The following are summaries of papers published in other parts of ICE Proceedings during 2007 that readers of Energy may find of interest. Summaries of all papers in ICE journals are freely available and fully searchable at the ‘journals online’ section of the ICE website. See www.ice.org.uk/journals for details.
Solving the puzzle of Britain's underground assets
J. Brayshaw
Proceedings of the Institution of Civil Engineers, Civil Engineering, 160, No. 2, May, 52, doi: 10.1680/cien.2007.160.2.52
The UK's National Underground Asset Group was launched two years ago to coordinate and share data on the country's vast and inconsistently charted network of buried services. ICE's representative on the Group, James Brayshaw of Ordnance Survey, provides an update.
Climate stability: an inconvenient proof
D. Bellamy and J. Barrett
Proceedings of the Institution of Civil Engineers, Civil Engineering, 160, No. 2, May, 66–72, doi: 10.1680/cien.2007.160.2.66
This paper demonstrates that the widely prophesied doubling of atmospheric carbon dioxide levels from natural, pre-industrial values will enhance the so-called ‘greenhouse effect’ but will amount to less than 1°C of global warming. It also points out that such a scenario is unlikely to arise given our limited reserves of fossil fuels—certainly not before the end of this century. Furthermore, the paper argues that general circulation models are as yet insufficiently accurate for civil engineers to rely on their predictions in any forward-planning decisions—the omission of solar wind effects being a potentially significant shortcoming. It concludes that the only certainty is that the world's fossil fuel resources are finite and should be used prudently and with proper respect to the environment.
Climate change: ICE aims for authority and balance
S. Heffernan
Proceedings of the Institution of Civil Engineers, Civil Engineering, 160, No. 3, August, 100, doi: 10.1680/cien.2007.160.3.100
Climate change is a vast, complicated and controversial topic. Seamus Heffernan explains how ICE is expending considerable effort in attempting to devise an authoritative and balanced policy to help members, stakeholders and society decide what can and should be done.
Climate change and civil engineering challenges
J. Hunt
Proceedings of the Institution of Civil Engineers, Civil Engineering, 160, No. 4, November, 170, doi: 10.1680/cien.2007.160.4.170
The greatest challenge facing civil engineers today is how to mitigate and adapt to climate change. However, as discussed in this paper, there are still considerable uncertainties about the trends of some critical aspects of climate change and thus doubts about the mechanisms controlling them. In developing future strategies, a major contribution of civil engineers will be through providing practical and financial evidence about projects and systems which work and do not work. Engineers also know about risk, which is intimately related to system design. The paper concludes that the UK engineering profession needs to be more closely involved in developing effective integrated policies, working with scientists, business and government agencies.
Briefing: Structural insulated panels in modern construction
R. Hairstans and A. Kermani
Proceedings of the Institution of Civil Engineers, Construction Materials, 160, No. 3, August, 91–94, doi: 10.1680/coma.2007.160.3.91
Structural insulated panels (SIPs) are typically formed from a thick layer of polystyrene foam sandwiched between two layers of oriented strand board. They have improved insulation qualities due to reduced cold bridging effects and satisfy all other building regulations. They are also durable if a stringent manufacturing procedure is used. SIPs are a sustainable and cost-effective alternative to traditional timber-frame construction.
GGBS and sustainability
D. Higgins
Proceedings of the Institution of Civil Engineers, Construction Materials, 160, No. 3, August, 99–101, doi: 10.1680/coma.2007.160.3.99
Concerns about climate change have heightened interest in sustainable construction materials. Ground granulated blast-furnace slag offers civil engineers a high-quality, environmentally-friendly material, which can replace much of the Portland cement used in concrete. This article looks at its manufacture and environmental impact and gives examples of its use.
