Plenary Sessions Preview

David Baxter

Monday 26 April

1. Plenary AP.1 – Carbon Storage and Climate

EUBCE starts with an overview of the growing need to understand the capacity of our living environment to accommodate ever increasing carbon emissions, particularly regarding carbon capture and storage.

Modelling is key in the determination of the Earth’s capacity to sequester CO2 emitted by human activity. There are many models and six versions of four key examples are presented and discussed in the plenary by Holm et al. It has been identified that Earth System Models (ESMs) need to be improved by inclusion of plant demography and the dynamics of vegetation to more realistically represent plant ecology and the processes that govern carbon-climate feedbacks. It is reported that the Earth’s intact tropical forests provide for roughly half of the global net terrestrial sink. Forest recovery processes after human induced clearcutting are important for climate stability and are difficult to monitor, so the authors describe remote sensing techniques as a way of obtaining reliable data for subsequent modelling.

Given the limited capacity of the human-affected natural system of the earth to sequester CO2, negative emission technologies (NETs), and specifically bioenergy with carbon capture and storage (BECCS) are attracting increasing attention.

Work presented by Almena-Ruiz et al. considers the individual impact associated to land use change, biomass production and harvesting, feedstock pre-treatment and conversion process, together with the emissions caused by biomass handling and transportation between the supply chain stages, all of which impact on the net-negative potential frequently presumed for BECCS. Two case studies illustrate that BECCS systems can achieve high carbon capture efficiencies of 87% to 94% allowing substantial reduction of GHG emissions-per-capita.

In an extension of BECCS, the plenary presented by Menin et al. looks at the benefits of integration of the potentially very high conversion efficiency processes of syngas biomethanation and power-to-gas within the BECCS concept, and how selection of specific technologies for individual process steps influence both overall process efficiency and resulting economic performance. The work involved techno-economic modelling and field data from Italy and Denmark to indicate costs for five operating modes.

Monday 26 April

2. Plenary AP.2 - Circular Economy and Biochar

For this plenary session two strategic approaches to reduce global warming on a large scale are presented.

A circular economy is considered a key component in the use of natural resources in the future. Building a biobased economy means reducing the reliance on fossil fuels, resource efficiently, full valorisation of wastes and residues, maintaining carbon and nutrient cycles, and extending high-quality use of biomass (cascading). The plenary by Vural Gursel et al. define what circularity specifically implies for biobased products and propose a list of indicators for circularity in a biobased economy. From there, a circularity assessment framework is described with a set of existing and newly proposed indicators. While existing approaches are generally limited to food, renewable energy and recycling of biowaste, work presented here aims to extend to biobased products and the extent the quality to which biomass is retained in use and subsequent cycles.

The main carbon sinks are first, the oceans and second, soils. Chiaramonti et al. describe the long-term storage of C in the soil through the incorporation of biochar, which is known to improve moisture retention capacity of the soil while at the same time helping to reconstitute the soil structure, improve the environment for soil microorganisms, regulate soil pH, help retain nutrients while allowing slow release for healthy crop growth, and slow down nutrient leaching and N2O emission. The authors use the results of studies on sugarcane processing value chains, involving combinations of biochemical and thermochemical steps, as well as bioenergy and bioproducts to illustrate the many benefits of biochar.

Tuesday 27 April

3. Plenary BP.1 - Alternative Fuels

There is a strong drive to find alternative fuels for the replacement of fossil fuels and some examples of recent progress are presented in this plenary session.

A comparison of existing kerosene with a number of new fuels for aviation, including biofuels, electrofuels, electric batteries and hydrogen, is presented by Su-ungkavatin et al. Current technological status, market perspective and environmental impacts were assessed for two time horizons, 2035 and 2045. In their assessment, the authors take into account the increasing maturity of technologies in the time frames considered. For 2035, it is  reported that hydroprocessed ester and fatty acid (HEFA) from waste would be the most significant pathway, whilst by 2045 alcoholic fermentation (AF) will probably be the optimum technology solution. Existing or advanced lithium ion batteries for static and mobile applications, and alkaline water electrolysis for hydrogen production are promising technologies for both time horizons.

