Energy Assessment
A very important step in the process of reducing both energy use and utility costs comes during the assessment stage. An Energy Assessment is a detailed evaluation of how a facility uses energy, what the facility pays for the energy, and finally, a recommended program for changes in operating practices or energy consuming equipment that will cost effectively reduce utility bills. The stages of an industrial assessment are:
- Utility cost analysis
- Pre-assessment Planning
- Conducting the in-plant assessment
- Identifying energy efficiency actions
- Energy savings and economic analyses
- Implementation, verification and continuous improvement
The sections below provide a brief description of each stage.
Utility Cost Analysis
Primary energy sources for Arkansas’ industry are electricity and natural gas. Utility costs for an industrial facility can be confusing, whether the facility is large or small. Understanding rate structures and the effects of reducing energy usage and reducing demand are important when deciding which energy conservation opportunities will be the most cost effective. A review of your rate structures and 12-18 months of your utility bills is an important first step of an energy management program. Recalculating the bills provides insight and often cost reduction opportunities. This is the time to also determine the marginal costs for each unit of energy or power. For example, the marginal costs for electrical energy ($/kWh), electrical demand ($/kW), and natural gas ($/MMBtu) should be determined. The Clearinghouse can walk you through this process, just give us a call.
Pre-Assessment Planning
Before conducting the on-site assessment, other information is needed. It is useful to have an understanding of the plant processes and systems. Time is spent understanding the material and energy flows into the plant. Knowing the major energy consuming systems (boilers, furnaces, compressed air, refrigeration, process motors …) within the plant provides insight as to the potential energy savings measures available. By combining the knowledge of the energy systems and the historical electric bills, an approximate distribution of energy consumption for the plant can be determined. This is important as energy efficiency measures associated with the largest energy consumers should be pursued. The Department of Energy has a good initial screening software tool known as the Quick Plant Energy Profiler (i.e., QuickPEP, http://www1.eere.energy.gov/industry/bestpractices/software_quickpep.html). QuickPEP provides an industry-sector specific energy use distribution and recommendations of proven energy efficiency actions (EE ACTIONs).
Conducting the In-Plant Assessment
There are several levels of assessment that are commonly performed. The essence of each is to identify potential utility cost savings through energy reduction measures. The differences typically depend on the level of detail and the amount of time taken to study each energy system. Depending on the complexity, sometimes portable data loggers are used to better understand the system. The electric utility company can sometimes provide hourly or 15-minute interval data that shows trends and information regarding peak electric demand.
The general approach to an assessment is to learn the processes from where the raw materials enter the building through the finished product. This approach provides the perspective where energy flows can be recognized and wastes/inefficiencies can also be identified.
Identifying Energy Efficiency Actions
During this process, all potential energy efficiency actions should be listed for further consideration. Utilize lists of common energy efficiency opportunities to help spawn ideas. Publicly available lists are on this website for various industrial systems. Other sector-specific lists are available. Sub-metered energy use data or nameplate data can be used to determine the power and energy. Also, knowledge of operational characteristics may provide insight into changes that will reduce operating times. Energy reductions can be obtained by either reducing the equipment’s power requirements (the rate at which energy is used) or the length of time the equipment needs to operate.
Economic Analysis
Each potential energy efficiency action should be evaluated to determine its economic feasibility. The marginal costs should be used to determine potential costs savings. The most common approach is to determine the economic simple payback and tested against the company’s payback threshold. Other methods include net present value (NPV), internal rate of return (IRR), and other life-cycle cost analysis methods.
Implementation, Verification and Continuous Improvement
When your self-assessment is complete, you will have a list of potential energy projects that can save your business money. Some of these projects will be easy to implement and require nothing more than operational changes. Other projects can be quite complex and will require engineering expertise to implement. There are a multitude of resources available to you for these large projects. Your utility companies and equipment vendors can be valuable resources in helping you to reduce energy usage. There are also a number of energy engineering consultants in Arkansas that can help you with energy conservation projects. As always, you can contact the clearinghouse for more information, or just to help you get started.
After implementation, it is often valuable to measure and monitor (i.e., track) the savings to maintain and document savings. Furthermore, it is important to periodically perform plant assessments and achieve continuous improvement. As technology evolves and as your processes change, new opportunities become available. Most corporate energy management programs set long-term goals for energy reductions.
Sources of information
http://www1.eere.energy.gov/industry/bestpractices/conducting.html
http://www1.eere.energy.gov/industry/bestpractices/plant_assessments.html
http://www1.eere.energy.gov/industry/saveenergynow/
http://www1.eere.energy.gov/industry/saveenergynow/assessments.html
http://www1.eere.energy.gov/industry/bestpractices/iac_eligibility.html
