Power Generation

Solar photovoltaic power plants have emerged in recent years as a viable means of large-scale renewable energy power generation. A critical question facing these PV plants at the utility scale remains the competitiveness of their energy generation cost with that of other sources. The relative cost of electricity from a generating source can be compared through the commonly used levelized cost of electricity (LCOE) calculation. The LCOE equation evaluates the life-cycle energy cost and production of a power plant, allowing alternative technologies - with different scales of operation, investment, or operating time periods - to be compared. This article reviews the LCOE drivers for a PV power plant and the impact of a plant’s capacity factor on the system LCOE, as well as the effects of various factors such as capacity and geographical location. The economic tradeoffs between fixed and tracking systems are evaluated as well as a review of land use, plant operation and maintenance costs.

New interconnections requirements for utility-connected photovoltaic systems are coming into play in several European countries, armed with the task of supporting the grid operation and stability. This approach to better integration of photovoltaic systems into the electric power system enables a larger selection of renewable energies. This paper presents the new grid code in Germany as an example of this improved integration, complemented by a brief report regarding activities currently being undertaken to ensure European harmonisation of interconnection requirements.

Thin-film or crystalline photovoltaic modules? One of the consequences of the rapid introduction of new photovoltaic technologies is the buzz generated in the industry. Large-scale photovoltaic applications are especially sensitive to any question connected with cost optimization. Therefore, stakeholders involved in photovoltaic project development are questioning whether the time has arrived to shift module technologies to large-scale applications. A great variety of opinions are exposed every time this question arises. This paper’s aim is to uncover the key questions that should be taken into consideration in order to select the proper technology for large-scale photovoltaic applications and to provide the maximum amount of practical information for this decision.

The past year was characterised by MW-range solar power plants and it was also a year with the highest market growth related to large-scale photovoltaic systems ever. Not only in Spain, where progress does not need to be commented upon at all, but also in some other countries where the cumulative installed power increased significantly. In the European Union progress was observed in among other countries Italy, Czech Republic and France; the German market however decreased slightly but in terms of capacity of installed power output Germany was, despite the market explosion in Spain, almost the same as in year 2007.

Electricity has been around for a long time and no doubt will be for the foreseeable future, but it is quickly changing its nature. Owing to evolutions in power electronics, sustainable electricity generation and consumption came to the fore and now it is nigh on impossible for photovoltaics to operate without this technology. This holds true for efficient consumption such as plug-in electric and hybrid vehicles or compact efficient lighting. Power electronics need to be taken into account in relation to grids, for example in novel voltage-source HVDC connections. Photovoltaic energy conversion requires power electronics in order to adapt the floating DC-output to a fixed DC-level and typically further to a grid-compatible AC electricity. These converter (mainly inverter) technologies have evolved considerably over the past few years, in much the same way as has PV cell technology, but in a much less apparent fashion. It is, however, expected and required that the technologies will evolve even further to meet the demands of the future market and the electricity grid to which they will be connected. This article intends to give an overview of the challenges ahead for power electronics in photovoltaic energy conversion.

The U.S. residential solar market is poised for growth. For solar companies seeking to capitalize on the growth potential of this market, the keys to success will be sales volume and operating efficiency. Solar employee purchase programs (solar EPPs), which have been initiated by companies as diverse as SunPower, REC Solar, and SolarCity, represent a new and potentially important channel for increasing sales and improving sales efficiency. Driving these programs are increasing corporate sustainability initiatives and growth in voluntary employee benefit offerings, especially employee purchase programs and green benefits. This article provides an introduction to solar employee purchase programs, analysis of the business ecosystem, and discussion of an example program. It is based on the industry’s first report to identify and analyze this emerging trend, which was published by AltaTerra Research in November 2008 [1].

This paper presents a detailed assessment of the value of photovoltaic energy within the German energy supply structure, taking into account the correlation between actual consumption and local power generation. Contrary to previous statistical approaches, this paper takes a new dynamic approach, modelling the dynamic behaviour of the PV power generation as a one-year time series. A comparison with the time series of the power demand allows assessment of the value of PV energy. The value of PV energy mainly results from its ability to substitute conventional power generation and the benefit of this kind of decentralized power generation for network stability and quality. An evaluation of these aspects is carried out for the year 2005 and a likely scenario in 2015.

Apart from some obstacles and bureaucratic hindrances, the Italian PV market has recently joined the upper echelons of the solar industry. Along with small and medium-sized systems, the commercial and large-scale segment in particular has a great deal of promise. Even though the local industry is still trying to block the domestic market from international competitors, increasing numbers of foreign investors are entering the market. In this close-up of the Italian PV market, the country’s participation in the solar energy industry is reviewed and a projection to 2010 is given, with particular emphasis on the country’s potential to be a major player in the large-scale installation sector.

Anyone familiar with the PV industry can attest to the remarkably accelerated pace of innovation aimed towards generating solar power more cost effectively relative to conventional means of producing electricity. Many of high-technology’s best minds are bringing expertise in materials, manufacturing process, and electronics to tackle the challenge. The resultant gains in cost effective manufacturing, silicon availability and greater irradiance conversion efficiency will make continuous and sustainable impact to cost per kW generated akin to the predicable improvements in transistors per mm2 which has fuelled the semiconductor industry for the past 25 years (although we are not yet so bold as to devise the PV version on Moore’s Law). As less than 0.01% of electricity generated comes from PV installations [1], demand will materialize and the need for public subsidies will decline as the economics improve. This paper will investigate the steps required to make every solar project a “perfect” project by putting forth parameters for evaluating solutions for the problem areas.

The costs of a photovoltaic installation are driving the market and the need for subsidized schemes, such as feed-in tariffs. Concentrated photovoltaics (CPV) is leading the development of future lowcost renewable energy sources in two ways: on one hand offering high efficiency systems, and on the other, being most capable of reducing manufacturing costs. The idea to decrease the cost of the photovoltaic system using optical elements to focus the radiation into the cell to reduce the size of the cells has been in the mind of the scientists since the 1970s [1]. But, apart from a reduced market, there were several issues that did not allow CPV success at that time. This paper puts forth the proposition that the key is to replace the area of active material, which is the most expensive, with optic elements, which are well known and cheaper.