Impact case study database

The ACT process **[**e.g. R3] developed by Hills and team underpinned the spin-out company Carbon8 Systems (C8S) in 2006 [I1a], and its operating arm, Carbon8 Aggregates (C8A) in 2010 [I1b]. In 2012, following the first ‘End of Waste’ agreement of its kind for C8A’s aggregate by the Environment Agency (the aggregate obtained the status as a product, or secondary raw material), C8A established the first fixed ACT manufacturing facility in Brandon, Suffolk, using pure, bottled CO₂ gas. In doing so, a ‘CO₂-utilisating/sequestering’, management solution for municipal solid waste incinerator (MSWI) air pollution control residues (APCr) was offered to the UK for the first time. The carbonated aggregates entered the UK aggregate market, competing with virgin stone and offtake is subject to commercial supply agreements.

The research innovated UK Waste management, as the APCr-based aggregate enabled the first ever ‘carbon-negative’ building block.*

The C8A’s APCr-based aggregate was used to make carbon-negative blocks by a block manufacturing company, Lignacite Ltd. The high-performance masonry product developed promted the aggregate to be declared as the UK’s ‘Best Recycled Product’. Key to this recognition was that the ‘low-carbon’ aggregates **[**e.g. R2, R3] captured and sequestered more CO₂ than was emitted during their manufacture, and reduced environmental harm.

Since REF 2014, the UoG’s CO₂ mineralisation research has enabled the spin-out company to increase supplies of high-quality carbon-negative, cost-effective and sustainable light-weight aggregates (compliant with, e.g. BSEN 13055; 13242 and ISO 9001), to the construction industry. This has enabled >100 kt/pa of APCr (currently 25% of UK’s APCr production) [I2] to be diverted from landfill via its incorporation in carbonated APCr-based aggregates.

Process scaling-up by C8A (subsequently re-named OCO Technology Ltd.) increased the UK supply of the low-carbon APCr-based aggregate.

Since REF 2014, C8A’s UK fixed plants have increased from 1 to 3, and currently c.a. 350 kt/pa aggregates enter the UK market for use in construction blocks (e.g. CEMEX, Lignacite, Hairds, Forterra and Thomas Armstrong).

The continued research and its commercial implementation (2014-2020) have contributed to social, economic and environmental impacts, and environment policy as evidenced below:

1. social impacts are realised in terms of (i) reduced environmental harms (diversion of c.a. 550 kt of APCr from landfill, so using waste as a resource and reducing leaching into the environment), and (ii) employment opportunities (C8A/OCO and C8S have >110 staff) [I5],

1. environmental impacts include (i) reduced risks from waste (as above), (ii) CO₂ sequestration/utilisation (unpublished data shows the direct mineralisation of CO₂ to be c.a. 130 kt), and (iii) low-carbon aggregate products (1.3 Mt of manufactured aggregates contained ca. 0.13 Mt of mineralised CO₂ and replaced c.a. 1.8 Mt of virgin/quarried stone (1 t of carbonated aggregate replaces 1.4 t of natural aggregates, as the aggregate is a light-weight product), (iv) reduced carbon footprint of carbonated aggregates/blocks (carbonated aggregate is carbon negative) provides additional benefits to the businesses to achieve circular economy and lower emissions [I2], and

1. economic impacts include: (i) value to waste, as landfill avoidance saves £94/t in tax currently (typically 120€/t in the EU) excluding gate fees, and aggregates sales are at £10/t (€20/t in EU), (ii) employment generation (as indicated above), (iii) savings on landfill costs, with unpublished data showing c.a. 550kt APCr to date was transformed into 1.3 Mt of aggregates, saving £60 M in landfill tax fees, whilst preserving >1.8 Mt of virgin stone, and generating £13 M worth of aggregate sales. Therefore, the economic and environmental advantages of the carbonated aggregates are substantial, as the process involves very little energy, since it is reliant on the CO₂ reactivity of the waste material [R2, R3, I2].

ACT is recognised as an exemplar of CCUS technology by, e.g. CO2Value Europe (>70 members including Solvay, Mitsubishi and Total), GCI, and CO2Chem KTN (a network of >1000 members). The importance of CO₂ utilisation to Europe’s future economy is illustrated by recent policy recommendations (CO2Value Europe, 2020-2024) [I3a, I3b], with mineralisation considered for inclusion in the European Emissions Trading Scheme (ETS) [I3c].

From 2016, Hills and team’s research **[**e.g. R2, R3] underpinned the construction of two new ACT plants by C8A to enhance capacity in manufacture of the APCr-based aggregate (Avonmouth, 2016; Leeds, 2017) [I1b]. The APCr management capability of the company has increased 3-fold. As such the aggregate has a carbon footprint of -44 kg/t, meaning that it is truly carbon negative. As a result of supply not yet meeting construction block industry demand, 10-30% w/w (total aggregate weight) aggregate is typically used as a substitute for virgin stone. The substitutions will still lower the carbon footprints of the blocks, which they comprise.

