With carbon dioxide concentrations at their highest in recorded history and temperatures predicted to rise to dangerous levels, low carbon energy solutions and CO2 utilization is vital to reduce the effects of climate change.
Can CO2 become a resource for energy production? What may sound far-fetched is actually much closer to reality, and in my eyes, very necessary for societies transition to low carbon energy production. Increasing energy demands, coupled with renewable energy capacities that are not yet at the required level and a reliance on oil & gas by-products (such as plastics and fertilizers), means solutions are required to bridge the transition to low carbon energy.
How does CO2 recycling help?
CO2 recycling provides a fairly comprehensive solution to these problems in theory, yet unfortunately, catalyst limitations in stability and selectivity are currently holding the technology back. Electricity powers the reaction which combines water and CO2 into valuable products such as ethanol and ethylene.
This has three distinct advantages. Firstly, CO2 can be used as an energy store. At low demand, renewable energy can be used to convert CO2 to a fuel and at high demand, the fuel can be burnt to provide extra energy increasing the overall capacity of renewable energies. Secondly, CO2 to fuel can increase the viability of carbon capture by turning CO2 into a sought after resource. And finally, CO2 to valuable products (such as ethylene for plastics) aids our transition away from fuel by replacing oil and gas by-products.
Where does my project fit into?
My research has centred around developing catalysts to optimise the reaction between CO2 and H2O and reduce the energy required to power it. I am currently trying to improve the selectivity of the reaction through controlling active sites on the atomic scale. When designing these experiments around the theory, its easy to swap viability for performance e.g replacing earth abundant metals/elements for harsh-on-the-earth rare metals in the name of short-term success. The electrode materials need to perform well but not at the expense of scalability. Taking a step back and hearing about other processes and sectors resets the goals for success. With ease of application, financial cost and environmental cost driving the transition from lab to industry, understanding the bigger picture allows me to make better decisions on the details.
Heating and cooling of the built environment accounts for half of the world’s energy consumption. As of today, 75% of this energy is produced from fossil fuels. In order to move towards a net zero society, it is essential to look at decarbonising this sector. This challenge was also included in the UK government’s recent “Ten Point Plan for a Green Industrial Revolution”, setting out a path which moves away from gas boilers for heating of buildings towards lower carbon alternatives such as heat pumps.
A technology which could be implemented to provide large-scale low-carbon heating and cooling of buildings is Aquifer Thermal Energy Storage (ATES) where thermal energy is stored at shallow depths in the subsurface (20-200m) in layers of water-bearing rock (an aquifer). This is a technology that can be used to provide space heating and cooling to large buildings such as university campuses and hospitals as well as small-scale domestic and commercial buildings.
The operating principle of an ATES system is shown in the Figure below. Usually, an ATES system will consist of two wells: one ‘warm’ well and one ‘cold’ well. In the winter, water is pumped from the ‘warm’ well and the water temperature is raised using a heat pump to obtain a suitable temperature for heating. The water is then circulated through buildings to provide heating and, finally, reinjected at a lower temperature at the ‘cold’ well. In summer, the process is reversed. Cold water is pumped from the ‘cold’ well to directly cool buildings. The water is then re-injected at a warmer temperature at the ‘warm’ well.
The potential for ATES worldwide is widespread. The only pre-requisites for an ATES development are the presence of a seasonal climate (i.e. seasonal energy demand) and a large aquifer. The UK is therefore an ideal candidate for large-scale ATES implementation, with the presence of large aquifers such as the Chalk Aquifer or the Sherwood Sandstone Aquifer which underlie major urban and industrial centres. Currently, uptake in the UK is low with only a few projects of a total capacity of 12MW (current heating and cooling demand is of the order of 50GW for comparison). One of these ATES installations is situated just a few miles away from Imperial College in the Wandsworth Riverside Quarter with 8 wells provides heating and cooling to 500 flats.
Developing and operating sustainable ATES deployments is challenging and a number of considerations must be taken into account: where will wells be placed, how can an optimal efficiency be reached to recover a maximum of the injected thermal energy, how will local conditions such as ambient groundwater flow or geological heterogeneity affect the efficiency of such systems?
