A field study of urban microclimates in London

This paper aims to address the characteristics of urban microclimates that affect the building energy performance and implementation of the renewable energy technologies. An experimental campaign was designed to investigate the microclimate parameters including air and surface temperature, direct and diffuse solar irradiation levels on both horizontal and vertical surfaces, wind speed and direction in a dense urban area in London. The outcomes of this research reveal that the climatic parameters are significantly influenced by the attributes of urban textures, which highlight the need for both providing the microclimatic information and using them in buildings design stages. This research provides a valuable set of microclimatic information for a dense urban area in London. According to the outcomes of this research, the feasibility study for implementation of renewable energy technologies and the thermal/ energy performance assessment of buildings need to be conducted using the microclimatic information rather than the meteorological weather data mostly collected from non-urban environments.

Using reanalysis data to quantify extreme wind power generation statistics : a 33 year case study in Great Britain

With a rapidly increasing fraction of electricity generation being sourced from wind, extreme wind power generation events such as prolonged periods of low (or high) generation and ramps in generation, are a growing concern for the efficient and secure operation of national power systems. As extreme events occur infrequently, long and reliable meteorological records are required to accurately estimate their characteristics. Recent publications have begun to investigate the use of global meteorological “reanalysis” data sets for power system applications, many of which focus on long-term average statistics such as monthly-mean generation. Here we demonstrate that reanalysis data can also be used to estimate the frequency of relatively short-lived extreme events (including ramping on sub-daily time scales). Verification against 328 surface observation stations across the United Kingdom suggests that near-surface wind variability over spatiotemporal scales greater than around 300 km and 6 h can be faithfully reproduced using reanalysis, with no need for costly dynamical downscaling. A case study is presented in which a state-of-the-art, 33 year reanalysis data set (MERRA, from NASA-GMAO), is used to construct an hourly time series of nationally-aggregated wind power generation in Great Britain (GB), assuming a fixed, modern distribution of wind farms. The resultant generation estimates are highly correlated with recorded data from National Grid in the recent period, both for instantaneous hourly values and for variability over time intervals greater than around 6 h. This 33 year time series is then used to quantify the frequency with which different extreme GB-wide wind power generation events occur, as well as their seasonal and inter-annual variability. Several novel insights into the nature of extreme wind power generation events are described, including (i) that the number of prolonged low or high generation events is well approximated by a Poission-like random process, and (ii) whilst in general there is large seasonal variability, the magnitude of the most extreme ramps is similar in both summer and winter. An up-to-date version of the GB case study data as well as the underlying model are freely available for download from our website: http://www.met.reading.ac.uk/~energymet/data/Cannon2014/.

The importance of accurate wind resource assessment for evaluating the economic viability of small wind turbines

The techno-economic performance of a small wind turbine is very sensitive to the available wind resource. However, due to financial and practical constraints installers rely on low resolution wind speed databases to assess a potential site. This study investigates whether the two site assessment tools currently used in the UK, NOABL or the Energy Saving Trust wind speed estimator, are accurate enough to estimate the techno-economic performance of a small wind turbine. Both the tools tend to overestimate the wind speed, with a mean error of 23% and 18% for the NOABL and Energy Saving Trust tool respectively. A techno-economic assessment of 33 small wind turbines at each site has shown that these errors can have a significant impact on the estimated load factor of an installation. Consequently, site/turbine combinations which are not economically viable can be predicted to be viable. Furthermore, both models tend to underestimate the wind resource at relatively high wind speed sites, this can lead to missed opportunities as economically viable turbine/site combinations are predicted to be non-viable. These results show that a better understanding of the local wind resource is a required to make small wind turbines a viable technology in the UK.

