Renewable Energy in Practice. The Ashton Green Community Concept


Academic Paper, 2006

14 Pages, Grade: 2


Excerpt


Table of content

Table of content

Executive Summary

Introduction

The Ashton Green Community Concept

Solar Hot Water

Photovoltaic

Wind

Biomass CHP

Geothermal Heat Sources

Integrated approach for Ashton Green

Summary

References

Executive Summary

Being on the global agenda C02 reduction influences a vast amount of policy areas. Brought down to national and local levels renewable energies have great potentials to reduce carbon emissions. An example of a renewable energy approach is the Ashton Green Project in Leicester, UK. While planning a sustainable community the energy demand is planned to be met entirely by renewable energy generation.

Three concepts are supposed. Biomass CHP and solar hot water are amended by PV-cells and/or wind turbines. The great challenge in Ashton Green is to meet the staggering domestic energy demand. The cooperation with an adjacent industrial estate is valued as an option. However, as geothermal energy is not considered at all, a new concept including biomass CHP, wind turbines and a geothermal heat pump is introduced.

All adequate renewable energy options are described briefly.

Introduction

Climate is predicted to change on a large scale in the next decades. The change is induced by the emission of greenhouse gases (GHG), of which carbon dioxide (C02) is regarded to be the most driving one. C02 is amongst others emitted by fossil fuel combustion for electricity generation.

Global policies are seriously addressing the C02 emission reduction issue since 1992 when the United Nations Framework Convention on Climate Change (UNFCCC) was produced. The following Kyoto Protocol in 1997 introduced for the first time legally binding emission reduction targets designated to the year 2012 for its participating industrialised countries.

A major emission reduction potential is seen in increasing energy efficiency. Reducing the demand for energy decreases consumption and consequently carbon emissions.

Moreover emission reduction can be achieved by altering the supply of energy from its current fossil fuel driven system to a system fuelled by renewable energy resources.

Energies that can be utilised continuously and sustainably are denoted renewable energies and water, wind, solar, wave, tide and biomass (DTI, 2003) are some representatives of renewable energy sources.

Besides the emission reduction argument renewable energies furthermore are thought to replace fossil fuels as these will not last indefinitely. Oil, gas and coal resources are going to be exploited or their exploration is going to become uneconomical on the long term scale. Facing these two challenges, namely emission reduction and security of long term supply, renewable energies are supported and brought forward on all scales of politics. The European Union ambitiously committed its EU-15 countries to averagely generate 22% of its electricity from renewable energy resources by 2010. The United Kingdom (UK) established with its energy white paper labelled “Our energy future - creating a low carbon economy” (DTI, 2003) the target to supply 10% of its electricity requirements by renewable energies. The doubling is aspired by 2020.

To support renewable energies and to strive for the realisation of the targets, the UK introduced some legislations, including the Renewable Obligation, which urges suppliers to obtain an increasing amount of electricity from renewables, and furthermore the renewable energy exclusion from the Climate Change Levy which normally is raised on industrial electricity consumption.

Moreover planning instruments, such as the Planning Policy Statement 22 (PPS22; yore PPG22), are “intended to encourage the appropriate development of ... renewable energy schemes” (ODPM, 2004).

In order to “translate the national targets into developments on the ground” (LUC, 2001) a capacity assessment for different renewable energy resources is vital. This was conducted and published for the East Midlands in England in 2001.

A project that aims at an integrated and sustainable energy service approach is represented by the Ashton Green community planned in and by Leicester, UK. This project in the East Midlands is the item of this report and the energy options of Ashton Green are introduced and evaluated.

The Ashton Green Community Concept

The new 100ha development is planned as an extension of Leicester City. Leicester City Council is the owner of the area. It is design to accommodate about 3,500 houses, with additional shops and community facilities. A high quality concept is suggested for this project in terms of design and site layout. This includes sustainable objectives, such as energy efficiency and the implementation of renewable energy options.

The vision is to supply the entire energy demand with heat and electricity generated from renewable resources. To assess potentials and feasibilities Leicester City Council asked the Institute for Energy and Sustainable Development (IESD) to produce “An Energy Strategy for Ashton Green” which was completed by Ajiboye et al. in 2001.

The following describes renewable energy options to then appraise the integrated approach with is suggested for Ashton Green by Ajiboye et al. (2001).

Solar Hot Water

Solar Hot Waster (SHW) is an active solar technology that does not produce energy directly but by supplying hot water to buildings it decreases the requirement of other energy sources, such as electricity, gas or oil.

One advantage of SHW technology is that it operates effectively even when no direct sunlight is available and therefore the overall efficiency of these devices are increased. Other factors, including geographical location, orientation and the device’s installation angle, have to be considered carefully as they influence the systems performance.

The collecting devices are mainly represented by two types of collectors. (A) Pipes are mounted to a flat plate when using a flat plate collector. The solar radiation is absorbed by the plate and the generated heat is drawn off by a fluid that distributes the energy to heating or storing devices. (B) The technology of evacuated tubes provides a more efficient system to utilise the energy supplied by the sun. As the absorbing and the first heat transfer take place in an evacuated tube heat loss is reduced by both reduced convective heat loss and better insulation. Single tubes are combined to bigger arrays and the heat of each tube is transferred to a second heat carrying fluid.

The technology of SHW is “well proven”, failures rare and maintenance inexpensive (LUC, 2001). Although there are seen great lacks in awareness and skilled installers the LUC predicts a great potential of these technology in the East Midland region (2001).

