Preliminary Energy Use Analysis

Preliminary Energy Use Analysis

ASHRAE defines the Preliminary Energy-Use Analysis (PEA) as the starting point for an energy audit that aims to determine the overall energy efficiency of a facility. The first step of PEA is to convert the annual energy use to a common unit of measurement, which is British Thermal Units (BTUs). Regardless of whether a building uses electricity, natural gas, fuel oil, propane, or any other energy source, the individual energy uses can be converted to BTUs and then combined to determine the total annual energy use. Dividing the total annual energy use by the building area (in square feet) gives the Energy Utilization Index (EUI). The EUI is an effective measure of building energy use that enables the comparison of one building's energy efficiency to similar buildings. It is the generally accepted engineering practice for such comparisons.

All three levels of audits require a Preliminary Energy Use Analysis which involves the following:
• a site visit to assess the building and energy consuming equipment
• analysis of the utility bills to determine whether savings can be had by changing the utility rate
• a summary of utility bill data
• calculation of the energy use intensity (EUI)
• benchmarking to compare the site’s energy usage to that of similar sites in the same region
• estimate of the energy and costs saved if the building met an energy use intensity target

What is Energy Benchmarking?

Energy benchmarking is the process of tracking your building’s energy consumption over time and comparing it across regular time periods. You can incorporate related factors such as electricity usage, building occupancy, fixture upgrades, and weatherproofing. When done correctly, energy benchmarking allows you to analyze your building’s energy performance and set new goals.

The process typically begins with an energy audit that establishes a baseline consumption. This hard data can then be compared to metrics collected on a regular basis, allowing you to set goals for reducing energy consumption.

The audit also identifies areas of inefficiency and wastage, along with potential causes. Energy benchmarking is the first step toward correcting wasteful behaviors, upgrading equipment that drains electricity, and improving the building’s energy envelope.

Why Do You Need Energy Benchmarking?

Energy benchmarking is not a one-time project. To maximize its benefits, you must regularly measure your building’s energy performance and compare it to past results. It’s worth the time, though, as it allows you to collect valuable data that guides your overall building strategy. Here are the key reasons you should implement energy benchmarking in your organization:

• IDENTIFY YOUR STARTING POINT As with any sort of goal, you cannot plan and achieve improvements until you’ve established a baseline. Energy benchmarking gives you the metrics you need to track your progress. It also allows you to put hard numbers to your building’s energy usage, including the actual costs of consumption and wastage. By putting energy costs in context, you can prove which building features are costing your organization too much money — and you’ll also be better able to demonstrate the ROI of energy upgrades.
• MAKE A PLAN FOR ENERGY UPGRADES Some building owners invest in upgrades (e.g., solar panels) without understanding their building’s current energy costs. Then, they don’t reap the full benefits because the core problem has not been addressed. There have been cases in which an organization invested heavily in renewable energy only to discover that its building was losing energy because of its improper air balance from your HVAC system. In short, it’s crucial to know where your building is underperforming before you invest in new infrastructure. Energy benchmarking not only identifies problem areas but also provides numbers you can use to justify energy investments and more accurately predict cost savings.
• EDUCATE OCCUPANTS ON ENERGY-SAVING PRACTICES. It’s one thing to tell your organization’s staff to turn off lights to save energy. It’s another to have hard numbers in hand so you can tell them the actual cost savings of turning off lights. Knowing the details of your building’s energy consumption can help convince occupants to adopt better practices. The energy benchmarking process may also identify areas and behaviors that no one realized were draining energy. On the flip side, energy benchmarking allows you to identify behaviors and equipment that are performing well, so you can duplicate that infrastructure throughout the building. You’ll also be able to build upon that good performance to achieve further cost savings.

How to Get Started with Energy Benchmarking

Once you’ve obtained buy-in for the initial audit, it’s time to start your benchmarking process. Follow these steps:

• Be as thorough as possible when establishing your baseline It’s a good idea to have a dedicated team or an energy management company who can perform the audit within a couple of days. Trickling in random data over the course of a few weeks or more defeats the purpose. One solution is to do a cursory audit of your building to collect your baseline data, then revisit areas with significant energy consumption for more detailed insights.
• Use the Energy Star Portfolio Manager This free tool allows you to collect your current energy consumption data and start tracking it over time. You can then generate reports to share with senior management. The Energy Asset Scoring Tool by the U.S. Department of Energy is also helpful; it lets you drill down into your building’s energy profile.
• Set your goals The Energy Star Portfolio Manager allows you to compare your building’s energy consumption to those of a similar size and profile. From there, you can decide how much you want to improve your building’s performance (e.g., reduce overall electricity usage by 20%). You should also look at the Commercial Buildings Energy Consumption Survey to see how your building performs and how much you need to improve.