Advancements in the United States Photovoltaic Program

The major trends in PV technologies, applications and markets show promise for the future of renewable energy. The 30% growth projected for PV shipments in 1998 appears sustainable if current trends in new markets and applications reinforce and accelerate improvements in PV costs and performance. Through established partnerships and programs, R&D continues to focus on improving efficiency of solar energy systems, increasing manufacturing capability, reducing solar energy systems costs, enhancing reliability and flexibility of PV products, and producing innovations in thin-films and other emerging PV technologies. Continued research and market development in the US and other nations will advance quality and performance standards, and reduce the overall price of PV systems, laying the foundation for large-scale market expansion worldwide.     

莱州秸秆气化集中供气示范项目考察报告

本文对莱州市开展的秸秆气化示范工程进行了考察,针对目前项目存在的问题,文章建议,应建立和落实好秸秆气化运行管理体制,以确保秸秆气化系统的持久可靠运行,同时将秸秆气化应与发电结合,国家应给予相应的政策支持。     

用战略眼光谋求光伏产业市场化--江苏省光伏产业市场化专题调研

江苏省目前已形成了光伏产业群，全省的太阳电池生产能力占全国80%以上，集聚了一批优秀的光伏技术人才，积累了一批自主知识产权，产业链相对完整，形成了一定的竞争力。但是为了进一步开拓国内外光伏市场，困难还不少，例如硅原料紧缺，产业链还较脆弱，产品的供产、销受制于国外市场。为了进一步推进江苏光伏产业市场化，江苏省政府应当加强政策扶持，包括进行绿色电价改革启动示范项目等，企业也要在推进技术进步的基础上努力降低生产成本。为了我国光伏产业的健康发展，应当加强我国硅原料的研制开发。     

Hawaii: RE in the Island State

Hawaii is blessed with a variety of renewable energy resources,” says Representative Mina Morita, who chairs the state House of Representatives committee on energy and the environment. “Lots of sunshine, strong, reliable trade winds, fast-growing crops, flowing streams, geothermal heat, and both hot and cold ocean waters.” Tom Koppel looks at Hawaii's renewable energy potential, the extent to which it is being utilized, and at new developments that are either in the works or being proposed.     

光伏并网逆变器死区效应研究

在并网逆变器中,为防止同一桥臂上的上下两个器件发生直通现象,必须注入微秒级的死区时间。死区时间越长,并网逆变器的工作越安全,但逆变器输出的电压波形质量会变差,同时对负载及电网造成不同程度的影响。因此有必要对死区效应进行深入研究。本文对死区效应进行了理论分析,研究了并网逆变器中死区时间对输出电压的影响,最后对并网系统的死区效应进行了仿真实验研究。     

