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Abstract Despite generally having significant renewable energy potential, islands tend to depend on imported fossil fuels with volatile prices. This paper aims to provide technical inputs for reorganizing the energy planning for Ometepe Island. The result of the wind and solar resource assessments indicates wind power densities of 147 W/m2 and 178 W/m2 at elevations of 80 m and 120 m, respectively, and an irradiation level of 5.3 kWh/m2/day. The estimated wind LCOEs are significantly lower than current diesel plant operating prices. Photovoltaic systems will probably become cost-effective 15 years from now for all non-subsidized end customers. However, it would be necessary to store energy to phase out diesel generation, and analyses were conducted to determine the possibility of a pumped-storage hydro plant. The annual biogas potential was estimated as ∼550,000 Nm3, and in conjunction with electric stoves, it could be used to replace other fuels for cooking. Electric buses are an option for replacing the current diesel-run public buses, but advantageous financial conditions and reorganization of the bus schedules would be required. Also, a street lighting program was found to be cost-effective. The renewable energy transformation of the island might act as a role model for energy transition in Nicaragua. Highlights • A low-medium wind potential and a high-medium solar potential are found. • The possibility of a hydro-pumped storage plant in the island is shown. • The energy and economics aspects of a public electric mobility are analyzed. • LPG-wood/electric stoves-biogas for cooking are considered. • A street lighting retrofit is cost-effective and helps to integrate renewable sources. [ABSTRACT FROM AUTHOR]

Abstract While most of Colombia's power comes from large-scale hydroelectricity generation, it still depends on fossil-fuel-based technologies. Alternative cleaner energy sources have been largely neglected despite their abundance and the likely complementarities between different renewable resources. This limited mix of energy sources has made the system vulnerable to unpredictable and recurrent drought conditions (El Niño) occurring every 4–5 years. In the past, El Niño brought high energy costs and power supply losses. This paper proposes an optimisation model to study the insertion of renewable energy systems (RES) into the Colombian electricity sector. The model considers a cost-based generation competition between conventional technologies (hydro and thermal) and alternative RES (solar photovoltaic (PV) and wind). It aims at minimising system costs, CO 2 emissions, and the number of blackout events. The model is solved by following two procedures known as Implicit Stochastic Optimisation (ISO) and Robust Optimisation (RO), and the results indicate that alternative renewables should replace all fossil-fuel-based technologies for economic and environmental reasons. Solar PV seems particularly promising to expand system capacity, as it contributes to both the reduction of the overall system costs and to the ability of the system to cope with extreme dry weather conditions. Highlights • The optimal insertion of renewables in Colombia is considered. • Conventional technologies and renewables freely compete. • Implicit Stochastic Optimisation and Robust Optimisation are used. • Results indicate that renewables largely dominate capacity expansion. • Solar PV and wind power replace current gas and coal thermal plants. [ABSTRACT FROM AUTHOR]

Abstract This paper features a Multi-Objective Particle Swarm Optimization for a power plant integrated in a micro grid. The plant modeling is flexible and can be set up for a wide range of sources, storages and loads. The model contains 12 parameters representing the size of each component which are modeled with power dependent efficiencies. The optimization goals are to reduce the annualized cost of system and the imported energy without failing to supply the load. The study is carried out in two locations (Tilos and Ajaccio) to show the problem dependence on the meteorological conditions. As a result, a pattern stands out for each site with a preferred source and a plant configuration according to the energetic autonomy wanted. Highlights • A Multi-Objective Particle Swarm Optimization algorithm. • A 12-parameter flexible plant modeling (various energy sources, storages and grid connection options). • Annualized plant cost and imported energy (or LPSP) minimization. • Power-dependent efficiencies. [ABSTRACT FROM AUTHOR]

Abstract Biogas calorific value upgrading into biomethane or methane-rich gas is an attractive choice for renewable energy alternatives. Exploitation of methane-rich gas from landfill has gained increasing traction recently due to its fuel source diversification potential towards carbon neutrality and energy security. In this paper, methane enrichment process in a membrane plant from a biogas mixture containing methane, carbon dioxide, nitrogen, oxygen, hydrogen sulfide and water vapor was modeled and compared with the actual plant data. Results from this work reveal an interesting relationship between purity-recovery and the process operating conditions. The model was capable of simulating the methane enrichment effectively with merely 0.07% error in predicting methane purity and 0.52% error in predicting methane recovery. The model allows optimization of methane purity from 87.26% to 99.87% and methane recovery from 91.63 to 99.49% at permeate to feed ratio (stage cut) of 0.30, without the need for re-staging of the plant. Highlights • Biogas upgrading in a membrane plant was modeled and compared with actual plant setting. • Model predicts methane enrichment with less than 1% error without re-staging. • CH 4 purity and recovery optimization of 99.87% and 99.49%, respectively at 0.30 stage cut. [ABSTRACT FROM AUTHOR]

Abstract This paper proposes a multi-objective optimization (MOO) based optimal day-ahead scheduling of thermal and renewable (wind and solar photovoltaic) power generation problem considering the intermittent/uncertain nature of renewable energy sources, load demands and thermal generators. System operating cost (i.e., cost of thermal, wind, solar PV and battery powers), reliability and emission cost are considered to be optimized simultaneously. The uncertainties due to generator outages, wind, solar PV and load demand forecast errors are incorporated in the proposed optimization problem using Expected Unserved Energy (EUE) and Loss Of Load Probability (LOLP) reliability indices. In the proposed approach, the amount of spinning reserves (SRs) required are scheduled based on the desired level of system reliability. The proposed multi-objective optimization problem is solved using NSGA-II algorithm. Different case studies are performed considering two or three different objective functions that may be selected by the system operator (SO) based on his/her preference. The simulation results obtained on a sample test system validate the benefits of solving the hybrid power system scheduling problem as a transparent and realistic MOO problem considering the uncertainty. Highlights • Multi-objective optimal day-ahead scheduling problem considering uncertainty is proposed. • System operating cost, reliability and emission are optimized simultaneously. • Generator, wind, solar PV and load forecast uncertainties are incorporated using EUE and LOLP indices. • Amount of spinning reserves required are scheduled based on desired level of reliability. • Proposed multi-objective optimization problem is solved using NSGA-II algorithm. [ABSTRACT FROM AUTHOR]