Investigating preferences for dynamic electricity tariffs: the effect of environmental and system benefit disclosure

Dynamic electricity pricing can produce efficiency gains in the electricity sector and help achieve energy policy goals such as increasing electric system reliability and supporting renewable energy deployment. Retail electric companies can offer dynamic pricing to residential electricity customers via smart meter-enabled tariffs that proxy the cost to procure electricity on the wholesale market. Current investments in the smart metering necessary to implement dynamic tariffs show policy makers’ resolve for enabling responsive demand and realizing its benefits. However, despite these benefits and the potential bill savings these tariffs can offer, adoption among residential customers remains at low levels. Using a choice experiment approach, this paper seeks to determine whether disclosing the environmental and system benefits of dynamic tariffs to residential customers can increase adoption. Although sampling and design issues preclude wide generalization, we found that our environmentally conscious respondents reduced their required discount to switch to dynamic tariffs around 10% in response to higher awareness of environmental and system benefits. The perception that shifting usage is easy to do also had a significant impact, indicating the potential importance of enabling technology. Perhaps the targeted communication strategy employed by this study is one way to increase adoption and achieve policy goals.

Assessing the benefits of domestic hot fill washing appliances

Washing machine and dishwasher appliance use accounts for approximately 10% of electricity demand in EU households. The majority of this demand is due to the operation of electric heating elements inside appliances. This paper investigates the potential benefits that can be realised by adding a hot fill connection to washing appliances, with respect to carbon emissions, demand side management and renewable energy integration. Initial laboratory testing of new hot and cold fill appliances has resulted in modifications to optimise hot fill intake, and a novel numerical model presents a method of characterising appliance electricity use in different configurations. In order to validate model findings and test the use of new hot fill appliances in situ, a pilot study has recorded appliances’ resource consumption at one-minute resolution in fourteen households. The addition of hot fill reduced the total dishwasher and washing machine electricity consumption by 38% and 67% respectively. Depending on how hot water is supplied to appliances it is estimated that hot fill use results in an annual household carbon saving of up to 147 kgCO2. Further to direct electricity reduction, hot fill appliances can offer a method of time shifting demand away from peak periods without inconveniencing occupants’ lifestyles.

Economic valuation of an offshore wind farm in Greece: the role of individual’s base-state influences and beliefs in the value formation process

The increased concern for the impacts of climate change on the environment, along with the growing industry of renewable energy sources, and especially wind power, has made the valuation of environmental services and goods of great significance. Offshore wind energy is being exploited exponentially and its importance for renewable energy generation is increasing. We apply a double-bound dichotomous Contingent Valuation Method analysis in order to both a) estimating the Willingness to Pay (WTP) of Greek residents for green electricity produced by offshore wind farm located between the islands of Tinos and Andros and b) identifying factors behind respondents’ WTP including individual’s behaviour toward environment and individual’s views on climate change and renewable energy. A total of 141 respondents participated in the questionnaire. Results show that the respondents are willing to pay on average 20€ every two months through their electricity bill in return for carbon-free electricity and water saving from the wind farm. Respondents’ environmental consciousness and their perception towards climate change and renewable energy have a positive effect on their WTP.

The role of subsidy in ensuring the sustainability of small-scale anaerobic digesters in Odisha, India

Small-scale anaerobic digester installation has been a development objective of the Indian government to provide rural households clean fuel. Anaerobic digester installation is heavily subsidised. Depending on caste, the rate of subsidy offered for the smallest system available (1m3) varies between 32.35% and 41.18% of the total installation price. Yet, there are gaps in knowledge regarding the usefulness of such subsidies from a sustainability perspective. A cost-benefit analysis was conducted to evaluate the circumstances required for digester sustainability. The analysis used household data collected from 115 cattle owning households in Odisha, India to evaluate profitability at three levels of subsidy (none, General caste subsidy, and Schedule Caste/Schedule Tribe subsidy). Additional analyses considered the effect of; taking a loan, replacing electric lighting with biogas lighting, and the wealth level of the household. The results indicated that access to subsidy improved profitability. Yet, profitability could be achieved without the use of subsidy. The level of benefit accrued by households was similar independent of wealth. However, the provision of subsidy was essential for ensuring profitability for those households required to take a loan to meet the expense of installation. Such findings highlight the importance of subsidy as a means of including the poor.

