Toward sustainable mountain huts with environmental impact assessment of used technologies

A mountain hut (MH) is usually located in very sensitive parts of the nature. Operation phase of the MH emits pollutants into environment, because of energy supply for electricity and heat and transport linked with MH operation. If energy carriers used are mainly fossil fuel based that can cause significant environmental impacts. One of the goals of the EU SustainHuts project (http://sustainhuts.eu) is identification of technologies used for heat and electricity generation in MH. Through environmental assessment, technologies are compared to show environmental impacts of each technology prior to make case studies of specific MH. Life cycle assessment (LCA) is the basic methodology used in the study. Functional unit is 1kWh of generated energy, heat or electricity. Gabi Thinkstep software was used for LCA modelling and in life cycle impact assessment CML2001 indicators were used with additional Sofi indicators. Generic data was used from Ecoinvent 3.5 and Gabi professional database. In all MH observed electricity is partly generated with diesel generators. On other hand it is good to realize that in many cases the photovoltaic (PV) is used at least to partially cover the electricity demand. In one case (Bachimaña, Pyrenes, Spain) there is small hydropower, but without optimal control. Wind turbine is a case in one MH but not working because of mechanical failure. For heat generation in many cases mixed wood is used as a main fuel source. In the case of Lizara hut propane-butane (natural gas) is used in gas heater, in the case of Bachimana diesel heater is present and the Refugio Torino is connected to the electrical grid what makes this MH unique in the sense of environmental assessment. For transportation main technologies are minivans, ropeways with electricity or diesel generators and helicopters in the case of inaccessibility. For electricity generation it is showed that from environmental point of view diesel electricity generation is the worst case, but still used in many MH since it is simple to manage and control. In many MH PV with battery energy storage/buffer slowly takes over that is much better from environmental point of view. Wind and hydro electricity generation have the lowest environmental impact, but they are not applicable in all locations. The worst case in heat generation is diesel and electricity heat generation. Natural gas has much smaller environmental impact than diesel or electricity heat generation. Wood heat generation has quite low environmental impact in global environmental indicators, but quite high in local environmental indicators, where combustion process of wood contribute to photochemical ozone creation, toxicity of marine/fresh water and also human toxicity.