In their work, Lessmann et al. (2005), propose the coefficients of variation CV ¼ 0.58, when calculating the integrated risk index in environmental management of contaminated areas in the chemical/petrochemical industrial zone in Tarragona, Catalonia, in Spain. In carcinogenic toxicity research of the above-mentioned industrial zone, Lessmann (2002) proposes to use a conservative coefficient of variation CV ¼ 0.9. However, when it comes to the analysis of environmental persistence of chemicals for the same industrial zone, described using triangular distribution, lognormal distribution is used, achieved from triangular distribution approximation based on standard deviation, calculated on the basis of triangular distribution parameters, described by Florito (2006).

In the MC simulation of input data in the LCA analysis of biopolymers, known for sugar or vegetable oil processing technology and created as part of the processes of generating renewable energy on the basis of biomass originating from cereal grains, Kim and Dale (2008) use standard deviation equal to 10% in a situation where there is not enough sufficient data defining the standard deviation of analysed input quantities in the process of generating renewable energy. The selection of standard deviations used in the simulation research of production and consumption of biofuels can be found in the Economic Research Service (Economic 2009).

95% confidence intervals are universally used in many different applications of statistics. This thesis focuses on the so-called classical interpretation of confidence intervals, as opposed to the so-called Bayesian approach, which makes it possible to treat the unknown population parameter as a random variable. Then it may be said that the unknown population parameter will be included in a given interval, with a probability of 0.95 (Aczel 2000).

There are a number of publications, which can be found in international literature, discussing the application of Bayesian inference in uncertainty analysis of simulation models in ecology. It is possibly worth quoting a statement made by Rubin (1970), mentioned in Smith’s publication (1995), which says that, “a good Bayesian does better than a non-Bayesian but a bad Bayesian gets clobbered”.

4.6Life Cycle Assessment of the Impact on Natural Environment of Energy Generation Processes in MSP S.A., Unit in Krako´w, Poland

4.6.1Aim and Scope of the Project

The LCA analysis of the energy generation processes, based on the example of MSP Power Plant, has been performed, for the purposes of the postdoctoral thesis, by the Mineral and Energy Economy Research Institute of the Polish Academy of Sciences (PAN), in Krako´w (Ocena 2008). It contains the material-energy balance (LCI) and the result expressed in the form of: characterisation, normalisation, and measurement stage results – values of which are given in eco-points (Pt) for individual

impact categories. The analysis has been performed in accordance with the international standards PN-EN ISO 14040:2006 (Environmental Management – Life Cycle Assessment – Principles and Framework) and PN-EN ISO 14044:2006 (Environmental Management – Life Cycle Assessment – Requirements and Guidelines).

The result of the LCA analysis is used here to present the stochastic comparative analysis of the environmental impact of the four scenarios of the energy generation processes in MSP Power Plant, in an annual cycle in 2005. The emphasis is on a more thorough characterisation of uncertainty in LCA studies, focusing on the uncertainty of source data. The quantitative data analysis has been performed based on MC simulation (Bieda 2008e, f, 2009a, b).

4.7Description of Energy Generation Processes in MSP S.A., Unit in Krako´w, Poland

In MSP Power Plant, in its power plant department (hereinafter referred to as “the power plant”), a fuel combustion for energy generation facility can be found. During the production activity the facility consumes non-renewable energy sources (hard coal) and water, it is a source of emissions into the atmosphere, and it generates various types of waste as well as noise emissions (Bieda 2007f, 2008c). In the examined year (2005), the Power Plant was using its seven steam boilers of the following power ratings, calculated using the heating value of fuels processed in the facility:

•TP 230 Boilers (4 units): 4 157 MWt ¼ 628 MWt,

•OPG-220 Boilers (2 units): 2 149 MWt ¼ 298 MWt,

•OP 230 Boiler (1 unit): 177 MWt.

