Energy Intensity Of Buildings Research Articles

Spatial distribution of energy consumption: Integrating climate and macro-statistics for insights from clustering and sensitivity analysis

Limited comprehensive methods exist for studying spatial energy consumption distribution, integrating statistical and energy data. This paper introduces a novel approach for analyzing residential heating and cooling energy demand distribution. It employs clustering algorithms to study climate variables’ impact on energy demand distribution and assesses building energy demand intensity regionally, taking China as a case study. Initially compiling a dataset comprising climate characteristics, socioeconomic factors, and energy demand through data collection and simulation, the study compares clustering algorithms, highlighting the effectiveness of K-means in clustering high-dimensional climate-energy datasets. K-means analysis reveals temperature-based daily methods significantly affect building energy intensity, alongside factors like radiation intensity and humidity impacting regional energy demand variably. Additionally, climate’s influence on residential building energy consumption intensity varies regionally, with total energy demand influenced by population and economic factors. This paper offers insights for energy management and policy formulation.

Energy consumption, power generation and performance analysis of solar photovoltaic module based building roof

Building energy intensity (BEI) of typical office buildings in Malaysia ranges from 200 to 250 kWh/m2/year, wherein a substantial portion is due to the cooling system. This study evaluates of the performance and suitability of double-laminated monocrystalline solar photovoltaic (PV) glass in comparison to traditional solar PV systems installed on roofs in Malaysian conditions. To address this aim, simulation studies have been conducted to examine the efficacy of Building Attached Photovoltaic (BAPV) and Building Integrated Photovoltaic (BIPV) systems. Key parameters such as heat transfer across the building envelope, cooling demand, daylight utilization, and solar irradiance were analyzed. Additionally, an evaluation of economic viability, including Return on Investment (ROI) and payback period (PBP), was undertaken. Analysis showed that more heat was transferred through the roof on the BIPV building as the U-value of the solar PV glass was higher than the metal deck roof on the BAPV building. The lighting energy in the BIPV building can be saved by up to 80 % as sufficient daylight was entering the building. More than 30 % of the building area had a daylight factor of 1.0 %–3.5 %. From economic viewpoint, the double-laminated monocrystalline solar PV glass had a longer payback period as the initial capital cost was much higher even though the one-off savings and annual savings in the BIPV building were more than the BAPV building.

Is South Korea's 2050 Carbon-Neutral scenario sufficient for meeting greenhouse gas emissions reduction goal?

In line with Global Climate Change Alliance initiated in 2007 by the European Commission, the South Korean government announced the “2050 Carbon-Neutral Strategy” in October 2020. The 2050 Carbon-Neutral Scenario was announced in October 2021, with the aim of reducing the country's greenhouse gas (GHG) emissions by 40 % by 2030 compared to those in 2018. The primary objective of this study is to conduct a scenario-based comparative analysis focusing on the forecast of greenhouse gas emissions and the potential for reduction within the building sector. The methodology employed in this study utilizes the greenhouse gas emission calculation methods outlined in the IPCC Guidelines of 1996 and 2006. Based on the national building energy and statistics database for the years 2015 to 2019, the study analyzes building types, building energy intensity, and floor areas to calculate emissions and energy consumption within the sector. The results indicate that the emissions will increase continuously from 2020 (156.9 million tons of CO2 equivalent) to 2050 (217.8 million tons of CO2 equivalent). We have considered the four scenarios outlined in the ‘2050 Carbon Neutrality Scenario’ as the most effective strategies for reducing greenhouse gas emissions in the building sector. These include: (1) Mandatory implementation of Zero-Energy Buildings (ZEB) for new buildings by 2050, (2) 100 % execution of green remodeling for existing buildings, (3) Promotion of high-efficiency devices to achieve a 25–30 % improvement in energy consumption efficiency compared to 2018 and an enhancement of device energy use per unit, and (4) Expansion of clean heat utilization such as fuel cells and waste heat utilization in district heating. Thus, the possibility of South Korea achieving the 2050 carbon-neutrality target in the building sector is low. Therefore, it is important to develop effective emissions reduction policies and plans for the building sector.