Abstract The petroleum fuels need a constraining research for another energy source as the diminish of diesel fuels and causes of health problems. This paper studies the castor biodiesel as another source of fuel for already having CI engines with the application of new biodiesel which having new fuel properties. The study explains the utilization of castor biodiesel as another fuel for the diesel, and it may considerably weaken the exhalation of greenhouse gases as well as strengthen the castor seed production which gives employment to farmers on the city or town sides. The study reveals that the usability of castor biodiesel as another source of fuel reduces carbon monoxide to 9% correlated to diesel HC reduced by 8.8% also a considerable reduction in oxides of nitrogen. Here there was increased in SFC by 4% and the thermal efficiency reduced by 2.2%. But the environmental issues and the employment for farmers and increase their production of castor plant prefers the castor biodiesel is another source of fuel for the automobiles, cultivation and power production sectors. Highlights • Environmental defects caused by Fossil fuel. • Biodiesel Production method. • Produces the employment and protects the cultivating. • Performance and emission studies of diesel and biodiesel. • Characterization and test fuel blends. [ABSTRACT FROM AUTHOR]

Abstract Heat pumps (HP) represent an attractive option as a heat source, since they utilise "free" ambient heat. However, as they need to be driven by electric energy, their ecological efficiency depends not only on their performance, but also on the energy mix used for electricity generation. Effectiveness of HP can be improved by applying renewable energy sources (RES) providing electricity to drive the system. In order to properly assess such a system, it should be evaluated within a global balance boundary reaching the level of primary resources. The authors propose the use of thermo-ecological cost (TEC) indices for exergo-ecological assessment. TEC is defined as cumulative consumption of non-renewable exergy connected with the fabrication of a particular product. TEC also includes additional consumption of non-renewable natural resources which results from the necessity of compensating environmental losses caused by rejection of harmful substances to the environment. Within the paper, a HP system has been analysed from the ecological point of view. The system consists of a heat pump driven by electricity, and photovoltaic panels or wind turbines as a basic source of electricity. The balance of electricity demand for HP is complemented by electricity from grid. To evaluate this system, real environmental data on solar radiation, wind and ambient temperature deciding on heat demand have been taken into account. The authors present the ecological benefits resulting from supporting heat pumps by electricity generated in RES. It has been demonstrated by comparing results obtained within local and global balance boundaries, that the second approach should be consequently applied when systems based on a mix of renewable and non-renewable energy are analysed, since the first approach may lead to misleading conclusions. Highlights • Simulation of heat pump supported with renewable electricity. • Application of exergy analysis to determine ecological effects. • Thermo-ecological analysis. • Demonstration of system exergy approach to evaluate ecological effects. [ABSTRACT FROM AUTHOR]

Abstract China's power sector has become the largest contributor to China's carbon emissions because of its coal-dominated power structure. Replacing fossil fuels with renewable energy is an effective way to reduce carbon emissions and, therefore, a series of targets for renewable electricity generation have been put forward in national plans. However, how these targets will be reached is unclear. This paper uses a Long-range Energy Alternative Planning system (LEAP) model to explore the optimum development path of China's power sector from 2015 to 2050, taking into consideration the impacts of the renewable energy targets. Three scenarios are designed to examine the costs and benefits of developing renewable energy and improving the technologies for renewable power generation, comprising a base scenario, a renewable energy policy scenario and a technological progress scenario. The results show that the power generation cost would increase by at least 2.31 trillion RMB and that CO 2 emissions would be reduced by 35.8 billion tonnes during 2015–2050 if power generation follows current planning. Furthermore, every 1% increase in the capacity factors of renewable electricity would on average result in the cumulative CO 2 emissions decreased by 979 million tonnes and average CO 2 abatement cost decreased by 5.56 RMB/tCO 2 during 2015–2050. Based on this study, several policy implications are proposed for the development of power sector in China. Firstly, government may reconsider the current planning for gas-fired power and nuclear power to reach low-carbon electricity generation. Secondly, adjusting the carbon price can offset the additional cost of renewable electricity generation. Thirdly, promoting advanced technologies to match renewable electricity generation can obtain greater economic and environmental benefits. Finally, from the perspective of development potential, reducing the costs of solar power would be the emphasis at this stage. Highlights • Effects of renewable energy development plan in power sector are evaluated for China. • The optimal development path with minimum cost for the power sector are given. • National plans for renewable electricity can reduce 35.8 billion tonnes of CO 2 until 2050. • Average CO 2 abatement cost for promoting renewable power is 64.53 RMB/tCO 2 during 2015–2050. • Every 1% increase of the capacity factors of renewable power would decrease the average CO 2 abatement cost by 5.56 RMB. [ABSTRACT FROM AUTHOR]

Abstract Traditional support policies for green energy have greatly contributed to the rise in prosumer numbers. However, it is believed that they will soon start to exert negative impact on stakeholders and on the grid. Policy makers advise to phase out two of the most widely applied policies – net metering and feed-in tariff, in favor of support policies that scale better with rising renewable generation. This work quantifies the impact of these traditional policies in future "what-if" scenarios and confirms the need for their replacement. Based on simulations with real data, we compare net metering and feed-in tariff to four state-of-the-art market-based mechanisms, which involve auction, negotiation and bitcoin-like currency. The paper examines the extent to which each of these mechanisms motivates not only green energy production but also its consumption. The properties and characteristics of the above mechanisms are evaluated from the perspective of key stakeholders in the low voltage grid – prosumers, consumers and energy providers. The outcome of this study sheds light on current and future issues that are relevant for policy makers in the evolving landscape of the smart grid. Highlights • Six support policies are evaluated in scenarios with various numbers of prosumers. • "What-if" scenarios are studied through multi-agent simulations with real data. • Net metering and feed-in tariff will cause issues in the immediate future. • Market-based support policies are a better fit when prosumer numbers rise. • Each policy offers different trade-offs between profits and costs for stakeholders. [ABSTRACT FROM AUTHOR]

