Description and aim:
The aim of this scenario is to assess the potential environmental benefits arising from producing hot water with renewable energy, i.e. solar energy.
Area of intervention:
● Hotspot addressed: the energy consumption during the use phase for domestic hot water.
● Whole basket – renovation and new buildings
● Life cycle stage: production + EoL phase (solar boiler) and use phase (energy consumption for the production of hot water)
Policy relevance: Energy and resource efficiency in the building sector Rationale for building the scenario:
Renewable energy is seen as an important strategy within the EU to reduce the carbon emissions and increase resource efficiency in the building sector. A simple technology with relatively high benefits which can be applied at the level of the dwelling is a thermal solar boiler for the production of domestic hot water. For this reason, the installation of a solar boiler is selected as the third scenario.
Parameters modified in the model:
The following parameters are modified to model this scenario:
● Production phase: solar boiler (i.e. collectors. pump. control system and storage tank) is added to the inventory
● Construction phase: no changes
● Use phase: calculated production of hot water with solar boiler to be deducted from the baseline hot water production. The calculation of the production of hot water takes into account the climatic zone and the number of people in the dwelling. ● EoL phase: solar boiler EoL treatment
Assumptions for the calculation of the production of hot water with solar boiler are the following. A collector surface of 1.2 m²/person is assumed for both the single family and multifamily houses.
Based on expert judgement, for the single-family houses a storage tank of 250 litres is assumed in the warm climate, and 200 litres in the moderate and cold climate. For the multi-family houses, it is assumed that one large storage tank (2500 litres in the warm climate, 1400 litres in the moderate and 1000 litres in the cold climate) is installed for the whole building. These assumptions lead to the following modelling parameters:
Table 56. Size of solar collector (m²) / dwelling
<1945 1945-1969 1970-1989 1990-2010 <1945 1945-1969 1970-1989 1990-2010
zone 1 4.12 4.12 4.12 4.12 2.44 2.44 2.44 2.44
zone 2 3.25 3.25 3.25 3.25 2.46 2.46 2.46 2.46
zone 3 3.39 3.39 3.39 3.39 2.01 2.01 2.01 2.01
solar collector (m²)/dwelling
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Table 57. Size of water storage tank (litres) / dwelling
water storage tank (litres)/dwelling
SFH MFH
<1945 1945-1969 1970-1989 1990-2010 <1945 1945-1969 1970-1989 1990-2010
zone 1 250 =2500/16
zone 2 200 =1400/16
zone 3 200 =1000/16
It is furthermore assumed that the inhabitants consume 60 litres of hot water per day, per person with the following characteristics:
Tin (warm climate) = 15°C Tin (moderate climate) = 10°C Tin (clod climate) = 5°C Tout = 45°C
The solar boiler system contributes to the production of domestic hot water, resulting in a reduced need of additional water heating. The production by the solar boiler system has been calculated with dynamic energy simulations (Baldinelli, 2016) and have led to the results presented in Table 58. Table 59 summarizes the remaining annual energy demand for domestic hot water by the conventional system (i.e. not covered by the solar collector), expressed in kWh/dwelling*year. Both the amount of energy produced by the solar system as the remaining amount to be covered by the conventional systems (in line with the assumptions of the BoP baseline scenario) are summarised in the tables.
Table 58. Results dynamic energy simulations: annual energy production by solar collector
system (kWh/dwelling*year)
Table 59. Remaining annual energy demand for domestic hot water to be covered by the
conventional system (kWh/dwelling*year)
Results:
Table 60 and Table 61 summarise respectively the characterised and normalised results for the fourth scenario for the whole BoP housing stock, expressed as impact per EU citizen. In the last column of the tables, the results are also shown for the baseline scenario in order to get a first idea on the effect of this first intervention analysed.