Use of publicly available data to create a dataset for data-driven urban commercial building energy intensity classification: Model accuracy, interpretation, and implications of an open data framework in Hong Kong

Previous studies relied on structured databases containing energy use intensity (EUI) and building features to develop data-driven urban building energy models (D-UBEMs). However, such databases are not available in most cities. In Hong Kong, energy audit is required for commercial buildings, but only EUI is publicly released without any building information. We assessed the adequacy of input features collected and integrated from public sources to develop a precise D-UBEM. We separated Hong Kong commercial building samples into “below-median” and “above-median” EUI categories based on the bimodal distribution of log10EUI and developed a data-driven binary classifier to predict the category. Using publicly available input features, the average classification accuracy is 78.73%. We used the D-UBEM to reveal the association of “above-median” EUI category with input features, and spatially visualize floor areas of Hong Kong commercial buildings belonging to the “above-median” EUI category. In the discussion, we examined the causes of misclassified buildings and highlighted the limitations of our database from public sources in developing accurate and useful D-UBEMs. We suggested an open-data policy framework for releasing building information alongside EUI data and establishing a central database that contains more precise values for building geometries, usage, and thermal performance in Hong Kong.

Adaptive thermal comfort in the offices of three climates of North-East India

Buildings not only provide shelter to the occupants but also security, safety and comfort, as well as signifying economic and socio-cultural status. The high energy intensity of buildings has become a matter of concern worldwide in the context of climate change and global warming. Adaptive comfort principles and guidelines afford greater design opportunities for reduced energy intensity without compromising occupant thermal comfort and indoor environmental quality performance. However, thermal adaptation opportunities of office occupants in the North-Eastern part of India are rarely addressed by previous thermal comfort studies conducted in the Indian subcontinent. A yearlong questionnaire-based adaptive thermal comfort study with concurrent indoor environmental measurements was conducted in naturally ventilated office buildings located in three locations, i.e., Tezpur, Imphal and Shillong, representing the climatic zones of North-East India. A total of 2326 valid questionnaire responses were collected. ASHRAE Class-II field study protocols, seven-point thermal sensation and five-point preference scales were used to collect objective and subjective comfort assessments. It was found that the clothing insulation (clo) levels worn by occupants varied non-linearly with indoor temperatures. The estimated preferred temperatures for building occupants in Tezpur, Imphal and Shillong were 24 °C, 23.5 °C and 22 °C, respectively. Probit analysis of thermal sensation data indicated that the indoor temperature stimulus associated with a shift of one thermal sensation unit differed between the warm and cool side of the 7-point thermal sensation scale. Increasing indoor air velocity up to 0.8m/s shifted the upper threshold of discomfort to 32 °C. It was also found that 80% of office occupants were comfortable within the temperature range of 25 °C–30 °C. The adaptive comfort model derived from the current database shows lower sensitivity of subjects to outdoor temperature changes compared to existing International standards like ASHRAE Standard 55 or EN16798. The present study demonstrates the potential for low-energy, naturally ventilated office design strategies in similar climatic conditions in North-East India and other parts of the world. Above all, it enriches the worldwide thermal comfort database.

Energy Utilization and Carbon Reduction Potential of Solar Energy in Residential Blocks: A Case Study on a Tropical High-Density City in China