Abstract Wind turbines are among the most popular sources of renewable energy. The energy available from wind varies widely because wind energy is highly dependent on continually fluctuating weather related parameters such as wind speed and wind direction. Wind farms have difficulties with system scheduling and energy dispatching because the availability of wind power is not known in advance. Therefore, the growth of wind power penetration in the emerging power system has made a precise wind forecasting method indispensable for system operators to include wind power generation in unit commitment and economic scheduling. This paper proposes two methods for wind speed and direction forecasting based on the nonlinear relations between the internal states of echo state networks. The methods decrease the number of internal states, and reduce the computational load compared to classical ESNs with fixed sizes and topologies by reducing the orders of the weight matrices. The design is simple with high learning capability and prediction accuracy, and does not require extensive training, parameter tuning, or complex optimization. The methods are tested with wind speed and direction data provided by the Nevada department of transportation (NDOT) roadway weather stations in the Reno, NV area. To demonstrate the efficiency of the proposed methods, they are compared with classical echo state networks (ESN) and with adaptive neuro-fuzzy inference system (ANFIS). The results of the new methods compare favorably with both ESN and ANFIS. Highlights • A reservoir including linear internal states and readout containing units using nonlinear functions of the internal states. • High learning capability and forecasting accuracy without significant deterioration with time. • Fewer internal states and lower order weight matrices relative to ESN, which reduces the computational load considerably. • A simple design, far less computation, and do not require extensive training, parameter tuning, or complex optimization. • Significantly lower error values than those of ANFIS and ESN for different wind profiles. [ABSTRACT FROM AUTHOR]

Abstract Power-to-Gas (P2G) is a technology that converts electricity to gas and is termed gaseous fuel from non-biological origin. It has been mooted as a means of utilising low-cost or otherwise curtailed electricity to produce an advanced transport fuel, whilst facilitating intermittent renewable electricity through grid balancing measures and decentralised storage of electricity. This paper investigates the interaction of a 10MW e P2G facility with an island electricity grid with limited interconnection, through modelling electricity purchase. Three models are tested; 2016 at 25% renewable electricity penetration and 2030 at both 40% and 60% penetration levels. The relationships between electricity bid price, average cost of electricity and run hours were established whilst the levelised cost of energy (LCOE) was evaluated for the gaseous fuel produced. Bidding for electricity above the average marginal cost of generation in the system (€35–50/MW e h) was found to minimise the LCOE in all three scenarios. The frequency of low-cost and high-costs hours, analogous to balancing issues, increased with increasing shares of variable renewable electricity generation. However, basing P2G systems on low-cost (less than €10/MW e h) hours alone (999 h in 2030 at 60% renewable penetration) is not the path to financial optimisation; it is preferential to increase the run hours to a level that amortises the capital expenditure. Highlights • The viability of P2G depends on the electricity market in which it operates. • Low bid prices allow for lower run hours producing less gas at a higher LCOE. • Increased capacity factor due to higher bid price leads to a more economical system. • Bidding above the average marginal cost of generation minimises the LCOE. • Solely consuming cheap or otherwise curtailed energy is not economically viable. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates different criteria for the design of multi-unit renewable energy (RES) auctions in small markets. The multi-technology RES auctions which are to be implemented in Denmark in 2018 serve as an exemplary case for the assessment. Focus of the analysis is how setting the auction schedule and the auctioned volume per round impacts the auction outcomes, accounting for the particular challenges of small markets. Agent-based modelling of the Danish auctions scheme demonstrates that the Danish RES market provides sufficient competition to auction higher volumes and follow more ambitious expansion goals. Furthermore, with a fixed budget, it is more effective in terms of deployment achieved, to hold fewer auctions with a larger volume. A flexibility mechanism that allows up to 50% of the auction volume to be shifted between auction rounds to accommodate potential large-scale marginal bidders, proves to be a useful tool to increase deployment rates, without negatively affecting bid prices. Furthermore it was shown that at current cost levels, only onshore bidders would be awarded in the envisaged multi-technology scheme. Also, large-scale and multi-project bidders are likely to be most cost competitive - indicating that further measures to maintain diversity could be useful. Highlights • Volume and frequency have to be carefully balanced for RES auctions in small markets. • A too small volume per round can deter especially large scale bidders and lower deployment. • A flexible auction volume is suitable to maximise deployment rates. • Further measures to avoid concentration in the long run are advised in Denmark. • Currently, onshore wind and solar PV are not cost competitive in joint auctions in Denmark. [ABSTRACT FROM AUTHOR]

Abstract In India, utility-scale power plants face problems like, availability of larger land, Transmission & Distribution losses (T&D), Aggregate Technical & Commercial losses (AT&C) and availability of the grid because of which around 240 million of people do not have access to electricity. Increasing installed capacity of fossil-based power plants to meet the power requirement will increase the greenhouse gas emissions, our dependency on fossil fuels, adverse environmental and social impacts. Decentralized solar rooftop PV system, because of its proven technology and environmental benefits, will overcome these factors in a sustainable way. The growth and development of solar rooftop PV, as per the current status, are of substandard level despite the fact that the Government of India has set a target of installing 40 GW of decentralized solar rooftop PV up-to 2022. Therefore, this paper highlights the solar power policies adopted for the decentralized solar rooftop PV segment along with various business models adopted and current status in India. The author has also analyzed various factors which motivate the end consumer to invest in solar rooftop PV. At the end, the author has summarized some key barriers to the growth and development of the solar rooftop PV segment in India. Highlights • Policy & regulations for solar rooftop sector in India. • Motivational factors for investing in the decentralized solar rooftop PV. • Business models for the growth of the solar rooftop PV sector. • Current status and key barriers of the solar rooftop PV sector. [ABSTRACT FROM AUTHOR]

Abstract Nowadays, renewable energy resources are increasingly used to supply electrical loads in micro grids, which these units should be scheduled coordinately. In this paper a stochastic model for coordinated scheduling of renewable and thermal units is proposed. Understudied units consists of fuel cell units with proton exchange membrane which generate heat and power simultaneously (PEMFC-CHP), wind and photovoltaic units. Moreover, the strategy of storing hydrogen is also considered for PEMFC-CHP units. Uncertainties of wind speed, solar radiation and market prices are considered using scenario based method. In the proposed stochastic programming problem, the strategy of storing hydrogen is considered by a mixed integer nonlinear programming (MINP) problem. The uncertainties of parameters convert the MINP problem to a stochastic MINP one. Moreover, optimal coordinated scheduling of renewable energy resources and thermal units in micro-grids improve the value of the objective function. To solve this problem, Modified Teaching-Learning-Based Optimization (MTLBO) algorithm is used and its performance is evaluated on a modified 33 bus distribution network. Simulation results represent that by using MTLBO method, the revenue increases more than 5 percentages in comparison with other optimization methods. In addition, considering CHP increases total profit of the system more than 15%. Highlights • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Hydrogen storage is considered for fuel cells. • Maximizing profits of micro grid is considered as objective function. • Considering the uncertainties of problem lead to profit increasing. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a simulation software initially developed by the author for educational purposes. The computational tool supports the design of power systems with large penetration by renewable energy sources. In particular, the problematic of power intermittency and its counter strategies are targeted. The main innovation of this simulation is the detailed transient analysis of the essential balance between power generation and consumption. Even so, the focus of the simulation tool is simple usage and interpretation of results, it successfully captures important characteristics of renewable power systems. The user selects the composition of a power system from conventional power plants, photovoltaic, windpower and tidal power. Following system definition, power generation and power demand are calculated based on local weather data. Energy storage can be added to balance mismatches between power demand and supply. Following the completion of a simulation system autonomy, carbon emission and electricity cost are evaluated to assess the performance of energy systems. Highlights • Holistic simulation of a renewable energy system. • Suitable for educational use due to high-level approach. • High adaptability to represent local conditions. • Identification of optimum power system compositions with renewable energy penetration. [ABSTRACT FROM AUTHOR]

