A Comparison of the Environmental Impact of Different Heating Systems Using the Life Cycle Approach

The goal of this study is to define the environmental burden of residential heating alternatives, namely natural gas, liquefied petroleum gas (LPG), and an air to water heat pump (HP), using life cycle assessment (LCA) and environmental life cycle cost (ELCC) methods. A novel methodology was presented for ELCC by dividing the LCA results into two parts as raw material based LCA (LCA(R)) and emission based LCA (LCA(E)) to avoid the double counting of environmental impact. Six impact categories were investigated in the LCA: elemental-based abiotic depletion potential (ADP(e)); fossil fuel based abiotic depletion potential (ADP(ff)); global warming potential (GWP100); human toxicity potential (HTP); acidification potential (AP); and photochemical oxidation potential (POP). In ELCC, a steady-state cost model was used. An eco-efficiency (EE) index was used to integrate environmental and economic results. According to the results, natural gas has the lowest impact apart from ADP(ff). The LPG heating system has the highest GWP100 value. In contrast, the HP heating system has the higher impact values for ADP(e), HTP, AP, and POP than those of natural gas and LPG. The ELCC value of natural gas (6.06euro) is lower compared with LPG (14.55euro) and of the HP (coefficient of performance value = 3.5) (10.30euro). The HP would have the lowest ELCC value if the electricity had been supplied from a photovoltaic panel (1.43euro). According to the EE index based on GWP100, LPG and the HP fall under the entire non EE area relative to the natural gas.