Overview of Concentrated Solar Power

CSP （concentrated solar power） has been viewed as the technology that if properly developed could lead to a large scale conversion of solar energy into electricity. CSP is a type of solar energy converter that is classified as thermal converter because the output power produced is a function of the operating temperature. The main components of a CSP plant are the solar field which is made up of the heliostat arrays, the receiver tower, the heat transfer fluid, the molten salt thermal energy storage tanks and the power conversion unit, which is made up of the turbine and the generator. The main advantage of CSP is that of a cheap thermal storage （i.e., molten salt storage） which makes it possible to dispatch power at a cost comparable to the grid electricity. Simulations run with the SAM （systems advisory model） developed by NREL （National Renewable Energy Laboratory） showed that CSP is capable of delivering electricity at the cost of 17UScents per kWh for the 30-year life of the plant. The main disadvantage of CSP however, is that of low efficiency （8%-16%）. There are ongoing research works to improve the efficiency of the CSP. One way to improve the efficiency is to increase the operating temperature of the system. In this paper, the authors discussed different modules of the CSP plant and suggested ways to improve on the conversion efficiencies of individual modules. Finally, an overall systems performance simulation is carried using SAM and the simulation results show that electricity can be produced using CSP at the cost of RI.05 per kWh.     

Limiting Use of Potential Energy Storage Compared to Batteries for a Lebanese Hybrid Wind/PV System

In l,ebanon, hybrid wind/PV systems are used to provide electricity when the public electricity is cut off This paper treats the storage problems of electrical energy generated by the used renewable sources. A theoretical study on two types of electrical energy storage systems is given. These systems are the electrochemical energy storage devices （batteries） and the potential （or hydraulic） energy storage system. In order to find the limiting case of use between these two energy storage systems, economical study and comparison between them are discussed and analyzed.     

Apply of Low-Carbon Technology in Building Energy Conservation in Hot Summer and Cold Winter Area

Building energy conservation is the basis for carbon emission reduction, through elaborating the relationship between low carbon and energy efficient building. It points out that the construction of energy-saving emission reduction is an effective means to solve the problems of high energy consumption of the building, and it is also an important measure for China＇s carbon emission reduction. According to the climate characteristics in hot summer and cold winter area, low carbon technology suitable for the construction of energy-efficient hot summer and cold winter area is proposed which is based on the analysis of the current main building energy-saving technical measures.     

Net Energy Ratio and Greenhouse Gas Analysis of a Biogas Power Plant

The results of a net energy life cycle analysis and greenhouse gas analysis for a 1.45 MW （0.71 MW electrical） biogas power plant operating with a 70% corn silage and 30% cow dung feedstock mixture are presented after its initial five years of operation. A ratio of 8.0 for the total output electrical energy divided by the total input energy from fossil fuels is found. A net efficiency of 1.2% of converting solar energy into electricity and usable heat （0.6% electricity） is achieved. Only 16 g CO2 per kWh are generated in the process. If all greenhouse gases are considered, this process even actively reduces the total greenhouse gas load on the atmosphere. In terms of producing transportation biofuels, this process provides 3.8 times more yield per hectare than bioethanol generation.     

Statistical Analysis and Energy Planning of Electric Power Supply Systems with Intelligent Control

The study presents possibilities for reconstruction of electric power supply systems in Bulgarian Black Sea resorts and possibilities to use statistical methods in energy planning. The paper shows the use of classic statistical methods in combination with advanced digital measurement systems in order to obtain the correlation dependencies, nature of energy consumption and opportunities for energy forecasting. The main purpose of the study is to obtain statistical dependencies of the nature of power consumption and correlations between electricity consumption and ambient temperature in order to improve the accuracy of energy planning. The analysis includes application of energy management systems for proper energy planning, improving economical efficiency and reducing power and energy losses.     

Analysis of Energy Saving Achievable through Solar Photovoltaic Systems on School Roofs： A Case of the City of Rome

Embracing renewable energy technology makes a lot of sense for the public sectors and schools as it meets the government sustainability goals and provides a financially viable means of achieving carbon savings while offering income potential. This study is aimed to quantify the achievable energy saving by spread use ofphotovoltaic systems on public building stock in the city of Rome. The installation of PV （photovoltaic） systems in the historic center depends on the feasibility conditions, generally more complex compared to the cases examined in the consolidated city, because they require compliance with the formal and aesthetic characteristics of the buildings, so the choice must be made between compatible components, which allow to minimize the transformation. The suburbs are characterized by large plane roofs in bad conditions and belonging to isolated buildings, so the useful surface, according to shading condition, offers a big potential for renewable technologies. The research provides an evaluation of maximum production of solar energy and the subsequent energy saving and reduction of greenhouse gasses, using parametric data, and an evaluation of the cost-effectiveness, with a rough calculation of return on investment.     

