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A zero-energy building, also known as a zero net energy (ZNE) building, net-zero energy building (NZEB), or net zero building, is a building with zero net energy consumption, meaning the total amount of energy used by the building on an annual basis is roughly equal to the amount of renewable energy created on the site,〔"Zero Energy Buildings: A Critical Look at the Definition" Paul Torcellini, Shanti Pless, and Michael Deru, National Renewable Energy Laboratory; Drury Crawley, U.S. Department of Energy. National Renewable Energy Laboratory report: NREL/CP-550-39833. June, 2006. http://www.nrel.gov/docs/fy06osti/39833.pdf〕〔"A Common Definition for Zero Energy Buildings" US Department of Energy, September 2015. http://energy.gov/sites/prod/files/2015/09/f26/A%20Common%20Definition%20for%20Zero%20Energy%20Buildings.pdf〕 or in other definitions by renewable energy sources elsewhere.〔"Net-Zero Energy Buildings: A Classification System Based on Renewable Energy Supply Options." Shanti Pless and Paul Torcellini. National Renewable Energy Laboratory report: NREL/TP-5500-44586, June 2010. http://www.nrel.gov/sustainable_nrel/pdfs/44586.pdf〕 These buildings consequently do not increase the amount of greenhouse gases in the atmosphere. They do at times consume non-renewable energy and produce greenhouse gases, but at other times reduce energy consumption and greenhouse gas production elsewhere by the same amount. Most zero net energy buildings get half or more of their energy from the grid, and return the same amount at other times. Buildings that produce a surplus of energy over the year may be called "energy-plus buildings" and buildings that consume slightly more energy than they produce are called "near-zero energy buildings" or "ultra-low energy houses". Traditional buildings consume 40% of the total fossil fuel energy in the US and European Union and are significant contributors of greenhouse gases.〔Baden, S., et al., ("Hurdling Financial Barriers to Lower Energy Buildings: Experiences from the USA and Europe on Financial Incentives and Monetizing Building Energy Savings in Private Investment Decisions." ) ''Proceedings of 2006 ACEEE Summer Study on Energy Efficiency in Buildings,'' American Council for an Energy Efficient Economy, Washington DC, August 2006.〕〔US Department of Energy. (''Annual Energy Review 2006'' ) 27 June 2007. Accessed 27 April 2008.〕 The zero net energy consumption principle is viewed as a means to reduce carbon emissions and reduce dependence on fossil fuels and although zero-energy buildings remain uncommon even in developed countries, they are gaining importance and popularity. Most zero-energy buildings use the electrical grid for energy storage but some are independent of grid. Energy is usually harvested on-site through energy producing technologies like solar and wind, while reducing the overall use of energy with highly efficient HVAC and lighting technologies. The zero-energy goal is becoming more practical as the costs of alternative energy technologies decrease and the costs of traditional fossil fuels increase. The development of modern zero-energy buildings became possible not only through the progress made in new energy and construction technologies and techniques, but it has also been significantly improved by academic research, which collects precise energy performance data on traditional and experimental buildings and provides performance parameters for advanced computer models to predict the efficacy of engineering designs. Zero Energy Building is considered as a part of smart grid. Some advantages of these buildings are as follow: * Integration of renewable energy resources * Integration of plug-in electric vehicles * Implementation of zero-energy concepts The net zero concept is applicable to a wide range of resources due to the many options for producing and conserving resources in buildings (e.g. energy, water, waste). Energy is the first resource to be targeted because it is highly managed, expected to continually become more efficient, and the ability to distribute and allocate it will improve disaster resiliency.〔https://sftool.gov/plan/420/net-energy〕 ==Definitions== Despite sharing the name "zero net energy", there are several definitions of what the term means in practice, with a particular difference in usage between North America and Europe. ; Zero net site energy use: In this type of ZNE, the amount of energy provided by on-site renewable energy sources is equal to the amount of energy used by the building. In the United States, “zero net energy building” generally refers to this type of building. ; Zero net source energy use: This ZNE generates the same amount of energy as is used, including the energy used to transport the energy to the building. This type accounts for losses during electricity transmission. These ZNEs must generate more electricity than zero net site energy buildings. ; Net zero energy emissions: Outside the United States and Canada, a ZEB is generally defined as one with zero net energy emissions, also known as a ''zero carbon building'' or ''zero emissions building''. Under this definition the carbon emissions generated from on-site or off-site fossil fuel use are balanced by the amount of on-site renewable energy production. Other definitions include not only the carbon emissions generated by the building in use, but also those generated in the construction of the building and the embodied energy of the structure. Others debate whether the carbon emissions of commuting to and from the building should also be included in the calculation. ; Net zero cost: In this type of building, the cost of purchasing energy is balanced by income from sales of electricity to the grid of electricity generated on-site. Such a status depends on how a utility credits net electricity generation and the utility rate structure the building uses. ; Net off-site zero energy use: A building may be considered a ZEB if 100% of the energy it purchases comes from renewable energy sources, even if the energy is generated off the site. ; Off-the-grid:Off-the-grid buildings are stand-alone ZEBs that are not connected to an off-site energy utility facility. They require distributed renewable energy generation and energy storage