Ratios of UV, PAR and NIR components to global solar radiation measured at Botucatu site in Brazil

The relationships between the four radiant fluxes are analyzed based on a 4 year data archive of hourly and daily global ultraviolet (I(UV)), photosynthetically active-PAR (I(PAR)), near infrared (I(NIR)) and broadband global solar radiation (I(G)) collected at Botucatu, Brazil. These data are used to establish both the fractions of spectral components to global solar radiation and the proposed linear regression models. Verification results indicated that the proposed regression models predict accurately the spectral radiant fluxes at least for the Brazilian environment. Finally, results obtained in this analysis agreed well with most published results in the literature. (c) 2010 Elsevier Ltd. All rights reserved.

A Genetic Algorithm for Solar Boat

Genetic algorithm has been widely used in different areas of optimization problems. Ithas been combined with renewable energy domain, photovoltaic system, in this thesis.To participate and win the solar boat race, a control program is needed and C++ hasbeen chosen for programming. To implement the program, the mathematic model hasbeen built. Besides, the approaches to calculate the boundaries related to conditionhave been explained. Afterward, the processing of the prediction and real time controlfunction are offered. The program has been simulated and the results proved thatgenetic algorithm is helpful to get the good results but it does not improve the resultstoo much since the particularity of the solar driven boat project such as the limitationof energy production

Facade integration of polymeric solar collectors

The present paper examines building integrated solar collectors with absorbers of polymeric materials. Efficiency measurements of façade-integrated collectors with non-selective black and spectrally selective coloured absorbers are carried out. The performance of the polymeric absorber was compared with solar glass and polycarbonate twin-wall sheets as collector cover. Simulations demonstrate a high solar fraction for a solar combisystem with façade collectors for a well-insulated house in a Nordic climate. Two examples of house concepts with façade collectors are presented which address a new type of customer than the solar enthusiasts with special interest in renewable energy

PV-Wind Hybrid Systems for Swedish Locations

PV-Wind-Hybrid systems for stand-alone applications have the potential to be more cost efficient compared to PV-alone systems. The two energy sources can, to some extent, compensate each others minima. The combination of solar and wind should be especially favorable for locations at high latitudes such as Sweden with a very uneven distribution of solar radiation during the year. In this article PV-Wind-Hybrid systems have been studied for 11 locations in Sweden. These systems supply the household electricity for single family houses. The aim was to evaluate the system costs, the cost of energy generated by the PV-Wind-Hybrid systems, the effect of the load size and to what extent the combination of these two energy sources can reduce the costs compared to a PV-alone system. The study has been performed with the simulation tool HOMER developed by the National Renewable Energy Laboratory (NREL) for techno-economical feasibility studies of hybrid systems. The results from HOMER show that the net present costs (NPC) for a hybrid system designed for an annual load of 6000 kWh with a capacity shortage of 10% will vary between $48,000 and $87,000. Sizing the system for a load of 1800 kWh/year will give a NPC of $17,000 for the best and $33,000 for the worst location. PV-Wind-Hybrid systems are for all locations more cost effective compared to PV-alone systems. Using a Hybrid system is reducing the NPC for Borlänge by 36% and for Lund by 64%. The cost per kWh electricity varies between $1.4 for the worst location and $0.9 for the best location if a PV-Wind-Hybrid system is used.