My PhD focusses on addressing some of these questions through numerical modelling of ATES systems. From homogeneous aquifers to complex heterogeneous aquifers, I look at how numerical modelling can inform us on how to develop sustainable and efficient ATES deployments. We aim to inform policy makers and industry professionals on how to best plan and operate these systems, regarding optimal well locations, operating strategies for maximum thermal recovery and avoiding groundwater pollution. This will be key for the successful deployment of ATES projects and therefore increasing the uptake in ATES in the UK and beyond.
Today, approximately 3.1 billion people rely on improved on-site sanitation facilities, like pit latrines and septic tanks, to access sanitation services [WHO/UNICEF 2019]. The material that accumulates in such facilities, known as faecal sludge, can have detrimental environmental and public health impacts, if not safely managed.
The UN Sustainable Development Goal (SDG) 6 calls for universal access to sanitation services, as well as adopting sustainable management practices for the faecal sludge that is being contained and collected. At the same time, there is a new paradigm of looking at faecal sludge as a source of valuable resources to be recovered rather than just waste to be safely discharged. In this context, sustainable sanitation systems can support progress towards multiple SDGs, through the recycling of water, carbon, energy and nutrients.
My PhD work places resource recovery at the centre of faecal sludge management, using a treatment process called pyrolysis (the thermochemical conversion of biomass in an oxygen-limited or oxygen-free environment), to treat and recover resources from faecal sludge. The end-products of pyrolysis, a solid output known as biochar, a bio-oil and gas products, offer several reuse opportunities, including energy and nutrient recovery.
I will be investigating faecal sludge-derived biochars as organic fertilisers that can contribute to global food security by replacing unsustainable mineral fertilisers, which depend on depleting phosphorus resources and costly synthetic nitrogen forms. By using organic fertilisers made from faecal sludge, we can contribute not only to SDG 6 (“Clean water and Sanitation”), but also others including “Zero hunger” (SDG2) and “Responsible consumption and production” (SDG12).
These interactions among SDGs make it evident that sanitation sits within a wider system of human interventions and natural ecosystems. Therefore, faecal sludge management choices can impact and be impacted by the environment around them. Investigating such interactions can be complex and requires the adoption of a systems approach to define the sanitation and faecal sludge management chain.
I am using systems thinking and life-cycle analysis tools to describe some of the key interactions among faecal sludge management components and study the integration of man-made sanitation systems to the natural and socio-economic environment in which they function, through resource recovery. My work will include assessing environmental impacts of real-world sanitation case studies to better understand the effects that sanitation interventions may have on their surrounding environment. I hope that this work will contribute to global sanitation and resource recovery efforts, ultimately helping developing countries meet the SDGs.
In the face of climate change, exploding world population and inevitable shortages in fossil resources within the next 50–100 years, it keeps getting harder and harder for agriculture to keep up with demand. Taken together with the fact that conventional chemical fertilisation destroys natural biomes, this calls for immediate action and alternatives.
One such possible alternative dwells underground, well hidden from the eye. An illustrious circle of soil fungi have been found to associate with nearly every terrestrial plant on earth, rendering them one of the key players in ecosystem stability and carbon sequestration. They interact with the plant’s roots and form a symbiosis commonly known as the mycorrhiza. These mycorrhizal fungi span vast mycelial networks, exploring the soil for minerals, which they exchange with the plant for photosynthesis products, like sugars. Furthermore, the symbiosis increases the plant’s resistance against soil pathogens, heavy metals or drought, reduces nutrient leaching and improves the environment for the establishment of fresh seedlings. The fungus acts as an elongation to the roots and stores large amounts of carbon, even beyond the plant’s life, remaining in a state of quiescence just waiting for the next plant to team up with.
In order to harness the fungus’ abilities, more basic research is needed. Their natural habitat is the intransparent soil, a complex environment with an enormous range of physical obstacles, nutrient and mineral gradients and numerous interacting species of each of nature’s kingdoms as well as their metabolites. In order to mimic these structures and simulate real-life conditions, which is impossible with conventional techniques, we set out to design our own microenvironment using so-called microfluidic technology.