<1945 1945-1969 1970-1989 1990-2010 <1945 1945-1969 1970-1989 1990-2010
zone 1 1,554 1,554 1,554 1,554 860 860 860 860
zone 2 439 439 439 439 397 397 397 397
zone 3 453 453 453 453 314 314 314 314
annual energy production solar collector (kWh)/dwelling
SFH MFH
<1945 1945-1969 1970-1989 1990-2010 <1945 1945-1969 1970-1989 1990-2010
zone 1 516 516 516 516 365 365 365 365
zone 2 2,403 2,403 2,403 2,403 1,747 1,747 1,747 1,747
zone 3 2,850 2,850 2,850 2,850 1,642 1,642 1,642 1,642
annual remaining energy demand to be covered by the conventional system (kWh)/dwelling
93
Table 60. Characterised results. BoP housing scenario solar collector for DHW compared to
baseline scenario (yearly impact EU citizen)
Impact category Unit
Scenario solar collector for DHW Baseline scenario
Climate change kg CO2 eq 2.56E+03 2.62E+03
Ozone depletion kg CFC-11 eq 3.24E-04 3.33E-04
Human toxicity. non-cancer effects CTUh 2.68E-04 2.70E-04
Human toxicity. cancer effects CTUh 3.51E-05 3.48E-05
Particulate matter kg PM2.5 eq 2.85E+00 2.90E+00
Ionizing radiation HH kBq U235 eq 2.01E+02 2.05E+02 Photochemical ozone formation kg NMVOC eq 6.00E+00 6.11E+00
Acidification molc H+ eq 1.32E+01 1.34E+01
Terrestrial eutrophication molc N eq 1.81E+01 1.84E+01
Freshwater eutrophication kg P eq 1.48E-01 1.48E-01
Marine eutrophication kg N eq 1.65E+00 1.68E+00
Freshwater ecotoxicity CTUe 1.13E+03 1.14E+03
Land use kg C deficit 4.74E+03 4.84E+03
Water resource depletion m3 water eq 1.47E+02 1.51E+02
Resource depletion kg Sb eq 1.18E-01 1.18E-01
Table 61. Normalised results. BoP housing scenario solar collector for DHW compared to
baseline scenario (yearly impact EU citizen)
Impact category Scenario solar collector for DHW Baseline scenario
Climate change 2.81E-01 2.89E-01
Ozone depletion 1.50E-02 1.54E-02
Human toxicity. non-cancer effects 5.03E-01 5.06E-01
Human toxicity. cancer effects 9.51E-01 9.42E-01
Particulate matter 7.48E-01 7.62E-01
Ionizing radiation HH 1.78E-01 1.81E-01
Photochemical ozone formation 1.89E-01 1.93E-01
Acidification 2.78E-01 2.83E-01
Terrestrial eutrophication 1.03E-01 1.05E-01
Freshwater eutrophication 1.00E-01 1.00E-01
Marine eutrophication 9.77E-02 9.94E-02
Freshwater ecotoxicity 1.29E-01 1.30E-01
Land use 6.35E-02 6.49E-02
Water resource depletion 1.81E+00 1.85E+00
Resource depletion 1.17E+00 1.17E+00
The comparison with the baseline scenario is also graphically presented in Figure 24 for the characterised results. The environmental impact of the BoP housing has reduced for the majority of the impact categories by 0.6% - 2.6% dependent on the impact category. Two impact categories have slightly increased in impact: human toxicity – cancer effects (0.9% increase) and resource depletion (0.2% increase).
The impact to human toxicity is mainly coming from the flat plate collector. Looking at the flat plate collector, the highest contribution comes from the aluminium and chromium steel and to a lesser extent from the copper. The slightly increased impact on resource depletion is coming from the additional materials used for the production of the solar collector itself.
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Figure 24. Characterised results. BoP housing scenario solar collector for DHW compared to
baseline scenario (yearly impact EU citizen)
When interpreting the results, it is worth noting that the heating of domestic hot water had the highest contribution in the use phase of the baseline (around 10%-15% in almost all the impact categories). The use phase contributed for 87% of the overall impact of the BoP housing on PM. Therefore, the contribution of domestic water heating was around 13% of the overall impact of the BoP on most of the impact categories. The reduction obtained through the implementation of this scenario is proportional to this contribution.
Table 62 shows the results per person. Table 63 reports the environmental impact associated to a single dwelling in each climatic zone taking into account the number of dwellings for each different age of construction and their impact (weighted average). Compared to the baseline scenario, the environmental impact is reduced for each dwelling type in each climatic zone for the majority of the impact categories. The impact of the average EU housing has reduced for all impact categories with the highest reduction for ozone depletion (2.5%), climate change (2.4%), water resource depletion (2.3%) and ionizing radiation (2.1%). An increase in impact is identified for the impact categories human toxicity – cancer effects (0.9%) and for resource depletion (0.2%).
95
Table 62. Annual environmental impact per person. Each line has a green (lower impact) to red (higher impact) colour scale.
Table 63. Annual environmental impact for a dwelling in EU-27. Results per dwelling: each line has a green (lower impact) to red (higher impact)
color scale.