Energy efficiency in high-density urban areas is increasingly gaining more attention as the energy crisis and environmental issues worsen. Urban morphology is an essential factor affecting the energy consumption and solar energy development potential of buildings. In response to the research gap of previous studies that only analyzed building energy consumption or solar energy potential from a single objective, this paper aims to combine the two objectives of block-scale building energy consumption and solar development potential to explore the joint influence of urban residential morphological elements on correlations between the two. By investigating and summarizing 100 sample cases of Wuhan city blocks, 30 urban residential block prototypes were constructed. The correlations between the leading morphological indicators of the blocks with the building energy consumption and solar energy potential of the residential prototypes were quantified, respectively. The study results show that at certain floor area ratios, the highest solar power generation can be achieved with a mixture of high-rise slabs and high-rise towers, but the building energy intensity level is relatively high; combining building energy consumption and solar power generation, the residential block form of high-rise towers and low-rise villas has incredible energy-saving potential. In addition, the regression analysis results show that three block form indicators, namely the roof-to-envelope area ratio, compacity, and site coverage, have the most prominent influence on building energy intensity and solar power generation, and they all show positive correlations. This study can provide suggestions for urban residential planners and managers to promote urban energy conservation at the design stage.

Investigation into energy performance of a multi-building complex in a hot and humid climate: efficacy of energy saving measures

PurposeCommercial buildings, which include office buildings, are one of the three major energy-consuming sectors, alongside industrial and transportation sectors. The vast increase in the number of buildings is a positive sign of the rapid development of Malaysia. However, most Malaysian government office buildings tend to consume energy inefficiently due to lack of energy optimization. Most of the previous studies focused on the performance of green buildings in fulfilling the green development guidelines. As such, it is essential to study the energy performance of existing government office buildings that were constructed before most energy-efficient standards were implemented to mitigate energy wastage due to the lack of energy optimization. This study aims to analyse the energy performance of existing non-green Malaysian government office buildings and the factors that influence building energy consumption, as well as to evaluate the efficacy of the existing energy conservation measures.Design/methodology/approachThis study was conducted by a literature review and case study. The chosen buildings are six government office building blocks located in Kuala Lumpur, the capital city of Malaysia. In this study, a literature review has been conducted on the common factors affecting energy consumption in office buildings. The energy consumption data of the buildings were collected to calculate the building energy intensity (BEI). The BEI was compared to the MS1525:2019 and GBI benchmarks to evaluate energy performance. SketchUp software was utilized to illustrate the solar radiation and sun path diagram of the case study buildings. Finally, recommendations were derived for retrofit strategies based on non-design factors and passive design factors.FindingsIn typical government office buildings, the air-conditioning system consumed the most energy at 65.5%, followed by lighting system at 22.6%, and the remaining 11.9% was contributed by office appliances. The energy performance of the case study buildings is considered as satisfactory as the BEI did not exceed the MS1525:2019 benchmark of 200 kWh/m2/year. The E Block recorded the highest BEI of 183.12 kWh/m2/year in 2020 due to its north-east orientation which is exposed to the most solar radiation. Besides, E Block consists of rooms that can accommodate large number of occupants. As such, non-design factors which include higher occupancy rate and higher cooling demand due to high outdoor temperature leads to higher energy consumption. By considering passive design features such as building orientation and building envelope thermal properties, energy consumption can be reduced significantly.Originality/valueThis study provided a comprehensive insight into the energy performance of Malaysian government office buildings, which were constructed before the energy-efficient standards being introduced. By calculating the BEI of six government office buildings, it is found that the energy performance of the case study buildings fulfils the MS1525 benchmark, and that all their BEIs are below 200 kWh/m2/year. Malaysia's hot and humid climate significantly affects a building's cooling load, and it is found the air-conditioning system is the major energy consumer of Malaysian government office buildings. This study discusses the efficacy of the energy-saving measures implemented in the case study buildings to optimize energy consumption. Recommendations were derived based on the non-design factors and passive design factors that affected the energy consumption of the case study building. It is envisioned that this study can provide practical strategies for retrofit interventions to reduce energy consumption in Malaysian office buildings as well as for office buildings that are in a similar climate.

