Energy from arable coppice — Some environmental impact considerations

The use of energy crops for electricity is set to undergo significant expansion on a global basis. As with any form of energy production, some impact on the environment is inevitable and it is important for the successful development of this technology that full account is taken of the environmental impacts of new projects.This paper focuses on some of the environmental issues that need to be addressed in arable coppice power generation.     

An investigation of the impacts of climate change on wave energy generation: The Wave Hub,Cornwall, UK

In this paper a generic methodology is presented that allows the impacts of climate change on wave energy generation from a wave energy converter (WEC) to be quantified. The methodology is illustrated by application to the Wave Hub site off the coast of Cornwall, UK. Control and future wave climates were derived using wind fields output from a set of climate change experiments. Control wave conditions were generated from wind data between 1961 and 2000. Future wave conditions were generated using two IPCC wind scenarios from 2061 to 2100, corresponding to intermediate and low greenhouse gas emissions (IPCC scenarios A1B and B1 respectively). The quantitative comparison between future scenarios and the control condition shows that the available wave power will increase by 2–3% in the A1B scenario. In contrast, the available wave power in the B1 scenario will decrease by 1–3%, suggesting, somewhat paradoxically, that efforts to reduce greenhouse gas emissions may reduce the wave energy resource. Meanwhile, the WEC energy will yield decrease by 2–3% in both A1B and B1 scenarios, which is mainly due to the relatively low efficiency of energy extraction from steeper waves by the specific WEC considered. Although those changes are relatively small compared to the natural variability, they may have significance when considered over the lifetime of a wave energy farm. Analysis of downtime under low and high thresholds suggests that the distribution of wave heights at the Wave Hub will have a wider spread due to the impacts of climate change, resulting in longer periods of generation loss. Conversely, the estimation of future changes in joint wave height-period distribution provides indications on how the response and power matrices of WECs could be modified in order to maintain or improve energy extraction in the future.     

The economics of a solar/diesel hybrid — A case study

The energy system, discussed, was a typical hybrid where a farmer decided that with the escalating cost of diesel as well as the logistics attached to the supply of diesel to his farm, adding a photovoltaic array to his diesel based system would make economic sense. A study of the energy consumption in comparison with the cost input for different scenarios was carried out.     

Climate change impacts of power generation from residual biomass

The European Union relies largely on bioenergy to achieve its climate and energy targets for 2020 and beyond.We assess, using Attributional Life Cycle Assessment (A-LCA), the climate change mitigation potential of three bioenergy power plants fuelled by residual biomass compared to a fossil system based on the European power generation mix. We study forest residues, cereal straws and cattle slurry.Our A-LCA methodology includes: i) supply chains and biogenic-CO₂ flows; ii) explicit treatment of time of emissions; iii) instantaneous and time-integrated climate metrics.Power generation from cereal straws and cattle slurry can provide significant global warming mitigation by 2100 compared to current European electricity mix in all of the conditions considered.The mitigation potential of forest residues depends on the decay rate considered. Power generation from forest logging residues is an effective mitigation solution compared to the current EU mix only in conditions of decay rates above 5.2% a⁻¹. Even with faster-decomposing feedstocks, bioenergy temporarily causes a STR(i) and STR(c) higher than the fossil system.The mitigation potential of bioenergy technologies is overestimated when biogenic-CO₂ flows are excluded. Results based solely on supply-chain emissions can only be interpreted as an estimation of the long-term (>100 years) mitigation potential of bioenergy systems interrupted at the end of the lifetime of the plant and whose carbon stock is allowed to accumulate back.Strategies for bioenergy deployment should take into account possible increases in global warming rate and possible temporary increases in temperature anomaly as well as of cumulative radiative forcing.     

