Scenarios of energy efficiency and CO 2 emissions reduction potential in the buildings sector in China to year 2050

Transcription

1 SUPPLEMENTARY INFORMATION Articles In the format provided by the authors and unedited. Scenarios of energy efficiency and CO 2 emissions reduction potential in the buildings sector in China to year 2050 Nan Zhou*, Nina Khanna, Wei Feng, Jing Ke and Mark Levine China Energy Group, Energy Analysis and Environmental Impacts Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. * NZhou@lbl.gov Nature Energy

2 Supplementary Information Scenarios of energy efficiency and CO 2 emissions reduction potential in buildings sector in China to year 2050 Nan Zhou*, Nina Khanna, Wei Feng, Jing Ke, Mark Levine China Energy Group, Energy Analysis and Environmental Impacts Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA * NZhou@lbl.gov

3 Supplementary Figures a 90 b 30 Floorspace per capita (square metre/person) US France Germany UK Japan China Floorspace per capita (square metre/person) US Germany France Japan UK China Supplementary Figure 1 Per capita floorspace by country, residential and commercial buildings. a, residential floorspace per capita 1 4. b, commercial floor space per capita 2,5, China estimated by authors. 2.5 Annual new construction (billion square metres/year) Commercial Urban Residential Average Average Supplementary Figure 2 China's projected average annual new construction for 2010 to 2020, and 2021 to Source: calculated by authors stock turnover analysis.

4 5,000 Carbon dioxide (CO 2 ) emissions (million metric tons of CO 2 ) 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1, Commercial Residential 0 Supplementary Figure 3 Potential 2050 CO 2 emissions reduction for buildings in the TEP Scenario. Dark blue bars show total CO 2 emissions for 2010 and 2050 under High Energy Demand (HI) and Technoeconomic Potential (TEP) scenarios. Green bars show 2050 annual CO 2 emissions reduction potential by specific technology package, with darker shade representing savings in residential buildings and lighter shade representing savings in commercial buildings. Supplementary Tables Supplementary Table 1 Macroeconomic assumptions in 2050 DREAM model Macroeconomic assumptions GDP (trillion 2010 USD) Population (billions) Urbanisation (percent)

5 Supplementary Table 2 Average heating and cooling data for office building sector Region Year & scenario Heating useful energy (load) Heating efficiency Heating primary energy use Cooling useful energy (load) Cooling efficiency Cooling primary energy use (kwh/m 2 ) (kwh/m 2 ) (kwh/m 2 ) (kwh/m 2 ) % % HI 67 69% % 45 North 2050 BAU 56 69% % AP 49 77% % TEP 44 81% % % % HI 47 84% % 50 Transition 2050 BAU 37 85% % AP 30 99% % TEP % % N/A % HI 0 N/A % 54 South 2050 BAU 0 N/A % AP 0 N/A % TEP 0 N/A % 18 Values shown are the weighted-average values of the entire office building sector across 3 existing building envelope efficiency levels and 2 new building envelope efficiency levels. HI is High Energy Demand Scenario of no new policies, BAU is Business-as-Usual scenario with continued policies, AP is Aggressive Policy Scenario and TEP is Techno-economic Potential scenario. Supplementary Table 3 Final energy intensities of non-space conditioning end-uses by scenario Building type Year & scenario Appliances/Equipment Lighting Cooking Water heating* Urban residential Rural residential (kwh/m 2 ) (kwh/m 2 ) (kwh/m 2 ) (kwh/m 2 ) HI BAU AP TEP N/A HI N/A BAU N/A AP N/A TEP N/A N/A HI N/A 23.5 Commercial 2050 BAU N/A AP N/A TEP N/A 10.2 *For rural households, cooking energy use is reported together with water heating energy use.