Abstract: Energy from waste (EfW) has been identified as a source of ‘green electricity’ and has been used as a way of reducing greenhouse gas (GHG) emissions. Nevertheless, selecting an EfW strategy for municipal solid waste management is a challenging task not least because of the uncertainty involved in quantifying the potential economic and environmental impacts. This paper analyses five alternatives for managing the municipal solid waste of Sydney for their ‘green electricity’ and GHG savings potential under conditions of uncertainty. The impact of paper recycling on the ranking of alternatives was investigated, too. Our analysis shows that maximizing EfW generation potential does not result in greater GHG saving. A combination of food and green waste composting, recycling of metals, paper, glass and plastics while only landfilling waste fractions that are not recyclable may result in the best GHG savings. Furthermore, recycling of paper does not always achieve the best outcome; anaerobic digestion or composting may yield better results from an environmental and energy generation perspective. [Copyright &y& Elsevier]

Abstract: In recent years the decentralized rural electrification is becoming cost effective and convenient for areas where grid extension is very difficult. The present paper deals with the electrification of dense forest areas of Uttarakhand state in India by Integrated Renewable Energy Optimization Model (IREOM). The IREOM consists of locally available renewable energy resources such as Micro-Hydropower (MHP), biomass, biogas, wind and solar photovoltaic (SPV) systems have been used to meet electrical energy and cooking energy needs of a cluster of villages. The paper includes the selection of different system components, sizing and development of a general model to find out optimal combination of energy subsystems for the selected study area in order to minimize the cost of energy (COE) generation for a required reliability values. The sizing of different renewable energy system components has been carried out so that they are suitable for four different seasonal load profiles. The two reliability values are considered for the selection of optimum solution of year round application. The model developed for this purpose, has been found to be quite useful in optimizing the renewable energy system sizes that are available in market. The proposed model totally depends on the renewable energy systems and eliminates the use of conventional energy systems. [Copyright &y& Elsevier]

Abstract: This paper presents a refined description of the wave climate observed in a Portuguese location for marine energy projects. The data used in this case study were derived from 3-month in situ measurements carried out using three directional buoys that have been deployed simultaneously – yet independently (various buoy types and water depths) – on the Atlantic coast in the neighbourhood of Figueira da Foz. Two ways of reporting the statistics were adopted. In the first one, each recorded sea state was summarized as a set of global parameters accounting for energy, mean frequency and direction, spectral bandwidth and directional spreading related to the main ongoing wave field considered as unimodal. In the second one, each sea state has been decomposed into its own wave components – swells and wind-sea – which are characterised separately and individually by the same set of parameters as previously. Besides the adopted data processing techniques and the illustration of such thorough wave climate description modes, the paper also addresses the advantages and limits of each adopted parameterization in the frame of simultaneous and independent in situ wave measurements. [Copyright &y& Elsevier]

Abstract: The need for new sources of renewable energies and the rising price of fossil fuels have induced the hope that agricultural crops may be a source of renewable energy for the future. We question in this paper the best strategies to convert solar radiation into both energy and food. The intrinsic efficiency of the photosynthetic process is quite low (around 3%) while commercially available monocristalline solar photovoltaic (PV) panels have an average yield of 15%. Therefore huge arrays of solar panels are now envisaged. Solar plants using PV panels will therefore compete with agriculture for land. In this paper, we suggest that a combination of solar panels and food crops on the same land unit may maximise the land use. We suggest to call this an agrivoltaic system. We used Land Equivalent Ratios to compare conventional options (separation of agriculture and energy harvesting) and two agrivoltaic systems with different densities of PV panels. We modelled the light transmission at the crop level by an array of solar panels and used a crop model to predict the productivity of the partially shaded crops. These preliminary results indicate that agrivoltaic systems may be very efficient: a 35–73% increase of global land productivity was predicted for the two densities of PV panels. Facilitation mechanisms similar to those evidenced in agroforestry systems may explain the advantage of such mixed systems. New solar plants may therefore combine electricity production with food production, especially in countries where cropping land is scarce. There is a need to validate the hypotheses included in our models and provide a proof of the concept by monitoring prototypes of agrivoltaic systems. [Copyright &y& Elsevier]

Abstract: This paper presents a brief history of energy harvesting for low-power systems followed by a review of the state-of-the-art of energy harvesting techniques, power conversion, power management, and battery charging. The advances in energy harvesting from vibration, thermal, and RF sources are reviewed as well as power management techniques. Examples of discrete form implementation and integrated form implementation using microelectromechanical systems (MEMS) and CMOS microelectronic processes are also given. The comparison between the reviewed works concludes this paper. [Copyright &y& Elsevier]

Abstract: Building integrated photovoltaic (BIPV) systems are likely to become a dominant type of small-scale embedded generator (SSEG) on public low voltage (LV) distribution network in Malaysia due to the enormous amount of initiatives and efforts taken by the government to promote the use of BIPV. The growth of BIPV systems on LV distribution networks has the potential to alter the direction of power flow across the distribution networks, hence imposing several serious technical issues relating to power quality, distribution system efficiency and possible equipment overloading. Therefore, the utility companies need to study the following technical issues: (i) voltage regulation, (ii) voltage rise, (iii) voltage unbalance, (iv) network power losses, and (v) cable and transformer thermal limits. This paper describes research carried out to investigate and quantify the impacts of BIPV on LV networks with particular reference to developing countries striving to increase the utilisation of renewable energy. This paper presents and discusses the impacts of BIPV systems on two types of LV distribution network: a commercial LV distribution network and a residential LV distribution network in the state of Selangor, Malaysia. The results of these studies are compared with those from European networks to identify how the differences in the electrical network characteristics influence the allowable penetration of small-scale embedded generators. [Copyright &y& Elsevier]