In the past decades microfluidic technology has arisen as a new promising tool. In general, the field of microfluidics deals with the behaviour of fluids in miniature dimensions down to picoliters and involves the fabrication of microdevices for all kinds of tasks in biology or chemistry, either for analytics or synthesis. We can specifically tailor microenvironments to the task at hand, implanting physical obstacles, introducing chemical gradients or facilitating co-habitation with beneficial, hostile or just co-existing character. The applications are vast, stretching over investigations involving all kinds of environmental cues, chemical or physical, and their influence on the fungus.
With this new approach for basic mycorrhizal fungi research, we hope to understand these essential fungi and their symbiosis better, paving the way for new strategies in biofertilisation, as an alternative to conventional fertilisers based on fossil resources as well as sustainable forestry.
As the urgency to phase-out fossil fuels from the energy sector increases, biorefineries, which convert sustainably grown biomass into a variety of chemicals, biomaterials and advanced biofuels are being turned to, to help address today’s global environmental and economic issues. One under-utilised biomass is Brewer’s Spent Grain (BSG), a waste biomass produced by beer breweries with a promising potential for the creation of renewable chemicals and materials, as well as protein as an additional value-added product.
More than a pint of beer
As Brits flock to beer gardens and their local pubs for their post lockdown pint, it’s no surprise that Brewer’s Spent Grain (BSG) is one of the major industrial biomass by-products in the UK. One unique feature of BSG is that it has a high protein content compared to other woody waste biomass that typically power biorefineries. However, the stubborn fibrous structure of spent grain limits its use as low-value animal feed for a few livestock species, where its nutritional value is solely in its protein. Here lies an opportunity to extract the protein in BSG to create higher-quality feed for a larger variety of animals – whilst producing bio-derived chemicals and materials from its non-protein portion. But the question is, how can such a biorefinery be developed?
The ionoSolv process
The answer (hopefully) lies in some of the work already done at Imperial. A process that has been developed in my research group, and is currently being commercialised by Imperial start-up Lixea, utilises low-cost ionic liquids for the pretreatment (i.e. fractionation) of biomass into its main components: cellulose, hemicellulose and lignin.
It is a one-size fits all process that has the ability to break down stubbornly structured plant matter, called lignocellulosic biomass. These include agricultural residues, commercial forest and wood waste. Thanks to Ionic liquids, a group of organic salts that are liquid at ambient temperatures, lignocellulosic biomass can be broken down safely with few steps and high solvent recovery, lowering the process and environmental costs typically associated with biomass pretreatment techniques. Once fractionated, the lignocellulosic biomass components can be used to make a plethora of biochemical based products: lignin-based carbon fibres, nanocellulose and other biobased composites to name a few. However, this technology is yet to be optimised for protein-rich biomass, such as BSG.
Preliminary data shows that ionoSolv ionic liquids can successfully extract protein from BSG, leaving a cellulose rich fraction. The protein can be recovered in a separate fraction and has been shown to be pre-hydrolysed, making it easily digestible by the stomach. But there are steps that will need to be taken to optimise the extraction, recovery and purity of the proteins from BSG, while still maximising the quality of other components, if a successful biorefinery is to be built. My research aims to do this, with the ultimate goal of developing a biorefinery blueprint for all protein-rich biomass – not just spent grain.
Let’s face it: we live in a plastics world. Plastic pollution is doubtless a major societal challenge that raises serious questions about the sustainability of modern consumption patterns. The increasing amount of plastic waste generated each year, dominated by single-use plastics, has created an ecological and waste management crisis. Yet in difficulty often lies opportunity, and throughout history humankind has demonstrated its ability to overcome challenges with ingenuity. In the context of plastic pollution, recognising the ripple effects of a fossil-based economy – conventional plastics are traditionally made from crude oil – alternatives materials loosely referred to as bioplastics, have emerged on the market. But ‘bio’ doesn’t necessarily mean more sustainable and any material substitution must be carefully assessed. My PhD aims to assess the sustainability of these novel bioplastics to ensure they contribute towards tackling the plastics issue, rather than exacerbate it.
