Life Cycle Assessment of a solar thermal system in Spain, eco-design alternatives and derived climate change scenarios at Spanish and Chinese National levels

Abstract

Solar thermal energy is considered a 'clean' form of energy; however, environmental impacts occur during its life-cycle. The present work compares the environmental performance of two scenarios: a solar thermal system for providing domestic hot water (DHW) used in conjunction with a traditional natural gas heating system, and the natural gas heating system on its own. Weak points are found and different eco-design scenarios are evaluated in order to achieve a more circular economy. In addition, the authors explore what would be the national Greenhouse Gas emission reduction potential of a wider use of domestic solar hot water systems (DSHW) in China's and Spain's built environment. In this case, five displacement methods are suggested to show how the emissions reduction vary. Through a review of the state of the art and a Life Cycle Assessment of a solar system the two scenarios are assessed. Some impact categories, such as global warming, suggest a markedly better performance of the solar system (-65%). However, weak points in the solar solution have been identified as there is an increase of impacts in cases such as acidification (+6%) and eutrophication (+61%), mostly due to the metals used. The components with higher environmental impact are the collector, the tank, and the copper tubes. The reduction of national emissions by promoting DSHW depends on the actual displaced technology/ies. The consequences on national emissions reduction depending on these choices are assessed. The potential reduction of emissions, if 30% of the DHW were covered with solar sources, would be between 0.38% and 0.50% in the case of Spain and between 0.12% and 0.63% in China.

Compost Heat Recovery Systems: Global Warming Potential impact estimation and comparison through a Life Cycle Assessment approach

“…Indeed, from literature some data about the use of Electricity and Natural Gas Systems (NGS) for domestic heating were also collected: from Martinopolous et al emerged a value of 1.41 kg CO2-eq /kWh if the thermal load is entirely covered by electricity, using country specific data for electricity production in Greece (Martinopoulos et al, 2013) and Pratiwi reported a value of Bayer et al of 1.18 kg CO2-eq /kWh as electricity mix average carbon emission in Poland (Bayer et al, 2013;Pratiwi and Trutnevyte, 2020). Moreover, Albertì et al reported 0.264 kg CO2-eq /kWh for domestic hot water production from NGS (Albertí et al, 2019).…”

“…Having the total thermal load expressed in kWh and the total emissions expressed in kg CO2-eq , the values were expressed in kg CO2-eq /kWh. Albertí et al (2019) directly reported the values of the Global Warming impact in kg CO2 . All of the other cited studies (Frick et al, 2010;Karlsdottir et al, 2014;Lacirignola and Blanc, 2013;Pratiwi et al, 2018;Trutnevyte, 2020, 2021) reported the values of the Global Warming impact in kg CO2-eq /MWh so the values were just expressed in kg CO2-eq /kWh.…”

Life Cycle Analyses for Solar Thermal Collectors

“…Also, the materials used in product assembly, which accounted for less than 1% of the weight of solar panels, were left out of this analysis. The DHWSs were estimated to have a 10-year life cycle even if there are working systems that are 20 years old, (Albertí et al, 2019).…”

Environmental assessment of central solar heating plants with seasonal storage located in Spain

“…(Hang et al, 2012) carried out a comparative LCA of thermal solar systems focused exclusively on the analysis of flat plate collectors and vacuum tubes. Other authors (Albertí et al, 2019;de Laborderie et al, 2011) compare the environmental performance of solar thermal system for providing DHW used in conjunction with complementary heating systems and more conventional scenarios providing the same service (as natural gas heating system). The CSHPSS technology is an environmentally and sustainable and feasible option, both in warm and Mediterranean climates (Tulus et al, 2016) and in coldest regions (Welsch et al, 2018), where district heating should be featured prominently among other options.…”