Impacts of Data Limitations in Developing Organization-Level Greenhouse Gas Inventories

Organizations often underestimate the commitment required to develop a greenhouse gas (GHG) emission inventory and to identify and assess potential reduction opportunities. To establish a complete accounting of GHG emissions, the amount and source of all energy use, both direct and indirect, must be determined or estimated. Energy use data, even for energy used directly in operations, is often not available for a variety of reasons. Energy source data is yet more difficult to acquire.

In 2008, Alliance Technical Services, Inc. (ATS) developed a GHG inventory for a major Eastern U.S. regional bank and identified potential GHG emission reduction opportunities. The inventory was based on data collected for eleven facilities, including two data centers. Corporate vehicle use and employee commuting were included in the inventory. The total building space represented in the analysis was over three million square feet, and the total number of employees working in these facilities was over 7,600. In developing the GHG inventory and analyzing emission reduction opportunities, the bank encountered significant challenges in acquiring sufficient equipment and energy use data to enable a complete and accurate inventory. The information gaps for this project are detailed, and a methodology for estimating GHG emissions with incomplete data is presented.

Because of the structure of the energy use agreements in place for the bank, actual electricity use for each building could not be obtained. Energy use was thus estimated using building data, equipment inventories, available information on corporate vehicle use, and available information on employee commuting habits. The energy used to heat or cool a building depends on many factors, including building size, climate, roofing material, insulation, window types and sizes, ventilation, building purpose, heating and cooling equipment and HVAC system configuration, thermostat controls, the number of building occupants, number of heat-generating devices and appliances such as computers, etc. The bank had little information on the building construction, such as roofing materials and the U-factor of the windows, as the buildings were leased. Bank personnel thus had to inquire about this information to the building owners.

GHG-generating equipment that was inventoried included computers, servers, heating and cooling systems, copy  machines, printers, kitchen equipment (coffee makers, microwaves, etc.), phones, and other devices. The development of this equipment inventory required bank personnel to visually scan the entire premise for each building, noting the make, model, type, and/or serial number for each item so that accurate information on average energy use could be obtained. For example, to accurately estimate the energy use and consequent emissions for a printer, information on the size of the printer and whether it is laser or inkjet was needed.

A further challenge in the bank’s development of its GHG emission inventory was lack of information on gasoline and diesel usage in its corporate vehicles. Because gasoline and diesel purchases were not specifically tracked, fuel use had to be estimated based on approximate annual miles driven and published data on fuel economy for specific vehicle models. This data collection effort was complicated at some facilities by lack of complete information on fleet inventories.

Obtaining information on employee commuting proved to be another challenge faced by the bank in developing its GHG emission inventory. Because data on commuting did not exist for the bank’s employees, ATS suggested that the bank conduct a survey of its employees to determine commuting distance, mode (personal vehicle, bus, rail, etc.), and frequency. However, the bank opted not to conduct the survey due to the costs (employees’ time) and concerns about how responsive employees would be.

A phased approach was employed in the development of the bank’s GHG emission inventory. Building construction details and equipment inventories were initially estimated by bank personnel using visual inspections to develop a ballpark estimate of the bank’s emissions. ATS then developed detailed data sheets for the bank to use in acquiring consistent and complete information on building construction, equipment inventory, corporate vehicle use, and employee commuting. The detailed data was requested in order to develop a GHG emission inventory with sufficient accuracy and documentation to 1) enable identification and evaluation of potential emission reduction opportunities, and 2) satisfy the requirements for potential GHG emission reduction credits.

In many cases, the initial estimates of equipment inventories were inconsistent with the detailed data developed later, and inconsistencies had to be resolved before the analysis could be completed. An additional challenge in developing the bank’s emission inventory was the dynamic nature of the business environment; equipment and even building inventories are constantly changing. A method for accounting for changes in the bank’s operations over the analysis timeframe had to be developed.

Limitations in the amount of time bank personnel were able to spend in completing the detailed data sheets resulted in incomplete information with regards to building construction and equipment inventories. ATS researched similar buildings and business operations to develop engineering factors and statistical approaches to estimate the emissions with incomplete information on energy use. Similarly, published data on general commuter habits (distances, modes of transportation, frequency of commuting, etc.) in the locales of the bank’s facilities were used to estimate the contribution of employee commuting to the emission inventory.

Complete and accurate GHG emission inventories are important in the identification and evaluation of GHG reduction opportunities. Some GHG emission reductions can be achieved with minimal effort or expense (e.g., enacting switch-off policies for lights), while others require considerable commitment (e.g., installing a solar roof). Knowing where emissions originate is critical to determining strategies for reducing the emissions. An accurate baseline inventory is also necessary for determining emission reductions.

In addition to the data collection effort required to develop their GHG emission inventory, a significant effort from bank management was required to identify the importance of a variety of factors, including facility factors, operations and maintenance factors, cost and economic factors, safety and environment factors, and implementation and market factors, in order to evaluate potential emission reduction opportunities. An assessment of the bank’s values and capabilities with respect to implementing emission reduction options was vital to ranking the emission reduction opportunities.

Understanding the extensive commitment required to develop a greenhouse gas (GHG) emission inventory and to identify and assess potential reduction opportunities is an important first step in developing a successful GHG emission reduction program. The accuracy, completeness, and level of detail of the energy use data available for developing the inventory has a significant impact on an organization’s ability to identify and evaluate emission reduction opportunities. Input from management is also critical to developing a successful emission reduction program within an organization.