Gabi 4.3 - life cycle assessment software

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Gabi 4.3 software is versatile program which can be used for life cycle assessment, cost analysis, efficiency analysis, Global Reporting Initiative-reports (GRI) and companies annual reports. Basic idea is to model all the processes, which are needed to create a product. These processes include all the flows, which are needed for manufacturing the product or which are formed because of manufacturing.

The model of energy production in Helsinki Metropolitan area is made by Gabi 4,3 life cycle assessment program. The basic idea of life cycle assessment is to model every flow and emission from raw material to end of the product. In this case every flow and emission is impossible to model, because vast amount of flows and emissions in energy production, but the main flows and emissions are modelled.

In the model Helsinki Metropolitan area is divided to four areas by the cities; Espoo, Helsinki, Kauniainen and Vantaa. Each city has a process to define need of thermal energy in the city and how much each heating method produces energy, which are calculated based on district heating and floor area statistics and calculations in [[]] [Statistics of Finland 2008].

Use of floor area statistics makes calculation results unreliable, because it is based on building registry. Building registry is not updated, if the change of heating method does not require building permission. This why estimations for other used heating methods fractions are made better by using Haaparanta et all 2003 report of small scale combustion in Helsinki Metropolitan area.

In Haaparanta et all 2003 report is estimated that 44 % in Helsinki, 60 % in Espoo and 66 % in Vantaa of separate residential houses, which does not use wood as main heating source, use wood for supplementary thermal energy production. Main method to produce thermal energy in residential buildings is a thermal energy reserving stove in Helsinki Metropolitan area, 90 % of thermal energy is produced by this type stove. Almost all the new residential houses are assessed to have a stove for wood use. In the model calculations 153 850 GigaJoules (GJ) of thermal energy is produced in buildings, which use wood as main fuel, and in Haaparanta et all 2003- report total thermal energy produced from wood is estimated to be 945 000 GJ in 2002. The total thermal energy produced from wood can estimated to be significantly higher than the floor area statistics show [Haaparanta et all 2003]. In this study total thermal energy production fraction from wood is estimated to be six times more what the statistics show. Estimation is made based on Haaparanta et all 2003- report.

Amount of district heating production in a city is taken from district heating statistics and a single district heating production unit values from energy company data, those values are reliable.

Large scale district heating units are not modelled individually like small scale district heating units. Emissions of large scale district heating units are calculated by using fuel information of district heating statistics and emission factors for district heating units are taken from Kivihiilitoimikunta 2004 and Karvosenoja M., 2008 – reports or calculated by using companies emission data [Fortum Heat and Power 2008, Helsingin energia 2008, Vantaan energia 2008]. Large scale district heating units are divided to six groups based on the fuel or heat source, which are natural gas, coal, heavy fuel oil, light fuel oil, biogas and geothermal heat.

Possible new nuclear plant is modelled to be in Loviisa, if the plant is build. All the nuclear plant parameters are taken from Fortum’s application for the 6th nuclear plats in Finland. It is estimated to produce energy in 2020 and to produce 1000 MW thermal energy to the district heating network of Helsinki. This would be more than enough to cover total need of thermal energy in Helsinki and some of the needs of thermal energy in Vantaa and Espoo. This would dramatically change energy production in Helsinki metropolitan area and would lower the carbon dioxide emissions considerably, because the fossil fuels would be replaced by nuclear fuel. If the nuclear plant is connected to the district heating network of Helsinki, it would produce excess energy. In the model this excess thermal energy is estimated to be transferred then evenly to the district heating networks of Vantaa and Espoo. Thermal energy flows between district heating networks are modelled also. [Fortum Heat and Power Oy 2008].

In the figure 11 is shown the model in 2007 situation. Shown flows in the figure are thermal energies. Sub-plans for the other used heating methods and small scale district heating unit processes are used to make the model structure simpler.

Figure 11. Simplified figure of the gabi-model for the year 2007.

From the figure 11 shows, most of the thermal energy in cities is produced by district heating, except in Kauniainen. District heating is produced mainly from coal and natural gas and produced thermal energies in small scale district heating units is very small in fraction.

In Figure 13 is presented the division of other used heating methods.

Figure 13. Other used heating methods sub-plan of Helsinki. Division of other used heating methods are made based on floor area statistics, where the other used heating methods are divided to nine groups; coal, geothermal, electricity, heavy fuel oil, light fuel oil, natural gas, peat, wood and other-unknown heating.