Biomass resources assessment for power generation: A case study from Haryana state,India

India generates over 370 million tonnes of biomass every year. In addition to the direct harvesting from plants, biomass is also produced as a by product in many agro based industries such as rice husk from rice mill, saw dust from saw mill, bagasse from sugar mills etc. It has been estimated that about 17 GW of power can be generated through cogeneration, combustion and gasification routes from the available biomass. However, for this potential to be realized, data on production, present usage patterns, prices and seasonal fluctuation on biomass is essentially required. The present article is based on the resource assessment of non-plantation surplus biomass with a view to using it for energy production and its utilization in the state of Haryana, India.Being an agricultural state, Haryana has a huge potential of biomass availability in the form of crop residue and saw dust. In the agricultural sector, a total 24.697 Mt y^?1 of residue is generated, of which 71% is consumed in various domestic and commercial activities within the state. While in agro based industrial sector, a total of 646 kt y^?1 of sawdust is generated, of which only 6.65% is consumed in the state. Of the total generated biomass in the state, 45.51% is calculated as basic surplus, 37.48% as productive surplus and 34.10% as net surplus. The power generation potential from all these three categories of surplus biomass is 1.499 GW, 1.227 GW and 1.120 GW respectively.     

A study of an integrated land-fill and coppice power station

The use of methane from controlled landfill sites is well established as a method of generating usable energy from waste. However, the economics of this method are prejudiced by factors such as the restricted lifetime of the site and the initial capital costs in setting up the generating plant and the grid connection. Here we consider the benefits anticipated as a result of integrating wood fuels into the system and show that as well as the obvious shared capital costs and increased security of supply there is an increase in overall power output.     

Macroeconomic impacts of bioenergy production on surplus agricultural land—A case study of Argentina

This paper assesses the macroeconomic impacts in terms of GDP, trade balance and employment of large-scale bioenergy production on surplus agricultural land. An input–output model is developed with which the direct, indirect and induced macroeconomic impacts of bioenergy production and agricultural intensification, which is needed to make agricultural land become available for bioenergy production, are assessed following a scenario approach. The methodology is applied to a case study of Argentina. The results of this study reveal that large-scale pellet production in 2015 would directly increase GDP by 4%, imports by 10% and employment by 6% over the reference situation in 2001. When accounting for indirect and induced impacts, GDP increases by 18%, imports by 20% and employment by 26% compared to 2001. Agricultural intensification reduces but does not negate these positive impacts of bioenergy production. Accounting for agricultural intensification, the increase in GDP as a result of bioenergy production on surplus agricultural land would amount to 16%, 20% in imports and 16% in employment compared to 2001.     

Economic analysis of power generation from parabolic trough solar thermal plants for the Mediterranean region—A case study for the island of Cyprus

In this work a feasibility study is carried out in order to investigate whether the installation of a parabolic trough solar thermal technology for power generation in the Mediterranean region is economically feasible. The case study takes into account the available solar potential for Cyprus, as well as all available data concerning current renewable energy sources policy of the Cyprus Government, including the relevant feed-in tariff. In order to identify the least cost feasible option for the installation of the parabolic trough solar thermal plant a parametric cost–benefit analysis is carried out by varying parameters, such as, parabolic trough solar thermal plant capacity, parabolic trough solar thermal capital investment, operating hours, carbon dioxide emission trading system price, etc. For all above cases the electricity unit cost or benefit before tax, as well as after tax cash flow, net present value, internal rate of return and payback period are calculated. The results indicate that under certain conditions such projects can be profitable.     

The environmental and economic impacts of the UK climate change agreements

The climate change agreements (CCAs) in the UK were negotiated with a number of energy-intensive industrial sectors, and offered a reduction in the rate of the climate change levy (CCL), provided that negotiated energy efficiency targets were met. Through modelling and by analysis of the results of the first target period, this paper analyses the stringency of the targets, and the economic and environmental implications of the CCAs. It concludes that, while the targets in themselves were not stringent, and were in the main met well before the due date, the CCAs appear to have had an ‘awareness effect’ in stimulating energy savings. This has resulted in overall environmental benefits above those which would have derived from the imposition of a flat-rate tax with no rebate and no CCAs, and economic benefits for the sectors and companies with which CCAs were negotiated.     

