B. Corona

Social Life Cycle Assessment of a Concentrated Solar Power Plant in Spain: A Methodological Proposal

Measuring the sustainability of goods and services in a systematic and objective manner has become an issue of paramount importance. Life cycle sustainability assessment (LCSA) is a holistic methodology whose aim is to integrate into a compatible format the analysis of the three pillars of sustainability, namely, economy, environment, and society. Social life cycle assessment (S†LCA) is a novel methodology still under development, used to cover the social aspects of sustainability within LCSA. The aim of this article is to provide additional discussion on the practical application of S†LCA by suggesting a new classification and characterization model that builds upon previous methodological developments. The structure of the social analysis has been adapted to maintain coherence with that of standard LCA. The application of this methodology is demonstrated using a case study—the analysis of power generation in a concentrated solar power plant in Spain. The inventory phase was completed by using the indicators proposed by the United Nations Environment Program/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) Guidelines on S†LCA. The impact assessment phase was approached by developing a social performance indicator that builds on performance reference points, an activity variable, and a numeric scale with positive and negative values. The social performance indicator obtained (+0.42 over a range of –2 to +2) shows that the deployment of the solar power plant increases the social welfare of Spain, especially in the impact categories of socioeconomic sustainability and fairness of relationships, whose results were 1.38 and 0.29, respectively.

Environmental Assessment of a HYSOL CSP Plant Compared to a Conventional Tower CSP Plant

The aim of this paper is to evaluate the environmental performance of a Concentrating Solar Power (CSP) plant based on HYSOL technology. The plant under investigation is a solar tower system with 14 hours thermal energy storage using biomethane as auxiliary fuel and using a 100 MWe steam turbine and a 80 MWe gas turbine in the combined cycle (Brayton and Rankine) characteristic of the HYSOL technology. The results evidence that HYSOL technology performs significantly better in environmental terms than conventional CSP. This evidence is particularly relevant in the climate change category where HYSOL plants presents 43.0 kg CO2 eq /MWh. In contrast, the hybrid CSP plant operating with natural gas emits 370 kg CO2 eq /MWh. This difference is attributable primarily to the nature of the auxiliary fuel (biomethane in HYSOL and natural gas in conventional CSP), but also to the higher thermal efficiencies achieved in the HYSOL configuration, which prevents the emission of 106 kg CO2 eq /MWh. The environmental significance of the additional components and infrastructure associated with the Brayton cycle in the HYSOL technology (gas turbine, Heat Recovery System and Low Temperature Energy Storage) are negligible.

Technical and Environmental Analysis of Parabolic Trough Concentrating Solar Power (CSP) Technologies

With over 100 commercial projects in operation or under construction worldwide, concentrating solar power (CSP) has the potential to play a key role in the mass production of power. Despite the enormous potential, this technology suffers from a number of weaknesses that are related to the intermittency and variable nature of the solar resource, which results in reduced capacity factors and operation flexibility. The incorporation of energy backup systems provides a solution to these drawbacks, allowing CSP to become more dispatchable, cost effective, and easier to integrate into existing power grids. Backup systems may come in the form of thermal energy storage (TES) or auxiliary fuels (mostly natural gas but also coal, fuel, solid biomass, biogas, biomethane, and syngas). Auxiliary fuels are usually integrated using conventional furnaces or boilers, although higher efficiencies may be achieved when using conventional or aeroderivative gas turbines. The possibility of using heat transfer fluids (HTF) with higher thermal stability (like molten salts) would permit integration of energy backup systems in a more efficient and cost-effective manner. A great deal of research and development is going on at present with the aim of devising CSP plants capable of competing with other energy resources and technologies. This paper provides a critical analysis of CSP technologies based on parabolic trough solar collectors, describing the pros and cons associated with incorporating backup energy systems. This analysis includes technical and environmental aspects of different CSP configurations.

Environmental and economic analysis of power generation in a thermophilic biogas plant

This paper investigates the environmental and economic performance of the power production from biogas using Life Cycle Assessment, Life Cycle Costing and Cost Benefit Analysis methodologies. The analysis is based on a commercial thermophilic biogas plant located in Spain where is installed a Combined Heat and Power system that produces electricity that is sold to the grid. Power generation has been assumed as the only function of the biogas system, expanding the system boundaries to include the additional function related to the end-of-life management of the biowastes. Thus environmental burdens from the conventional management of residues were calculated separately and subtracted. The base scenario involves using agri-food waste, sewage sludge and pig/cow manure as substrates. This situation is compared against an alternative scenario where the production of synthetic fertilizer is surrogated by the digestate. The results have shown that the most impacting activities in all impacts categories of power production are primarily attributable to the operation and maintenance of the biogas plant except for water resource depletion and climate change. The avoided emissions associated with the conventional management of pig/cow manure more than offset GHG emissions of the biogas system resulting in a negative impact value of -73.9gCO2eq/kWh in the base case scenario. The normalized results show that local impact categories such as primarily human toxicity, fresh water ecotoxicity and particulate matter are the most significantly affected by the biogas system while global impact categories as climate change and ozone depletion are less severely affected. The operation and maintenance phase is also shown to be the largest contributor after the life cycle cost analysis, followed by the construction and dismantling of the biogas plant and the profitability of the project is primarily related to the income obtained from the management of the biowastes used as substrates.

Socio-economic Effects of a HYSOL CSP Plant Located in Different Countries: An Input Output Analysis

The aim of this paper is to estimate the socioeconomic effects associated with the production of electricity by a CSP plant with HYSOL configuration, using Input Output Analysis. These effects have been estimated in terms of production of Goods and Services (G&S), multiplier effect, value added, contribution to GDP, employment creation and labor intensity. The analysis has been performed considering that the plant was established in four countries contemplated as suitable for HYSOL technology: Spain, Mexico, Chile and Kingdom of Saudi Arabia. The results indicate that producing electricity in a HYSOL CSP plant generates positive impacts on the economy and the employment in every country, producing the following ranges of socio-economic effects: a 0.05%-0.38% increment of the national GDP, creation of 11662-21053 jobs-year and production of 1412-2565 M

Environmental, energy and economic analysis of a biomass supply chain based on a poplar short rotation coppice in Spain

of domestic G&S. The economic results are particularly favorable for Spain and Chile, which has been associated with higher multiplier effects (2.05 and 2.01 respectively) and higher demand of G&S in the Operation and Maintenance phase. In the case of Chile, favorable results are also due to the national production of nitrate salts employed in the thermal energy storage system. Employment results are more favorable in Mexico and Chile, which has been associated with the higher labor intensity of its national economies.