Impact categories
SFH_warm SFH_moderate SFH_cold MFH_warm MFH_moderate MFH_cold Average SFH Average MFH
EU housing average
Climate change kg CO2 eq 1.59E+03 2.83E+03 3.01E+03 1.80E+03 3.00E+03 2.95E+03 2.60E+03 2.58E+03 2.59E+03
Ozone depletion kg CFC-11 eq 1.80E-04 3.51E-04 6.70E-04 2.04E-04 3.72E-04 6.26E-04 3.31E-04 3.25E-04 3.29E-04
Human toxicity, non-cancer effects CTUh 1.95E-04 2.73E-04 4.90E-04 2.47E-04 2.80E-04 4.67E-04 2.67E-04 2.77E-04 2.71E-04
Human toxicity, cancer effects CTUh 2.31E-05 3.61E-05 5.81E-05 3.04E-05 3.80E-05 6.33E-05 3.45E-05 3.65E-05 3.53E-05
Particulate matter kg PM2.5 eq 2.07E+00 2.93E+00 5.35E+00 2.56E+00 2.92E+00 4.88E+00 2.86E+00 2.89E+00 2.87E+00
Ionizing radiation HH kBq U235 eq 1.46E+02 2.01E+02 3.95E+02 1.57E+02 2.27E+02 3.83E+02 1.98E+02 2.10E+02 2.03E+02
Photochemical ozone formation kg NMVOC eq 3.74E+00 6.50E+00 9.70E+00 4.24E+00 6.81E+00 9.24E+00 6.11E+00 6.02E+00 6.07E+00
Acidification molc H+ eq 7.68E+00 1.44E+01 2.11E+01 8.54E+00 1.55E+01 2.02E+01 1.34E+01 1.33E+01 1.33E+01
Terrestrial eutrophication molc N eq 1.22E+01 1.91E+01 3.31E+01 1.38E+01 1.99E+01 3.16E+01 1.83E+01 1.83E+01 1.83E+01
Freshwater eutrophication kg P eq 1.08E-01 1.48E-01 2.86E-01 1.17E-01 1.68E-01 2.80E-01 1.46E-01 1.56E-01 1.50E-01
Marine eutrophication kg N eq 1.11E+00 1.73E+00 3.04E+00 1.25E+00 1.82E+00 2.90E+00 1.67E+00 1.67E+00 1.67E+00
Freshwater ecotoxicity CTUe 7.17E+02 1.21E+03 1.80E+03 8.98E+02 1.24E+03 1.82E+03 1.14E+03 1.15E+03 1.14E+03
Land use kg C deficit 3.14E+03 5.02E+03 8.96E+03 3.73E+03 5.09E+03 7.76E+03 4.83E+03 4.73E+03 4.79E+03
Water resource depletion m3 water eq 1.09E+02 1.48E+02 2.66E+02 1.13E+02 1.68E+02 2.70E+02 1.46E+02 1.53E+02 1.49E+02
Mineral, fossil & ren resource depletion kg Sb eq 7.94E-02 1.12E-01 1.76E-01 1.61E-01 1.15E-01 1.99E-01 1.08E-01 1.35E-01 1.19E-01
Impact categories
SFH_warm SFH_moderate SFH_cold MFH_warm MFH_moderate MFH_cold Average SFH Average MFH
EU housing average
Climate change kg CO2 eq 5.46E+03 7.68E+03 8.51E+03 3.66E+03 5.87E+03 4.94E+03 7.36E+03 5.05E+03 6.20E+03
Ozone depletion kg CFC-11 eq 6.18E-04 9.52E-04 1.89E-03 4.14E-04 7.27E-04 1.05E-03 9.38E-04 6.36E-04 7.86E-04
Human toxicity, non-cancer effects CTUh 6.68E-04 7.39E-04 1.39E-03 5.01E-04 5.52E-04 7.83E-04 7.54E-04 5.47E-04 6.50E-04
Human toxicity, cancer effects CTUh 7.91E-05 9.78E-05 1.64E-04 6.16E-05 7.58E-05 1.06E-04 9.76E-05 7.25E-05 8.50E-05
Particulate matter kg PM2.5 eq 7.10E+00 7.94E+00 1.51E+01 5.20E+00 5.76E+00 8.18E+00 8.10E+00 5.70E+00 6.89E+00
Ionizing radiation HH kBq U235 eq 5.02E+02 5.45E+02 1.12E+03 3.19E+02 4.44E+02 6.41E+02 5.61E+02 4.11E+02 4.86E+02
Photochemical ozone formation kg NMVOC eq 1.28E+01 1.76E+01 2.74E+01 8.61E+00 1.34E+01 1.55E+01 1.73E+01 1.18E+01 1.45E+01
Acidification molc H+ eq 2.63E+01 3.89E+01 5.96E+01 1.73E+01 3.04E+01 3.38E+01 3.78E+01 2.60E+01 3.19E+01