Sub-plan of small scale district heating units in Vantaa is shown in figure 13.

Figure 13. Sub-plan for small scale district heating units in Vantaa.

Small scale district heating units are individually modelled. Produced thermal energy and emissions are assessed individually for each small scale district heating unit, based on data of energy production companies [Fortum Heat and Power 2008, Helsingin energia 2008, Vantaan energia 2008].

On an assessment of district heating and cooling future in Finland has evaluated future consumption of district heating and cooling up to year 2050 and which fuels will be used to produce the needed district heating. On that assessment demand of district heating is estimated to start decreasing after year 2020 in Finland and distribution of used fuels is presented in future in figure 14 [Vehviläinen et all 2007].

Figure 14. Distribution of used fuels in district heating units now and in the future [Vehviläinen et all 2007].

Decreasing of district heating consumption probably wont happen in Helsinki Metropolitan area as the calculations shows in chapter 3.1, but the increase of district heating consumption can be estimated be lower than in the past.

Calculations in the chapter 3.1 and YTV 2003 report is used for future estimations. District heating fraction of total floor area future development in a city has given three scenarios in this study. In base scenario floor area of district heating building is estimated to remain in 2007 level. In scenario 1 floor area of district heating buildings is estimated to keep same fraction of total floor area as in 2007. In scenario 2 floor area of district heating buildings fraction of total floor area is estimated to increase at the same rate as in figure 15 [Vehviläinen et all 2007].

Figure 15. District heating building floor area fraction of the floor area in the future, if estimated that the increase would be as it has been between years 2000 and 2007 [Statistics of Finland 2000, Statistics of Finland 2008, City of Vantaa 2008].

Helsinki Metropolitan Council estimates that emission per inhabitant will remain more or less at the same level as today. [Aarnio et all 2008]. A heating method fraction of total floor area of other used heating methods is estimated to be same as in 2007 in this study, because there are not studies or calculations of future changes for other used heating methods.

On large scale district heating unit production, YTV estimates that major changes area won’t happen until year 2016 in Helsinki metropolitan, only minor changes on fuel side to less carbon dioxide emissions affecting fuels. Emission trading and clean air for Europe-program will affect pressures to lower the emissions in energy production [Aarnio at all 2008].

Thermal energy production changes in large scale district heating units are not assessed in this study, because it is not in boundaries of this study. Distribution of used fuels and structure of large scale district heating units are estimated to be same as in 2007 in this study.

The model calculates the produced thermal energy for each heating method and district heating unit. When the produced energy is know, can be the emissions calculated by using emission factors and efficiencies of different energy production methods. District heating units emissions are calculated by using emission factors, which are presented in table 15, and district heating of Finland statistics, where is listed fuel use of the district heating companies. For other used heating methods is used estimation in Haaparanta et all 2003-report, where efficiencies of other heating methods are calculated by using statistics of produced energy in Finland 2002. Those calculations are presented in table 18.

Table 18. Efficiencies of other used heating methods [Haaparanta et all 2003, Statistics of Finland 2001]

	Consumption of energy	Beneficial energy	Fraction	Efficiency
	TJ	GWh	%	%

Wood 41400 6325 13 55 Peat 510 85 0,2 60 Coal 90 15 0,03 60 Heavy fuel oil 3330 768 1,6 83 Light fuel oil 43100 9338 19 78 Natural gas 2020 505 1 90

Emission factors, which are used in the model, are presented in table 19.

Table 19. Used emission factors in the model [Kivihiilitoimikunta 2004, Karvosenoja 2008].

	Natural gas	Coal	Heavy fuel oil	Light fuel oil	Wood 	Peat

Carbon dioxide [t/MWhfuel 0,203 0,34 0,278 0,267 0,409 0,382 PM2,5-factor for large scale district heating plants [kg/MWhthermal] 0 0,01476 0,1116 0,00072 0,01476 0,01476 PM2,5-factor for small scale district heating plants [kg/MWhthermal] 0 0,108 0,1116 0,00072 0,108 0,108 PM2,5-factor for other used heating methods [kg/MWhthermal] - - - 0,00072 2,52 -

See also

• GaBi website
• EC website about GaBi databases
• PE international, GaBi developer.