The To-Syn-Fuel project aims to demonstrate a process for the conversion of waste biomass such as sewage sludge into renewable liquid fuels and hydrogen. Hornung et al. describe progress of the demonstration plant designed for feedstock input up to 500 kg per hour, running for 5,000 hours to produce more than 200,000 liters of biocrude oil. The process integrates thermo catalytic reforming (TCR®) with hydrodeoxygenation (HDO) and pressure swing adsorption (PSA) to produce H2-rich synthesis gas, biochar and liquid bio-oil that can subsequently be upgraded to green fuels. The authors report progress of the project in which demonstration plant commissioning is scheduled for 2021.

A project on aviation biofuel production via hydrothermal liquefaction and catalytic hydrotreating is presented by Castello et al. Biomass feedstocks including algae and sewage sludge are converted using carefully selected catalysts and process conditions to produce bio-oil after fractional distillation. The final biofuel product fully meets the requirements of the existing aviation fuel standard ASTM D1655, which means that it can be used as a drop-in fuel. The authors report that the fuel has been tested in a lab-scale aviation turbine blended with conventional Jet A1 fuel to prove “in-field” performance.

Bello de Oliveira reports on accumulated experience and potential new opportunities for low-carbon fuels in Brazil.

Tuesday 27 April Plenary

4. Plenary BP.2 - Technological Advances

Wherever we look, technologies are being continuously developed and processes for the conversion of biomass to bioproducts are no exception. In this plenary session overviews of the progress made in two key areas, biogas and biomass gasification will be given.

The field of biogas has many relatively mature, while still improving technologies applied to the processing of a very wide range of feedstocks to a range of bioproducts. Holm-Nielsen reports on increased biogas potential by a factor three by 2030 in the EU, compared to 2020, using biodegradable wastes and residues from agriculture and from many industrial processes, as well as aquatic biomass. Case studies are used to illustrate successes and future potentials for the role biogas technologies in integrated infrastructures providing bioenergy, biomethane for static and mobile applications, energy storage, balancing of increasingly wind and solar fed electricity grids, natural gas grid greening, bio-CO2 recovery and Power-to-X, while playing a key role in the circular economy by recycling nutrients back to the soil.

Biomass gasification has already been achieved at large scale though economic performance remain a challenge. Anca-Couce et al. report that gasification-based processes can significantly contribute to increase the bioenergy use for bioheat, power and biofuels, and present some of the main challenges for the future, namely emissions reduction, reduction in bioheat production, gasification technologies developments for power or biofuels and increased efficiency in power production with solid oxide fuel cells (SOFC). Gasification processes have the possibility to achieve high electricity generation efficiencies and allow synthesis of numerous products, including advanced biofuels. Advances will be presented for modern biomass boilers with low primary air ratios and flue gas recirculation in the fuel bed as well as extended reduction zones, significantly reducing NOX and PM emissions and increasing feedstock flexibility; as well as micro-gasifiers for traditional biomass utilization, significantly reducing the emissions of unburnt products with extended combustion chambers.

Wednesday 28 April

5. Plenary CP.1 - Sustainable Aviation Fuels

One of the key transport areas not yet using significant quantities of green fuels is aviation. This plenary session will address some of the options and opportunities for greater use of green fuels in this sector.

Sustainable Aviation Fuel (SAF) is the subject of a new policy in the EU and new legislation is expected in the near future. There is an urgent need to reduce aviation fossil fuel emissions, however green fuels conforming with strict fuel specifications, and specifically fuels produced from wastes and residues, are so far in very limited supply. O’Malley et al. report on studies on the availability of feedstocks to meet growing demand. SAF made from fats, oil, and greases (FOGs), agricultural and forestry residues, the biogenic fraction of municipal and industrial waste, and cover crops are considered in an estimate of the potential feedstock availability in 2030, also taking into account the maturity of fuel conversion pathways and competing uses of the feedstocks. Non-biogenic feedstocks such as industrial flue gases and renewable power-to-liquids technologies are also considered.

Algae has long been a candidate feedstock for sustainable aviation fuel production and hydroprocessed esters and fatty acids (HEFA) production pathways from algae have recently been certified for aviation use. However, high production costs for microalgae feedstocks and low energy yield have hindered market uptake, at least using existing technologies.

Prussi et al. report on GHG emission performance taking into account recent new investments in large-scale algae production plants commonly combined with waste streams recovery using algae (for example wastewater treatment) and technological developments in dewatering system that reduce costs. Results of attractive GHG saving potential in comparison with more traditional SAF feedstock are discussed.

