The use of polymer materials for photovoltaic applications is expected to have several advantages over current crystalline silicon technology. In this paper, we perform an environmental and economic assessment of polymer-based thin film modules with a glass substrate and modules with a flexible substrate and we compare our results with literature data for multicrystalline (mc-) silicon photovoltaics and other types of PV. The functional unit of this study is '25 years of electricity production by PV systems with apower ofl watt-peak (W p)'. Because the lifetime of polymer photovoltaics is at present much lower than of mc-silicon photovoltaics, we first compared the PV cells per watt-peak and next determined the minimum required lifetime of polymer PV to arrive at the same environmental impacts as mc-silicon PV. We found that per watt-peak of output power, the environmental impacts compared to mc-silicon are 20-60% lower for polymer PV systems with glass substrate and 80-95% lower for polymer PV with PET as substrate (flexible modules). Also in comparison with thin film CuInSe and thin film silicon, the impacts of polymer modules, per watt-peak, appeared to be lower. The costs per watt-peak of polymer PV modules with glass substrate are approximately 20% higher compared to mc-silicon photovoltaics. However, taking into account uncertainties, this might be an overestimation. For flexible modules, no cost data were available. If the efficiency and lifetime of polymer PV modules increases, both glass-based and flexible polymer PV could become an environment friendly and cheap alternative to mc-silicon PV.@en

In electricity systems in which wind generators and photovoltaic cells play a large part in the production of electricity, a major problem is the matching of production and demand. This problem can be solved by means of storage facilities together with back-up generating capacity. To analyse the value of short-term as well as long-term storage facilities, a computer model has been developed which can simulate electricity systems that are fed largely by renewable energy sources. A brief description of the model is given. With this model calculations have been made for a possible situation where electricity in the Netherlands is supplied mainly by wind generators and PV cells, whereas and combined cycle units and gas turbines are used as back-up power.@en

A simple approximation model is proposed to estimate the output power of a PV (photovoltaic) module coupled directly to a battery, given the array plane irradiation and the battery voltage. Calculations were performed on a PV streetlight system in the Netherlands; the PV modules of the system were made up of 40 cells. The average overestimation of the array output for the investigated periods is 6%, due to systematic errors at irradiation levels below 300 W/m2 and at high module temperatures. Comparisons are made to a more elaborate calculation method based on a one-diode model for a PV module. The latter model gave a better accuracy of 2%. However, when pyranometer irradiation data were used instead of reference cell data, an overestimation of up to 10% for both models was found. It is therefore concluded that the error introduced by the approximation model may be acceptable in comparison with the uncertainty introduced by using pyranometer data.@en