Abstract: Over the past decade, several new approaches have emerged to renewable energy education that seek to address the needs of the 21st century for sustainable energy supply systems. In addition, unlike conventional architectural education which does not cover renewable energy issues in its curriculum, these days, renewable energy education has an identity of its own within the discipline of architecture. This paper will clarify academic obstacles that are impeding the development of sustainable architectural education. These obstacles include: ambiguous definitions of sustainable architecture, confusion over the meaning of sustainability, and lack of experts in this field. In the last part of this paper we compare academic architectural education in the field of renewable energy in two countries, Iran as a developing country in Asia and Australia as a developed country in Oceania. Lessons can be drawn from these case studies in regard to the obstacles and progress in the development of sustainable architecture education. [Copyright &y& Elsevier]

Abstract: Conventional hydropower systems that can take advantage of low head movement of water require substantial flow rates. However, these systems cannot harvest hydro energy from small sources of water with low head and low discharge, such as streams and creeks. The reciprocating hydropower system discussed in this paper can harvest power from such low flow discharge and low head sources. This paper presents a detailed proof-of-concept study of the hydropower model, including the underlining theoretical principles. Laboratory test results demonstrating the dependence of the lift force in the reciprocating small scale hydropower model as a function of flow velocity, size and rotational speed of the cylinder and comparison of the results with a previous study are also included. Two methods of power harvesting from the output displacement obtained from the hydropower system are discussed. The first employs electromagnetic induction principles and the other is based on a linear inertial generator using a conventional second order spring mass damper system. Finally, results from a finite element analysis of the hydropower system are presented and facilitate future design of the structural aspects of the housing for the reciprocating cylinder. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a new voltage dip generator that allows the shape of the time profile of the voltage generated to be configured. The use of this device as a tool to test the fault ride-through capability of wind turbines connected to the electricity grid can provide some remarkable benefits: First, this system offers the possibility of adapting the main features of the time–voltage profile generated (dip depth, dip duration, the ramp slope during the recovery process after clearing fault, etc.) to the specific requirements set forth by the grid operation codes, in accordance with different network electrical systems standards. Second, another remarkable ability of this system is to provide sinusoidal voltage and current wave forms during the overall testing process without the presence of harmonic components. This is made possible by the absence of electronic converters. Finally, the paper includes results and a discussion on the experimental data obtained with the use of a reduced size laboratory prototype that was constructed to validate the operating features of this new device. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a multi-agent (MAS) solution to energy management in a distributed hybrid renewable energy generation system. An introduction and analysis of the system, including its constituents, characteristics and excitation mechanism are presented first. Then, validation of the MAS solution demonstrates its feasibility in meeting all the requirements of the system. Five kinds of agents are proposed to present the Energy Management System. Each agent is built as a three layered architecture. A macro MAS is also presented in detail with a framework containing its overall optimisation function based on JADE (Java Agent Development). Discussion about the agents’ behaviours and a scenario case study on the MAS and its testing process are included in the paper. It indicates that the MAS is a suitable solution for the energy management of the distributed hybrid renewable energy generation system. [ABSTRACT FROM AUTHOR]

Abstract: CO2 emissions of the electricity supply sector in China account for about half of the total volume in the country. Thus, reducing CO2 emissions in China’s electricity supply sector will contribute significantly to the efforts of greenhouse gas (GHG) control in the country and the rest of the world. This paper introduces the development status of renewable energy and other main CO2 mitigation options in power generation in China and makes a preliminary prediction of the development of renewable energy in the country for future decades. Besides, based on the situation in China, the paper undertakes a comprehensive analysis of CO2 mitigation costs, mitigation potential, and fossil energy conversation capacity of renewable energy and other mitigation options, through which the influence of renewable energy on the mitigation strategy of China is analyzed. [ABSTRACT FROM AUTHOR]

Abstract: This paper details the design, deployment and operation of a power take off system for a 1:4 scale offshore Oscillating Water Column (OWC) Wave Energy Converter (WEC). Ocean energy device prototypes at this scale present a unique set of challenges in that the integration of prime movers and generators typically begins to take place at this particular development stage, which may also represent first deployment at sea.The presence of electrical equipment and rotating machinery in the offshore environment brings its own engineering and operational difficulties. Moreover, such devices are typically not grid connected, necessitating the development of custom power conversion and control equipment. The paper describes the design considerations, details of design, deployment experiences, operational experiences of such a system and concludes with recommendations for future projects in the area. [ABSTRACT FROM AUTHOR]

Abstract: In order to investigate the steady heat transfer characteristics of a porous media solar tower receiver developed in China, this paper applies the steady heat and mass transfer models of the porous media to solar receivers, chooses the preferable volume convection heat transfer coefficient model, solves these equations by using the numerical method, and analyzes the typical influences of the porosity, average particle diameter, air inlet velocity, and thickness on the temperature distribution. The following conclusions have been drawn: in the same position or relative position along the downstream, the bigger the average particle diameter is, the higher the solid matrix dimensionless temperature is, the higher the air dimensionless temperature is. The bigger the porosity is, the lower the solid matrix dimensionless temperature is, the bigger the porosity is, the higher the air dimensionless temperature is. The bigger the thickness is, the lower the solid matrix dimensionless temperature is, the higher the air dimensionless temperature is. In a certain depth, the bigger the air inlet velocity is, the higher the solid matrix dimensionless temperature is. After a certain depth, the bigger the air inlet velocity is, the lower the solid matrix dimensionless temperature is, and the bigger the air inlet velocity is, the higher the air dimensionless temperature is. The paper can provide a reference for this type of receiver design and reconstruction. [Copyright &y& Elsevier]

Abstract: Biodiesel is an alternative fuel for conventional diesel that is made from natural plant oils, animal fats, and waste cooking oils. This paper discusses the economics of producing biodiesel fuel from algae grown in open ponds. There is potential for large-scale production of biodiesel from algal farms on non-arable land; however, previous studies have failed to demonstrate an economically viable process that could be scalable to a commercialized industry. The problems include inconsistent and insufficient algal productivities, uncertain capital and operating costs, volatile market prices and unknown levels of government support. Although intensive work is being done on many technological issues, the economic studies and data are incomplete and out of date. This paper presents an updated financial analysis of the production and economic conditions that could have a profound effect on the success of this important alternative fuel production process. [Copyright &y& Elsevier]