Durability of silica fume and ggbs concrete in a tidal zone
E. Ganjian and H. S. Pouya
Proceedings of the Institution of Civil Engineers, Construction Materials, 160, No. 3, August, 103–111, doi: 10.1680/coma.2007.160.3.103
This paper summarises investigations that were conducted to assess the durability of plain and blended type II Portland cement exposed to marine tidal environments. In this research the performance of cement paste and concrete mixes incorporating 7 and 10% silica fume as a cement replacement was investigated in three exposure conditions with seven days' initial curing in potable water. The performance of plain and blended cements was evaluated by monitoring changes in compressive strength and capillary absorption. The results show that plain type II Portland cement performed better than blended silica fume cement under cyclic wetting and drying conditions. Silica fume specimens under cyclic wetting and drying conditions in simulated seawater exhibited higher strength loss in comparison with plain type II Portland cement when cured under potable water. In addition, the greater the silica fume amount used in the mixes, the more the capillary water absorption under tidal zone exposure and/or under wetting and drying simulation. Further, the ternary-blended ground granulated blast-furnace slag mix was the worst-performing mix in all exposure conditions. An extended initial curing time is recommended for these types of mixes.
Life-cycle assessment and embodied energy: a review
G. F. Menzies, S. Turan and P. F. G. Banfill
Proceedings of the Institution of Civil Engineers, Construction Materials, 160, No. 4, November, 135–143, doi: 10.1680/coma.2007.160.4.135
In this paper life-cycle assessment (LCA) is studied and a brief review and classification of databases and inventories is given. The factors affecting the dissimilar results in various databases are examined and discussed. The main obstacles to LCA and life-cycle energy studies, and their sources, are discussed, together with the role of data in inventory analysis. Embodied energy results are reviewed and compared, and the causes of dissimilarities and variations in these studies are presented. This paper focuses on methodologies developed and adopted for data processing, and inventory analysis for building materials. The data LCA relationship is investigated, and the importance and role of data in LCA is reviewed. A case study of steel as a building material is introduced and a number of life cycle energy assessment studies are evaluated. The paper concludes by outlining a number of issues which need to be handled with care when performing a life-cycle study, and which warrant further qualitative and quantitative analysis.
VIP and their applications in buildings: a review
X. Wang, N. Walliman, R. Ogden and C. Kendrick
Proceedings of the Institution of Civil Engineers, Construction Materials, 160, No. 4, November, 145–153, doi: 10.1680/coma.2007.160.4.145
The properties of insulation materials used in the building envelope have a strong influence on thermal performance of buildings, in particular the U-value of their walls/roofs. This paper summarises current research and developments of vacuum insulation panels (VIP), which provide a quantum leap forward in thermal insulation, offering exciting opportunities for both new and retrofitted buildings. Use of VIP not only provides excellent thermal performance to meet the requirements of building regulations, as well as offering a great potential to reduce energy consumption in buildings, but also increases the available internal area of buildings. However, a real indication of overall thermal performance in use must take into account the thermal bridging that occurs around the edges of the panel caused by the construction details. The performance is also dependent on the maintenance of a vacuum against the influences of envelope permeability, outgassing, moisture and physical damage. More research and development is needed in the practical application of VIP in building solutions.
Briefing: BREEAM—making what is important measurable
V. Mistry
Proceedings of the Institution of Civil Engineers, Engineering Sustainability, 160, No. 1, March, 11–14, doi: 10.1680/ensu.2007.160.1.11
Environmental effects from building stock in the UK are extremely high. For example, approximately 50% of UK CO2 emissions results from the operation of buildings such as homes, offices, schools, shops and leisure facilities. This figure alone is significant but rises to 75% if CO2 emissions from the manufacture and transport of construction materials and transport CO2 emissions (usually taking us from one building to another) are also included. This means that three quarters of the UK CO2 emissions are attributable in one way or another to the building industry. This is just one reason why the Energy Performance in Buildings Directive (EPBD) is essential.
