Life Cycle Cost Structure of a Government Office Green Building – Case of the Ministry of Public Works and Housing Main Building

One of the efforts to reduce the large impact of building sectors on the environment is the concept of environmentally friendly building known as green buildings. With the increasing global interest in this concept, green building development in Indonesia was also expected to increase. Cost is one of the most important focus for promoting green buildings, so it is necessary to conduct a cost analysis of a green building to provide a clearer understanding of the life cycle cost structure of a green building in its life cycle as a study to develop the knowledge of Infrastructure Asset Management. In this study data related to the cost component of the government office green building was identified to determine the overall cost of the building from the beginning of its construction until recent year, which can be described as: Initial Cost, Operation and Maintenance Cost, and Energy Cost. The result of this study finds out that during 8 year period of its lifetime the total building expenditure is Rp 483.649.711.849,00 and the life cycle cost structure percentage are: initial cost 43,94%, operation and maintenance cost 39,48%, and energy cost 16,57%. The total energy cost saving is Rp 28.072.536.738,00.


INTRODUCTION
Nowadays the awareness about climate change and the environment has increased significantly and aroused great attention from governments around the world. Various movements were carried out to protect the earth by implementing efforts to use energy efficiently and minimizing the environmental impact. The building sector is one of the major targets for improvement as according to UNEP (2009) this sector has estimated to have consumed nearly 40% of world's energy consumption, 30% raw material use, 25% solid waste product, 25% water use, 12% of land use, and 33% of related global greenhouse gas (GHG) emissions. Many attempts have been initiated to evaluate the environmental impacts of building, their materials, components, systems, and to explore any opportunities to reduce their environmental impacts (Chau et al., 2015). Any efforts to reduce carbon emissions and saving energy in the building sector will greatly influence the efforts to reduce global warming in general.
Since 2011 the Government of Indonesia has committed to voluntarily reduce GHG emissions by 26% until 2020 under business as usual scenario and can reach up to 41% with international support (Bappenas, 2012). The follow up to the government commitments is the issuance of Minister of Public Works Regulation No. 11 of 2012 concerning the National Action Plan for Mitigation and Adaptation to Climate Change 2012-2020 and Minister of Public 3 based on this information in the construction of office buildings in the future and as a study to develop the knowledge of Infrastructure Asset Management.

LITERATURE REVIEW Green Building
Green building is a new building or an existing building that has been planned, implemented and operated by taking into consideration the environmental/ecosystems factors and meets certain requirements of sustainability such as: land use, indoor air quality, water usage saving, energy saving, materials saving, and reduce waste (GBCI, 2019).
Based on the Minister of Public Works and Public Housing Regulation Green Buildings are buildings that meet the building requirements and have significant measurable performance in energy saving, water usage saving, and other resources through the application of the principles of green buildings following its functions and classifications in each stage of the development (Permen PU 02/PRT/M/2015).

Life Cycle Cost
Basic Components of Public Infrastructure Life Cycle Costs consists of investment cost, administration cost, annual operation cost, annual maintenance cost, rehabilitation cost, development cost, removal cost, and annual management cost. It must be noted that the Investment Cost and the Development Cost are normally far higher than the Annual Operation, and Annual Maintenance Cost. The Rehabilitation Cost can also be very high, it depends on the seriousness of infrastructure damage (Soemitro & Suprayitno, 2020).
Life cycle costs are summations of cost estimates from inception to disposal for both equipment and projects as determined by an analytical study and estimate of total costs experienced during their life. The objective of LCC analysis is to choose the most costs effective approach from a series of alternatives so the least long term cost of ownership is achieved (Barringer, 2003). According to Kelly and Male (1993) the definition of life-cycle costing is a technique for economic evaluation which accounts for all relevant costs during the investor's time horizon and adjusting for the time value of money. The cost of the life cycle of an item is the sum of all expenses relating to the item since designed to unused (Pujawan, 2004). Based on these definitions LCC can be formulated as follows: LCC = Initial Cost + Cost of Usage + Cost of Care and Replacement.
… (1) wherein the initial cost is the cost of the planning and execution of the building, the cost of usage is the cost incurred during the building operations, cost of care and replacement are costs for maintenance and replacement the constituent components of the building during the design life of the building (Kaming, 2017).