The impact of large scale atmospheric circulation patterns on wind power generation and its potential predictability: A case study over the UK

Over recent years there has been an increasing deployment of renewable energy generation technologies, particularly large-scale wind farms. As wind farm deployment increases, it is vital to gain a good understanding of how the energy produced is affected by climate variations, over a wide range of time-scales, from short (hours to weeks) to long (months to decades) periods.By relating wind speed at specific sites in the UK to a large-scale climate pattern (the North Atlantic Oscillation or “NAO”), the power generated by a modelled wind turbine under three different NAO states is calculated. It was found that the wind conditions under these NAO states may yield a difference in the mean wind power output of up to 10%. A simple model is used to demonstrate that forecasts of future NAO states can potentially be used to improve month-ahead statistical forecasts of monthly-mean wind power generation.The results confirm that the NAO has a significant impact on the hourly-, daily- and monthly-mean power output distributions from the turbine with important implications for (a) the use of meteorological data (e.g. their relationship to large-scale climate patterns) in wind farm site assessment and, (b) the utilisation of seasonal-to-decadal climate forecasts to estimate future wind farm power output. This suggests that further research into the links between large-scale climate variability and wind power generation is both necessary and valuable.     

Hybrid solar–wind domestic power generating system—a case study

A techno-economic study to design a hybrid solar photo-voltaic-wind domestic power generating system for a site on the western coast of India is described. The system uses short-term electrical power storage using lead-acid batteries, and auxiliary power from the A.C. mains power supply.The optimum system would be able to supply 84.16% of the annual electrical energy requirement of the site. The annualized cost of this power in Rs./kwh works out to be several times the present price of government supplied electricity.     

Distributed power generation: A case study of small scale PV power plant in Greece

In recent years, energy systems have been undergoing a development trend characterised by privatisation of the most important energy sectors (electricity and natural gas) that has turned former monopolies into free-market competitors. Furthermore, community awareness of environmental impact caused by large conventional power plants is growing, together with a greater interest in distributed-generation (DG) technologies based upon renewable energy sources (RES) and cogeneration. In this context, renewable energy technologies are emerging as potentially strong competitors for more widespread use. Despite the remarkable progress attained over the past decades, RES have not yet been fully integrated into the power sector. Some RES-technologies have already achieved a significant market share. The industry is now quite mature, although far from having developed its global potential.     

Electricity generation from renewable energy sources in Germany — Potentials, costs and implementation strategies

The objective of this paper is to analyse the technical potentials and the costs of renewable energy sources for electricity generation in Germany and to define and discuss possible strategies for a largescale implementation of such renewable sources into the German power generation system. Four renewable options are discussed: hydropower, windtechnical and photovoltaic electricity generation and the possible electricity production of biomass. First the technical potentials are identified for the present and future reference years. Then the specific costs are analysed, as well for the present and the future. Finally an exemplary implementation strategy is defined and discussed leading to a total renewable electricity generation in the year 2020 of about 86 TWh/a which would be a share of about 19 % of the total present electrical energy demand.     

Analysis of wind power generation and prediction using ANN: A case study

Many developing nations, such as India have embarked upon wind energy programs for areas experiencing high average wind speeds throughout the year. One of the states in India that is actively pursuing wind power generation programs is Tamil Nadu. Within this state, Muppandal area is one of the identified regions where wind farm concentration is high. Wind energy engineers are interested in studies that aim at assessing the output of wind farms, for which, artificial intelligence techniques can be usefully adapted. The present paper attempts to apply this concept for assessment of the wind energy output of wind farms in Muppandal, Tamil Nadu (India). Field data are collected from seven wind farms at this site over a period of 3 years from April 2002 to March 2005 and used for the analysis and prediction of power generation from wind farms. The model has been developed with the help of neural network methodology. It involves three input variables—wind speed, relative humidity and generation hours and one output variable-energy output of wind farms. The modeling is done using MATLAB toolbox. The model accuracy is evaluated by comparing the simulated results with the actual measured values at the wind farms and is found to be in good agreement.     