capability (for when the sun is not shining, wind is not blowing, etc.). An energy autarkic house is a building concept where the balance of the own energy consumption and production can be made on an hourly or even smaller basis. Energy autarkic houses can be taken off-the-grid. ; Net zero-energy building: Based on scientific analysis within the joint research program “Towards Net Zero Energy Solar Buildings” a methodological framework was set up which allows different definitions, in accordance with country’s political targets, specific (climate) conditions and respectively formulated requirements for indoor conditions: The overall conceptual understanding of a Net ZEB is an energy efficient, grid connected building enabled to generate energy from renewable sources to compensate its own energy demand (see figure 1). The wording “Net” emphasizes the energy exchange between the building and the energy infrastructure. By the building-grid interaction, the Net ZEBs becomes an active part of the renewable energy infrastructure. This connection to energy grids prevents seasonal energy storage and oversized on-site systems for energy generation from renewable sources like in energy autonomous buildings. The similarity of both concepts is a pathway of two actions: 1) reduce energy demand by means of energy efficiency measures and passive energy use; 2) generate energy from renewable sources. However, the Net ZEBs grid interaction and plans to widely increase their numbers〔European Parliament and the Council of the EU (16.06.2010): Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (EPBD 2010), Article 9: Member States shall ensure that: (a) by 31 December 2020, all new buildings are nearly zero- energy buildings; and (b) after 31 December 2018, new buildings occupied and owned by public authorities are nearly zero-energy buildings〕 evoke considerations on increased flexibility in the shift of energy loads and reduced peak demands.〔Salom, Jaume; Widen, Joakim; Candanedo, Jose A.; Sartori, Igor; Voss, Karsten; Marszal, Anna Joanna (2011): Understanding Net Zero Energy Buildings: Evaluation of Load Matching and Grid Interaction Indicators. Proceedings of Building Simulation 2011: 12th Conference of International Building Performance Simulation Association. Sydney〕 Within this balance procedure several aspects and explicit choices have to be determined: * The building system boundary is split into a physical boundary which determines which renewable resources are considered (e.g. in buildings footprint, on-site or even off-site, see〔Marszal, Anna Joanna; Heiselberg, Per; Bourelle, Julien; Musall, Eike; Voss, Karsten; Sartori, Igor; Napolitano, Assunta (2011): Zero Energy Building – A Review of definitions and calculation methodologies. In: Energy and Buildings 43 (4), pages 971–979〕) respectively how many buildings are included in the balance (single building, cluster of buildings) and a balance boundary which determines the included energy uses (e.g. heating, cooling, ventilation, hot water, lighting, appliances, IT, central services, electric vehicles, and embodied energy, etc.). It should be noticed that renewable energy supply options can be prioritized (e.g. by transportation or conversion effort, availability over the lifetime of the building or replication potential for future, etc.) and therefore create a hierarchy. It may be argued that resources within the building footprint or on-site should be given priority over off-site supply options. * The weighting system converts the physical units of different energy carriers into a uniform metric (site/final energy, source/primary energy renewable parts included or not, energy cost, equivalent carbon emissions and even energy or environmental credits) and allows their comparison and compensation among each other in one single balance (e.g. exported PV electricity can compensate imported biomass). Politically influenced and therefore possibly asymmetrically or time dependent conversion/weighting factors can affect the relative value of energy carriers and can influence the required energy generation capacity. * The balancing period is often assumed to be one year (suitable to cover all operation energy uses). A shorter period (monthly or seasonal) could also be considered as well as a balance over the entire life cycle (including embodied energy, which could also be annualized and counted in addition to operational energy uses). * The energy balance can be done in two balance types: 1) Balance of delivered/imported and exported energy (monitoring phase as self-consumption of energy generated on-site can be included); 2) Balance between (weighted) energy demand and (weighted) energy generation (for design phase as normally end users temporal consumption patterns -e.g. for lighting, appliances, etc.- are lacking). Alternatively a balance based on monthly net values in which only residuals per month are summed up to an annual balance is imaginable. This can be seen either as a load/generation balance or as a special case of import/export balance where a “virtual monthly self-consumption” is assumed (see figure 2 and compare〔Sartori, Igor; Napolitano, Assunta; Voss, Karsten (2012): Net Zero Energy Buildings: A Consistent Definition Framework. In: Energy and Buildings (48), pages 220–232〕). * Beside the energy balance, Net ZEBs can be characterized by their ability to match the building's load by its energy generation (load matching) or to work beneficially with respect to the needs of the local grid infrastructure (grind interaction). Both can be expressed by suitable indicators which are intended as assessment tools only. The information is based on the publications,〔〔Voss, Karsten; Sartori, Igor; Lollini, Roberto (2012): Nearly-zero, Net zero and Plus Energy Buildings. How definitions & regulations affect the solutions. In: REHVA Journal 6 (49), pages 23–27〕 and〔Voss, Karsten; Musall, Eike (2012): Net zero energy buildings – International projects of carbon neutrality in buildings. 2nd edition. Institut für internationale Architektur-Dokumentation, München, ISBN 978-3-920034-80-5.〕 in which deeper information could be found. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zero-energy building」の詳細全文を読む スポンサード リンク
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