RESEARCH METHODS
The general objective is to identify cost components of Green Building projects in government offices from the design stage to the specified age and determine the life cycle cost structure by using a real case The Ministry of Public Works and Housing Main Building. For the first step, data collection methods used in this study includes the preparation stage to formulate the research problem, research objectives, and explore data to the stakeholders involved in the project. The next stage is data collection by taking the field survey of the research location and conduct the permitting process for data collection to the stakeholders which are Bureau of General Affairs Ministry of Public Works and Housing as the owner, SNVT P4SBPUPRL as Construction Project Officer and PT. Airkon Pratama as building management operator. Later Data Analysis was performed after the data was collected to create This building is the first ministerial office building that applied the green building concept. Based on the vision to make the Ministry of Public Works and Housing become an avantgarde in building technology applications, the development of this building aims to make an example for other governmental projects. The details administration of the project are:   1. Energy Efficiency -Active and Passive Design a. Orientation and Building Design Design modification applied to anticipate excessive sun radiation with minimizing area of west and east zone while maximizing area of north and south zone, change the rectangular form into "H" form, set up office room at north and south of the building, and create public and service area at the middle of the building. Design modification is a narrow building form to maximizing daylight performance. Other than that by placing the Parking Building on the west side/zone of the building to reduce sun exposure, those parking zones still get optimal natural daylight. Facade Design Some strategies conducted to handle solar radiation from windows to decrease Overall Thermal Transfer Value (OTTV) which are :  Use thermal resistant glass for windows to support the energy efficiency program, which are: stopsol super silver dark blue 8 mm, plate glass-cladding 0.015  Provide insulation on the wall: external surface film, cladding aluminium, calcium silicate/gypsum, fiberglass insulation internal surface film.  Installing the sun shading on windows.  Installing perforated material on the west side to control solar radiation and increase natural lighting.  Installing the sun shading on windows to adjust and divert direct sunlight, so that natural lighting can enter optimally by making it reflected to ceiling and redistributed to the floor to expand the daylighting area.  By applying strategy above, artificial lighting can be reduced at noon because lamps on the outer zone (near to window) can be turned off by that time.  Sun shading installation resulted in a 47% room area illuminated by sunlight with an illumination value of 300 lux.  Office room design with clear glass partition with many openings, so that natural lighting can be distributed to the deepest area of the room. The lighting system was designed by applying a zone system between natural and nonnatural lighting. Lux sensor installed to monitor the illuminance level of the room, which will turn off automatically the artificial lighting within the natural lighting area if the room illuminance reaches more than 300 lux. Therefore it reduces the energy consumption of artificial lighting. Motion sensors will turn off lamps if it detects no movement inside the room and vice versa will turn on lamps if detecting any movement inside the room. While, scheduling control the on-off of lamps at a predetermined time. e. Natural Ventilation Natural ventilation is located in the lobby area, a public area along the west wall. Parking building without walls on the periphery allows outdoor air distribution to substitute mechanical ventilation. f. Other passive design concepts:  Integrated elevator lobby and main stairs: stairs placed on edge of elevator lobby corridor to reduce lift usage. This facility expects occupants to use stairs when going to the neighboring floor (one or two floors upward or downward). 7  Expansion of softscape area from 21.93% to 33.53% and hardscape area reduce from 41.25% to 32.58%. g. Air-conditioning system Air conditioning is designed by a centralized air conditioning system that has several energy efficiency features, that are:  Use 3 (three) units water cooled screw chiller (2 chillers running and 1 chiller standby) with capacity for each 300 RT. The chiller is using environmental-friendly refrigerant R134.  Chilled and condenser water pump equipped with Variable Speed Drive (VSD).  Use 2 (two) units cross flow closed type cooling tower each of 3 (three) cells system with heat rejection capacity for each is 510 RT and make-up water consumption is 30% less compared to open type.  On the airside using with Fan Coil Unit (FCU) to allow for individual control.  Motorized modulating 2-way valves installed on every FCU to control cooling capacity to overcome cooling load variety.  Chiller system controlled by Building Automation System, the SetPoint (SP) determined appropriately with load condition per FCU. BAS can monitor temperature at rooms (Point Value, PV)) and also can monitor the opening percentage of the motorized 2-way valve for every FCU. h. Lighting systems: the use of T5 and LED lamp with 10 W/m 2 energy expenditure. i. Vertical transportation: with 6 (six) units passenger lift, 1 (one) unit executive lift, 1 (one) unit service lift, the strategy applied to achieve energy efficiency for vertical transportation is by applying Variable Voltage Variable Frequency (VVVF) feature. This feature will cause rotation of motor become softer (soft starting) and inrush current become lower. Car light/fan shut off also applied to decrease energy consumption because this feature will automatically shut off lamp and fan in lift when lift idle.