Borlänge och Falun Brundtland städer

Development of an infrastructure for Brundtland Renewable Energy Network - BREN är ettEuropean Commission Alterner Project med Contract no XVII/4. 1030/Z96-032.Projektet har sitt ursprung i UN rapporten “Our Common Future” 1989. Grundläggande för att nå de mål som rapporten föreslog var att förändra och minska användningen av energi. I Danmark tog man fram en handlingsplan för hur energiförbrukningen skulle kunna minskas “Energi 2000 - Handlingsplan för en bäredygtig udvikling”. De danska och schleswigholstenske energiministrarna överenskom att starta vars ett energisparprojekt i en mindre stad. Projektet kallades “Brundtlandby” och de två första var Toftlund i Sönderjylland och Bredstedt i Nordfriesland. Efter en kort tid anslöt sig ytterligare två tyska städer, Rheinsberg och Viernheim, samt Rajec i Slovakien. Mellan städerna formades ett nätverk för att utbyta information. Nätverket, Brundtland City Project, var inspirerande för de ingående städerna i det fortsatta arbetet med energisparåtgärder. Brundtland City Project presenterades på en internationell konferens “Cities and Energy” i Trondheim, Norge, december 1995. Projektet väckte intresse och det föreslogs att nätverket, som ett pilotprojekt, skulle utvecklas i norra Europa för att senare utökas med andra europeiska länder. En ledningsgrupp tillsattes medrepresentanter från de nordiska länderna.En ansökan sändes till European Commission, Alterner Program, och denna beviljades i juli 1996. Projektet indelades i (9 Activities. Aktivitet 1, var att sammanfatta erfarenheterna av Brundtland City Project i Toftlund, Danmark och Brundtland Cities Nätverket i Sovakien, Tyskland och Danmark. Den nordiska delen startar med Aktivitet 2, vilket var att engagera kommuner/städer i Finland, Norge och Sverige. Som samordnade för den svenska delen utsågs Solar Energy Research Center SERC vid Högskolan Dalarna. Projektet presenterades vid ett seminarium den 30 september för representanter för Borlänge och Falu kommuner. Den 10 december 1996 accepterade de två kommunerna inbjudan att ingå i det nordiska nätverket. Uppgiftslämnare i Borlänge kommun har varit Pelle Helje, Borlänge Energi och i Falu kommun Anders Goop, stadsbyggnadskontoret samt för underlag till Newsletter Jan Kaans, fastighetskontoret.Rapportering till Brundtland Center Danmark av arbetet i Borlänge och Falu kommuner har skett vid tre tillfällen, Aktiviteterna 2-5, 1997-12-16, Aktivitererna 6-7 inkluderande delar av aktiviterna 8-9, 1998-05-03 samt underlag till Newsletter, 1998-07-01. De nordiska rapporterna har sammanställts vid Brundtland Center Danmark för rapportering till European Commission. Gemensamt språk har varit engelska. Efter rapportering av aktiviterna 2 - 5 inbjöds till ett projektmöte och en studiedag vid Brundtland Center den 23 och 24 mars 1998. Det var första tillfället deltagarna i projektet strålade samman och nätverket tog därmed en mera konkret form. Man beslutade också att nästa projektmöte skulle hållas i Borlänge i augusti 1998 med Borlänge Energi och Solar Energy Research Center SERC som organisatörer. Beroende på att Brundtland Centre Danmark upplösts av ekonomiska skäl blev projektmötet i Borlänge inställt.Sammanställning av Final Report, October 1998, har utförts av Esbensen Consultants.Framtida utveckling av nätverketArbetet med Brundtland City Network avses fortsätta som ett “EU Thermie B-project” och nätverket kommer att utökas med fyra nya Brundtlandstäder från Österrike, Tyskland Italien och Storbritanien. Dessutom kommer samhället Putja i Estland att ingå i nätverket men detta financieras av EU-Phare programme.