BUILDING ENVELOPE RETROFIT FOR ENERGY SAVINGS IN MALAYSIAN GOVERNMENT HIGH-RISE OFFICES: A CALIBRATED ENERGY SIMULATION

With over a third of global energy used for building construction and operation, an optimum design for building envelopes is essential to improve the energy performance of the existing buildings. This study revealed that typical government high-rise office buildings in Malaysia have an average Building Energy Intensity (BEI) of 161 kWh/m2/year before any upgrading works on the air-conditioning and mechanical ventilation (ACMV) systems were conducted. This value is higher than the recommended value in Green Building Index (GBI) for commercial office buildings (150 kWh/m2/year) and the Economic Planning Unit (EPU) standard for public buildings (140 kWh/m2/year). Therefore, this study employed a case study approach combined with calibrated computer simulation to determine the optimal building envelope retrofit strategies and identify the three levels of interventions (minor, moderate and major levels) with corresponding energy reduction. A validated model representing a typical existing government high-rise office building in Malaysia was chosen as the base case model for energy evaluation studies. The effectiveness of each level of intervention and its energy retrofit measures (ERMs) were evaluated compared to the actual electricity bills. The results showed that all levels of interventions provided between 4% to 7% savings in annual energy consumption. The proposed interventions demonstrated compliance with the BEI benchmark margins of the GBI and EPU standard, namely 116 kWh/m2/year (minor intervention level), 113 kWh/m2/year (moderate intervention level), and 110 kWh/m2/year (major intervention level).

Features of Project Management of Industrial Enterprise Reconstruction on the Basis of Technical, Economic, Legal and Technological Factors

One of the main forms of industrial enterprise development is reconstruction. The main task is to improve the technical level of the enterprise, the quality of products, introduce energy-saving and resource-saving technologies using existing fixed assets. There is a growing interest in reducing maintenance and repair costs, as well as in significantly increasing the time between repairs and reducing the energy intensity of buildings. This article is devoted to the peculiarities of managing a project for the reconstruction of an industrial enterprise, which includes a cultural heritage site. The study was conducted on the example of one of the oldest enterprises in Russia - Joint Stock Company 'Votkinsky Zavod'. The purpose of this study is to develop a methodological basis for the effective management of the reconstruction of an industrial facility based on a database of the technical condition of the main production assets of the Joint Stock Company 'Votkinsky Zavod'. In the course of the study, a detailed analysis of the historically established fund of buildings and structures, in-cluding a cultural heritage site, was carried out with the aim of their possible most optimal further adaptation. The main periods of the development of the plant in the history of its existence are highlighted. The result of the study is an assessment of the technical condition of buildings and structures of the industrial en-terprise under consideration, the classification of a group of buildings according to the periods of construction, according to design schemes and materials used, as well as according to the main defects and damage to structures. As a result of the study, a list of the most common defects and damages to the building structures of buildings and structures was compiled, and a base of technical information on the state of the enterprise's fixed production assets was formed. An algorithm for choosing the optimal variant of the project for the reconstruction of a building, structure or complex is proposed based on the observance of a certain sequence of economic analysis when considering technical, economic, social, aesthetic and time indicators with comparability of design solutions for reconstruction options.

A Rational Plan of Energy Performance Contracting in an Educational Building: A Case Study

Energy performance contracting (EPC) is the best solution for an educational building to implement energy conservation measures (ECMs) because of its high capital expenditure and operational expenditure needed for retrofit and maintenance. It is also considered a win–win mechanism for organising building energy efficiency retrofit projects. It aims to assist educational buildings in acquiring new high-efficiency equipment and maximising energy use reduction, as guaranteed by energy service company (ESCO). This study developed an EPC model using regression analysis, in which the inputs are based on the data collected during the preliminary energy audit in University A. As a result, with a quantum sharing ratio of 0.95/0.5 for ESCO/University A, the forecasted energy savings from the proposed ECMs, chiller optimisation and replacement, lighting retrofit, and energy management system are estimated to save 25.6% energy use, which reduces 5,672,057 kilowatt-hour (kWh) in electricity consumption; saves RM 2,762,291.76/year; carbon dioxide (CO2) mitigation equal to 3,771,061.22 kgCO2/year; return of investment of 4.2 years with a 5% interest rate; and building energy intensity of 93.55 kWh/m2/year. A sensitivity analysis of various quantum sharing ratios found that the saving value of ESCO is inversely proportional to that of University A as the client when the quantum sharing ratio for the former is increasing.