So far, my research has addressed the conflicts that emerge as we shift from conventional to bioplastics, while uncovering some of the opportunities too. Life-cycle thinking is at the core of my approach, which helps me look at the issue more holistically. For example, bioplastics are often biodegradable (not all of them are!), which makes them compatible with food waste recycling. However, this potential can only be fulfilled with an adequate and coordinated waste collection system. My latest findings highlighted the concerns over the suitability of biodegradable plastics in food waste treatment strategies, calling for increased collaboration between industry, academia and policy.
Working in a topical and highly mediatised research area is both a blessing and a curse. People immediately connect with the issue of plastic pollution, and tend to show genuine interest in the outputs of my work. However, it also means being acutely aware of all the false promises, misleading claims and unintentionally detrimental effects of public shunning of plastics. Ultimately, we need to recognise that achieving sustainability requires a systems-thinking approach. As Albert Einstein put it: “We cannot solve our problems with the same thinking we used to create them”. In practice, this will mean redesigning our linear consumption model, rather that retrofitting the system at the very end.
The infographic below covers some of the concepts explored here, in common parlance. Thinking about the big picture, my research aims to fulfill the ambitions of a circular economy, which is essentially about keeping materials and products inside the loop for a long as possible.
Around 86% of all global fire events occur in savannas. These fire events contribute to 10% of total annual carbon emissions. African savannas make up most (71%) of the total contribution of savannas to carbon emissions. Humans and savannas have co-existed, and co-evolved, for the last 400,000 years. However, long-term patterns in fire events – known as fire regimes – are changing due to human activity. Current fire regimes in East African savannas, and the new wildfire patterns that are emerging because of them, are complicated by four challenges: 1) the social construction of savanna ecosystems, 2) recent colonial history and persisting neocolonial influence, 3) population growth and urban expansion, and 4) the global environmental agenda.
In this blog I will outline these four challenges in the context of East African savannas and explain how my research contributes to the sustainable management of savanna fires.
A ‘Natural’ Narrative?
Evidence reveals the habitual use of fire by early humans across African savannas dating back to ~400,000 years ago (Bird and Cali, 1998). Fires have an ancient geological history on earth and have influenced global biogeochemical cycles and evolution independent of humans for millennia. However, elemental carbon studies have inferred that fire incidences in sub-Saharan Africa were low until this time, suggesting that humans have exercised significant control over savanna structure and fire regimes for centuries (Bird and Cali, 1998; Bowman et al. 2011). The co-evolution of humans and savannas makes it difficult, and perhaps impossible, to distinguish between natural and anthropogenic fire regimes (Reid, 2012; Laris and Jacobs, 2021).
Fire scientists have recognised a global shift in fire dynamics, a concept termed a ‘pyric transition’, whereby humans have fundamentally altered the two main conditions fires depend upon: geophysical dynamics, such as temperature and relative humidity, and vegetation (Bowman et al. 2013). Fires require living biomass to exist in the landscape (Sa et al. 2011) and human activity causes a departure from ‘natural’ background levels of fire activity by actively manipulating vegetation and soil, such as through agricultural practices, land use change (e.g., deforestation), ignition patterns (e.g., seasonality), and land management- and fire-related policies (e.g., active suppression).
In recent history, human-driven climate change and the transformation of ecosystems globally have resulted in a shift in human influence over the geophysical, as well as the vegetational conditions wildfires synthesise (Bowman et al. 2011), altering conditions above recorded natural variability levels (Jones et al. 2020). Jolly et al. (2015) show that fire seasons, defined by fire-prone weather conditions, lengthened across 25.3% of Earth’s vegetated surface between 1979 and 2013. This resulted in an 18.7% mean increase in the global fire season duration, with some regions, such as East Africa experiencing wildfire seasons more than a month longer than they were in the 1980s. This trend is predicted to accelerate due to this recorded extension having caused an 108.1% increase in burnable vegetated area. The interrelated environmental, social, economic, political, legal, and institutional systems that contextualise and precipitate current and future projected wildfires are, thus, inherently distinct from geologic past (Pyne, 2020).
Western-centric Fire Suppression Policy
Across Eastern Africa, this pyric transition, can be directly attributed to European colonization which led to adoption of a standardised suppression approach to eradicate fire from the landscape. In the late-nineteenth and early-twentieth century, western conservationists initiated a global movement towards the preservation of wilderness, resulting in the eviction of local and indigenous groups across vast areas of protected savanna ecosystems and a ban on their traditional fire practices. Globally, this has reinforced the wildfire paradox, whereby the exclusion of fire from the landscape has induced larger and more intense fires due to excess fuel accumulation and moisture availability. The intensification of fire conditions has not, however, increased the frequency and intensity of fires; many East African savannas that ecologically depend on fire now experience no fire at all.