6 Supplementary Notes Supplementary Note 1 Supplementary Figure 3 shows the energy-related CO 2 emissions reductions associated with each strategy between the HI and TEP scenarios, as these two scenarios show the technical potential of energy savings absent policy considerations. Similar to energy savings, space conditioning and thermal integrity have the largest CO 2 reduction potential, particularly for residential buildings, in Fuel switching and renewable electricity have more notable CO 2 reductions compared to energy savings, due to shifts away from carbon-intensive fuels towards renewables. By building type, rural residential buildings only represent 2% of the CO 2 reduction potential, with largest potential coming from urban residential buildings with 56% share and commercial buildings with 42% share. Supplementary Note 2 Fig. 4 in the main text shows the energy pathways necessary to go from the HI to the TEP case. Note that TEP is a construct to illustrate the full magnitude of potential energy savings. It is needed to construct the AP scenario. The AP scenario, which we consider to be plausible, assumes that 60% of the full effect of the policies is achieved (75% of the whole building market by 2050 and 80% of energy savings from policies achieved) in This figure and accompanying text provide essential guidance for priorities and the outline of a blueprint for action. Fig. 4 in the main text, which shows energy savings by building type and vintage (new/existing), is also relevant to the discussion of policies. The greatest potential is represented by Pathway 1, space conditioning systems. This and Pathway 2 are also the most complex pathways. Pathway 1 requires: Efficiency standards for space conditioning equipment that are as stringent as those in advanced economies. Presently, China s appliance efficiency program is very active and sophisticated but issues standards that are less stringent than those in the E.U. or U.S. Development and widespread application of field procedures that ensure that distribution systems (from chiller to room if a centralised system is used) are and remain through their life efficient and fully functional. Support for the commercialisation of distributed heating and cooling systems that can take the place of centralised systems when appropriate. Development of design criteria for design institutes to evaluate when distributed systems will save energy and be cost-effective in replacing centralised systems for new or retrofit buildings. Research, development and deployment (RD&D) on modern biomass burning heating systems to increase their efficiency so that they can compete with fossil or biomass systems in the rural north of China.

7 RD&D leading to ubiquitous use of sensors and control systems and control strategies that turn space conditioning systems off when serving unoccupied spaces. RD&D leading to ubiquitous use of sensors and controls for other energy using equipment in a building that alert building managers when energy efficiency is significantly compromised by any part of the building that is not functioning correctly. Training and requirement for building managers to serve all new buildings in China (where the manager may serve multiple buildings). Incorporation of all relevant aspects of space conditioning systems (as distinct from heaters and chillers) into building energy codes so that (1) efficient systems are installed in buildings, (2) with the assistance of monitors and sensors they are shown to perform properly on installation, and (3) a means of periodically checking performance is defined in the building energy standards and implemented. Policies to promote Pathway 2, reduction of building loads, include: State of the art building energy codes requiring, as appropriate to climate, most of the following: o insulation in walls o plugging of leaks in building envelope o thermally well-designed window systems o appropriate glazing types and characteristics o reflective roofs (and walls) if appropriate to climate o ground/basement insulation o infiltration control with mechanical ventilation and heat recuperation or with economisers o credit for design and operation of successful integration of windows, lighting, and sensors and controls (daylighting) for perimeter of commercial buildings. Strong encouragement (leading to requirements by 2030) for integrated design (including design of buildings with passive features); and extensive training for both designers and engineers in the integrated design process and in application of passive features where appropriate into building designs Labels for green buildings that go beyond the standards by incorporating solar photovoltaics and extensive passive solar features and/or whose performance in use is substantially better than buildings that just meet standards. Programs that are adequately staffed to check up on success of code compliance including building commissioning after construction and check-ups periodically (review of sensor monitoring data and fixing problems at least annually). This last point, checking up on buildings energy performance at least annually, is probably the most important of the policies identified. It is well known that buildings typically use more, sometimes much more, energy than their design would indicate. Building standards are based on design. Monitoring actual