Motorway noise barriers as solar power generators
D. R. Carder, L. Hawker and A. R. Parry
Proceedings of the Institution of Civil Engineers, Engineering Sustainability, 160, No. 1, March, 17–25, doi: 10.1680/ensu.2007.160.1.17
During 2001 the Highways Agency (HA) commissioned TRL Limited to undertake a study to assess the feasibility of generating renewable energy on motorways and trunk roads. This study recommended that the HA undertake a full-scale trial of noise barriers incorporating solar panels. In 2004, two rows of solar barriers were installed in a cutting to the east of junction 9 of the M27. The trial was carefully monitored and showed that south-facing land alongside highways can successfully be used for solar barriers. In terms of maintenance, rainfall was effective in washing the panels; however, vegetation needs to be cut back at least annually unless the barrier is installed in a paved area. There was no evidence that drivers were distracted by the presence of the barriers or that noise reflected from the barriers would create any significant disturbance opposite the site. Although solar barriers are a feasible means of generating renewable energy on the highway estate, a whole-life cost analysis showed that the electricity generated over 30 years would not pay for the cost of installing the barriers unless the price of electricity was many times its current value.
Energy generation from a Severn Barrage prior to full commissioning
M. J. Watson and T. L. Shaw
Proceedings of the Institution of Civil Engineers, Engineering Sustainability, 160, No. 1, March, 35–39, doi: 10.1680/ensu.2007.160.1.35
The Severn Estuary provides the UK with a unique opportunity to harness a large amount of renewable energy from the tides. A barrage 10 miles (16 km) long has been proposed as a means of harnessing this energy. The scheme would be similar, but on a larger scale, to that in the Rance Estuary, northern France, which has consistently and predictably produced electricity over the last 40 years. The studies presented here illustrate the output patterns of the Severn Barrage once the barrage is closed but before project completion, taking into consideration important factors such as: National Grid integration; environmental sensitivities and turbine and pumping characteristics. Assuming the main determinand of operating procedure is production of maximum energy, total barrage output could be 33 TWh by project completion. This is equivalent to almost two years of output from the completed scheme. Furthermore, if barrage closure were to occur earlier than previously envisaged, significantly more electricity would be produced during the construction phase, thus further enhancing the project's economic prospects.
Strategic environmental assessment for wind farm sites
M. Rogers, M. Rogers and I. Magee
Proceedings of the Institution of Civil Engineers, Engineering Sustainability, 160, No. 2, June, 79–85, doi: 10.1680/ensu.2007.160.2.79
Using strategic environmental assessment, the current paper strives to assemble a site selection process for wind farms in order that suitable locations can be identified in a coherent and logical manner. Such a course of action is seen as preferable to the existing process where wind farm proposals are treated as one-off applications, with each subject to a lengthy decision process which may result in an unsuccessful outcome for one of the parties to the appraisal. Strategic environmental assessment is seen as providing a comprehensive framework for this process, enabling the decision to be made in a more efficient and environmentally sustainable manner, aiding the system by which wind farms can be sited in the least ecologically sensitive locations possible. The application of strategic environmental assessment to the siting of wind farms within County Cavan in Ireland is used to illustrate the operation of such a proposed assessment process.
Thermal waste treatment for sustainable energy
C. Ryu, V. N. Sharif and J. Swithenbank
Proceedings of the Institution of Civil Engineers, Engineering Sustainability, 160, No. 3, September, 133–140, doi: 10.1680/ensu.2007.160.3.133
Waste disposal, energy production and pollution minimisation are key problems that must be addressed for sustainable cities of the future. In a world with finite resources witnessing a population explosion, much effort is being made to change the way in which developed societies consume energy and materials and dispose of waste. This paper reviews the current UK practices of segregation and treatment of municipal solid waste (MSW) with focus on advanced thermal treatment technologies. MSW is segregated either at source or at dedicated facilities across the country. The residues of waste segregation can be thermally treated for energy recovery. Direct incineration of unsorted waste is currently the main route practiced by the energy from waste (EfW) industry. Typical MSW incinerators can burn wastes with a wide range of calorific values without any waste pre-processing. However, these incineration systems have low energy efficiency and suffer from unfavourable public opinion. Consequently, gas clean-up technologies associated with waste incinerators have been developed further, especially for dioxin removal and fly ash treatment. The two main alternatives to incineration are gasification of pre-processed waste and production of solid recovered fuel (SRF) from mechanical and biological treatment (MBT). Both processes have potentially higher energy efficiencies than incineration and more flexibility in the use of primary products. Further technology developments with regulatory drivers are required to compete with incineration. Another route available for EfW is pyrolysis, producing cheap and storable fuel products. Pyrolysis is suitable only for specific types of waste material. Pyrolysis of waste wood can produce a good-quality char that can be readily burned in coal-fired power plants or other higher energy efficiency thermal systems.
