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Environmental Screening and Evaluation of Energy-using Products (EuP) Final Report 4 Boilers and combi-boilers (gas/oil/electric) and water heaters (gas/oil/electric) (Lot 1 and 2)
4.1 BackgroundThe Ecoinvent database includes data on boilers. However, there are no data on “water heaters”. For this screening purpose, it has been assumed that the environmental focus points of water heaters are close to the environmental focus points of boilers. Accordingly, the two product groups are discussed together in spite of they constitute two different studies in the EuP scheme. In the EuP preparatory studies, the following definitions have been used:
The EuP studies for Lot 1: Boilers and combi-boilers (gas/oil/electric) and Lot 2: Water heaters (gas/oil/electric) were conducted from February 2006 to October 2007. The Final Commission workshop was held 11 September 2007. Both studies are concluded and the final documents and background information produced for the studies are available on www.ecoboiler.org and www.ecohotwater.org. The Executive Summary of the Eco-boiler project states: “In 2005 the space heating function of gas- and oil-fired central heating boilers consumed 10.880 PJ primary energy (ca. 250 mtoe) and emitted 16-17% of all fuel-related CO2 in the EU-25. Carbon emissions are of the same magnitude as with the total Road Transport. Around 5 % of acidification emissions (NOx, SOx) in the EU-15 can be attributed to the space heating function of boilers. For most environmental impact categories (Global Warming, Acidification, etc.) 80-99 % of impacts follow from the use phase of the products and are mostly directly linked to energy efficiency” 4.2 Environmental screening based on the Ecoinvent databaseThe Ecoinvent database contains a range of processes that are relevant for the product groups “combi-boilers (gas/oil/electric)” and “water heaters (gas/oil/electric)”:
However, the environmental screening for Boilers and combi-boilers (gas/oil/electric) and water heaters (gas/oil/electric) are only based on a few of these Ecoinvent processes, as the results “on a general view” leads to the same conclusions (however, the boilers based on heavy fuel oil has significant higher contributions to many environmental impacts, as expected). The Ecoinvent processes marked with a “*” has been used for the screening. The Ecoinvent processes for boilers only include the production of the boilers and the use. The final disposal of the boiler has (to our knowledge) not been included. From Figure 4.1 shows that when burning heavy fuel oil in a large 1 MW industrial furnace, the main contributions to all environmental impacts come from burning the heavy fuel oil and from the extraction and processing of the heavy fuel oil. The construction of the industrial furnace itself, construction of the chimney and construction of the oil storage are insignificant relative to the contributions from extraction and burning of the heavy fuel oil. However, when dealing with smaller boilers (light fuel oil, burned in boiler 10kW, non-modulating), the construction of the boiler and the oils storage do have significance, see Figure 4.2:
The electricity consumption is not very significant in Figure 4.1 and Figure 4.2. As discussed in chapter 3, the electricity production in the Ecoinvent database is mainly based on “Swiss electricity production”. When changing this to “electricity production based on hard coal”, the total environmental impacts in general are raised by 5 %. Accordingly it can be concluded that the electricity consumption for the systems should not be the main focus area. The natural gas based boilers (Figure 4.3. and Figure 4.4) gives a clear picture: For global warming, the most significant contribution comes from burning the natural gas. For most other environmental impacts the main contributions come from extraction and processing of the natural gas. As for the small oil based boilers, the production of the boiler itself contributes to “Mineral extraction” and “Ecotoxicity, terrestrial”. 4.3 Ecolabel requirementsIn the Nordic Ecolabelling programme there is a criteria document for Swan labelling of boilers and burners for liquid and gas fuels [NE2005]. The product group in the Ecolabel document encompasses installations for heating dwellings (installations up to 120 kW). The focus points of the Swan Ecolabel criteria document are:
Those parts of an installation that are eligible for a Swan label are: the burner and boiler itself up to the opening of the chimney, and parts sold together with the installation and essential for the installation to be capable of fulfilling the Swan requirements. This means that if the installation is, for example, fitted with oxygen regulating equipment and if this equipment is necessary in order to fulfil the Swan label requirements, then it will be encompassed by the requirements applicable to materials unless otherwise specified. And if the installation needs to be combined with solar heating in order to fulfil the requirements, then the solar heating equipment will form part of the system. Nordic Ecolabelling consider to incorporate criteria regarding requirements to the technique for inhibiting corrosion for condensing boilers in the next revision of the criteria for boilers and burners for liquid and gas fuels. 4.4 Technology and market trendsUntil today there has been little EU policy to improve efficiency of electric water heaters, due to the lack of suitable measurement standards, the many different types of water heaters (gas, district heating, solar, electric). Past activities for electric water heaters have concentrated on storage (tank) models and in particular on the reduction of the standing losses, through increased insulation. The only real policy action was a unilateral agreement by the main European manufacturers through their trade association, CECED. The agreement was concluded by the manufacturers at the end of 1999, and lasted till the end of 2003. The main terms of the agreement where: 1) a standing losses declaration in the form of additional and clearly visible data; 2) a stepwise phase-out of less efficient appliances ranking in certain draft energy label classes; and 3) a reduction of the European fleet consumption of appliances, as calculated by a notary system heaters [CEC1999]. The first report published in year 2003 [CEC2003] and covering the year 2001 reported successful implementation by manufacturers, reaching the agreed target. A promising emerging technology allows for co-production of electrical power and heat in the same unit. In this method, coal-derived fuel compositions are prepared while simultaneously producing electricity utilizing a co-generation configuration based on the so-called hydrodisproportionation of coal. The char produced from the coal is gasified to simultaneously produce steam for electrical power generation and syngas to produce methanol. The methanol purge gas is used as a fuel gas for a gas-driven power generating turbine. The waste heat from the power generation is used as the process heat for hydrodisproportionation. Co-producing boilers