Geothermal resources assessment in Hawaii

The Hawaii Geothermal Resources Assessment Program was initiated in 1978. The preliminary phase of this effort identified 20 Potential Geothermal Resource Areas (PGRAs) using available geological, geochemical and geophysical data. The second phase of the Assessment Program undertook a series of field studies, utilizing a variety of geothermal exploration techniques, in an effort to confirm the presence of thermal anomalies in the identified PGRAs and, if confirmed, to more completely characterize them. A total of 15 PGRAs on four of the five major islands in the Hawaiian chain were subject to at least a preliminary field analysis. The remaining five were not considered to have sufficient resource potential to warrant study under the personnel and budget constraints of the program.The results of these studies have allowed us to attempt an estimate of the probabilities of low- to moderate-temperature (50–125°C) and of moderate- to high-temperature (125 – 360°C) geothermal resources in 12 of the survey areas; inadequate data or interpretational difficulties did not allow a valid estimate to be made for the remaining three study sites. Table 11 presents estimated probabilities for these PGRAs that are based on all currently available data.The results of these studies have also demonstrated that no single surface geothermal exploration technique is capable of providing unequivocal proof of a subsurface thermal anomaly under all field conditions; it is more frequently the case that an estimate of the geothermal potential of a given PGRA must rely on a synthesis of all geological, geophysical and geochemical data available. Experience in the Kilauea East Rift Zone, a Known Geothermal Resource Area, has also demonstrated that none of the currently available surface exploration techniques are capable of yielding definitive information regarding the production capabilities of a specific parcel of a geothermal reservoir; the only technique that has proven capable of providing this information has been the drilling and flow testing of deep exploratory wells.The island of Kauai (Figs 1 and 2) was not studied during the current phase of investigation. Geothermal field studies were not considered to be warranted due to the absence of significant geochemical or geophysical indications of a geothermal resource. The great age of volcanism on this island would further suggest that, should a thermal resource be present, it would be of low temperature.The geothermal field studies conducted on Oahu focused on the caldera complexes of the two volcanic systems which form the island: Waianae volcano and Koolau volcano. The results of these studies and the interpreted probability for a resource are presented below.Lualualei Valley: (Figs 1 and 3). Geologic mapping located the focus of the late-stage eruptive activity near the back of Lualualei Valley and tentatively identified the Waianae caldera boundaries within the valley. Soil geochemistry studies defined anomalous zones of mercury concentrations and radon emanation that appeared to be coincident with the caldera boundary faults. Groundwater chemistry and temperature measurements identified a distinctly anomalous well near the back of the valley and several others with slightly anomalous conditions on the caldera boundary faults. Geophysical soundings indicated low subsurface resistivities within the valley that were interpreted to correspond to warm fresh to saline water-saturated basalt. On the basis of the available data, the probability for a low- to moderate-temperature resource (50–125°C) within 3 km of the surface is assessed at 10–20%. The probability for a higher temperature resource is less than 5%.Mokapu Peninsula and Koolau Caldera: (Fig. 3). Geologic mapping identified three post-erosional volcanic vents on Mokapu Peninsula; the inferred ages were on the order of 300,000 years. Geochemical studies on Mokapu were unable to identify a self-consistent pattern of soil geochemical anomalies or significant groundwater chemical anomalies that would suggest a geothermal resource. Resistivity soundings determined subsurface resistivities that were consistent with cold seawater-saturated sediment. The probability for even a low-temperature geothermal source at depths of 3 km or less beneath Mokapu is considered to be less than 5%.Results of preliminary soil geochemical studies and interpretation of available groundwater data to the south of Mokapu, within the Koolau caldera, suggest that some thermally induced alterations may be present. Interpretation of geophysical data indicates that the temperatures within the ancient Koolau magma chamber are less than 540°C and that the shallow subsurface resistivities show no evidence of thermal effects. On the basis of the rather sparse data currently available, the probability for a low- to moderate-temperature resource associated with the Koolau magma chamber is considered to be 10% or less.Due to the anticipated small demand for geothermal power on the island of Molokai in the foreseeable future, only preliminary efforts were made to assess the potential for a resource on this island. An abandoned well reported to have produced warm water when it was first drilled during the 1930s was located, but temperature measurements were unable to detect anomalies within the open portion of the hole; collapse of the lower third of the bore did not permit access to the water table, however. Soil geochemical analysis did not indicate significant mercury concentrations or unusual alteration minerals in the vicinity of the well. In the absence of detectable anomalies from the preliminary investigation, further studies were not considered to be warranted. The probability for a resource on West Molokai is not considered to be high; however, sufficient data are not available to offer an estimated probability for a resource.Geothermal assessment activities on Maui included an evaluation of the major rift zones and post-erosional volcanic vents on both West Maui volcano and Haleakala volcano. Field surveys conducted on West Maui yielded the following results (Fig. 19).Olowalu and Ukumehame Canyons: extensive geologic mapping characterized the southwest and southeast rift zones of West Maui volcano and interpreted these structures to suggest a migration of the rift zone activity late in the formation of West Maui. Numerous late-stage alkalic and trachitic dikes and plugs were also identified in the survey area. Ground-water geochemical and temperature measurements identified distinctly anomalous water chemistry and temperatures. Resistivity sounding data for the area was interpreted to indicate a thick layer of warm, fresh to saline water beneath the Olowalu and Ukumehame Canyons. The probability of a thermal resource having a temperature greater than or equal to 50°C is estimated to be 50–60%, whereas a temperature greater than or equal to 125°C has an estimated probability of 10% or less.Lahaina-Kaanapali: soil geochemical surveys were unable to identify a self-consistent pattern of soil mercury concentrations or radon emanation rates that would suggest a thermal resource. Groundwater temperature measurements and chemical analyses were similarly unable to detect significant thermal alterations. Geophysical soundings detected subsurface resistivities consistent with cold water-saturated alluvium and basalt. The probability of a thermal resource existing in this area is less than 5%.Honokowai: groundwater chemistry and temperature data for this area were unable to confirm the existence of any thermal impacts and geophysical soundings indicated normal subsurface resistivities. Hence the probability for a resource in this location is believed to be less than 5%.Field surveys on Haleakala were confined to the lower portions of the three major rift zones and yielded the following analyses:

• Haleakala Northwest Rift: soil geochemical and groundwater chemical studies in this area both indicate potential anomalies. The interpretation of the anomalies with regard to thermal alterations was not, however, unequivocal. Geophysical soundings were unable to identify significantly anomalous subsurface resistivities or self-potential variations. The probability of a low- to moderate-temperature resource is placed at 10–20%, whereas that for a high-temperature resource is less than 5%.
• Haleakala Southwest Rift: geologic mapping has determined that several flows on this rift are less than 10,000 years of age and that a few are less than 1000 years old. Preliminary geochemical studies were unable to identify unequivocal evidence of thermal effects on the lower rift zone area, whereas geophysical soundings indicated that thermal groundwaters may be present at depths of less than 3 km. The probability for a low- to moderate-temperature resource is estimated to be 30–40%, whereas that for a high-temperature resource is placed at 15–25%.
• Haleakala East Rift Zone: preliminary geochemical and geophysical surveys were performed in this area. The results of these efforts did not identify significant anomalies; however, difficulties in interpretation and the small amount of data available do not allow an assessment of geothermal potential to be made.

The island of Hawaii, being the youngest and most volcanically active island in the Hawaiian chain, was found to have the largest number of PGRAs (Fig. 34). The current assessment program performed field surveys in six of the most promising PGRAs on Hawaii, which yielded the following results:

• Kawaihae: geophysical surveys performed over this area indicate a set of magnetic and resistivity anomalies that suggest that an intrusive body, associated with the Puu Loa cinder cone, may be heating local groundwaters. Groundwater chemistry and temperature anomalies confirm the existence of a heat source in the vicinity; however, the temperatures are not indicated to be very high. The probability of a low- to moderate-temperature resource in the survey area is indicated to be 35 to 45% and a moderate- to high-temperature resource to be 15% or less.
• Hualalai: geologic mapping on the western flank of Hualalai suggests that frequent eruptive activity has occurred during the last 5000 years. Geophysical surveys have identified distinct magnetic, resistivity and self-potential anomalies near the summit of Hualalai, whereas the lower western flank has not shown significant thermal effects. Geochemical data on the lower flanks were similarly unable to identify any obvious thermally induced anomalies. These data suggest that there is a 35–45% probability of a low- to moderate-temperature thermal resource near the summit of Hualalai and a 20–30% probability of a high-temperature resource in this area. Probabilities for comparable resources existing on the lower flanks are estimated at 15–25 and 5% or less, respectively.
• Mauna Loa Southwest Rift: limited geophysical surveys performed on the lower southwest rift were unable to detect significant resistivity anomalies to depths equivalent to the local water table, and a self-potential traverse detected only one anomalous gradient that was interpreted to be the result of a downgoing streaming potential. No strong geothermal anomalies were identified; however, the limitations of the available data set do not allow a probability estimate to be made of the resource potential in this area.
• Mauna Loa Northeast Rift: geophysical and geochemical field studies performed in this PGRA were unable to detect any evidence of a geothermal anomaly in this location. The probability for even a low temperature resource is estimated to be less than 5%.
• Kilauea Southwest Rift: geologic mapping has indicated several areas of steaming ground and warm coastal springs adjacent to the rift systems. A re-analysis of available geophysical data for this area concluded that warm groundwater was present within the rift zone. Magnetic anomalies observed over the rift indicate that subsurface temperatures may exceed the Curie temperature. The probability for a low- to moderate-temperature resource on this rift is considered to be 100%, whereas that for a high-temperature resource on the upper rift is estimated at 70–80%.
• Kilauea East Rift Zone: an extensive body of geological, geophysical and geochemical data concerning the East Rift Zone is available and virtually all of this data indicates that a high-temperature thermal system is associated with the entire rift. Deep exploratory geothermal wells drilled into the rift zone have identified temperatures in excess of 350°C and continuous production from one of these wells for a period of more than two years indicates that sufficient recharge is available for production of geothermal electrical power. The probability for both a low- and high-temperature resource on this rift zone is 100%.