Benguela CommunitylUNAM Wind Power Demonstration Projectm——Experiences in Implementation

The government of Namibia has committed itself to promote the use of economically viable RE （renewable energy） technologies, as a complement to grid electrification, and to improve energy provision to rural areas. This paper presents the implementation of the Benguela Community-UNAM Wind-Power Demonstration Project, which is a community-run wind-power mini-generation pilot plant in Luderitz, Namibia. Luderitz is located in South-Western Namibia along the Namib Desert. The region experiences abundant south-westerly winds and the coastal weather conditions make it a suitable location for wind energy. This project is an initiative from the community of Luderitz and a first of its kind in Namibia. It demonstrates the application of small-scale wind energy systems in Namibia and contributes to the growing national awareness of RE and use of wind power in the country. Through its activities, the project has created a dialogue between the local authorities, business community, schools and the greater community. The balance of the paper discusses lessons learned; envisaged future development plans; highlights technical, administrative and management activities; as well as potential for replication and barriers encountered during the project implementation including institutional constraints. The solution-methods developed are presented and discussed.     

Energy Planning in Small Municipalities Based on Monitoring Results and Demand Side Management

Recent estimates state that the European Union is on course to achieve only half of the 20% energy consumption reduction target by 2020. As the first governmental stakeholders involved in the implementation of energy saving initiatives, municipalities play a strategic role in the energy planning process. This paper focuses on establishment of an energy planning methodology for small municipalities with numbers of inhabitants in range of 1,000-10,000 which often face common problems associated with low efficient district heat supply systems and decreasing energy consumption in buildings. Particular attention is paid to DSM （demand side management） activities. DSM scheme includes legislative and financial flows with small investments from municipality side. Based on increased information and motivation it promotes reduction of energy consumption in all kinds of buildings. Practical experience has shown that application of DSM measures allows achieving 20% energy savings in municipal buildings during the first year.     

Germany＇s Energy Transition and the European Electricity Market： Mutually Beneficial？

Germany＇s energy system is in transition towards less nuclear, lower carbon emissions and more renewables. Notwithstanding widespread neglect of its European dimension, this Energiewende will further exacerbate current network fluctuations due to the significant increase in wind and solar power. Key data from Denmark show that this transition will soon bring the German national power system to its limits for absorbing the resulting intermittency, and increase the need for more cross-border power transfers. Yet network analysis of import/export data shows that Germany＇s position in the European power system is contrary to the Danish case. The need for a European solution for Germany＇s energy transition will therefore soon become evident. In order to establish the necessary infrastructure, the Energiewende needs hence to be guided by an economic approach designed to prevent further fractures in the Internal Electricity Market. Constructive negotiations with neighbouring countries on market designs and price signals will be important preconditions. The article emphasizes the still neglected European paradox of Germany＇s energy transition and presents working examples and possible solutions to uphold electricity supply in Europe＇s power house.     

Energetic and Environmental Optimization of the Biomass Using

Biomass energy conversion can be done in several ways-combustion, gasification, pyrolysis or anaerobic fermentation （biogas production）. Each of these technologies has certain advantages and disadvantages from the point of view of energy generation for final consumption. In parallel, each of them has certain environmental impact in terms of emissions. The proposed EU directive prefers utilization of primary energy sources by application of highly efficient co-generation. Such change in assessment of energy effectiveness also means a completely new approach in assessment of current technologies. This report presents a guide for optimization of biomass energy conversion technologies assuming application of this new condition and minimal environmental impact. Specific values of emissions from particular technologies are used for the evaluation.     

Early Stage CAD-Compliant Energy Performance Assessment Method

A simple calculator for early stage energy performance assessment in residential buildings was developed and partially validated in this study. The calculator is based on the correlation of heat loss and energy need for heating and has fixed internal heat gains as intended for compliance assessment. With the calculator, the effect of any parameter implemented can be immediately seen on delivered and primary energy. Because of simple equations, it is suitable for implementation into CAD （computer aided design） design tools including basic BIM （building information modeling） data. Results showed that the accuracy of the correlation for the cases with practical relevance was not worse than 14% of the energy need of space heating. This applies for passive house insulation level; for less insulated building envelopes, the deviations were smaller. This 14% equals to only 3 kWh/（m2.a）, i.e., the percentage difference in the total delivered and primary energy was much lower because of other components in the energy balance. The deviations determined were implemented in the calculator as safety margin. Results prove that simple energy performance assessment based on specific heat loss coefficient is well justified for early stage energy analyses as well as for compliance assessment implemented in Estonian regulation.     