Abstract: This paper deals with a DC-micro-grid with renewable energy. The proposed method is composed of a gearless wind power generation system, a battery, and DC loads in a DC distribution system. The battery helps to avoid the DC over-voltages by absorbing the power of the permanent magnet synchronous generator (PMSG) during line-fault. In addition, the control schemes presented in this paper including the maximum power point tracking (MPPT) control and a pitch angle control for the gearless wind turbine generator. By means of the proposed method, high-reliable power can be supplied to the DC distribution system during the line-fault and stable power supply from the PMSG can be achieved after line-fault clearing. The effectiveness of the proposed method is examined in a MATLAB/Simulink® environment. [Copyright &y& Elsevier]

World’s energy picture is still framed in a context characterised by extensive use of the natural gas. Luckily there are significant opportunities for increasing energy efficiency and fostering energy recovery in natural gas infrastructures. In particular integration with renewable energies is an asset to be exploited. This paper presents a novel configuration of the so-called natural gas pressure reduction stations equipped with sun-tracking parabolic trough solar collectors. In addition, the system is coupled with thermal energy storage. The energy and environmental performance of this new configuration is investigated with the support of a dynamic model implemented in Matlab-Simulink ® . Energy saving has been calculated for three European cities, namely Genoa, Naples, and Amsterdam, characterised by different latitudes and hence solar irradiations. The results revealed that, despite the technical and physical constraints, it is possible to achieve carbon-free operations in summer periods for southern locations. The proposed system configuration has shown to be a strategic retrofit intervention to pursue reducing carbon emissions linked to the gas distribution operations. [ABSTRACT FROM AUTHOR]

A wave energy converter (WEC) should be controlled in order to increase the average output power. In this paper, economic aspects of latching applied to a point absorbing WEC with a linear generator power take-off (PTO) are discussed. The capacity utilisation factor (CUF) is suggested to be used along with average absorbed power for control optimisation. Optimum and suboptimum latching controls are assessed for the WEC and compared with a constant damping PTO force control. The WEC performance is simulated using monochromatic waves for the wave conditions of the Wave Hub test site, UK. The linear wave theory is used in a hydro-mechanical two-body simulation model. It is shown that the latching controls possess considerable practical challenges significantly increasing the return of investment time periods. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to address the issue of the frequency deviations induced by the fluctuating power injected into the grid by doubly-fed induction generator based wind turbines in a weak or isolated power system that is based in a frequency dependent smoothing of the wind power. An algorithm that allows an improved maximum power point tracking curve shifting as a function of the blade pitch angle variation has been proposed, taking advantage of the combined effect of two frequency control strategies: one based on the use of the stored kinetic energy by means of the concept of virtual inertia, and the other, by limiting the captured wind power through blade pitch angle regulation. This algorithm has been devised to reduce the turbine deload requirements, and at the same time, to increase the available kinetic energy in the turbine. This results in a more effective fast-frequency response with a lower amount of non-dispatched wind energy. The effectiveness of the proposed method is assessed by considering a real wind profile in time-domain simulations. [ABSTRACT FROM AUTHOR]

The objective of this paper is to calculate the single diode model parameters ( A , R s , R sh , I L , and I 0 ) of photovoltaic modules in most straightforward way no using iterative techniques and an additional information of pre-measured/digitized current-voltage curves. For that purpose, a new method based on solely datasheet information is introduced. The novelty of this method is to use a dark saturation current as an initial parameter as calculating the single diode model parameters. The effectiveness of proposed was validated using current-voltage curves of five commercially available photovoltaic modules at standard test conditions. The current-voltage curves were simulated using the proposed method and compared with datasheet supplied current-voltage curves by means of a root means square error tool. It has been founded that the new method, which proposes a very simple calculation procedure to obtain the single diode model parameters, meets international standards as simulating current-voltage curves of photovoltaic modules. [ABSTRACT FROM AUTHOR]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

Abstract: Exergy analysis is a more powerful tool than mere energy analysis for showing the improvement potential of energy systems. Direct use of solar radiation instead of degrading other high quality energy resources found in nature is advantageous. Yet, due to physical inconsistencies present in the exergy analysis framework for assessing direct-solar systems commonly found in literature, high exergy losses arise in the conversion process of solar radiation in direct-solar systems. However, these losses are disregarded in indirect-solar systems. In this paper, contradictions and physical inconsistencies which result from including the conversion of solar radiation only for direct-solar systems are shown. An evaluation framework physically coherent for systems making direct and indirect use of solar radiation is derived and its physical correctness is thoroughly discussed. Results from case studies using the proposed framework are presented and compared with the conventional approach, enabling their direct comparison and better understanding of the benefits and correctness of the proposed method. The new method allows recognizing clearly the suitability of direct-solar systems, being appropriate for highlighting more sustainable energy supply systems. Although this paper focuses on building systems, the framework might be used for exergy analysis of direct-solar systems in the context of other energy uses. [Copyright &y& Elsevier]

Abstract: In this paper, an energy and exergy analysis is performed on four different wind power systems, including both horizontal and vertical axis wind turbines. Significant variability in turbine designs and operating parameters are encompassed through the selection of systems. In particular, two airfoils (NACA 63(2)-215 and FX 63-137) commonly used in horizontal axis wind turbines are compared with two vertical axis wind turbines (VAWTs). A Savonius design and Zephyr VAWT benefit from operational attributes in wind conditions that are unsuitable for airfoil type designs. This paper analyzes each system with respect to both the first and second laws of thermodynamics. The aerodynamic performance of each system is numerically analyzed by computational fluid dynamics software, FLUENT. A difference in first and second law efficiencies of between 50 and 53% is predicted for the airfoil systems, whereas 44–55% differences are predicted for the VAWT systems. Key design variables are analyzed and the predicted results are discussed. The exergetic efficiency of each wind turbine is studied for different geometries, design parameters and operating conditions. It is shown that the second law provides unique insight beyond a first law analysis, thereby providing a useful design tool for wind power development. [Copyright &y& Elsevier]