Moura et al. (2019) identified three main legacies of colonial fire management on East African savannas. Firstly, widespread tensions and conflicts between governments, authorities, and local and indigenous communities, often resulting in the extradition of the latter and repudiation of their rights. This has been widely recognised as a leading factor in unsustainable and exploitative natural resource management. Secondly, the accumulation of ground fuels and an increase in late dry season (LDS) fires that burn extensively and intensively. LDS fires are often associated with extreme wildfire events (EWEs) that adversely impact both human and natural biotic and abiotic systems, including short- and long-term increases in GHG emissions. And thirdly, accelerating ecosystem degradation due to woody and unpalatable shrub encroachment, causing a decline in vegetation and soil health, widespread biodiversity loss (e.g., affecting the life history traits of species that inhabit East African savannas, such as migratory herds that follow distinct rainfall and nutritional gradients), and therefore, increased inter- and intra-species competition for resources (Archibald, 2016).
My research explores the opportunities for equitable institutions, governance, and policy for addressing wildfire challenges across post-colonial East African savanna ecosystems – where all stakeholders and rights holders are recognised, equably represented, included in the decision-making process, and have access to the opportunities and benefits of implemented measures. Fires have a complex socio-ecological history in East African savannas, where wildfire challenges witnessed today reveal underlying environmental, social, economic, and political conflicts and struggles. To understand how different fire management practices and policies affect the delivery of ecosystem (dis)services across the Greater Serengeti-Mara Ecosystem (Kenya and Tanzania), I am going to create a socio-ecological systems model where each practice and/or policy is modelled under projected future climate-socioeconomic scenarios. Due to the diversity of voices and vested interests existing across this landscape, this model will allow us to explore how current and proposed fire management practices affect socio-ecological systems at multiple stakeholder and spatio-temporal scales. In addition to this, a series of workshops will be carried out with local stakeholders and rights holders to investigate local attitudes, empirical realities, and constructions of fire, and scope of future policy and management.
A cornerstone of the modern society is the freedom and ease of movement. In the UK, transportation accounted for a third of carbon dioxide emissions in 2018, of which over half came from cars and taxis. In order to transition to a zero-pollution society, vehicles must be further optimised to increase fuel economy while simultaneously reducing pollutant emissions, including but not limited to carbon dioxide. Other vehicle emissions, such as nitrogen oxides, play a major role in the air quality within our urban areas and must also be tackled. The solution is multi-faceted and will require continued development of the combustion devices within current and new vehicles to meet both our expectations and the standards set by governments.
My research is part-funded by Toyota, a leading manufacturer of hybrid vehicles, and aims to further optimise the hybrid powertrains in their vehicles. With cutting-edge experimental methods, we can probe the fundamental nature of the combustion of bio-derived fuels and fuel components under extreme conditions. This greater understanding of these novel combustion modes directly translates, through the use of computational models, to more efficient and cleaner vehicle technologies within relatively short time frames.
While extracting reliable and valuable data in order to ensure that the computational models used are accurate may often seem tedious, the direct applicability to current technology is a reminder of the instant impact that my research can have. Toyota produces close to ten million vehicles a year and in 2017 on average they emitted 101.2 grams of carbon dioxide per kilometre driven. Improving these vehicles by as little as 1% would result in over 10 tonnes per kilometre less carbon dioxide emitted. This is the equivalent emission from the average electricity usage of 17.7 households in the UK for a calendar year. The average car in the UK travels about 16,000 km a year. That means this saving is the equivalent of 283,000 houses!
Due to the nature of global economies of scale, the small improvements researchers can make could have a profound impact.
Undoubtedly, 2020 has been a year of unprecedented change. In such times, mental resilience is crucial. Having come from a background with research and development experience, where you may often expect the unexpected, I had naively thought this would not be a personal issue. However, it would be wrong not to say that at times I have felt lost, struggling to stay afloat in the wake of COVID-19. After all, what use is a lab-based student working from home? In such times I have found that it helps to see the bigger picture and understanding the bottom line of my work has been pivotal in addressing this. So here it is.