With close links to the aviation sector, Katharina et al. will give the SkyNRG view on which terms and conditions the European sustainable aviation fuels (SAF) mandate can enable growth of the sector.

The alcohol‐to‐jet (ATJ) process has been designed to convert alcohols to an alternative jet fuel using catalytic steps derived from the petrochemical industry that can be blended with existing jet fuel. Hull presents recent advances on the ATJ pathway and characteristics of the fuel.

Wednesday 28 April

6. Plenary CP.2 - Green Hydrogen

Hydrogen is the ideal fuel for avoiding carbon dioxide emissions, however there are many challenges to implementing its widespread use. This plenary session provides an overview of some opportunities for renewable hydrogen production and use as a sustainable fuel or feedstock for other processes.

Hydrogen is an increasingly interesting product in sewage sludge management. Papista et al. describe plans for investment in an economically and environmentally sustainable technology using sewage sludge as the feedstock for indirect production of hydrogen for the transportation sector. The general concept involves the development of a modified approach to waste management comprising two stages, one the anaerobic digestion of sewage sludge and used cooking oils into biogas and the subsequent conversion of biogas into high purity hydrogen. The authors describe a project being set up as part of the overall move to provide alternative energy when lignite mining is abandoned in the Western Macedonia Region of Greece by 2028.

Buffi et al. provide an overview of several pathways for the production of renewable hydrogen from biomass and give an exhaustive review of the most promising technologies for commercialisation. Production pathways are evaluated from a techno-economic point of view, focusing on an energy assessment and respective greenhouse gas emissions to evaluate their potential for market uptake. Reference is made to the EU Hydrogen Strategy (COM(2020) 301 final) which has a vision to enable hydrogen to become a viable solution to achieve decarbonising goals for a number of industry sectors, including replacement of fossil-derived hydrogen in refineries for chemical production, synthetic fuels production, as an energy carrier to decarbonise the natural gas grid, for decentralised power generation and of course for transport. The authors used data and methodologies from JEC Well-To-Wheels (WTW) related reports to integrate with data from literature on the current state of art to propose an estimation of the energy saving potential compared to fossil-derived hydrogen.

Thursday 29 April

7. Plenary DP.1 - Sustainability and Positive Impacts

Replacing fossil-derived energy and products in an emerging renewable society needs to ensure economic, social, and not least environmental sustainability. This plenary session will look at various uses of biomass and the positive feedbacks achievable.

Increasing world population and diet changes to include more meat-based protein is projected to have a significant negative impact on the environment due in large part to land use and land use change.  From an extensive literature survey, Javourez et al. identify existing and emerging waste-to-nutritious biomass conversion pathways, including the possibilities for transforming residues into food-quality ingredients as well as identifying the key parameters inherent in the process pathways. This work is part of a larger study assessing use of residual biomass for producing ingredients for the food and feed markets. Several parameters were considered, including but not limited to edibility, digestibility and bioconversion using living organisms. The authors stress the need for synergetic implementation of waste-to-nutrition strategies within broader conversion platforms, for example biorefineries, able to valorize all by-products.

Any move away from fossil fuels inevitably means an increase in biomass use alongside all other renewables and carbon storage. Increased use of biomass resources has many possible impacts, not least environmental sustainability. Thornley et al. introduce the UK’s Supergen Bioenergy Hub (SBH) sustainability indicator model to assess environmental, economic and social performances of bioenergy and thereby enable comparison of sustainability performances of bioenergy systems, feedstocks, conversion technologies and biomass supply chains.

The authors explain how some of the complexities of biomass conversion pathways can be handled in the model, and they explain how the extensive sustainability issues, that need to be balanced against each, other determine the trade-offs and the overall sustainability of a given bioenergy scheme. The presentation will introduce the SBH indicator model and provide sustainability assessment results for a number of well-established case studies.

Marginal land is often considered for non-food crops and can be a valuable source of biomass for bioenergy and bio-based products. Rettenmaier et al. report on the EU MAGIC project which aims at promoting the sustainable development of resource efficient and economically viable industrial crops grown on marginal lands. The environmental impacts for nine value chains were assessed by means of life cycle assessment (LCA). The authors will report results that indicate the calculated differences between bioenergy and bio-based products from standard agricultural land and from marginal land, in particular the wide scatter of results that is often found for marginal land cultivation. Also included in the assessments are the associated environmental impacts on biodiversity, water and phosphate, all of which are key parameters when considering marginal land.