Abstract: In late 1990''s some microalgae were found to be capable of producing lipids from carbon dioxide via photosynthesis with thirty times the efficiency of plants in terms of the amount of oil produced per unit area of the land allocated. This process raised hope in the fight against environmental problems caused by carbon dioxide accumulation in the atmosphere. In the present paper, exergetic efficiency of the environment friendly algal biodiesel production process and renewability of the algae-biodiesel-carbon dioxide cycle are assessed. If any process is not feasible thermodynamically, it can never be used in the real world; however, thermodynamic feasibility does not imply the immediate use of the process either. If the limits offered in thermodynamic analysis cannot be attained immediately with the present technology, they may still be used to understand the area where new technology is needed. This paper points the direction for the development of new technology to decrease the carbon dioxide accumulation in the atmosphere. The renewability indicator is found to be positive, showing that the algae-biodiesel-carbon dioxide cycle is indeed renewable. Any increase in the lipid content of the algae will improve the efficiency of the process. Genetic engineering techniques may be helpful to improve this efficiency drastically. [Copyright &y& Elsevier]

Abstract: The People''s Republic of China foresees a target of 30 GW for installed wind power capacity by 2010 (2008: 12 GW). This paper reports on the technical and economic potentials of wind power, the recent development, existing obstacles, and related policies in China. The barriers to further commercialization of the wind power market are important and may deter the 100 GW capacity target of the Chinese government by 2020. The paper concludes that the diffusion of wind power in China is an important element for not only reducing global greenhouse gas emissions, but also for worldwide progress of wind power technology and needed economies of scale. [Copyright &y& Elsevier]

Abstract: In the competitive electricity market it becomes very much important to give special consideration for development of renewable energy sources (RESs) due to environmental and other social problems related with conventional generations. So this paper presents an optimal model of congestion management with special emphasis for promotion of RES in competitive electricity market. This paper presents a generalized optimal model of congestion management for deregulated power sector that dispatches the pool in combination with privately negotiated bilateral and multilateral contracts while maximizing social benefit. This model determines the locational marginal pricing (LMP) based on marginal cost theory. It also determines the size of non-firm transactions as well as pool demand and generations. Both firms as well as non-firm transactions are considered in this model. The proposed model has been applied to IEEE-30 bus test system with addition of some RES for analysis of the proposed model. The RES supplies its power to load either through the firm transaction or through power pool. The power from RES is not subjected to any curtailment in proposed model of congestion management. [Copyright &y& Elsevier]

Abstract: Environmental concerns have increasingly led to the installation of Renewable Energy Technologies (RETs) despite the fact that they are recognized as expensive. Innovative efforts within the area are beset with difficulties , and they are at risk of producing misdirected or insignificant improvements in terms of the cost effectiveness of total energy conversion systems. This paper investigates how RETs can be evaluated, in terms of economy and engineering solutions, by studying the fundamental physics of renewable energy sources and how it matches with the RETs. This match is described by the “Degree of Utilization”. The findings indicate that new innovations should focus on the possible number of full loading hours. RETs that are correctly matched to their energy source generate a higher amount of electric energy and have a higher potential of becoming more competitive. In cases where this aspect has been ignored, leading to relatively small degrees of utilization, it can be understood as an engineering mismatch between installed power, converted energy, and the fundamental physics of the renewable energy sources. Since there is a strong and possibly biased support for so-called mature RETs and already existing solutions, a clarification of how fundamental physical laws affect the cost of investments and payback of investments is needed. The present paper is part I out of II and it focuses on the difference between power and energy and the physics of different energy sources and their utilization. [Copyright &y& Elsevier]

Abstract: Renewable energy technology and in particular solar energy is being considered worldwide due to the fluctuations in oil prices, global warming and the growing demand for energy supply. This paper investigates the climate conditions available in the United Arab Emirates (UAE) in particular Abu Dhabi to implement Photovoltaic (PV) technology. Measured solar radiation was analyzed for five different geographical locations to ensure the suitability of this region. Hourly, daily and monthly global horizontal irradiation (GHI) were collected and processed. Statistical methods were used to evaluate the computed GHI and showed high values especially during the summer period. Moreover, clearness index was calculated to investigate the frequency of cloudy sky days and results have shown a high percentage of clear days during the year. This paper highlights a promising future for Abu Dhabi in the solar energy sector and in particular Photovoltaic (PV) technology. [Copyright &y& Elsevier]

Abstract: Wind energy is an important renewable energy source because of its reliability due to the maturity of the technology, good infrastructure and relative cost competitiveness. Rich wind resources and strong support in regulations by the Chinese government have enabled the wind power industry to grow at a fast speed and the primary market scale has been achieved, making it the second largest wind power market in the world. There has also been an increase in wind energy research in various regions in China during the last few years. As utility-size wind turbines increase in size, and correspondingly their initial capital investment cost, there is an increasing need to monitor the health of these structures. However, most of the research papers in China are about the manufacture and production, such as the simulation of the wind turbine generator system model, the systematic resonance and stability for the world turbine, the wind speed, wind power and pitch adjustment simulation model, and so on. Few papers focus on the structural health monitoring (SHM) techniques of the wind turbine. In this paper, we review the status of the current SHM techniques in wind turbine and analyze the problems of them in China. The aims of this paper are to let more scholars and experts know the status of the current SHM techniques and to do something for building a successful industry in China. [Copyright &y& Elsevier]

Abstract: Ocean thermal energy is a type of renewable energy. The phase change process of the thermal glider propelled by ocean thermal energy was numerically and experimentally investigated in this paper. The gliding process was analyzed and optimized while the glider was operating in the ocean thermocline near the equator. The results showed that the time of a cycle decreases by 30% and the gliding depth decreases by 40% after optimization. The gliding process was also analyzed when the PCMs were partly melted with the volumetric expansion rate at 50%, 60%, 70%, 80% and 90% of the total value. With the decreasing of the volumetric expansion rate, the depth and the duration of a cycle decrease significantly, but the output work does not decrease obviously. It is helpful to reduce the manufacturing cost and prolong the duration of the glider. In addition, it can improve the energy harvest efficiency from the ocean thermocline. The vehicle''s gliding process can be further investigated in different ocean thermoclines based on the numerical model presented in this paper, which can provide helpful information for optimal design of the thermal glider. [Copyright &y& Elsevier]