The use of probability theory in fracture mechanics—A case study

A probabilistic approach to fracture mechanics in the form of a typical case study is described wherein the integrity of a high-pressure water pipeline is assessed. An analysis methodology is discussed incorporating the probability density functions of defect sizes, the statistics of defect occurrences and the statistical distribution of material properties. This method enables the analyst to supply a very simple assessment of safety, based on the probability of failure (a single number) which may be compared to accepted industrial standards (e.g. 10⁻⁶ for nuclear applications). It is argued that this method often offers the only way to scientifically and economically assess the integrity of fracture prone structures.     

The availability of daylight from tropical skies—a case study of Malaysia

In Malaysia, no long-term daylight data are measured. It was only recently that the need to measure the availability of daylight became urgent when the importance of daylighting in buildings was rediscovered. The hourly daylight availability has been simulated for the Malaysian sky using daylight modelling techniques based on empirical and measured solar irradiation and cloud cover data. This paper presents the techniques involved in producing exterior illuminance data. These data were then compared with measured illuminance at Shah Alam and Bangi, Malaysia. The global illuminance levels are generally high, with values exceeding 80,000 lux at noon during the months when solar irradiation is highest. Even during the months when the ground receives less solar irradiation, the peak illuminance can reach 60,000 lux. Applications and uses of such data are in daylighting design, both for visual and thermal comfort, task illuminance and energy-conscious design of buildings. Recommendations are made at the end of the paper on the various climatic data that are required to be measured for overall daylighting design applications.     

Geothermal energy potential for power generation in Turkey: A case study in Simav,Kutahya

Geothermal energy and the other renewable energy sources are becoming attractive solutions for clean and sustainable energy needs of Turkey. Geothermal energy is being used for electricity production and it has direct usage in Turkey, which is among the first five countries in the world for the geothermal direct usage applications. Although, Turkey is the second country to have the highest geothermal energy potential in Europe, the electricity production from geothermal energy is quite low. The main purpose of this study is to investigate the status of the geothermal energy for the electricity generation in Turkey. Currently, there is one geothermal power plant with an installed capacity of 20.4 MWe already operating in the Denizli–Kizildere geothermal field and another is under the construction in the Aydin–Germencik field.This study examines the potential and utilization of the existing geothermal energy resources in Kutahya–Simav region. The temperature of the geothermal fluid in the Simav–Eynal field is too high for the district heating system. Therefore, the possibility of electrical energy generation by a binary-cycle has been researched and the preliminary feasibility studies have been conducted in the field. For the environmental reasons, the working fluid used in this binary power plant has been chosen as HCFC-124. It has been concluded that the Kutahya–Simav geothermal power plant has the potential to produce an installed capacity of 2.9 MWe energy, and a minimum of 17,020 MWh/year electrical energy can be produced from this plant. As a conclusion, the pre-feasibility study indicates that the project is economically feasible and applicable.     

Availability analysis of combustion flue gases—A case study

The thermodynamic availability of combustion flue gases was analysed and modelled. The results were correlated in a polynomial of third degree with a high degree accuracy. It was found, for combustion processes, that the availability losses may reach up to 55% due to draft and dew point limitations in most fired heaters.     

Feasibility of large scale offshore wind power for Hong Kong — a preliminary study

This paper investigates the potential and the feasibility of offshore wind energy for Hong Kong. The 1998 wind data taken from an island were analysed. The wind resource yields an annual mean wind speed of 6.6 m/s and mean wind power density of 310 W/m². With commercially available 1.65 MW wind turbines placed on the whole of Hong Kong’s territorial waters, the maximum electricity generating potential from offshore wind is estimated to be 25 TWh which is about 72% of the total 1998 annual electricity consumption. However, potential is significantly reduced if other usages of the sea such as shipping are considered. A hypothetical offshore wind farm of 1038 MW capacity is then sited on the East-side waters. The extreme wind and wave climates, as well as the seasonal variation of wind power and demand are examined. The electricity generation costs are estimated and compared with the local retail tariff. Initial results indicate the wind farm is economically viable and technically feasible.