Efficacy of Energy Conservation Measures and Building Energy Intensity of a Multi-Building Complex in Malaysia

As Malaysia continues to develop at a fast pace, the number of buildings in this country rapidly increases. Commercial buildings which include office buildings are one of the three major energy consuming sectors, which includes industrial and transportation sectors. Most Malaysian government office buildings tend to consume energy inefficiently due to lack of energy optimization. This study aims to analyse the energy performance as well as the factors that influence energy consumption in government office buildings. The chosen buildings for this case study are six government office buildings located in Kuala Lumpur, the capital of Malaysia. In this study, literature review has been conducted on the common factors affecting energy consumption in office buildings. The energy consumption data of the buildings were collected and analysed by comparison among the buildings and the SketchUp software. The Building Energy Intensity (BEI) of each building was also calculated using the formula in MS 1525:2019. Literature review and results from the case study show that air-conditioning system is the major energy consumer in office buildings, followed by lighting system while other office equipment consumed the least energy. The findings also highlight that energy consumption in office buildings is affected by non-design factors such as building occupants’ behaviour, number of building occupants, outdoor temperature as well as passive design factors such as building orientation and window-to-wall ratio. Recommendations were derived based on the findings from literature review and the case study for best practices to optimize energy consumption in government office buildings in Malaysia.

Twin Rooms – new experimental test cells for testing advanced facade elements

Nowadays the global trend is the integration of new materials, constructions and technological principles, which are simultaneously implemented in individual scientific and engineering disciplines. Reducing the energy intensity of buildings will increasingly resonate in individual political and professional circles. As a result, new fragments of building envelopes in the field of facade engineering are being developed and tested. Testing of building envelope is carried out either in static (laboratory) boundary conditions or in dynamic (climatic, real) conditions. The determination of the test method is conditioned by the specific intention or the investigated phenomenon within the construction of the building envelope. Currently, we finished the development and realization of the new experimental facility Twin Rooms for testing advanced elements of building envelopes in dynamic boundary conditions (in the real climate of Central Europe - Bratislava) in terms of building thermal engineering and energy efficiency of buildings. It is based on the concept of pavilion measurement. The essence of the research is that the outdoor climate is modelled by the conditions of the real outdoor climate. Test cells consists of a solar laboratory - two-room for a comparative study of the effect of solar radiation and heat transfer on energy consumption and indoor climate. The space of two identical laboratory rooms is situated inside a container - a pavilion, whose climate is a compensating space. Only the tested facade element walls are exposed to the outdoor climate. The exchange of energy with the environment is possible only through this measured facade wall. The article brings a detailed description of this experimental equipment, basic technical parameters of its technological circuits and methodology of experimental measurements.

Are the later-urbanized regions more energy-efficient in the building sector? Evidence from the difference-in-differences model

Urbanization has an important impact on building energy consumption. Unfortunately, whether the later-urbanized provincial regions are more energy-efficient than those early-urbanized regions in the building sector is still unclear. This study innovatively adopts the difference-in-differences (DID) model to examine the event effect of urbanization on building energy intensity with China's provincial evidence from 2000–2015. Moreover, its influence mechanism is identified with the mediating effect model. Results demonstrate that: (1) The building energy intensity is higher in provincial regions where the urbanization rate reached 45% earlier, indicating that the later-urbanized regions are more energy-efficient. (2) Considering heterogeneity, the event of urbanization rate reaching 45% contributes positively to building energy intensity in the eastern and central regions, but the effect in the western region is insignificant. This can further validate the later-mover advantage of the urbanization. (3) Regarding influence mechanism, urbanization can drive building energy intensity by increasing the proportion of the tertiary industry and population density or reducing the proportion of building coal consumption and the plot ratio of the urban area. This study can facilitate the related theoretical and practical exploration of the event effect of urbanization on energy consumption, which is conducive to formulating differentiated energy-conservation strategies.