We as individuals, a collective and a planet are experiencing an increasing number of catastrophes which are, in some part, man-made – whether those be industrial, medical, political or otherwise. More often than not, these issues are derived from a lack of foresight or understanding for the implications of a given action we make. After all, by priding ourselves on going boldly where no one has gone before, can we always be certain of the consequences? This certainly seems to have become the case in the post-industrial era with regards to the processing and handling of material wastes.
As a researcher, my work focusses on only one aspect of the pollution issue – recovering the oily foodstuffs which many of us pour down our drain, referred to as Fat, Oil and Grease, or “FOG”. Unaddressed, such pollution in the UK has already been associated with the formation of major ‘fatberg’ blockages in our sewers – some of which have been found to weight over 100 tonnes, costing £50 million to control and up to £40 million in damages in the UK annually. As populations grow, more foodstuffs are disposed to drains and our sewer system ages, this problem will only become more pressing. However, there is also hope. If handled correctly, new technologies could enable us to remove and reuse oily pollutants for new purposes, for example as biofuels or in new synthetic products. In the future, ideas like this may be at the heart of treating waste as part of a wider circular economy.
Perhaps counterintuitively, with this big picture in mind, I aim to address fat, oil and grease with science at the nanoscale. That is to say with materials whose properties are well defined at sizes more than one thousand times smaller than the width of human hair. This will enable the development of new technological solutions which more heavily leverage the behaviour of oily pollution for Fat, Oil and Grease separation instead of more typical energy-intensive operations such as manual removal. In doing this, my position within Imperial College London’s Transition to Zero Pollution Cohort (and more widely, the Science and Solutions for a Changing Planet Doctoral Training Programme, or “SSCP-DTP”) is instrumental to my research in enabling me to maintain a balance of perspectives from other academics on both the intricate details of my work and the bottom line it addresses. This is no better demonstrated than through the exposure which these groups have afforded me already – allowing me to better understand both the wider issues of man-made pollution and our current solutions, as well as the way in which my own scientific expertise can interface with that of other, unrelated fields.
Written by Emma Hibbett, PhD student at Grantham Institute – Climate Change and Environment & Centre for Environmental Policy
COVID-19 has catapulted air pollution into the political foreground as new evidence is emerging which connects coronavirus fatality to air pollution exposure. In the UK, air pollution is already the largest environmental threat; responsible for 36,000 deaths and 3 million lost working days each year. Although the UK government has taken steps to manage the crisis of pollution, 15 million people still live in areas with pollution levels that exceed WHO guidelines for particulate matter.
How politicians decide to manage air pollution matters; whose voice, knowledge, and experiences are included in policy making process will influence the types of solutions that emerge. In a democratic society, local communities should be able to have their voices heard in decisions which affect their lives. However, in air pollution policy making, some community voices are excluded from this process, resulting in policies which do not always reflect the experiences of local people. Often, the most excluded voices are those of the most vulnerable, who disproportionately experience the health impacts of air pollution. In London, for example, just 2% of the capital’s richest experience NO2 levels which exceed EU limits, compared to almost half of the most deprived communities.
When the stakes are this high, it is crucial that the experiences of all are included into policy making in order to ensure that solutions benefit everybody. Community inclusion in policy making is even more critical in times of crisis, but this is when exclusion is at its worst. During the pandemic, local authorities have rushed to pass emergency measures without consulting communities, resulting in tensions and policies which overlook the experiences of certain communities.
My PhD work examines these critical questions of voice and inclusion in our society. To do this, I explore how different community groups do, or do not, gain access to political decision making, and what resources and relationships help them to influence policy making.
My preliminary results highlight critical tensions in our democracy regarding who gets to speak, and who is heard. COVID has brought these tensions in sharp focus; providing an exemplar case of whose voices and experiences are represented in policy change. If we are to successfully transition towards a zero pollution future, we must prioritise these questions of representation and justice. If not, we will continue to exclude vulnerable communities from solutions which are supposed to build a fairer, healthier, and more just society.