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. Flows are determined in the process, so the can be physical or nonphysical. 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.

On assessment of small-scale energy production in the Helsinki metropolitan area, the 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. [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 in this type stove. Almost all the new residential houses are assessed to have a stove for wood use. In 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 single units values from energy companies 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 be built in 2020 and to produce 1000 MW thermal energy to the district heating network of Helsinki [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 units processes are used to make the model structure more simpler.


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

Thermal energy flows between district heating networks are also modelled. There is also a plan to build sixth nuclear plant to Finland. One of the discussed locations for the new nuclear plants has been Loviisa and in according to Fortum, it would be possible to link nuclear plant to Helsinki metropolitan’s district heating network. Fortum estimated that, if the plant is build and connected to the district heating network, it would produce about 1000 MW thermal energy to the network each year. 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 [Fortum Heat and Power Oy 2008]. In the model this excess thermal energy is estimated to be transferred then evenly to the district heating networks of Vantaa and Espoo.

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].

Calculations and YTV 2003 report is used in future estimations. Fractions of district heating is estimated to increase same rate as it has between year 2000 and 2007 in each city, except in Vantaa, where district heating fraction of the floor area is estimated to increase 2,1 % to year 2010, because of Marja-Vantaa extension to the district heating network. District heating is planned to be main heat source in Marja-Vantaa and floor area is estimated to increase 300 000 m2 and this increase would mean 2,1 % increase to district heating fraction [City of Vantaa 2008]. District heating fraction of the floor area estimations are presented in figure 14.


Figure 14. District heating fraction of the floor area estimations [Statistics of Finland 2000, Statistics of Finland 2008, City of Vantaa 2008]. Other heating methods fractions and small scale district heating units thermal energy production rate is also estimated to remain in 2007 level. New small scale district units are not expected to be build [Aarnio et all 2008].

On large scale district heating units 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. In this study it is estimated that large scale units production and structure will be same as in 2007.

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 mentioned in table 13, 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 13.


Table 13. 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 14.

Table 14. 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

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