Borlänge and Falun Brundtland cities

Development of an infrastructure for Brundtland Renewable Energy Network - BREN is a European Commission Alterner Project with Contract no XVII/4. 1030/Z96-032.The project has its origin in the UN-report “Our Common Future”, 1989. A change in and reduction of the use of energy was fundamental in order to reach the goals which the report proposed. Denmark decided on an action plan on how energy consumption could be reduced “Energi 2000 - Handlingsplan för en bäredygtig udvikling”. The ministries of energy in Denmark and Schleswig Holstein both agreed to start an energy saving project in a smaller town. The project was called “Brundtlandby” and the two first were Toftlund in South Jutland and Bredstedt in North Friesland. After a short period a further two German Cities, Rheinsberg and Viernheim, and Rajec in Slovakia joined the group. A network for the exchange of knowledge and experience between the cities was formed. The network, Brundtland City Project, inspired the participating cities in the continuing work with energy saving measures. The Brundtland City Project was presented at an international conference “Cities and Energy” in Trondheim, Norway,in December 1995. Great interest was shown in the project and it was decided that a network should be developed in northern European countries as a pilot project to be enlarged with other European countries later on. A steering committee was formed with representatives from the nordic countries.An application was sent to the European Commission, Alterner Program, and was approved in Juli 1996. The project was subdivided into nine activities. Activity 1, consisted of summarising the experiences of the Brundtland City Project in Toftlund, Denmark and the Brundtland Cities network in Slovakia, Germany and Denmark. The Scandinavian part started with Activity 2, to engage municipalities/cities in Finland, Norway and Sweden in the project. The Solar Energy Research Center, SERC, Högskolan Dalarna was appointed as co-ordinator for the Swedish part. The project was presented at a seminar on the 30th September for representatives from the municipalities of Borlänge and Falun. On the 10th of December 1996 the two municipalities accepted the invitation to join the Northern network. Pelle Helje, Borlänge Energi, has been informant for the municipality of Borlänge and Anders Goop, Department of Urban Planninginformant for the municipality of Falun with Jan Kaans, Estates department providing information to the basis for the Newsletter.Reports on the work in Borlänge and Falun municipalities have been made to Brundtland Center Denmark on three occasions; Activities 2-5, 16-12-1997, Activities 6-7, including parts of activities 8-9, 03-03-1998, and the basis for the Newsletter, 01-07-1998. The Nordic reports have been compiled at the Brundtland Center Denmark for submission to the European Commission. English has been the common language. After the report of activities 2 - 5 the participants wereinvited to a project meeting and a workshop at Brundtland Center the 23rd and 24th March 1998.This was the first occasion the participants in the project met and the network thus took a moreconcrete form. It also was decided that the next meeting should be in Borlänge in August 1998,with Borlänge Energi and Solar Energy Research Center SERC as organisers. As BrundtlandCentre Denmark was wound up for financial reasons, the project meeting in Borlänge wascancelled.Compilation of the Final Report was carried out by Esbensen Consultants in October 1998Future development of the networkIt is intended to continue the work with the Brundtland City Network as an “EU Thermie Bproject”and the network will be enlarged with the addition of four new Brundtland Cities from Austria, Germany, Italy and Great Britain. In addition the village of Putja in Estonia will join the network but this will be financed by the EU-Phare programme.

Vindkraft i Dalarna : Från acceptans och lokalisering till planering och eftertanke

This thesis examines prerequisites for wind power diffusion in a county in Sweden that quite recently was concidered to be of interest for electricty production from renewable energy sources. Three different municipalities: Falun, Mora and Orsa in the county of Dalarna are highlighted.  Their view on permitting processes of wind power installations are investigated. Other actors, such as exploiters and local citizens are also being analysed. This study shows that the local acceptance was very high when the first wind power parks were built, much thanks to local politicians and local citizens. For the politicians the wind power symbolised a key to a better green society, for the local citizens the wind power meant some economical advantages. The first wind power parks were localised to areas because of good wind conditions and social factors, especially from local communities. However, results from this study shows that the acceptance for wind power the last few years, in generel, has decreased.  The local authorities have also been conscious of some negative consequenses from already built wind power parks.  As a response they started to add planning tools to the permitting process.