Abstract: Tidal current is considered to be one of the promising alternative green energy resources. Tidal current turbines are devices used for harnessing tidal current energy. The development of a standard for tidal current turbine design is a very important step in the commercialization of tidal current energy as the tidal current industry is growing rapidly, but no standard for tidal current turbines has been developed yet. In this paper, we present our recent efforts in the numerical simulation of the characteristics (e.g., power output, torque fluctuation, induced velocity, and acoustic emission) of tidal current turbines related to the development of the standard. The relationship between the characteristics and the parameters of an example turbine are extensively discussed and quantified. The findings of this paper are expected to be helpful in developing the standards for tidal current turbines in the near future. [Copyright &y& Elsevier]

Abstract: Distributed generation expansion planning (DGEP) has been frequently reported in the literature around the world. In this scope, renewable technologies which are considered as a kind of distributed generations are developing due to their environmental benefits. However, only a few renewable energies have proven to be competitive so far, while their economic viability is also limited to certain regions of the world. In this paper, an encouraging mechanism is proposed in favor of clean technologies in the planning process. This mechanism is defined based on a grant function of emission not polluted which is paid to DG owners to promote renewable and clean technologies. In the planning process, a multi-objective optimization algorithm is applied to produce a Pareto set of optimal planning schemes by taking into account different objective functions (cost and grant functions). The best planning scheme among the Pareto set is chosen based on a composite utility which are obtained through a Monte Carlo simulation of uncertain situations. Distributed generation technologies which are considered in this paper are conventional and renewable technologies, namely photovoltaic (PV), wind turbine (WT), fuel cell (FC), micro turbine (MT), gas turbine (GT), and reciprocal engine (RE). To assess the ability of the proposed method, a typical distribution system is used for expansion planning under two environmental scenarios. [Copyright &y& Elsevier]

Abstract: Senegal is one of the less developed countries in the world (position 158 in a list of 174 countries). 85% of its rural population does not have access to electricity and there''s no doubt that this is an important barrier for socio-economic development. In this context, the project Microgrids aims at contributing to solve this problem. This project is part of the Intelligent Energy – Europe Programme supported by the European Commission. Its objective is the promotion and dissemination of the use of micro-grids with high content of Renewable Energy Sources (RES) for the electrification of villages far away from the grid in Senegal. One of the results of the project was the analysis of rural electrification needs, which is described in another paper [Camblong H, Sarr J, Niang AT, Curea O, Alzola JA, Sylla EH, Santos M. Microgrids project, part 1: analysis of rural electrification with high content of renewable energy sources in Senegal. Renewable Energy, submitted for publication.]. This paper presents the design of an electrification kit based on the information provided by that analysis [Analyse des besoins locaux pour l''électrification de zones rurales au Sénégal. Technical report of Microgrids project; 2007. Available from: http://www.microgrids-eie.com.]. After identifying necessary previous conditions for the sustainability of any electrification project, a methodology is proposed for the design of the electrification kit. This methodology is applied to a typical village and results are extended to differently sized villages in the areas of Thies, Fatick and Kaolack. Economic considerations are also included to establish the relationship between electrification costs and paying capability of the communities. Now the Microgrids'' consortium hopes to set-up a new project to apply the designed kit on some rural non-electrified villages. [Copyright &y& Elsevier]

Abstract: Africa is the poorest continent in the world and this poverty is linked to the lack of access to energy of its population. A big part of inhabitants live in rural zones where the lack of energy and in particular of electricity is still more flagrant. The aim of the Micro-grids project was to promote the electrification of rural regions of Senegal by the installation of micro-grids with high content of renewable energies. This paper presents some results of this project. Surveys have been carried out in three regions of Senegal to study the needs of electrical energy of non-electrified rural villages'' households. These surveys have led to the estimation of electricity needs of the concerned households. The potential in renewable energies of the three regions has also been examined. It has been concluded that the solar energy potential is excellent while the wind energy potential can be interesting in some specific sites. The biomass could also be an efficient source if livestock farming was properly managed in the future. Moreover, many events have been carried out in the three regions to analyse the obstacles for the development of micro-grids in the Senegalese energy context, and to establish suitable solutions to overcome these obstacles. The results presented in this paper have been used to design a rural electrification kit which is described in another paper. Now the Micro-grids'' consortium hopes to set up a new project to apply the designed kit on some rural non-electrified villages. [Copyright &y& Elsevier]

Abstract: This paper presents the potential challenges of integrating wind farms into the future power systems in Taiwan. It first describes the developments of wind power in Taiwan and the basic criteria and general practices of connecting renewable energy resources to transmission and distribution systems at Taiwan Power Company. The paper then discusses current and future developments of power systems and wind farms in Taiwan and the possible system integrations of these potential wind farms. Finally, it identifies the major general and specific challenges of wind farm integration to the future power systems in Taiwan and concludes with suggested approaches to meet these challenges. [Copyright &y& Elsevier]

Abstract: The renewable energy industry is growing rapidly amidst rising concerns about oil depletion and climate change. Renewable energy is seen by many as part of the appropriate response to these concerns and some national Governments have put programs in place to support the wider use of sustainable energy systems. This has led to a rapid increase in demand for renewable energy specialists who are able to design, install and maintain such systems. Most engineers are not trained to use these renewable energy technologies and most are not aware of the principles of sustainability. There is therefore an urgent need to develop and implement new courses that prepare engineers, scientists and energy planners to work with renewables to produce sustainable energy generation systems. Renewable energy education is a relatively new field and previously it formed a minor part of traditional engineering courses. These days it has an identity of its own, with special techniques, standards and requirements which are not normally encountered in other disciplines. Attempts to add one or two units of study on renewables into traditional science and engineering degrees are unlikely to produce graduates with sufficient knowledge or understanding to use renewables effectively. Modern renewable energy education includes a study of the technology, resources, systems design, economics, industry structure and policies in an integrated package. This prepares the graduates to design sound systems from amongst the range of options available. There are more pitfalls in the use of renewables than there are in using the more mature conventional technologies and systems. Designers, installers and service personnel need to be particularly aware of the industry and the characteristics of the various firms and their technologies. Over the past decade several new approaches have emerged to renewable energy education that seek to address the needs of the 21st century for sustainable energy supply systems. This paper will describe the aims, philosophy, structure and outcomes of several of these initiatives. It includes courses in renewable energy science, renewable energy engineering, renewable energy policy and planning and renewable energy technician training. The paper will also describe some aspects of the training of researchers in cooperation with the renewable energy industry. [Copyright &y& Elsevier]