Promotion of Wind Energy in Germany

This paper concentrates on the most important findings and the lessons learned from German experience in the field of wind energy integration. It reflects the work of the governmental experts who were auditing the 2008-revision of the Renewable Energy Sources Act （EEG 2008） in the EEG-Report 2011 and the actual political debate in Germany in 2013. The EEG report 2011 makes it clear that a feed-in-tariff-mechanism lowers entry barriers and open the market for new competitors but, also, that incentives without a favorable legal framework fail to fulfill the purpose.     

Current Situation and Perspective of Second Generation Solid Biofuels Production： Case Study——CMR （Campinas Metropolitan Region）, Sao Paulo,Brazil

This proposal aims to assess the market introduction of advanced technologies for the production of 2nd generation solid biofuels, specifically technologies for the production of briquettes and pellets from agro-industrial wastes. The development of this project will evaluate the socio-environmental and techno-economical feasibility and use of 2nd generation solid biofuels in the CMR （Campinas Metropolitan Region）. The successful introduction of second generation briquettes and pellets to market depends, mainly, on two aspects： logistics in supply chains which generate waste, and the efficiency of production technologies. The study of logistics （supply chain） is based on survey data of the main productive supply chains, analysis, and modeling to optimize the facility location in the network for each case. The evaluation of the efficiency of production technology is provided by testing specially designed waste compacting devices, and comparing these results with the resulting power consumption during the production, in demonstration-scale, of a round of briquettes. The costs and consumption during the demonstration-scale production of briquettes are used for validation and correction of an optimization model. This project was approved in late 2012 with a period of two years for its implementation. Later in 2013, it was decided also to extend its implementation to the Metropolitan Region of Manaus, Amazon. Due to its recent beginning, the results shown here are only preliminary.     

A Predictive Nighttime Ventilation Algorithm to Reduce Energy Use and Peak Demand in an Office Building

The effect of two nighttime ventilation strategies on cooling and heating energy use is investigated for a prototype office building in several northern America climates, using hourly building energy simulation software （DOE2.1E）. The strategies include： scheduled-driven nighttime ventilation and a predictive method for nighttime ventilation. The maximum possible energy savings and peak demand reduction in each climate is analyzed as a function of ventilation rate, indoor-outdoor temperature difference, and building thermal mass. The results show that nighttime ventilation could save up to 32% cooling energy in an office building, while the total energy and peak demand savings for the fan and cooling is about 13% and 10%, respectively. Consequently, finding the optimal control parameters for the nighttime ventilation strategies is very important. The performance of the two strategies varies in different climates. The predictive nighttime ventilation worked better in weather conditions with fairly smooth transition from heating to cooling season.     

Feasibility of Wind Power Generation for the Reduction of Power Costs in Residential Buildings

The installation of wind power generators on buildings located in areas with regular winds may be a suitable investment in a renewable power source. Brazil has a high eolic potential, where the annual mean wind speed may reach over eight meters per second. This case study is aimed to assess the economic feasibility of the installation of small wind power plants in urban areas. This work evaluates a project for the installation of a vertical axis wind turbine in three buildings （15-, 22-, and 26-story） including the following stages： （1） installation of a real-time power meter in the 15-store unit; （2） demand analysis of the 26-store building＇s power consumption; （3） winds survey along the coast of the State of Ceara; （4） analysis of the wind turbines available in the market; （5） simulation aimed to choose the system. Vertical wind power generators offer better conditions of use in urban areas. The turnover time was established to be between four and six years in the three studied units. The installation of a wind power generator on buildings in regions with an adequate eolic regimen reaches a financial return of the investment before the end of the equipment＇s lifespan.     