Energy consumption, CO2 emissions and electricity costs of lighting for commercial buildings in Southeast Asia

Building energy intensity (BEI) has been used to assess a building’s overall energy performance. However, the energy performance, CO2 footprint and electricity costs due to lighting in buildings are currently required to assist relevant authorities to develop, revise and implement energy-efficient lighting policies that are effective and acceptable for the country. This work presents an estimation approach for lighting in commercial buildings in Southeast Asia and its decarbonisation pathway for benchmarking. Application of this approach to a selected library in Brunei Darussalam showed that an energy-efficient light-emitting diode (LED) lighting system would make the building greener. We projected reductions in lighting energy consumption by 6.7 times (3.98 kWh/m2/year), its associated CO2 emissions by 8 times (0.59 kg CO2/m2/year) and electricity costs by 8.7 times (B$7.07/m2/year) by 2050 if existing lamps in the library are retrofitted with LED lamps.

A TAXONOMY STUDY OF MOSQUE ROOF DESIGN IN KLANG VALLEY, MALAYSIA

Energy is the most important issue to focus on as it contributes to economic development and social growth. Buildings were identified to significantly impact energy usage, where 40% of global energy comes from buildings. Nowadays, many buildings in a tropical climate are equipped with air-conditioners as it is seen as the fastest way to cool down buildings. However, this action impacts the environment. One of the affected buildings that are equipped with air-conditioners is a mosque. However, minimal attention has been given to mosques even though this type of building has a significant total space as other commercial buildings. Furthermore, mosques have a unique pattern of occupancy and energy use. While the major contributor to buildings' energy consumption comes from the roof, scarce information is found regarding roof design and energy consumption for air-conditioned mosques in Malaysia. The study aims at exploring the roof types of mosques in the Klang Valley. The objectives are 1) to identify mosques with air-conditioners in the Klang Valley built between 1998 and 2018, 2) to characterize and classify the specific roof types designed for these identified mosques, and 3) to investigate building energy intensity for mosque buildings in the Klang Valley. This paper presents a taxonomy study to classify roof design for air-conditioned mosques in Klang Valley. The study showed that the flat roof demonstrated high energy consumption and cost. The use of HVLS fans and the association with air-conditioners probably increased the building energy.

Revisiting the building energy consumption in China: Insights from a large-scale national survey

The increasing building energy consumption in China has been acknowledged as a key concern in future climate mitigation and sustainable development. Though reliable accounting of energy consumption is the prerequisite, estimates of China's building energy consumption remain subject to large discrepancies. One of the primary causes of these disparities is an inaccurate estimation of building energy intensities due to flaws in estimation methods and data. Here, we present a bottom-up approach and use large-scale nationwide building energy survey data (covering 30 provinces, four different types of buildings, and district heating from 2009 to 2016) to correct the existing, widely used assumption of normal distribution for building energy intensity and provide a more accurate estimate of building energy consumption in China. Our improved estimate of China's building energy consumption differs by −10% to 36% from existing mainstream estimates, indicating a significant bias in existing research and applications.

The trend of using solar energy of a green intelligent building and thermal energy storage to reduce the energy intensity of the building

The trend is to reduce the energy intensity of buildings. Thermal energy storage (TES) is the biggest challenge for buildings. It is a technology that supplies thermal energy by heating or cooling a tank, which then serves for the system in the building. Comparison of hitherto known systems ATES, BTES, PTES and research TTES. The most important factors for the accumulation of thermal energy are capacity (the energy stored in the system - depends on the storage process, the medium, and the size of the system), power (how fast the energy stored in the system can be discharged and charged), efficiency (the ratio of the energy provided to the user to the energy needed to charge the storage system. It accounts for the energy loss during the storage period and the charging/discharging cycle), storage (how long the energy is stored and lasts hours to months), charging and discharging (how much time is needed to charge or discharge the system), and cost (refers to capacity (€/kWh) or power (€/kW) of the TES system and depends on the capital and operation costs of the storage equipment and its lifetime).

