Policy Review: The Independent Review of Greenhouse Gas Removals and the Role of Bioengineered Systems
1. Overview
In March 2025, the UK Government published the Independent Review of Greenhouse Gas Removals (GGRs), a major assessment of how engineered and nature-based carbon removal can contribute to achieving net zero. The Review emphasises that GGRs must move from conceptual to operational scale through clarity of regulation, credible monitoring, and strong domestic innovation. It calls for clear definitions of permanence, high environmental integrity, and equitable regional deployment to ensure that removals deliver genuine national benefit.
The Review situates GGRs as an essential complement to emissions reduction, recognising that even the most ambitious decarbonisation pathways will leave residual emissions from heavy industry, agriculture, and transport. Engineered removals such as direct air capture (DAC), bioenergy with carbon capture and storage (BECCS), and biochar are expected to fill this gap.
2. The relevance of engineered biochar and algal systems
Among the portfolio of removals reviewed, biochar is identified as a low-regret option with strong co-benefits for soil health and circular economy outcomes. However, the Review highlights uncertainty in the permanence of carbon storage, variation in standards, and the need for rigorous monitoring, reporting, and verification (MRV).
These are areas where bioengineered algal systems can make a significant contribution. Integrating biological CO₂ capture with controlled thermochemical conversion enables traceable, high-integrity removals. In particular, systems that operate within defined process boundaries — from capture to sequestration — can address concerns about additionality, leakage, and double counting.
3. Nellie Technologies’ input to the Review
Nellie Technologies was invited to provide technical evidence to the Independent Review, reflecting its position as one of the UK’s leading developers of integrated CO₂ removal systems. The company submitted data from its operational pilot site in South Wales, detailing energy use, carbon capture efficiency, and biochar stability characteristics.
This contribution helped inform the Review’s discussion of engineered biological pathways and the role of algal feedstocks in the UK’s GGR landscape. Nellie’s evidence demonstrated that purpose-grown microalgal biomass can deliver consistent carbon capture without reliance on waste inputs or volatile commodity feedstocks.
4. Alignment with the Review’s key themes
Permanence and integrity
The Review calls for stronger definitions of permanence and for clear differentiation between temporary and long-lived carbon storage. Nellie’s system addresses this directly. Carbon fixed biologically is converted to stable biochar through pyrolysis and then incorporated into soils, where independent testing confirms high carbon stability.
Regulatory clarity
The Review recommends that Government clarify how biochar-based removals will be regulated and recognised within the UK’s GGR framework. Nellie supports this approach and advocates for standardisation that balances scientific robustness with accessibility for smaller modular operators.
Integration and control
Where the Review identifies risks associated with fragmented supply chains and uncertain feedstock sourcing, Nellie’s approach provides a solution. The company operates as a fully integrated project developer, growing its own proprietary biomass, processing it on-site, and managing sequestration directly. This closed-loop model avoids market volatility and ensures complete control over system boundaries and carbon accounting.
Equitable deployment and regional balance
A recurring theme of the Review is the need for GGR projects to support regional economies and avoid concentration in the South East of England. Nellie’s deployment in South Wales directly aligns with this principle. The company regenerates brownfield and post-industrial land for productive use, creating skilled engineering roles and contributing to regional decarbonisation infrastructure.
5. Resource and land use considerations
The Review notes that GGR expansion must not exacerbate competition for land, water, or biomass resources. Nellie’s model inherently avoids these pressures. Biomass is produced internally using controlled photobioreactors, requiring no agricultural land conversion and minimal freshwater input. Sites are co-located with existing infrastructure and carbon sources, demonstrating compatibility with the UK’s principles for sustainable land use and resource efficiency.
6. Economic and policy outlook
The Review’s economic chapter highlights Contracts for Difference (CfDs) as a potential mechanism for early deployment of engineered removals. For operators with reliable, measurable outputs, CfDs could provide the financial certainty needed to scale domestic GGR capacity. Nellie Technologies is well placed to participate in such mechanisms due to its quantifiable carbon yields and predictable operational performance.
By integrating biomass production, carbon capture, and permanent storage into a single system, Nellie offers a pathway that aligns with Government priorities: durable removals, UK-based innovation, and verifiable environmental integrity.
7. Conclusion
The Independent Review of Greenhouse Gas Removals confirms that engineered solutions will be indispensable for the UK’s net zero transition. It also recognises the value of modular, regionally distributed projects that combine technological rigour with environmental responsibility.
Nellie Technologies’ operational model embodies these principles. By linking microalgal CO₂ capture with permanent biochar sequestration, and by delivering this through fully integrated, locally anchored systems, Nellie provides a blueprint for the kind of secure, scalable, and regionally balanced GGR infrastructure envisioned in the Review.
References
Department for Energy Security and Net Zero (2025). Independent Review of Greenhouse Gas Removals. GOV.UK, March 2025.
UK Government (2025). Independent Review of Greenhouse Gas Removals – Full Report. ISBN 978-1-5286-5365-9.
Nellie Technologies (2025). Technical Data Submission to the GGR Independent Review: Algal Biomass Carbon Removal and Biochar Stability. Submitted January 2025.