Water Efficiency
A strategy to decrease water consumption is by:  Using water usage saving fixtures: 72% under the SNI standard, such as low flow sink taps, wall taps and showers  Recycled water; greywater is processed in Sewage Treatment Plant (STP) and produces recycle water for water landscaping, flushing, and make up for water cooling tower. 8 Black-water from jet spray, urinary, and flushing toilets will be processed before wasted to city sewer.  Rainwater harvesting; due to eagerness to implement green concept (zero run off) in Ministry Public Works and Housing neighborhood, the ground rainwater tank installed (capacity 200 m 3 in zone A and 200 m 3 in zone B). After treatment, this clean water is distributed to the buildings on-site as domestic water. By this strategy, there is no water go to city sewer  Water treatment/recycling capacity: The recycling capacity: 150 m 3 /day, which is used for irrigation, flushing, and makeup water cooling tower.  f. Environmental tobacco smoke (ETS) and smoke control: The smoking bans regulation has been issued and socialized to the building occupant, put up smoking signs, not providing a smoking room. g. Lighting illumination: Based on Simulation (Dialux): 76% (19,404 m 2 ) area has more than 300 lux h. Others: Outside view to reduce eye tiredness by giving a long-range view and providing a visual connection to the outside the building.

DATA ANALYSIS
After obtaining permission to research at the predetermined location, an in-depth interview and data collection were conducted to provide actual data related to cost with the collaboration of stakeholders for this green building project. The results are as follows:

Initial Cost
All costs of initial construction work on the building, including the building work costs, which means the cost of building works and external works (presented in the SFCA element cost structure); and other construction-related costs, which mean all costs payable by the client in connection with the building or constructed asset (Kaming, 2017). The initial cost for this project is presented in Table 1.

Operation & Maintenance Cost
Operation costs are all costs of operating the building or facility arising from the building itself rather than from its occupancy. It includes: routine and specialist cleaning; windows and external surfaces such as cleaning windows, glazed screens, cladding, sun screening etc.; internal cleaning; and external works cleaning (Kaming, 2017).
Maintenance costs are all costs of replacement, maintenance, repair, and adaptation of the constructed asset (presented in the SFCA element cost structure. They consist of: major replacement costs, includes scheduled replacement and major components and this will form the detailed asset life cycle replacement program; minor replacement and repairs costs, scheduled replacement of parts and scheduled maintenance and repairs to components and associated making good and minor redecorations including planned preventative maintenance; unscheduled replacement, repairs and maintenance costs, allowance for unforeseen maintenance arising from early failure, inappropriate use, etc.; redecorations, scheduled redecorations; refurbishment and adaptation costs, scheduled refurbishment and adaptation during the period of analysis (Kaming, 2017).
Ministry of Public Works and Housing Main Building uses service from a third party contractor to operate the building and act as building management. The building owner (Bureau of General Affairs) makes a contract with PT. Airkon Pratama every year to operate and maintain the building with the principal of green. The scope of work for building management activities in the Main Building includes operational, maintenance and administrative activities. All operational, maintenance, and management activities of the Main Building and Parking 10 Building must be based on the Green concept which includes aspects: energy saving, water usage saving, and environmentally friendly. Green O&M focuses on energy and water consumption, which will be monitored and controlled to achieve a high-performance building level. To measure the level of achievement a set of Key Performance Indicator used to evaluate the performance, below are some of the benchmarks : Table 2. Key Performance Indicator of Green O&M Preventive and minor maintenance was carried out by building management to maintain the performance of the building, while major maintenance was carried out by the Bureau of General Affairs. Data collected regarding the contracts for operation and maintenance cost from the beginning of operation until recent year are as follow :  Maintenance work was conducted by separate third party service contractors for several kinds of work including mechanical, electrical, plumbing, civil, architecture, and landscape. Most of the maintenance work was being done regarding the building improvements in civil, architecture, and supporting facilities. From the data collected there was no major maintenance being done to the building before 2017 because the building is still relatively new and preventive maintenances was being done on a regular basis by the Building Management team. Table 4 below shows the major maintenance of the building that was carried out by the Bureau of General Affairs starting from the year 2017 until recent year. From Table 3 and Table 4 above a graph could be made to shows the operation and maintenance cost of the building over a period of 8 years, starting from the beginning of operation until recent year. Figure 13