Energy Star based benchmarking model for Malaysian Government hospitals - A qualitative and quantitative approach to assess energy performances

The hospital building's operation can be symbolised as high energy usage with different services provision and facilities. The energy performances for hospital buildings in Malaysia are often quantified using a simple Building Energy Intensity (BEI) as the indicator. However, this method has less accuracy on the building's performance due to complex energy systems and different sizes for hospital-built environments. Hereof, this study aims to establish an energy benchmarking indicator for government hospitals in Malaysia using the Energy Star score method. The actual large dataset of hospitals samples has been quantified, scrutinised and optimised using the multiple linear regression (MLR) analysis to identify specific parameters affecting the energy use. The proposed model found that the final output result had shown a good fit for all hospital datasets. Further classifications were conducted on hospitals according to their energy score and air-conditioned area (ACA) for ranking comparison and assessment. Subsequently, from the same benchmarking model, an energy benchmarking calculator was developed in order to assist hospitals in automatically assessing their energy performance and labelling. Therefore, better energy management practices and decisions may be suggested for the Malaysian hospital buildings' continuous improvement. The novelties for this study are the formulated benchmarking models by optimising significant parameters from the actual large dataset of Malaysian hospitals and the developed benchmarking calculator for the regulator and hospital use.

The evolution and future perspectives of energy intensity in the global building sector 1971–2060

Energy efficiency plays an essential role in energy conservation and emissions mitigation efforts in the building sector. This is especially important considering that the global building stock is expected to rapidly expand in the years to come. In this study, a global-scale modeling framework is developed to analyze the evolution of building energy intensity per floor area during 1971–2014, its relationship with economic development, and its future role in energy savings across 21 world regions by 2060. Results show that, for residential buildings, while most high-income and upper-middle-income regions see decreasing energy intensities and strong decoupling from economic development, the potential for further efficiency improvement is limited in the absence of significant socioeconomic and technological shifts. Lower-middle-income regions, often overlooked in analyses, will see large potential future residential energy savings from energy intensity reductions. Harnessing this potential will include, among other policies, stricter building efficiency standards in new construction. For the commercial sector, during 1971–2014, the energy intensity was reduced by 50% in high-income regions but increased by 193% and 44% in upper-middle and lower-middle-income regions, respectively. Given the large energy intensity reduction potential and rapid floor area growth, commercial buildings are increasingly important for energy saving in the future.

Net zero carbon: Energy performance targets for offices

The UKGBC Net Zero Carbon Buildings Framework was published in April 2019 following an industry task group and extensive consultation process. The framework acts as guidance for achieving net zero carbon for operational energy and construction emissions, with a whole life carbon approach to be developed in the future. In consultation with industry, further detail and stricter requirements are being developed over time. In October 2019, proposals were set out for industry consultation on minimum energy efficiency targets for new and existing commercial office buildings seeking to achieve net zero carbon status for operational energy today, based on the performance levels that all buildings will be required to achieve by 2050. This was complemented by modelling work undertaken by the LETI network looking into net zero carbon requirements for new buildings. In January 2020 UKGBC published its guidance on the levels of energy performance that offices should target to achieve net zero and a trajectory for getting there by 2035. This paper describes the methodology behind and industry perspectives on UKGBC’s proposals which aim to predict the reduction in building energy intensity required if the UK’s economy is to be fully-powered by zero carbon energy in 2050. Practical application: Many developers and investors seeking to procure new commercial offices or undertake major refurbishments of existing offices are engaging with the ‘net zero carbon’ agenda, now intrinsic to the legislative framework for economic activity in the UK. A UKGBC initiative effectively filled a vacuum by defining a set of requirements including energy efficiency thresholds for commercial offices in the UK to be considered ‘net zero carbon’. This paper provides all stakeholders with a detailed justification for the level of these thresholds and what might be done to achieve them. A worked example details one possible solution for a new office.