The Solar Hot Water technology is a basic element of the sustainable energy approach of Ashton Green in Leicester. The final report “An Energy Strategy for Ashton Green” (Ajiboye et al., 2001) for this development envisions the equipment of every single house with a set of solar hot water collectors. 65% of the energy requirement to heat the water is thought to be provided by the SHW devices. The great opportunity of Ashton Green is the early implementation of this technology into the planning process. Consequently the technology can be applied more effectively and with lower capital costs.

However, it is recognized that the SHW system works not as efficiently in winters as it does in summers (Ajiboye, 2001). Solar radiation is less in winter times. This is likely to cause seasonal peak demands in winter periods for other options, as the demand for heating already is greater and at the same time the energy utilised from the sun by the SHW arrays decreases in these times. This system incorporates an undesirable discontinuity and a more reliable and constant supply of space heating and warm water supply might be established. Although the maintenance effort for a single device is reported to be low (LUC, 2001) the installation of approximately 3,500 systems puts a great working load on the energy service company. Furthermore installing 3,500 single systems in a confined area might be not the most efficient solution as a lot of equipment is needed.

Finally the Solar Hot Water approach for the Ashton Green offers on the one hand an opportunity to decrease other energies’ usage but on the other hand is not a constant source of energy.

Photovoltaic

The energy provided by the sun can be transformed into electric energy by photovoltaic (PV) technology. With the help of the photons provided by sunlight electrons are transferred from the negative conductor to the positive conductor of the PV cell. Consequently current and voltage are generated which are not yet suitable for domestic application but can be conditioned with additional equipment so that it can be fed into the house’s grid. Approximately 20% of the system costs are incorporated in these conditioning equipments (DMU, 2004).

The cell production process can output three types of PV cells which all differ in their silicon structure. The most efficient one is denoted “thin film” cell or amorphous and transforms more than 25% of the energy provided by the sun into electricity under ideal conditions (DMU, 2004). Cells are combined to huge arrays for application.

Due to its increasing efficiency with increasing solar radiation PV arrays produce most of its output seasonally in summer times and daily at noon. Consequently energy is provided right in the time demand is low in domestic buildings. To store energy additional devices, such as batteries and hydrogen tanks, become necessary.

Overall a significant argument against PV technology is the cost factor. Only niche applications are cost effective but large scale domestic applications are still bounded to high costs (LUC, 2001). However, costs are predicted to come down with the while as efficiency and experiences increase (DMU, 2004). Great potentials are seen for PV cells in supplying remote areas with electricity as the cabling work to the main grid is not be necessary.

The energy strategy for Ashton Greens underlines the need of funding schemes that are necessary to implement PV technology. Otherwise a “widespread application” (Ajiboye et al., 2001) is not imaginable. Another problem of PV combined with the energy demand characteristic which is mainly coined by domestic requirements is that demand and supply does not correspond on the timescale. The system becomes more inefficient as storage capacity is necessary.

It is calculated that Ashton Green can supply 13% of its energy consumption by PV cells (Ajiboye et al., 2001) and again the opportunity of early incorporation into the buildings structure is given.

Additionally PV cells produce toxic waste in fabrication and disposal which needs “individual consideration” (Kazuhiko, 2001) and therefore the sustainable character of PV cells is arguable. Moreover Ajiboye et al. regard this technology not to be mature in England in 2001. Photovoltaic, recapitulating, is an electricity producing renewable source of energy which suffers from practical barriers, such as financing or disposal.

Wind

With the use of wind turbines energy can be drawn off the wind and transformed into electricity. To generate electricity huge blades are exposed to the wind. Starting to turn, the blades rotate around a hub which is connected to a gearbox and finally to a generator. Depending on wind speeds the output of wind turbines varies. Small domestic turbines generate capacities of a few hundred watts. Recent developments produced a five megawatt turbine of which the construction of a second plant is approved in Cuxhaven, Germany (RePower, 2005).

Data of suitable sites for such plants are available, for example, from the Department of Trade and Industry in London or from isovent maps. However, generalised data are only suitable for crude estimations of sites’ potential, as a lot of local impacts influence the feasibility of wind turbines, as well positively as negatively. Whether plant operates cost effectively or not is determined by the speed of the wind, which becomes the most important factor in site assessment.

The United Kingdom belongs to the countries with the highest potential of wind energy resource. However, the East Midland region is the least windy one in England (LUC, 2001). Although the “Viewpoints on sustainable Energy In The East Midlands” conducted by LUC in 2001 regards Leicester including the Ashton Green area to be a site with “little or no potential resource” based on the wind energy, the “An Energy Strategy for Ashton Green” report presents the findings of an wind energy company which indicate that wind speeds are “enough to invest in wind power” (Ajiboye et al., 2001).

[...]

Excerpt out of 14 pages

Details

Title
Renewable Energy in Practice. The Ashton Green Community Concept
Grade
2
Author
Year
2006
Pages
14
Catalog Number
V1030685
ISBN (eBook)
9783346460882
ISBN (Book)
9783346460899
Language
English
Keywords
Biomass, Solar, Wind, Tidal, Geothermal, Wave, Renewable Energy, Erneuerbare Energien, Sonnenenergie, Solarenergie, Solarthermie, Photovoltaik, Biomasse, Geothermie, Projekte, Beispiele, Best Practice
Quote paper
Bastian Görke (Author), 2006, Renewable Energy in Practice. The Ashton Green Community Concept, Munich, GRIN Verlag, https://www.grin.com/document/1030685

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