are only suitable for large-scale heat generation plants. Another step towards a reduced global warming (and other energy-related environmental impacts) is to combine the natural gas boilers with existing alternative energy systems such as solar panels, air-water heat pumps, borehole heat exchangers etc. In Denmark most heating installations are installed in the form of boilers or combi-boilers, i.e. an appliance designed to provide hot water for space heating and possibly domestic hot water or other functions as well. Several attempts to rethink the concept of houses are reported. In one Danish project, a new energy-producing house is being built. The main objective in the project is construct a house, in which there is no costs for heat or electricity, because the house itself produces all the energy needed. The main principle for achieving this is to use solar power for producing electricity and hot water combined with geothermic heat. Ventilation is combined with a highly efficient heat recovery system. A room for drying clothes saves the tumble drier. A cold room for food storage minimizes the size of the refrigerator. The Danish window manufacturers Velfac and Velux are partners in the project and the plan is to build 8 of these houses in Europe; the first one is built in Århus. For more information (in Danish) see: http://politiken.dk/tjek/bolig/energi/article499225.ece http://politiken.dk/tjek/bolig/energi/article499142.ece http://www.ue.dk/nyhedsarkiv/22156.aspx 4.5 ConclusionThe main road to a significant overall improvement in environmental impacts from boilers and water heaters is achieved by applying a systemic, life-cycle based approach and not a product oriented approach. Central generation of heat and hot water should be encouraged with all available instruments, while continuous environmental improvements in intelligent distribution networks should be supported and promoted. Moreover, in the long term, a rethinking of the entire concept of “providing hot water for space heating and hot sanitary water” is needed. Or even better – rethinking the entire concept of “keeping a house warm at winter and cold at summer” plus “providing hot sanitary water” should be stimulated. To facilitate this, competent authorities should fund and promote a number of “energy production houses” or, at least “energy neutral houses” across Europe. These new concepts and technologies are in the process of being demonstrated and evaluated, and can form the basis for formulation of demands on new buildings with regard to “energy production”. 4.5.1 Environmental impact in a system and life-cycle perspectiveThe main contributions to the overall environmental impacts come from combustion and extracting oil and gas. When using the STEPWISE2006 weighting method, the most significant environmental impacts from boilers are Global Warming and “Respiratory inorganics” (leading to respiratory troubles for especially asthmatics), mainly from nitrogen oxides, sulphur dioxide and small particulates. The extraction of non-renewable energy resources is significant, and it is totally dominated by the extraction of oil and gas for the combustion during use of the boilers. The extraction of non-energy related resources (called “Extraction of minerals” in the screening) is dominated by the extraction of minerals for the boilers, for oil storages and for material used for oil and gas extraction. The most important materials are (not in amounts but when including perspectives for the future possibilities for extracting these materials): Nickel, copper, iron, aluminium and chromium (used as construction materials for the boiler and the oil storage) The emissions of heavy metals during extraction of construction materials for the boilers and oil storage also give contributions to ecotoxicity and human toxicity. These are relatively more significant for smaller boilers (household size) as the oil and gas combusted in these are relatively lower. In the Ecolabel requirements for boilers some of these heavy metals must not be added to plastic parts, in the surface treatment and as metal plating. Other environmental issues regarding boilers that could be mentioned are leaking of oil storage tanks polluting the ground water and handling and treatment of discarded oil storage tanks. 4.5.2 Environmental perspective from new technologiesThe energy efficiency improvement potential for boilers and water heaters is considerable, especially when employing a system approach. The EuP background study assumes that at Least Life Cycle Cost (LLCC) targets on average an energy saving of close to 40% per unit can be achieved with respect of the Base Case. With Best Technology (BAT) the energy efficiency improvement can be over 60%. Carbon and NOx emission reductions per unit are in the same order of magnitude. For NOx an extra saving can be achieved with an additional emission limit value of 20 ppm, which would bring the EU in line with best international legislative practice. Improvements are also foreseen if the market is stimulated in the direction of co-producing boilers that produce both heating and electricity. Also larger industrial furnaces should be based on a combination of natural gas boilers and alternative energy sources. However, improving the energy efficiency of the existing boiler systems will not contribute radically towards reduced global warming, as long as the boiler systems are based on the combustion of oil and natural gas. In order to promote alternatives to gas, oil and electricity based boilers and water heaters, competent authorities at the national and EU level should promote and facilitate investment in technical improvements of solar heating systems, geothermic energy, heat pumps, etc. 4.5.3 RegulationThe EuP background study proposes to support minimum targets with a comprehensive labelling scheme, featuring 10 efficiency classes (A-G and more) as well as 9 size categories (small/ medium/large/ etc.). EU-wide consistency of EPBD standards would further promote energy efficient products and remove EU-internal trade barriers. Global competitiveness of the EU-industry will be enhanced rather than diminished by the measures, as current EU-legislation is significantly behind Japan, US, Canada, etc. in terms of ambition. Installers will benefit from the holistic approach, as it will help them to also install more sophisticated systems that are pre-set and pre-assembled. Moreover, it will probably give environmental benefits if setting requirements to the content of heavy metals in additives to plastic parts, surface treatment and metal plating, as done in the Ecolabel criteria. It is assumed that environmental benefits can be achieved if requirements regarding the content of heavy metals in additives to plastic parts, surface treatment and metal plating, is introduced as is the case in the Ecolabel criteria. The successful deployment of co-producing boilers in the consumer market requires that appropriate buy-back schemes exists for public utilities, in order that the consumer can sell excess electricity back into the electricity grid.
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