Partnerships for improving water utility management in Africa
J. Mugabi, S. Kayaga and C. Njiru
Proceedings of the Institution of Civil Engineers, Municipal Engineering, 160, No. 1, March, 1–6, doi: 10.1680/muen.2007.160.1.1
Urban water utilities in developing countries face enormous challenges in meeting the water needs of growing urban populations. Many of the challenges stem from poor utility management practices and the lack of a commercially oriented culture. For many years the debate on how to address this problem has been dominated by two extremes. On the one hand, private sector participation (PSP) has had only limited success. On the other, public management reform, which urges the creation of incentives for public utilities to become more efficient and commercially oriented, has not yet taken hold due to the slow pace of institutional reforms in developing countries. Given this situation, major players in the sector are seeking alternative approaches to improving utility management and performance in developing countries. Such alternative approaches include innovative multi-sector partnerships between private, public and civil society. This paper discusses a partnering approach (pioneered by the Water Utility Partnership (WUP) of Africa) between Loughborough University, Severn Trent Water, six African water utilities and utility management consultants. The aim of the partnership is to increase the management capacity of utility companies in order to improve the performance of water utilities in Africa. This innovative model has implications for policy and practice in this field.
Pyrolysis of biodegradable wastes using microwaves
J. P. Robinson, S. W. Kingman, C. E. Snape and H. Shang
Proceedings of the Institution of Civil Engineers, Waste and Resource Management, 160, No. 3, August, 97–103, doi: 10.1680/warm.2007.160.3.97
The pyrolysis of biodegradable wastes using microwaves was studied as a potential technology to divert waste streams from landfill by converting the biomass into a high-value char, with a potential market as a co-firing media in pulverised fuel power stations. It is demonstrated that pyrolysis can be achieved using inherent moisture as the microwave absorbing phase and that complete char formation can be attained. The efficiency of the process is dependent on the microwave cavity used and it was found that microwave pyrolysis is governed primarily by the rate at which energy is supplied to the waste material. When the heating rate is maximised, the calorific value of the produced pyrolysis gases is greater than the total microwave energy required, meaning that the process is potentially selfsustaining. The dielectric properties of other waste materials are presented and these are used to identify the prevalent design criteria for translating the pyrolysis process to pilot scale.
Anaerobic digestion of verge cuttings for transport fuel
A. Salter, M. Delafield, S. Heaven and Z. Gunton
Proceedings of the Institution of Civil Engineers, Waste and Resource Management, 160, No. 3, August, 105–112, doi: 10.1680/warm.2007.160.3.105
Roadside verges need to be cut for both safety and ecological reasons. This requires energy, currently acquired from fossil fuels with associated release of CO2. Leaving the cuttings in place has a detrimental effect on plant species richness; removal leads to increased biodiversity but produces green waste for disposal. This paper describes a model to determine the energy efficiency and surplus energy yield from the use of verge cuttings as a feedstock for anaerobic digestion. The model is scaleable and could be used by national and local authorities to find ways of reducing fossil fuel consumption. Although based on UK data, the same principles can be applied anywhere with roadside verges or similar sources of green cuttings. The model uses results from trials in Powys, Wales to determine the feasibility of collection and the potential methane yield of the cuttings. The results indicate that verge material can be collected in a manner that is both CO2 neutral and produces more energy than that required for cutting, transporting and processing. The nature of the fuel produced means the process is self-sustaining—biogas can be used to fuel vehicles required for cutting and transport and to provide heat and electricity for the anaerobic digestion process.
