G-19 Allocation case: production of renewable energy on-site

Aspect G-19 Allocation case: production of renewable energy on-site
 The production of on-site renewable energy can occur at different time of the day, month and year, and may or may not meet on-site needs. Renewable energy may be consumed on site, or may be exported to the electricity grid or to a heating network, for example, according to the instantaneous needs of the building.How should this on-site energy production be accounted for, and can the loads and benefits be allocated between the electricity grid and the building?

related study objective

stand-alone LCA comparative assertion

related study phase

goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for

new buildings existing buildings construction products screening LCA simplified LCA complete LCA
The amount of renewable energy produced with the help of on-site systems to supply operational energy for the use of the building should be accounted for as part of the LCI of the building being assessed, attributing the on-site production to the building life cycle.The allocation of exported energy follows the case studies of EN 15978, Annex B.
Rules from:
EN 15978 Boundary for the operational energy use (Module B6)
Annex B (informative) Exported energy – Case studies

Provisions: 7.9.3 Solving multifunctionality by allocation
Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision

The method for the calculation of on-site renewable energy production should be consistent with [EN 15643-1]. Renewable energy produced by systems located on the building site and supplying energy demand for building uses should be considered (e.g. thermal solar panels, photovoltaic panels, wind turbines…). Other thermal energy gain from on-site renewable energy sources (solar gains through windows or solar walls) can be also accounted for complete LCA. Calculation method should be reported and justified.Boundary for energy production at operational stage should be consistent with boundary for product (A1–A3) and construction processes (A4–A5) modules:

  • If the energy produced by the on-site system is accounted for in Module B6, the production system should be accounted for in Modules A1–A5.
  • The accounting of renewable primary energy for the operational stage should be consistent with the accounting of renewable primary energy for materials, the amount of renewable primary energy is the measured output energy, not the amount of energy potentially available.

For on-site systems exporting energy outside the building boundary see the aspect described in Module B6: “Operational energy calculation – Allocation of energy production for on-site systems connected to grid”.

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