental benefits in niche applications, their climate impact is inconsistent and hinges on feedstock type, manufacturing practices, and waste management. Therefore, we conclude that Deploy Bioplastics is “Worth Watching.”

What is it?

Bioplastics (also called biopolymers) are plastic alternatives made from renewable biological sources, such as corn, sugarcane, crop residues, or other plants, instead of fossil fuels. Bioplastics are produced by extracting sugars or starches from plants and converting them through chemical or biological processes into chemical building blocks that form the basic structure of plastics. Because plants absorb atmospheric CO₂ through photosynthesis, the carbon stored in bioplastics is considered biogenic, as it is already part of the natural carbon cycle. In contrast, petrochemical plastics are made by extracting and refining oil or natural gas, which releases new (formerly buried) carbon into the atmosphere. Bioplastics cut emissions by replacing fossil carbon feedstocks with biomass-based feedstocks. Some bioplastics are durable, non-biodegradable, chemically identical to traditional plastics (i.e., “drop-in” bioplastics), and recyclable. Others are biodegradable and can be designed to break down in compost. Emissions from bioplastics come from growing and processing biomass (which requires energy and land use), manufacturing the plastics, and managing their end-of-life waste. Bioplastics can achieve climate benefits when the emissions from production and end-of-life are kept low enough to realize the advantages of biogenic carbon.

Does it work?

The basic idea of bioplastics is scientifically and chemically sound, with their gradual development and commercialization ongoing since the 1990s. Numerous studies support the effectiveness of bioplastics in reducing atmospheric CO₂ emissions from feedstock production and manufacturing stages compared to fossil-based plastics, particularly when made from sustainably sourced biomass under energy-efficient conditions and properly composted or recycled. However, other studies show bioplastics have inconsistent emissions reduction performance. Global adoption also remains limited, representing only about 0.5% of total plastics production (approximately 2–2.5 million tons (Mt) out of 414 Mt, according to the organization European Bioplastics). 

Why are we excited?

Bioplastics, particularly biologically derived and biodegradable polymers, have functional advantages in reducing fossil fuel dependence and mitigating plastic pollution. By sourcing raw materials from renewable biomass instead of petroleum (e.g., oil, natural gas), bioplastics can lower CO₂ emissions in the production stage, especially when accounting for biogenic carbon uptake during plant cultivation. Some types of bioplastics are interchangeable with traditional plastics and can be produced with existing plastic manufacturing systems, easing the transition. Compostable plastics simplify disposal in applications where contamination with food or organic waste occurs, enabling organic recycling and returning carbon and other nutrients to soil. Biodegradable bioplastics are also advantageous for products that are often discarded and may leak into the environment. Studies show that two widely used commercial bioplastics, polylactic acid (PLA) and polyhydroxybutyrate (PHB), biodegrade 60–80% in composting conditions within 28–30 days, while cellulose-based and starch-based plastics can fully degrade in soil and marine environments in 180 days and 50 days, respectively. These functional benefits, combined with potential additional benefits, such as soil enrichment and waste stream simplification, make bioplastics appealing in specific, targeted use cases. More broadly, they can significantly contribute to emissions reduction efforts in materials production when designed for circularity and supported by infrastructure that facilitates appropriate end-of-life waste treatment. 

Why are we concerned?

Despite their promise, bioplastics have several limitations as a viable climate solution, including relatively low emissions reduction potential and possible risks and adverse impacts from their large-scale deployment. Current production is low. To reach a meaningful 20–30% marketplace share by 2040, bioplastics would need to expand manufacturing by approximately 30% per year, nearly double the current pace. This could put pressure on land and food systems, since current bioplastics rely on food-based crops for industrial-level production. This raises sustainability concerns around food security and could potentially drive unintended land-use changes such as deforestation or cropland conversion. Furthermore, the effectiveness of reducing emissions by replacing conventional plastics with bioplastics is low and inconsistent. Some bioplastics produce more life cycle emissions than conventional plastics. The likely climate impact of replacing 20–30% of traditional plastics with bioplastics is <0.1 Gt CO₂‑eq/yr. End-of-life treatment is also a major challenge. Many bioplastics are incompatible with home composting and current recycling streams, and improperly composted or landfilled biodegradable bioplastics can emit methane. Finally, bioplastics remain 2–3 times more expensive than conventional plastics.