     

Energy consumption trends in Hawaii

This study begins with a review of energy consumption by end-use sector in Hawaii. Then, the energy generated from renewable energy sources is analyzed between 1991 and 2006. The results show that while geothermal is a considerable source of renewable energy on the Island of Hawaii (also known as Big Island), fossil fuel is the main energy source in the State of Hawaii. The energy intensity index for the State of Hawaii is then calculated by dividing energy consumption per capita by the income per capita. The calculated energy intensity index reveals that energy consumption is directly controlled by per capita income. The results also indicate that the energy intensity index increases over time despite positive developments in energy efficient technologies. In the second part of the paper, the effect of the tourism industry on energy usage in the State of Hawaii is analyzed. The results show that tourism volume, measured in terms of tourist arrival numbers, does not change the energy consumption directly. However, a change in tourism volume does affect per capita income within a few months to a year. In the last part of the study, the energy efficiency index of Hawaii is compared with consumption averages for the US, California and the most energy efficient country in Europe, Denmark. The comparison shows that Hawaii lags behind California and Denmark in terms of energy efficiency. The comparison also shows that an increase in energy efficiency corresponds to an increase in per capita income across the board, which is in agreement with a recent report published by the American Physical Society.     

Photovoltaic cogeneration in the built environment

Building integrated photovoltaic (BiPV) systems can form a cohesive design, construction, and energy solution for the built environment. The benefits of building integration are well documented and are gaining significant public recognition and government support. PV cells, however, convert only a small portion of the incoming insolation into electricity. The rest is either reflected or lost in the form of sensible heat and light. Various research projects have been conducted on the forms these by-products can take as cogeneration. The term cogeneration is usually associated with utility-scale fossil-fuel electrical generation using combined heat and power production. It is used here in the same spirit in the evaluation of waste heat and by-products in the production of PV electricity. It is important to have a proper synthesis between BiPV cogeneration products, building design, and other HVAC systems in order to avoid overheating or redundancy. Thus, this paper looks at the state-of-the-art in PV cogen from a whole building perspective. Both built examples and research will be reviewed. By taking a holistic approach to the research and products already available, the tools for a more effective building integrated system can be devised. This should increase net system efficiency and lower installed cost per unit area. An evaluation method is also presented that examines the energy and economic performances of PV/T systems. The performed evaluation shows that applications that most efficiently use the low quality thermal energy produced will be the most suitable niche markets in the short- and mid-term.     

Photovoltaic in Switzerland

The adoption of a new article in the Swiss Constitution relating to energy and a 10 year moratorium on nuclear energy by Swiss voters on 23rd September 1990 had political consequences. The Swiss government (Federal Council), supported by the ruling parties, launched a 10 year national programme in November 1990, known as 'Energy 2000'. By the turn of the millennium, photovoltaic grid-connected installations generating a total of 50 MWp should be installed and brought into operation within the context of the Swiss national programme "Energy 2000". The local/regional utilities are supporting this ambitious objective by reimbursing the marginal costs of the energy supplied and additional accompanying measures.     

