Contracted energy flexibility characteristics of communities: Analysis of a control strategy for demand response

Increasing energy system flexibility through demand-side measures will help meet challenges brought by the transition to a low-carbon energy system. Through participation in demand response programmes, buildings can act as sources of contracted flexibility. Contracted flexibility, in this work, is defined as energy flexibility that is supplied to fulfil a set of contractual terms that define when and how demand modifications are delivered and under which incentives or penalties. This paper identifies the factors affecting contracted energy flexibility potential of homes implemented with a model-predictive control strategy designed to deliver a simplified but yet generalisable incentive-based demand response scheme. The control strategy was implemented in centralised and naive-decentralised architectures using co-simulations to observe interaction of the controller with an English community of 30 homes fitted with air-source heat pumps. The results showed that the control strategy was able to deliver sustained demand reductions without violating comfort by preheating the homes prior to demand response periods, if conditions were suitable. Preheating the homes increased overall energy consumption and, in some cases, caused a peak in electricity demand prior to the DR period. Modifying factors of control operation, like the coordination strategy, magnitudes of penalties, control constraints and notice period between call for demand reduction and its delivery, were shown to affect the ability to deliver demand reductions. The contracted flexibility potential of the community was shown to be characterised by the buildings and their systems, the physical and contractual environment, and behaviour and preferences of the occupants

Simulation of site-specific irrigation control strategies with sparse input data

Crop and irrigation water use efficiencies may be improved by managing irrigation application timing and volumes using physical and agronomic principles. However, the crop water requirement may be spatially variable due to different soil properties and genetic variations in the crop across the field. Adaptive control strategies can be used to locally control water applications in response to in-field temporal and spatial variability with the aim of maximising both crop development and water use efficiency. A simulation framework ‘VARIwise’ has been created to aid the development, evaluation and management of spatially and temporally varied adaptive irrigation control strategies (McCarthy et al., 2010). VARIwise enables alternative control strategies to be simulated with different crop and environmental conditions and at a range of spatial resolutions. An iterative learning controller and model predictive controller have been implemented in VARIwise to improve the irrigation of cotton. The iterative learning control strategy involves using the soil moisture response to the previous irrigation volume to adjust the applied irrigation volume applied at the next irrigation event. For field implementation this controller has low data requirements as only soil moisture data is required after each irrigation event. In contrast, a model predictive controller has high data requirements as measured soil and plant data are required at a high spatial resolution in a field implementation. Model predictive control involves using a calibrated model to determine the irrigation application and/or timing which results in the highest predicted yield or water use efficiency. The implementation of these strategies is described and a case study is presented to demonstrate the operation of the strategies with various levels of data availability. It is concluded that in situations of sparse data, the iterative learning controller performs significantly better than a model predictive controller

Human experience in the natural and built environment : implications for research policy and practice

22nd IAPS conference. Edited book of abstracts. 427 pp. University of Strathclyde, Sheffield and West of Scotland Publication. ISBN: 978-0-94-764988-3

Air pollution and livestock production

The air in a livestock farming environment contains high concentrations of dust particles and gaseous pollutants. The total inhalable dust can enter the nose and mouth during normal breathing and the thoracic dust can reach into the lungs. However, it is the respirable dust particles that can penetrate further into the gas-exchange region, making it the most hazardous dust component. Prolonged exposure to high concentrations of dust particles can lead to respiratory health issues for both livestock and farming staff. Ammonia, an example of a gaseous pollutant, is derived from the decomposition of nitrous compounds. Increased exposure to ammonia may also have an effect on the health of humans and livestock. There are a number of technologies available to ensure exposure to these pollutants is minimised. Through proactive means, (the optimal design and management of livestock buildings) air quality can be improved to reduce the likelihood of risks associated with sub-optimal air quality. Once air problems have taken hold, other reduction methods need to be applied utilising a more reactive approach. A key requirement for the control of concentration and exposure of airborne pollutants to an acceptable level is to be able to conduct real-time measurements of these pollutants. This paper provides a review of airborne pollution including methods to both measure and control the concentration of pollutants in livestock buildings

Global and Domestic Factors of Financial Crises in Emerging Economies: Lessons from the East Asian Episodes (1997-1999)

This paper suggests that a new approach is needed in order to identify the causes of the East Asian financial crises and that this new approach might be fruitful in reassessing the analyses and theories of financial crises in emerging economies. The first part of the paper presents a new empirical analysis of the state of fundamentals in East Asia before the crises. It suggests that the relevant fundamentals were both non-conventional and "intermediate" (or not "bad" enough to trigger the crises by themselves). Fundamentals were also different from those preceding previous turmoils in the 1990s, such as the ERM crisis in 1992-1993 and the Mexican crisis in 1994-1995. The second part highlights that existing theoretical models of currency crises miss some important points. Even second generation models, which stress self-fulfilling expectations and which acknowledge that crises might appear against the backdrop of non-conventional and intermediate fundamentals, explain only the role of fundamentals in relation to private expectations. But they do not explain how can it be that a shift in private agents' expectations turns out into a financial crisis. The third part suggests that the current process of globalization exacerbates failures in international capital markets and impinges upon capital flows and the pace and order of financial liberalization in emerging economies, increasing therefore uncertainty and rendering large domestic vulnerabilities. It also highlights how financial globalization was related to the East Asian crises. The main conclusion is that intermediate non-conventional fundamentals, shifts in private agents' expectations and financial globalization were arguably the main factors of the East Asian crisis. Therefore, in order to prevent future financial crises, governments in emerging economies should try to exit crises zones through improving their fundamentals, to proceed carefully with financial liberalization, to implement some kind of capital controls and to urge for the establishment of a new global financial architecture.

Comparison between the financial structure of SMES and that of large enterprises (LES) using the BACH database.

This study examines the financial structures and the performances of small and medium-sized enterprises (SMEs) as opposed to large enterprises (LEs) on the basis of the BACH database, which is the most advanced publicly available database for comparisons in this field. It covers the period 1990-1996 and concerns 9 countries: Austria, Belgium, France, Germany, Italy, Portugal, Spain, Japan and the United States. It deals with manufacturing only since this industry provides the best-quality data.SMES, LES, BACH Database, capitcal structures, financial structure and capital, profitability

A survey of announcement effects on foreign exchange returns

Researchers have long studied the reaction of foreign exchange returns to macroeconomic announcements in order to infer changes in policy reaction functions and foreign exchange micro­structure, including the speed of market reaction to news and how order flow helps impound public and private information into prices. These studies have often been disconnected, however; and this article critically reviews and evaluates the literature on announcement effects on foreign exchange returns.Foreign exchange