12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaPRIMARY ENERGY EFFICIENCY AND SYSTEMS ENGINEERINGM.Berner 1 , R. Ulseth 1 , J.Stang 21 Norwegian University of Science and Technology (NTNU)2 SINTEF Energy ResearchABSTRACTThe revised Energy Performance of Building Directive(EPBD) [1] emphasizes that the energy performance ofa building shall be calculated by use of Primary EnergyFactors (PEF). Calculation of CO 2 emission will not bemandatory so far. Thus EPBD will reduce the use ofnon-renewable energy, incite the use of energy fromcombined heat and power generation (CHP) andreduce the energy consumption in the building sector.A simplified method that enables comparison of thePEF from different energy chains is required. However,calculation of all the parameters affecting the PEFvalues like energy used for extraction, transportation,power and heat generation etc. is time-consuming. Themethod described in EN 15603 [2] is rather general land provides PEF values for 13 energy carriers andchains. This is based on average European values. LifeCycle Assessment methods include several of therelevant steps, but a complete LCA often implycollection of more than 6000 parameters.The systems engineering method used here havedemonstrated the feasibility of developing a genericmethod that provides credible data for calculatingprimary energy efficiency. It applies the generic methodon energy chains in the Nordic region which is relevantto CHP plants utilising bio based fuel.INTRODUCTIONBackgroundThe terms Primary Energy, Primary Energy Efficiencyand Primary Energy Factors (PEF) are introduced [3] -[8] in order to compare different energy sources andchains based on losses and a calculated environmentalimpact.Primary energy is energy that has not been subject toany conversion or transformation process. The use ofprimary energy factors takes into account the energythat are used from the extraction of the energy carrierand all of the losses until energy is delivered to the enduse in the desired form such as heat, cooling orelectricity .The primary energy factor (PEF) expresses how muchprimary energy is needed to deliver 1 unit of power,heat or cooling to the end user. The term primaryenergy efficiency (PEE) therefore is used to describethe total use of energy from extraction to the end user.ExtractionProcessingFigure 1 A Typical energy chainMethodologyAn energy chain might consist of several elements orprocesses from extraction, through processes such asdrying, storage, transport, power/heat/cool generation,and distribution to the end user. In order to ensure thatthere is a correct PEF, all elements that influence theenergy flow have to be accounted for.The energy balance or calculation of the energyefficiency of a process focuses primary on the energyinput in the form of fuel and the output in kWh, andlacks information on the energy used to buildinfrastructures such as the power plant, distribution net,transportation and the extraction.Life Cycle Assessment (LCA) might contribute toprovide such information in a generic method.However, the number of input parameters, often morethan 6000 in an ordinary LCA analysis demonstratesthe need for an easily accessible method.Systems engineering is a method that has beendeveloped gradually with increasing complexity ofprojects and systems. Systems engineering is oftenconsidered to have started at Bell Laboratories in the1940s, later applied in organizations such as NASAand formalized as a separate engineering field with theformation of INCOSE [9] in 1990. The benefits ofsystems engineering is the possibility to treat complexsystems with several subsystems. Therefore, as a firststep in the development of a method a systemsengineering approach has been chosen. The mainobjective is to develop systems and methods thatenable a sufficiently reliable calculation to be made ofthe primary energy factor (PEF) in general and fordifferent energy chains with required level of details.At present systems engineering approaches have notbeen found to have been previously applied on thedevelopment of generic PEF methods for differentenergy chains.ObjectiveStorageTransportGenerationTransformationTransmissionDistributionThe objective of this paper is to show how systemsengineering can be used as a tool to reveal important31