Evaluation of Building Integrated Photovoltaic Systems＇ Potential in the Industrial Sector： Case Study of Oinofyta-Viotia Zone,Greece

The aim of this paper is to propose a flexible and accurate methodology for the evaluation of the BIPV （building integrated photovoltaic） potential on industrial building roofs. The use of more realistic and case specific data obtained by accurate technical on-site audits is proved to be of significant importance in the reliability of the proposed methodology results. Moreover, the most recent PV market information is used, considering however that this factor is rapidly changing during the last years, owed to the vast growth of the PV sector. To this end, emphasis is given on the country of Greece, where besides the fact that there is an increase of PV installations; no progress has been met in the use of BIPV systems in the industrial sector, opposite to the situation met in other EU countries. Acknowledging the above, the proposed methodology is currently applied so as to evaluate the BIPV potential of a large industrial zone close to the Greek capital, Athens. The results of this study can be used by both other researchers, for similar evaluations, and energy policy makers, to support the clean energy production concept on the basis of BIPV systems in industrial areas.     

Implementation of a Forest Biomass-Based Biofuel Industry： A Canadian Experience

The forest biomass is an abundant renewable resource from which biofuels can be derived. In the Kraft process, the cellulose is extracted from the wood to form the paper pulp while the other organic components, primarily hemicelluloses and lignin, are burnt to produce steam. It is possible to divert part of the hemicelluloses or lignin to produce fuels on site, a mode of operation referred to as the integrated forest biorefinery. Hemicelluloses can be hydrolysed into sugars which in turn are converted into ethanol or butanol, while lignin can be extracted from a residual process stream, the black liquor, by acid precipitation, de-ionized, dried and directly used as a fuel or further processed into value added chemicals. Biorefinery processes have been proposed and analysed by simulation on Aspen Plus. Intensive integration of thermal energy, water and material systems is of paramount importance to the sustainability of the global site; the increased energy load on the utility systems could cause rising dependency of the global site on fossil fuels. To avoid this consequence, a new original energy efficiency analysis and enhancement methodology has been developed and validated on actual Canadian Kraft mills before being applied to the integrated biorefinery and, has produced remarkable results far superior to the current engineering practice. This has led to the concept of the GIFBR （green integrated forest biorefinery）, i.e., an industrial site with zero fossil fuel consumption and reduced GHG （greenhouse gases） emissions vs. the Kraft process and biorefinery plant alone. The GIFBR incorporates a woody biomass gasifier producing syngas as a fuel for the integrated biorefinery and for steam production or sale. It can also include a CHP （combined heat and power） unit driven by steam made available by liberated production capacity from the installed power plant.     

The Potential of Cassava Biomass as a Feedstock for Sustainable Biogas Production in South Africa

Cassava is currently being investigated for biogas production in South Africa as it offers multiple benefits such as high yields of starch and total dry matter. The chemical constituents of the cassava biomass were determined using standard methods. Using a locally fabricated laboratory batch fermenter, anaerobic digestion was carried out in a 25 L capacity digester maintained at 36 ± 0.5 ℃. Pre-treatment of the cassava biomass with spoilage fungi, Aspergillus niger and PeniciUium species yielded large amounts of fermentable sugars for digestion. Cassava slurry was made and mixed with zebra droppings （2：1 v/v） and loaded into the digester of 20 L working volume. Analysis results showed an increase in most nutrients after pretreatment except for starch which decreased from 76% to 60% as a result of its hydrolysis to fermentable sugars by the spoilage fungi. Theoretical biogas yields were between 0.71 nm3 and 0.75 nm^3 per kg VS （volatile solids） destroyed while the total biogas yields of between 250 nm^3 and 300 nm^3 per kg VS fed into the digester was obtained after 20 days residence time. Cassava is not yet a staple food in some BRICs countries like South Africa and the peels and other by-products of its processing are equally suitable for energy production. The use of cassava will be an alternative feedstock strategy for several rural biogas projects running with cow dungs inside South Africa. In addition, opportunities exist for decentralized, cheaper and socially advantageous bioenergy production from cassava considering that fuel and electricity needs are not satisfied in many rural areas. Finally, the incorporation of cassava anaerobic digestion facility at different scales will deliver additional benefits like the incorporation of nutrients and residual carbon into the land as fertilizer.     

Modelling of Chillers for Energy Performance Assessment of HVAC Systems

The reliable assessment of the annual energy demand has become necessary in view of building energy performance certification. Accurate models must be used to simulate the behaviour of HVAC （heating, ventilation and air conditioning） components in real operation, usually characterized by a wide variation of building loads. In this context, this paper deals with the development and validation of an algorithm aimed at the assessment of part load performance of various kinds of controls for vapour compresion based heat pumps and chillers, in particular referring to on-off, inverter-driven and multi-stage vapour compression. The reliability of this algorithm in the calculation of seasonal performances is checked against monitoring of heat pumps and chillers operating under real conditions.