Terrestrial eutrophication molc N eq 4.20E+01 5.17E+01 9.37E+01 2.81E+01 3.92E+01 5.29E+01 5.19E+01 3.61E+01 4.39E+01
Freshwater eutrophication kg P eq 3.69E-01 4.02E-01 8.10E-01 2.38E-01 3.30E-01 4.70E-01 4.13E-01 3.06E-01 3.59E-01
Marine eutrophication kg N eq 3.81E+00 4.70E+00 8.60E+00 2.54E+00 3.57E+00 4.85E+00 4.72E+00 3.28E+00 4.00E+00
Freshwater ecotoxicity CTUe 2.46E+03 3.27E+03 5.09E+03 1.82E+03 2.46E+03 3.04E+03 3.22E+03 2.27E+03 2.74E+03
Land use kg C deficit 1.08E+04 1.36E+04 2.54E+04 7.56E+03 9.99E+03 1.30E+04 1.37E+04 9.31E+03 1.15E+04
Water resource depletion m3 water eq 3.73E+02 4.03E+02 7.51E+02 2.30E+02 3.30E+02 4.53E+02 4.12E+02 3.02E+02 3.57E+02
96 Contribution by life cycle stages
Table 64 shows the contribution of different life cycle stages to the impact categories (based on the characterised inventory results before normalisation and weighting). The life cycle stages in orange are the ones identified as "most relevant" for the impact category, as they are contributing to more than 80% showing that there is a huge gap between the impact of the use phase (from 54% to 97%). Figure 25 and Table 65 summarise the contribution of the various life cycle phases to the overall impact per impact category. Compared to the baseline scenario a slight decrease (few percentages) in importance of the use phase is noticed and a slight increase in importance of the other life cycle stages.
Table 64. Contribution by life cycle stages of the BoP housing for the scenario solar
collector for DHW (SC4) compared to baseline (BL)
Climate change Human toxicity, cancer Particulate matter
Life cycle stage Contrib. (%) Life cycle stage Contrib. (%) Life cycle stage Contrib. (%)
SC4 BL SC4 BL SC4 BL
PRODUCTION 8 8 PRODUCTION 41 13 PRODUCTION 9 7
CONSTRUCTION 0.9 0.8 CONSTRUCTION 2.0 1.3 CONSTRUCTION 0.7 0.7
USE 91 91 USE 54 84 USE 87 87
MAINTENANCE 1.5 1.2 MAINTENANCE 3.9 2.7 MAINTENANCE 4.4 4.2 END OF LIFE -1.3 -1.3 END OF LIFE -0.1 -0.4 END OF LIFE 0.5 0.5
Ozone depletion Human toxicity, non-cancer Ionizing radiation HH
Life cycle stage Contrib. (%) Life cycle stage Contrib. (%) Life cycle stage Contrib. (%)
SC4 BL SC4 BL SC4 BL
PRODUCTION 4 4 PRODUCTION 13 40 PRODUCTION 4 4
CONSTRUCTION 0.86 0.81 CONSTRUCTION 1.4 1.9 CONSTRUCTION 0.8 0.7
USE 93 93 USE 82 56 USE 94 94
MAINTENANCE 1.3 1.3 MAINTENANCE 3.5 2.8 MAINTENANCE 1.2 1.0 END OF LIFE 0.95 0.76 END OF LIFE -0.5 -0.1 END OF LIFE 0.7 0.6
Photochemical ozone formation Acidification Terrestrial eutrophication
Life cycle stage Contrib. (%) Life cycle stage Contrib. (%) Life cycle stage Contrib. (%)
SC4 BL SC4 BL SC4 BL
PRODUCTION 11 10 PRODUCTION 7 6 PRODUCTION 11 11
CONSTRUCTION 1.8 1.7 CONSTRUCTION 1.0 1.0 CONSTRUCTION 2.1 2.0
USE 85 86 USE 88 88 USE 82 83
MAINTENANCE 2.7 2.4 MAINTENANCE 4.2 3.9 MAINTENANCE 2.8 2.5 END OF LIFE 0.1 0.1 END OF LIFE 0.3 0.3 END OF LIFE 2.0 2.1
Freshwater eutrophication Marine eutrophication Freshwater ecotoxicity
