Environmental impact of electricity from selected geothermal power plants in Italy

Geothermal plants supply a significant contribution to the electricity balance from renewable sources in Tuscany. However, this electricity conversion is not exempt from environmental drawbacks. In our study, the electricity production phases of four geothermal electricity plants are analyzed by means of a careful airborne emissions assessment carried out over the entire LCA of the plants. The impact categories considered are global warming (GWP), acidification (ACP) and human toxicology (HTP). The functional unit used is 1 MWh of electric energy produced from geothermal power plants in Mount Amiata area. For the environmental impact categories considered, the impact potentials are evaluated for each of the four geothermal power plants as follows: 380-1045 kg CO 2 eq/MWh for GWP, 0.1-44.8 kg SO2 eq/MWh for ACP and 1.1-31.6 kg, 1.4-DB eq/MWh for HTP. The main contributions to the impact are associated with the high content of NH3, H2S, CH 4 and CO2 gases present in the effluents of each plant. The impact change in relation to the geothermal site has a strong correlation to the basin of fluid withdrawal and is related to the technologies used for pollutants depletion. In some cases the impact is higher than that found for production of electricity from fossil fuels (for example, a coal plant of comparable power

Application and use of the ISEW for assessing the sustainability of a regional system: A case study in Italy

3noreservedThe Index of Sustainable Economic Welfare (ISEW) was introduced by Daly and Cobb in 1989 in order to integrate the information embodied in GDP. Since economic growth implies externalities and market failures, and a portion of it can be defined as "uneconomic", the ISEW method introduces some corrections and adjustments to the GDP calculation framework. The ISEW has been calculated for a number of nations but it has been rarely applied to sub-national systems. Its calculation at the local level is important especially in case of administrative decentralization, and autonomy and responsibility of local authorities in certain fields. For this reason, a more and more comprehensive knowledge of the characteristics and peculiarities of the territorial system they manage is necessary. This paper presents the results of the ISEW calculation for Tuscany, a region in central Italy, in the period 1971-2006. This is one of the few attempts to apply the ISEW in time series at the regional level. Final results show that a discrepancy between ISEW and GDP appeared in the 1970s. Social and environmental pressures increased during the period under study making the gap equal to about 30 percent of regional GDP in 2006. The ISEW can be used also as a tool for evaluating policies, but further adjustments in calculation of certain items are considered necessary for taking into account and evaluating punctual policies. A case of energy policy is presented. (C) 2011 Elsevier B.V. All rights reserved.mixedPULSELLI, F.M.; BRAVI, M.; TIEZZI, E.Pulselli, F. M.; Bravi, M.; Tiezzi, E

Life Cycle Assessment of advanced technologies for photovoltaic panels production

The study, developed through a detailed analysis of available data in the international literature, aims to better understand the nature and the extent of risks related to all stages of photovoltaic panels life cycle, produced by the most advanced technologies. For example, the CdTe (Cadmium Telluride) thin film photovoltaic technology is very promising from an economic and energetic point of view, but it shows challenges and risks related to the presence of a potentially very dangerous heavy metal, whose utilization has been actually banned in many products. Currently, CdTe photovoltaic panels are not included in European regulations limiting elements considered dangerous and regulating their disposal. In terms of environmental impact, previous studies showed that the CdTe modules have similar or less impact than other photovoltaic technologies and have a lower energy consumption relative to the production stage. Indeed, these studies are developed on the only energetic return and EPBT (Energy Pay-Back Time) basis, and they do not take into account the effects related to heavy metals pollution. In this context, the CIGS (Copper Indium Gallium di-Selenide) and amorphous/micromorph MCPH thin-film silicon technologies showed to have an environmental impact comparable to that of CdTe and in some cases even less. The lack of ascertained data on the extent of risks associated with production, use and disposal stages of these panels and the fast technological progress of solar technologies make difficult, but necessary to outline a reliable framework and to assess a balance between risks and benefits in the use photovoltaic modules on a large-scale. It is also urgent to implement an efficient action for the recovery and recycling based on the precautionary principle

Life cycle assessment of a Micromorph Photovoltaic System

In this paper the results from a in-depth life cycle analysis of production and use of a novel grid-connected photovoltaic micromorph system are presented and compared to other thin film and traditional crystalline silicon photovoltaic technologies. Among the new thin film technologies, the micromorph tandem junction appears to be one of the most promising devices from the industrial point of view. The analysis was based on actual production data given to the authors directly from the PRAMAC Swiss Company and it is consistent with the recommendations provided by the ISO norms and updates. The gross energy requirement, green house gas emissions and energy pay-back time have been calculated for the electric energy output virtually generated by the studied system in a lifetime period of 20 years. A comparative framework is also provided, wherein results obtained for the case study are compared with data from literature previously obtained for the best commercially available competing photovoltaic technologies. Results clearly show a significant decrease in gross energy requirement, in green house gas emissions and also a shorter energy pay-back time for the micromorph technology

Evaluation of the environmental sustainability of a micro CHP system fueled by low-temperature geothermal and solar energy

In this paper we evaluate the environmental sustainability of a small combined heat and power (CHP) plant operating through an Organic Rankine Cycle (ORC). The heat sources of the system are from geothermal energy at low temperature (90-95 C) and solar energy. The designed system uses a solar field composed only of evacuated, non-concentrating solar collectors, and work is produced by a single turbine of 50 kW. The project addresses an area of Tuscany, but it could be reproduced in areas where geothermal energy is extensively developed. Therefore, the aim is to exploit existing wells that are either unfit for high-enthalpy technology, abandoned or never fully developed. Furthermore, this project aims to aid in downsizing the geothermal technology in order to reduce the environmental impact and better tailor the production system to the local demand of combined electric and thermal energy. The environmental impact assessment was performed through a Life Cycle Analysis and an Exergy Life Cycle Analysis. According to our findings the reservoir is suitable for a long-term exploitation of the designed system, however, the sustainability and the energy return of this latter is edged by the surface of the heat exchanger and the limited running hours due to the solar plant. Therefore, in order to be comparable to other renewable resources or geothermal systems, the system needs to develop existing wells, previously abandoned. © 2013 Elsevier Ltd. All rights reserve