实现建筑节能

in BuildingsKNOWLEDGE NOTESENERGYEFFICIENCY INBUILDINGS 2Achieving Energy Efficiency inBuildings Why is energy efficiency in buildings relevant for Pakistan? Buildings in Pakistan account for over 43.7 percent of the country’s total energy use and representa significant opportunity for energy efficiency and conservation.i The high energy consumption inbuildings is primarily attributed to Pakistan’s predominantly sunny and hot climate, which driveshigh demand for cooling for most of the year—and the widespread reliance on inefficient gas andfirewood appliances for heating and cooking. Driven by rapid urbanization, population growth, andincreasing construction demand, energy use in buildings and greenhouse gas (GHG) emissionsassociated with buildings are projected to grow considerably. The buildings sector drove higherelectricity demand in 2024, growing four times faster than in 2023. Global electricity consumption inbuildings increased by more than 600 terawatt hours (TWh) (5 percent) in 2024.iiGlobally, buildingsaccount for 37 percent of energy and process-related carbon dioxide (CO2) emissions.iiiIn addition tothe high overall levels of energy consumption in buildings, seasonal variation in electricity and gasload patterns also pose a problem. For instance, electricity peak demand in summer rises briefly toover 25,000 megawatts (MW) from a baseload of only 8,500 MW.ivThe benefits of energy efficiencyin buildings however extend beyond reduced energy consumption or peak demand management.Energy-efficient buildings provide a healthier and more supportive living and work environment byimproving indoor air quality and enhancing overall occupant comfort. In addition, demand for newconstruction materials and techniques in the building industry generates livelihood opportunities.Key findings from the World Bank’s comprehensive assessment on Buildings Energy Efficiency inPakistan, conducted in 2022 and 2023, are presented below; details on the assessment’s approach,data collection, and methodology are provided in annex 1. What provisions are in place to improve building energyefficiency in Pakistan? Pakistan’s government modified building codes in 2023 to incorporate prescriptive, statutoryprovisions for sustainability and energy efficiency in building design and construction. The EnergyConservation Building Codes (ECBC 2023) have already been notified, while the Green BuildingCode of Pakistan (GBCP 2023) is in the final stages of notification. Adapted from the American Society of Heating, Refrigerating and Air-Conditioning Engineers(ASHRAE) standard 90.1, the energy provisions incorporated into the Energy Conservation BuildingCodes (ECBC)1apply to residential and commercial buildings and building clusters that meet certaincriteria. These include having a total connected load of 50 kilowatts (kW) or greater, a contract demandof 75 kilovolt amperes (kVA) or greater, a conditioned area of 200 square meters (m2) or greater, orunconditioned areas with a covered area of 300 square meters (m2) or more. (For further detailsplease see annex 1). The Green Building Code of Pakistan (GBCP) is developed in alignment with the 2021 InternationalGreenConstruction Code(IgCC-2021),aiming to integrate environmentally responsible andresource-efficient practices throughout the lifecycle of green buildings. Key areas of focus includeenergy efficiency, water conservation, waste minimization, and the utilization of sustainable materials.By contextualizing international standards to address local challenges in Pakistan, the GBCP establishesbaseline requirements designed to work in conjunction with existing regulatory frameworks adoptedby Development Authorities (DAs) or Authorities Having Jurisdictions (AHJs). Despitethe presence of policies and regulations,progress in implementing building energyefficiency has been slow, hindered by institutional and financial limitations. For example, the thermaltransmittance (Watts per meter squared Kelvin (W/m2·K), or U-values) of standard wall and roofsections in residential and other buildings in Pakistan are approximately 1.89 W/m2·K and 2.74 W/m2·Krespectively, significantly higher than the specifications outlined in the ECBC.2Given that Pakistan’shousing stock is expanding by roughly 3 percent every year, instituting energy efficiency throughpassive building design elements represents a considerable energy conservation opportunity.v What are the most accessible energy efficiency andconservation opportunities in new building construction? Buildingorientation,improvements in building envelope and external shading can conserve aconsiderable amount of energy in new buildings by lowering the need for mechanical cooling.3InPakistan’s context, three relatively simple building design modifications can achieve this (see box 1).4 Energy conserved through building orientation varies based on the design of the building andlocal climatic conditions.Average annual energy savings achievable through o