Life cycle stage Contrib. (%) Life cycle stage Contrib. (%) Life cycle stage Contrib. (%)
SC4 BL SC4 BL SC4 BL
PRODUCTION 9 8 PRODUCTION 10 10 PRODUCTION 19 19
CONSTRUCTION 0.8 0.7 CONSTRUCTION 2.1 2.0 CONSTRUCTION 3.9 3.9
USE 90 92 USE 83 83 USE 70 72
MAINTENANCE 2.3 1.0 MAINTENANCE 2.7 2.3 MAINTENANCE 3.8 3.2 END OF LIFE -2.0 -1.9 END OF LIFE 2.1 2.1 END OF LIFE 2.7 2.7
Land use Water resource depletion Resource depletion
Life cycle stage Contrib. (%) Life cycle stage Contrib. (%) Life cycle stage Contrib. (%)
SC4 BL SC4 BL SC4 BL
PRODUCTION 9 8 PRODUCTION 3 3 PRODUCTION 19 18
CONSTRUCTION 1.2 1.1 CONSTRUCTION 0.5 0.5 CONSTRUCTION 1.5 1.5
USE 88 88 USE 97 97 USE 57 59
MAINTENANCE 3.4 3.3 MAINTENANCE 0.4 0.3 MAINTENANCE 18.2 17.9 END OF LIFE -0.8 -0.8 END OF LIFE -0.5 -0.5 END OF LIFE 4.7 4.0
97
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Table 65. Environmental impacts related to housing per person per year in EU-27 (total and per life cycle stages) for the scenario solar collector. A
colour scale is applied to the results in each column from green (lowest contribution) to red (highest contribution).
Impact category Unit PRODUCTION % CONSTRUCTION % USE % Maintenance % EOL % TOTAL %
Climate change kg CO2 eq 2.09E+02 8.2 2.21E+01 0.86 2.32E+03 91 3.75E+01 1.5 -3.44E+01 -1.3 2.56E+03 100 Ozone depletion kg CFC-11 eq 1.32E-05 4.1 2.78E-06 0.86 3.01E-04 93 4.21E-06 1.3 3.07E-06 0.9 3.24E-04 100 Human toxicity, non-cancer effects CTUh 3.57E-05 13.3 3.67E-06 1.37 2.21E-04 82 9.43E-06 3.5 -1.21E-06 -0.5 2.68E-04 100 Human toxicity, cancer effects CTUh 1.42E-05 40.6 6.91E-07 1.97 1.88E-05 54 1.36E-06 3.9 -4.18E-08 -0.1 3.51E-05 100 Particulate matter kg PM2.5 eq 2.17E-01 7.6 1.95E-02 0.68 2.47E+00 87 1.26E-01 4.4 1.29E-02 0.5 2.85E+00 100 Ionizing radiation HH kBq U235 eq 7.76E+00 3.9 1.57E+00 0.78 1.88E+02 94 2.32E+00 1.2 1.33E+00 0.7 2.01E+02 100 Photochemical ozone formation kg NMVOC eq 6.31E-01 10.5 1.10E-01 1.83 5.10E+00 85 1.61E-01 2.7 4.05E-03 0.1 6.00E+00 100 Acidification molc H+ eq 8.89E-01 6.7 1.31E-01 1.00 1.16E+01 88 5.55E-01 4.2 3.45E-02 0.3 1.32E+01 100 Terrestrial eutrophication molc N eq 1.97E+00 10.9 3.86E-01 2.13 1.49E+01 82 5.07E-01 2.8 3.70E-01 2.0 1.81E+01 100 Freshwater eutrophication kg P eq 1.35E-02 9.1 1.12E-03 0.76 1.33E-01 90 3.42E-03 2.3 -3.04E-03 -2.0 1.48E-01 100 Marine eutrophication kg N eq 1.73E-01 10.5 3.49E-02 2.11 1.36E+00 83 4.49E-02 2.7 3.40E-02 2.1 1.65E+00 100 Freshwater ecotoxicity CTUe 2.19E+02 19.4 4.45E+01 3.93 7.94E+02 70 4.31E+01 3.8 3.08E+01 2.7 1.13E+03 100 Land use kg C deficit 4.08E+02 8.6 5.67E+01 1.20 4.14E+03 88 1.63E+02 3.4 -3.55E+01 -0.8 4.74E+03 100 Water resource depletion m3 water eq 4.51E+00 3.1 7.31E-01 0.50 1.42E+02 97 5.52E-01 0.4 -7.18E-01 -0.5 1.47E+02 100 Mineral, fossil & ren resource depletion kg Sb eq 2.19E-02 18.5 1.77E-03 1.50 6.75E-02 57 2.16E-02 18.2 5.53E-03 4.7 1.18E-01 100
99