Photovoltaic module-site matching based on the capacity factors

In this paper, a methodology for the selection of the optimum photovoltaic module for a specific power plant site is developed. The selection is based on the capacity factors (CF) of the available PV modules. Long term irradiance data recorded for every hour of the day for 30 years are used. These data are used to calculate the probability density function of the irradiance for different hours of a typical day in a month. The irradiance probability density function and the manufacturer's specifications on PV modules are used to calculate the capacity factors for the PV modules. The PV module with the highest average capacity factor for the specific site is the optimal and recommended PV module. In this paper, the price per installed maximum peak watt is approximately the same for different modules and hence the cost is not an issue     

Photovoltaic remuneration policies in the European Union

The purpose of this paper is to study the development of photovoltaic (PV) systems in some countries of the European Union (EU). We establish the stage of development of each country, their short- and long-term degree of compliance and the trends of international investors favouring one market or another. EU countries employ four major types of programs to encourage PV use: (1) feed in tariffs (FIT), (2) green certificates with a quota system, (3) investment and tax incentives, and (4) bids on the quota system. The FIT is the most widely used program to create incentives for the use of PV systems. During the past two years, PV tariffs have been reduced in many European countries. Investments in PV are still attractive, in some cases even overly generous with respect to the financial landscape in the world.This paper shows, for each country, the type of incentive and the trends in and forecast for installed capacity and calculates the internal rate of return (IRR) for investment in grid-connected PV systems.     

基于双面组件的可调支架光伏发电系统仿真研究

以双面光伏组件和可调支架系统为基础,以青海格尔木为模拟地点,利用PVsyst光伏仿真软件,分析了不同调节次数的可调支架系统与固定支架系统在组件正面和背面辐射量、系统发电量、系统收益的差异。研究结果表明：通过调节支架改变光伏组件的角度后,组件最低点离地高度也在变化,直接影响组件正面和背面的辐射接收;光伏方阵前后间距影响土地利用率（GCR）,土地利用率降低后,背面的辐射量和系统发电量都有一定的增加;相对于固定支架双面发电系统,可调支架双面系统在不同调节次数下的组件背面全年辐射量均有一定降低,但整体的发电量得益于正面辐射的增益,最高可达4.8%左右;技术和经济比较结果显示,双面组件采用可调支架系统,每年2次的调节方式,25年生命周期内系统收益最高。文章还分析了单面发电组件和双面组件系统使用可调支架的经济性对比,在相同的调节次数下,双面组件系统的增益明显高于单面组件系统。本文的研究成果对可调支架双面组件发电系统的设计具指导作用。     

Solar and wind energy applications in Hawaii

The study on solar radiation and wind power applications is a facet of the total State of Hawaii solar assessment program. Engineering consultants, governmental authorities from the Department of Energy, State of Hawaii, and counties, technology assessments specialists, and buinessmen were contacter for input into this paper. The resultant late 1977 survey is a broad implementation plan highlighting seven typical applications—three solar, three wind and one combination.It was not the intention of this study to produce refined engineering/economic analyses. However a principal objective was to stimulate the development of solar energy by assisting in the first crucial steps of the planning process.This investigation selected projects which had potential for immediate implementation in the State of Hawaii. Variety in form of application, type of engineering analysis and location within the State was sought. To a large extent these basic premises were well met, as applications range from agriculture to aquaculture to tourism to education on three islands.In varying degrees, each project is recommended either for further study or immediate implementation. Some of the economics may be dubious, as would be the situation in most original applications. However, with appropriate governmental aid or incentives, these pilot projects could serve to improve economy of scale, spur associated developments, and in the long run, improve Hawaii's balance of trade.     

