Energy production (Energiproduktion)
Heat and electricity can be produced from agricultural products.
Energy supply (Energiforsyning)
Heat and electricity is used in processes throughout the lifecycle of food products.
Electricity is usually drawn from the public grid which is continuously supplied by a variety of power plants located in Denmark and neighbouring countries. The sources of electricity vary during the day and over the year and the exact source of a given kWh electricity can not be identified. Changes in electricity consumption induced by the users influence the marginal electricity production technology whereas other production technologies remain unchanged. The marginal electricity production technologies are difficult to determine, but following Weidema (2003), natural gas fired power plants have been identified as the marginal electricity source of electricity in Denmark in the years to come. Hence, exchanges associated with marginal electricity production applied in this project are determined from emission factors derived from natural gas fired power plants (ETH 1996). Coal fired power plants are likely to be marginal electricity sources in Denmark as well (see Weidema 2003) and a sensitivity analysis with coal based electricity can be useful for detailed comparison of products or processes when impacts from electricity production are significant.
District heat is co-generated with electricity and environmental
impacts associated with heat and electricity production at
combined heat and power plants
must be shared between the two products.
It has been assumed 1) that district heat produced as a result of marginal
electricity production will be in excess in most cases and 2) that other factors than availability of excess
heat from electricity production determines the size of the district heat
network in the years to come.
Therefore, exchanges associated with combined heat
and electricity production is allocated entirely to the electricity.
Heat applied in Danish food industry is produced in many different kinds of furnaces with different fuels. In order to determine environmental impacts associated with food products produced in Denmark in general, a national mix of energy carriers specific for each sector has been applied (Danish NAMEA, 1999), see the table below.
Danish NAMEA (1999). National accounting matrices including environmental accounts. Statistics Denmark.
Weidema B (2003). Market information in life cycle assessments. Technical report, Danish Environmental Protection Agency (Environmental Project no. 863).
Veks (2001). Environmental declaration, Vestegnens Kraftvarmeselskab I/S.
Livscyklusvurdering af dansk el og kraftvarme (2000). Hovedrapport. In Danish.