C8A rebranded as OCO Technology Ltd. in 2019 [I1b] and has grown significantly with a current annual turnover of £13 million (2019), >90 staff, and supply 350Kt/pa of carbonated manufactured aggregate, being equivalent to 0.5Mt of virgin stone/pa. Production is projected to rise to 700 kt/pa over the next 3 years [I2] as OCO continues to increase its client base, including Thomas Armstrong and Tilbury MSWI [I1b, I5]. Further, an exclusive development agreement with Mitsubishi Corporation (to cut their GHG emissions to net zero by 2050) has been signed [I1b].

New innovation has enabled a mobile carbonation plant to directly extract CO₂ from flue gas and treat other (non-APCr) wastes.

A new development is a containerised mobile plant (‘CO₂ntainer’) that extends the technological solution, away from large remote fixed plants that use bottled gas. The innovative ‘CO₂ntainer’, is ‘plug-and-play’ ready and directly uses flue gas as the source of CO₂ for the carbonation process. With InnovateUK support, C8S trialled the ‘CO₂ntainer’ in Canada with CRH (>€27.6 Bn; 80,000 employees) in Ontario (2018-19) and Hanson (part of CRH) in the UK (2019-20) [I1].

The success of these trials and Innovate UK funding [I3c] led to the first commercial deployment of ACT by Vicat, the French national cement company, in 2020 [I4, I5].Vicat’s testimonial [T1] states: “ It is Vicat's intention to deploy the CO₂ntainer at our other cement plants in France as part of our commitment to become CO₂ neutral by 2050. We are convinced that ACT is a key technology to reach this target”. Vicat (>€2.74 Bn; >9000 employees) have installed the ‘CO ₂ntainer’ for treating cement by-pass dusts at their cement plant in Lyon. The 24 kt/pa of carbonated aggregates produced are being used internally. The commercial benefits for Vicat are savings of c.a. €2.5 M/pa at the cement plant from avoidance of landfill and reduction in virgin stone requirement. The global licence signed with Vicat is worth £8 M. Recent investment in C8S has totalled £2 M.

Following, AVR started an advanced demonstration of the ‘CO₂ntainer’ at its MSWI in Duvien (September 2020). AVR are the Netherlands largest Energy from Waste company and are using ACT to “ultimately target zero waste” by combining their APCr and pre-captured CO₂ (400 kt/pa) into products. This significant advance enables technology integration at complex industrial facilities and the valorisation of solid and gaseous wastes at source, e.g. Arcellor Mittal steel plants. Arcellor’s testimonial [T2] states:….” the latest commercial innovation concerning a mobile plant that can be employed at the sites of smaller emitters….combining solid and gaseous emissions is a game changer”.

Technology leadership has been widely acknowledged (CO2Value Europe, GCI, UNEP, and CO2Chem KTN - I6, I7, I8a).  In Nov 2016, BBC Radio 4 (audience typically 10M/week) exclusively featured ACT in its 30-minute ‘Costing the Earth’ programme and emphasised its potential contribution towards addressing CO₂ emissions [I9]. Overseas export potential was recognised by the Queen’s Award for ‘Enterprise: Innovation’ Sep 2017 [I8b]. The award citation stated “world leader in permanent capture of carbon dioxide using industrial wastes to form new products”.

The research was subsequently featured on BBC SE News in 2017 (ca. 0.5M viewers), discussing the realised benefits of ACT for waste management, including a laboratory-demonstration of the technology and the C8A Avonmouth plant [I10]. Invited articles and presentations evidence the emerging importance of ACT/mineralisation at UK and European levels.  The technology was recognised in the UNEP Pan-European Assessment GEO6 report (2016) as “a demonstrable contribution to the developing European circular economy” [I7] UNEP/UNECE 2016. The report highlights environmental state/ science-policy trends underpinning decision-making in the Pan-European region [I7]. A key emphasis is the 2030 Agenda for Sustainable Development and its Goals.  Recognition of ACT as an exemplar came from the 3 sponsor organisations: the UNEP, European Environment Agency and Economic Commission for Europe [I7]. More recently (2020), Hills was invited to contribute a Faraday Discussion (for wider dissemination of mineralisation technology). These recognitions have associated impact, e.g. informing the client-base, public and stakeholders of the academic/research, commercial and environmental benefits of Greenwich’s low-carbon technology.

The innovation(s) have informed teaching and research at the University of Greenwich.

The development of curricula in Engineering since 2014 has included specific themes related to low-carbon technology, and sustainable construction materials. Bespoke lectures on ACT at UG and PG-level courses (e.g. Environmental Engineering), research opportunities and training at Master’s and PhD (incl. ERASMUS) are offered. Hills delivers sessions at the CO2Chem Summer/Winter Schools (2017–2020) bringing the benefits and limitations of ACT to >80 PhD students/pa from across the country, as part of their training. Furthermore, C8S represents the ‘Utilisation’ cohort within the Carbon Capture and Storage and Association (CCSA) -the trade association (>60 members incl. Shell, BP and OCO) promoting the commercial deployment of CCUS and the Zero Emissions Platform.