Assessment of wave energy resources in Hawaii

Hawaii is subject to direct approach of swells from distant storms as well as seas generated by trade winds passing through the islands. The archipelago creates a localized weather system that modifies the wave energy resources from the far field. We implement a nested computational grid along the major Hawaiian Islands in the global WaveWatch3 (WW3) model and utilize the Weather Research and Forecast (WRF) model to provide high-resolution mesoscale wind forcing over the Hawaii region. Two hindcast case studies representative of the year-round conditions provide a quantitative assessment of the regional wind and wave patterns as well as the wave energy resources along the Hawaiian Island chain. These events of approximately two weeks each have a range of wind speeds, ground swells, and wind waves for validation of the model system with satellite and buoy measurements. The results demonstrate the wave energy potential in Hawaii waters. While the episodic swell events have enormous power reaching 60 kW/m, the wind waves, augmented by the local weather, provide a consistent energy resource of 15–25 kW/m throughout the year.     

光伏并网系统隔离变压器联接方式的应用研究

对光伏并网系统隔离变压器进行了仿真与实验,探讨适于光伏并网系统的变压器连接方式.对隔离变压器及其作用进行了简要论述,对谐振过电压、系统故障检测及系统谐波等问题进行了理论分析,确定了光伏并网系统隔离变压器连接方式选择的基本准则.研究结果表明,在单级式光伏并网发电系统中,隔离变压器的连接选择△/Yn方式较合适,为今后大容量光伏并网电站的发展提供了基础和依据.     

Photovoltaic activities in the Federal Republic of Germany

In this paper, the status of photovoltaic activities in the Federal Republic of Germany is described. Photovoltaic power has been regarded as a promising option since 1973, and it is now an area in which there are significant research and development efforts. This work is carried out in universities, in industrial research laboratories, and at newly established solar energy research centres. Funding comes from a variety of sources, including the Federal Government, major private companies and the Commission of the European Communities.     

Photovoltaic marketing in developing countries

Photovoltaic (PV) insolation-harnessing is acknowledged as the most practical economic solution to meet the requirements of one hundred million people without electricity in the developing countries. Industrialized countries in particular, have been active in utilizing such technologies because they can afford the current peak watt prices of US $3–15 for such systems. The market in those countries will soon be close to saturation and attention by suppliers will have to be shifted to the already established larger market in less developed countries (LDCs). PV marketing in these developing countries, i.e. ability to penetrate the potential market, is facing tremendous hurdles. This paper reviews the present status and future directions of the PV market in developing countries as well as discusses the current technical, social, financial or geopolitical barriers and constraints, which are making this market difficult at present. Possible policy frameworks are also proposed which are in line with the trends in the world. The paper concludes by making a global policy package proposal, in terms of an appeal on the global community concerned with PV to propagate this proposal more convincingly, perhaps to emanate from an internationally recognized “forum”, like a PV conference and exhibition, with cooperation and participation of PV manufacturers, suppliers, industrialized countries, NGOs, financial institutions and developing countries.     

Innovations in Solar Photovoltaic Technology

正The advances in photovoltaic(PV) technologies over the last decade have made possible many more smallerscale applications for everyday living,on a more personal level,not just the roofs or giant arrays of glimmering panels in the desert we used to think of.Improvements in design and configuration,energy storage,efficiency,and battery size have created opportunities for solar energy in a variety of situations.Following are some examples of innovative,low-cost ways solar energy has been being used to enhance our daily lives.     

Photovoltaic devices in hydrogen production

Hydrogen is an ideal fuel for the increasing human demand of abundant, clean and renewable energy. Various technologies are developed for the production of the hydrogen through water splitting, and in particular the photovoltaic device is widely regarded as an opportunity for the high efficiency, low cost and simple configuration devices. Three main systems are briefly reviewed in this article by demonstrating the typical devices of them, including the III–V group compound semiconductor, the multi-junction Si structure and the dye-sensitized solar cells. Although considerable disadvantages and limitations are obvious in performance, the challenging and competing criteria are outlined for the improvements. Moreover, the introduction of plasmonic metal nanostructures provides an intriguing prospect of extensive applications of the photovoltaic devices.