8 performance, made easy by low-cost monitors that could be very widely used well before 2030, and fixing problems is almost certainly the most significant and low-cost way to save energy in buildings. Policies to promote Pathway 3, high-efficiency lighting systems, include: Standards for lamps that are at global best levels by 2030 Standards and design guides for fixtures that are widely used disseminated through courses to building and lighting designers and engineers so that the best combination fixture/lamp for specific uses can be selected and installed in all new buildings Application of low-cost sensors, monitors, and controllers to lighting systems for optimal control under different circumstances, and courses and guidebooks to support such applications RD&D to improve task lighting, and courses and guidebooks to explain how task lighting can deliver performance at low energy cost A licencing requirement for professionals so that these courses on lamp and fixture standards; use of sensors, monitors, and controllers; task lighting; and new products of R&D on the market are taken at appropriate intervals (e.g., one course per year for the initial five courses) Policies for Pathway 4, super-efficient appliances (not including heating and cooling equipment) include: Continuation of appliance efficiency standards in China reaching global best practice efficiency levels by 2030 Rating of appliances so the consumer can choose to purchase appliances that are more efficient than the standard Incentive programs for super-efficient appliances likely provided either by local governments or electric utilities. The incentive programs are especially useful to support a constantly improving efficiency of the best appliances on the market so that upgrades to the standards (typically every five to seven years) can take advantage of these best products. Policies for Pathway 5, existing building retrofits, include: RD&D on low-cost sensors, monitors, and controls for use in retrofit applications Demonstration programs for building energy retrofits yielding a guidebook for such undertakings Courses based on the guidebook and other educational material for building professionals to obtain professional licenses Financial incentives for building energy retrofit, particularly for deep retrofits where 25-50% energy savings can be achieved and ESCOs may have a role to play. Over time, especially as sensors, monitors, and controls are widely disbursed, the cost of deep retrofits may come down. Policies for Pathway 6, fuel switching and employment of solar photovoltaics panels include:

9 For a short time as the industry matures, incentives are desirable to expand markets for photovoltaic systems on roofs and in the future on some walls Information about the desirability of advantages and disadvantages prepared by a reputable institution (preferably by or under contract to a government entity) will help consumers, builders, building engineers and designers to make better decisions on end-use technology and associated fuel choice. There is a 7 th pathway for lowering carbon emissions significantly in the TEP case: low- or zero-carbon electricity supply technologies, the power sector policy implications of which are discussed in a previous study 6. RD&D can support multiple pathways. Excellent opportunities for RD&D to reduce energy waste include: Technologies, practices, and techniques for building energy efficiency Exploratory means of reducing energy use (e.g., clothes that can be tuned to maintain a comfortable temperature so that space conditioning is not needed); transmitters that can signal to energy using devices the presence of a person (e.g., lighting could be configured so that different amount of lumens are provided as a function of the number of people in a given room) Trials relating to aspects of human behaviour that affect energy use in buildings (especially comfort conditions) Different systems to provide heat in northern China given the existing (inefficient) systems in place (district heating in urban areas; combustion of biomass for space heating, water heating and cooking) Efficient or more effectively controlled air conditioning and dehumidification systems in south China. We have identified 30 policies in the discussion above. It will require policies in all of these areas to begin to have impact in the timeframe (or in many cases earlier) for the 2050 AP scenario to be achieved. Supplementary References 1 Buildings Energy Data Book: 2.2 Residential Sector Characteristics (U.S. DOE, 2012). 2 European Union (EU). EU Buildings Database. (2017).

10 3 The Institute of Energy Economics. EDMC Handbook of Energy & Economic Statistics in Japan (The Energy Conservation Center, 2014). 4 National Bureau of Statistics of China. National Data. (2018). 5 Buildings Energy Data Book: 3.2 Commercial Sector Characteristics (U.S. DOE, 2012). 6 Khanna, N. Z., Zhou, N., Fridley, D. & Ke, J. Quantifying the potential impacts of China's powersector policies on coal input and CO 2 emissions through 2050: A bottom-up perspective. Utilities Policy 41, (2016).