Energy Cost
Energy Costs consist of electricity costs and water usage costs. Data collection regarding the energy cost was collected from the monthly electricity bill and water usage bill paid by the Bureau of General Affairs Annual Budget. The total energy cost over 8 years period of building operation are Rp24.235.486.784,00 as shown in Table 5 and Table 6 below. Num.  According to GBCI the Energy Consumption Intensity (IKE) standard for office buildings in Indonesia is 250kWh/m 2 /year. The tariff of electricity for a government office building with power limit above 200KVA (P-2/TM category) provided by National Electricity Company (PT. PLN Persero) is Rp1.115,00 for Non-Peak Load Hour (LWBP) and Rp1672,50 for Peak Load Hour (WBP) as stated in the Minister of Energy and Mineral Resources Regulation (Permen ESDM 28/2016). The average electricity consumption at Central Office Complex of the Ministry of Public Works and Housing observed in the Electricity Bill for a year are 87,5% at Non-Peak Load Hour and 12,5% at Peak Load Hour. By comparing the electricity consumption data from Table 5 with the Energy Consumption Intensity (IKE) standard for office buildings, total energy cost saving could be calculated as presented in the table below. Based on Indonesian National Standard (SNI 03-7065-2005) the minimum water usage according to building use is 50 liters/employee/day for an office building. The water tariff being paid to PAM Jaya as Regional Water Provider in Jakarta is Rp9.800,00/m 3 based on the Governor Regulation of DKI Jakarta Province (Pergub 91/2017). The total employee occupied the Ministry of Public Works and Housing Main Building are 1545 persons. Using the standard water usage, total employee, water tariff, and water usage data from Table 6 a calculation could be made to determine the water usage cost-saving, as presented in the table below.   Table 7 and Table 8

Building Expenditure and Building Cost History
Based on the Initial Cost, Operation & Maintenance Cost, and Energy Cost that has been compiled above the total building expenditure could be calculated and the result is Rp483.584.506.649,00 as presented in Table 9 below. From its inception until its operation until recent years a graph showing the building cost history over the years could be made based on the cost of the contract related activities. At the beginning of its inception in 2009 the early activities related to cost are construction management contract, followed by design and supervision contract and construction contract, all of it categorized as Initial Cost. Operation & Maintenance Cost and Energy Cost starts from 2012 were initiated after the building was completely built and FHO took place. The result presented as following :  From the result presented in Table 10 above a life cycle cost structure model could be presented as shown in Figure 15 below :

CONCLUSION
The study regarding Life Cycle Cost has been carried out at a government office green building to determine the Life Cycle Cost Structure over a period of its operational year, with the finding of the cost components. There are three categories of cost for LCC of a green building which are: 1. The implementation of green concept in the Ministry of Public Works and Housing Main Building was based on the aspects of energy saving, water usage saving, and environmental friendly. Operation and Maintenance of the building were carried out by the building management operator whose task to monitor and control the performance of the building to achieve a high level of efficiency and energy-saving. Over a period of 8 years of its operation the calculated total Energy Cost saving is Rp 28.072.536.738,00.