William F. Gale

An overview of the potential environmental impacts of large-scale microalgae cultivation

Cultivation of microalgae for applications such as fuel, food, pharmaceuticals and farming is a rapidly developing area of research and investment. Whilst microalgae promises to deliver many environmental benefits compared with existing biofuel technology, there are also issues to overcome in relation to wastewater management, emissions control, land use change and responsible development of genetically modified organisms. This review seeks to highlight both the positive and negative impacts of microalgae cultivation, focusing on impacts to the aquatic, atmospheric and terrestrial biospheres that may occur and would need to be managed should the microalgae cultivation industry continue to grow.

Approaches and Techniques for Modelling CO2 Emissions from Road Transport

Abstract Transport accounts for around a quarter of CO2 emissions globally. Transport modelling provides a useful means to explore the dynamics, scale and magnitude of transport-related emissions. This paper explores the modelling tools available for analysing the emissions of CO2 from transport. Covering a range of techniques from transport microsimulation to global techno-economic models, this review provides insights into the various advantages and shortcomings of these tools. The paper also examines the value of having a broad range of perspectives for analysing emissions from transport. The paper concludes by suggesting that the broad range of models creates a rich environment for exploring a spectrum of policy questions around the emissions from transport, and the potential for combining modelling approaches further enhances the understanding that can be attained.

Integrating microalgae into the Brazilian program for biodiesel production and use

Brazil‘s programme for production and use of biodiesel is a novel program, aimed at improving the sustainability of biodiesel by promoting social inclusion, whilst simultaneously increasing food security, diversifying feedstocks and producing a lower carbon fuel. The aims of the program have been evaluated by conducting a qualitative analysis of the system. The existing system is then compared with the introduction of microalgae as a feedstock. This research shows that revisions to the program are needed in order to address economic, social and environmental sustainability. Particular attention must be given to more thorough environmental criteria for land use and agricultural techniques. Family farmers need stronger support in order for biodiesel to become a sustainable product for them to grow. Microalgae could be included into a biodiesel program, provided sufficient incentives are given, and this could improve the overall sustainability of biodiesel production and use.

Capillary Hysteresis in Neutrally Wettable Fibrous Media: A Pore Network Study of a Fuel Cell Electrode

Hysteresis in the saturation versus capillary pressure curves of neutrally wettable fibrous media was simulated with a random pore network model using a Voronoi diagram approach. The network was calibrated to fit experimental air-water capillary pressure data collected for carbon fibre paper commonly used as a gas diffusion layer in fuel cells. These materials exhibit unusually strong capillary hysteresis, to the extent that water injection and withdrawal occur at positive and negative capillary pressures, respectively. Without the need to invoke contact angle hysteresis, this capillary behaviour is re-produced when using a pore-scale model based on the curvature of a meniscus passing through the centre of a toroid. The classic Washburn relation was shown to produce erroneous results, and its use is not recommended when modelling fibrous media. The important effect of saturation distribution on the effective diffusivity of the medium was also investigated for both water injection and withdrawal cases. The findings have bearing on the understanding of both capillarity in fibrous media and fuel cell design.

The Effective Use of Excess Capacity for Low Carbon Urban Transport Futures

A reduction in emissions from transport is essential and requires a system wide approach, inclusive of technological and behavioural changes. Defining capacity in urban transport as the space through which transport demand can be met, the research explores where there is excess capacity in the system and how this could be used to reduce emissions. Capacity may be physical capacity in the roadspace or seats within vehicles, or temporal capacity, where there are fluctuations in the use of the system, such as peak and off-peak flows. This is complementary to the International Energy Agency (IEA)’s definition of urban transport energy efficiency as maximising travel activity whilst minimising energy consumption through a range of approaches and techniques. This paper proposes that interventions designed to enable behavioural change could reduce emissions by changing the way that the urban transport system is used. Drawing on the literature, this work demonstrates how effective use of excess capacity might be facilitated through measures such as smarter choices programmes and the application of intelligent transport systems (ITS). Case studies are provided as examples of ways that urban transport infrastructure can be adapted for more efficient use, including shared space projects and the ‘complete streets’ policy in New York City. The paper concludes by presenting the potential impacts of effective use of excess capacity for reducing urban transport emissions as demonstrated through the case studies.