These boilers were used to produce superheated steam of high parameters (pressure 9.0 MPa, temperature 510–540 C). The productivity of the entire facility amounted to 1,360 t/h and the installed power (attainable) – 977 MW, including: 4 138 ¼ 552 MW (TP 230 Boilers), 2 131 ¼ 262 MW (OPG 220 Boilers), and 163 MW (OP 230 Boiler). The steam produced in the facility was later used to generate the following: electric energy, blast furnace wind, process steam, 1.6 and 0.8 MPa, heat in the heating water, gas-free and heated softened water, and heated demineralised water. The above-mentioned manufacturing processes, as they are technologically strictly connected with the production of steam, 9 MPa, are an integral part of the facility.

The productivity of all of the boilers (superheated steam at the temperature 510–540 C, and pressure 9.0 MPa) in 2005 was equal to 1,360 t/h and the total installed power (attainable) to 977 MW. The production size of steam, 9.0 MPa, in the years 2003–2005 was formed in the following way:

•The year 2003: 3,633,000 t,

•The year 2004: 3,000,000 t,

•The year 2005: 3,690,000 t.

The produced steam, 9.0 MPa, was used to feed four turbo-generators (station number 3, 4, 5, and 6), three turbo-blowers (no. 1, 6, and 7), as well as reductioncooling stations – 9/3 and 9/0.8 MPa. The steam, after underexpansion or reduction, turns to steam that is consumed by the needs of the power plant – entirely (3.0, 0.12 MPa) or partially (0.8 MPa).

The steam with the pressure of 3.0 MPa, and temperature of 400 C (the source of which is the turbo-generator no. 4 and – as a reserve – the reduction-cooling station 9/3 MPa), is used to feed the turbo-blower no. 4, as well as the reduction stations 3/1.6 MPa, three top feedwater heaters, and turbo-blowers’ and turbo-compressors’ auxiliary devices.

The controlled bleeder valves of the turbo-generators no. 5 and 6, and (as a reserve) the three reduction-cooling stations 9/0.8 MPa, as well as the second uncontrolled bleeder valve of the turbo-generator no. 3 are the source of steam, 0.8 MPa. The consumers, within the plant, of this steam are the top feedwater heaters of the central heating system (networked), the reduction-cooling stations 0.8/0.12 MPa, secondary degasifiers (feeders), and a facility for emergency and periodical steaming of gas piping of the Power Plant.

The controlled bleeder valves of the turbo-generators no. 3, 5, and 6, the three reduction-cooling stations 0.8/0.12 MPa, the expanders of periodic desludging, the secondary expanders of constant desludging, the expanders of dehydration in the turbo-blowers and turbo-generators house, and the third bleeder valves of turboblowers turbines (no. 1, 6, and 7), are the source of steam, 0.12 MPa. This steam is used to feed basic feedwater heaters of the central heating system, raw water heaters of ChOW, as well as degasifiers (preliminary, evaporator-based and linked).

The following energy carriers are the final products of the power plant:

•Electric energy (maximum power: 96 MW), used by separate objects at the Mittal Steel Poland S.A. Power Plant in Krako´w (including the power plant);

•Blast furnace wind (the output of the facility when two out of four turbo-blowers are in operation: 522,000 m3/h), generated to meet the needs of the blast furnaces department at the Mittal Steel Poland S.A. Power Plant in Krako´w;

•Process steam with the pressure – 1.6 MPa, generated to meet the technological needs of individual plants at Mittal Steel Poland S.A. Power Plant in Krako´w;

•Process steam with the pressure – 0.8 MPa, generated to meet the technological needs of individual plants at Mittal Steel Poland S.A. Power Plant in Krako´w and of the Power Plant itself;

•Heat in the heating water with the temperature of 150 C (the return temperature of 70 C), generated first and foremost to meet the heating needs at the Mittal Steel Poland S.A. Power Plant in Krako´w, and partially to meet the heating needs of the part of the Nowa Huta district;

•Gas-free and heated softened water (of parameters: 1.5–1.8 MPa, temperature 103–105 C), generated to meet the needs of evaporative cooling systems of