Historically, General Mills shared a similar challenge with other manufacturers—plant resources have little accountability for energy usage or it is a small component of their objectives, resulting in slow progress. At the same time, the scope of responsibilities for corporate energy managers is typically too large to understand the details of the energy usage in 25 plants to be able to drive sustained reductions. To overcome this issue, multiple energy audits are often funded. However, without a plant ”champion” for energy performance improvements, the list of ideas and projects resulting from the audits will be executed slowly or by external engineers, while no one in the plant has responsibility for sustaining the short term gains of this project-based effort. This results in a cycle of repeating the same improvements every couple of years. Also, general audits tend to focus on lighting, heating, ventilation and air conditioning (HVAC), variable frequency drive opportunities, and hot water. This covers the majority of energy spend for a commercial building, but only a small percentage of the energy use for an industrial user. Most of the energy is used in the processes, and no one understands the processes better than internal engineers. Typically, food manufacturing plants use specialized equipment to produce custom products with proprietary formulas. This specialized nature can make it difficult to identify where to capture energy and energy cost savings. General Mills has found more value in hiring specialists with deep technical expertise in specific technologies rather than generalists.
General Mills has used dedicated plant-based energy engineers to overcome these challenges and implement the company’s energy program. The plant-based energy engineers oversee both the plant’s utility building generation efficiency and operations use of the energy. While it may seem expensive to have an energy engineer dedicated to individual plants, many plants are large enough to pay an engineer’s salary with even a 3% per year energy reduction. Priorities for existing engineers were realigned to be 100% focused on energy in the largest plants and 50% of their time in smaller plants. General Mills developed a strong training program along with the standardized tools covering topics like sub-metering, energy allocations, and reducing energy losses that allowed new energy engineers to deliver savings quickly. These engineers train site personnel on energy efficiency practices. The corporate priorities are shared by each energy engineer, so the team members share new innovative solutions across all plants.
General Mills developed its own energy reduction CI program that combined the concepts from ISO 50001 and EPA’s ENERGY STAR Guidelines for Energy Management with its existing CI program. Using the standard General Mills’ CI tools and language enabled anyone from an operator to a Vice President to understand the process and allowed energy to more easily integrate into the company’s existing CI program.
General Mills’ energy reduction CI process is multi-step. It begins with corporate and plant-level commitment to energy reduction:
- Providing a dedicated plant-based engineer to lead the effort
- Allocating funding for innovative energy ideas, sub metering, and energy efficiency projects
- Establishing energy reduction goals that impact plant and corporate performance ratings
After a plant has demonstrated the above prerequisites, they will follow a systematic process to:
- Develop site energy allocations of each unit operations’ usage and identify significant energy users.
- Utilize science-based workbooks for each significant user that leverage best practices from all plants to automatically identify key energy loss opportunities, provide mitigation solutions, and calculate savings and return on investment based on the plant’s current state.
- Develop and execute 3-year improvement plans.
- Sustain reductions through real-time energy monitoring.
Sub metering
As a first step in the process, the plant executes an extensive sub-metering strategy on electricity, gas, compressed air, refrigeration, and water. This strategy is rolled out in four phases over several years.
- The first phase entails real-time tracking of all main feeds into a facility.
- The second phase involves metering the main headers, boilers, and large utility equipment.
- The third phase covers the production line level.
- The fourth phase, includes individual unit operations.
Following this strategy, General Mills has installed over 1,500 sub meters across its 25 U.S. plants. Using this metered data combined with nameplate ratings or one-time readings, the plant energy allocation exercise accounts for where every British Thermal Unit (BTU) is being consumed. For example, on the electrical side, it would include energy usage for lighting, compressed air, refrigeration, pumps, fans, processing motors by process line, and HVAC. On the thermal side, usage is broken out into HVAC, hot water, and each processing unit’s steam or gas usage.
Energy Loss Tools
After the energy allocation exercise, the significant energy users are identified. General Mills developed its own improvement tools for these significant users. Examples of significant users include steam, refrigeration, compressed air, industrial drying, lighting, motors, pumps, fans, HVAC, renewables, and combined heat and power units. Each software tool allows the plant energy engineer to input data from the relevant system, controls, and operation. The tools automatically identify key opportunity areas and calculate savings for each. The tools give specific instructions and proven solutions to eliminate energy loss through improvements in maintenance, operation, operator training, new innovative equipment, and controls. Previous project files are available to share reusable engineering of programming, equipment, and vendors. This makes it easy for the plant to prioritize the largest opportunity losses without having to identify and develop each solution from scratch. The tools were built on known solutions and best practices from other plants, (captured in workbooks and guidance provided to staff) which allows for quick justification for new projects as the company has already proven theses solutions’ impact.
These tools allow best practices to be easily replicated from plant-to-plant and to track progress on implementation of projects. Having defined the energy opportunity with these tools, energy engineers put together multi-year improvement plans and lead sites in the execution of these plans. Capital is prioritized for energy projects that pay back in less than four years. General Mills pursues utility and other incentives, which in many cases are the key driver to enable these projects to meet financial return requirements.
Sustaining Savings
The last step of the process is to sustain the savings already realized. The goal of this step is to move away from only looking at monthly utility bills to managing energy in real time. However, monitoring energy usage data without overlaying production data provides little clarity on how the plant is actually performing, since production mix has the largest impact on usage. To solve this issue, General Mills developed an energy reporting solution that allows each unit op meter to have a target energy usage based on real-time production data. This helps the operation view “energy as an ingredient” to the pounds of each product produced: material inputs plus energy yields a useful product. With this language, operations can manage energy usage in a manner similar to how the company has focused on reducing ingredient waste. These daily management systems include alarms when a unit operation is consuming outside of its optimal energy usage. It also engages production operators in energy management, allowing energy performance for each unit operations to be summarized quickly at shift production meetings.
To fuel new ideas into this reduction process, General Mills convenes an annual innovation pipeline meeting, where energy engineers brainstorm new and creative ideas, controls, technologies, and engage research and development staff for critical production process improvements. Examples include items such as advanced heat recovery techniques or a cooling control/instrumentation strategy to ensure consistent product quality, while also minimizing cooling load. General Mills uses a rigorous process to prioritize these innovative ideas. Each plant is assigned ideas to investigate and appropriate funding and resources are allocated. If an idea is successful, the solution and calculations are added to the official improvement tools, and responsibility is placed on all the other energy engineers to execute it as well. This ensures that the plant maintains a three-year pipeline of identified energy opportunities by replenishing it every year with new innovative, proven solutions. The company’s showcase project for the Better Plants Challenge, a major heat recovery project in Cedar Rapids, Iowa, is a great example.
General Mills has developed a number of different tools and resources to help guide and implement its energy management program. Some examples include the company’s:
- Energy Management Process, which combines best practices and concepts from ISO 50001 and EPA ENERGY STAR guidelines with the company’s existing CI program. More details are available here.
- Metering Strategy, which has guided the company’s installation of more than 1,500 sub-meters at its plants. A schematic of a sample gas system metering system is available here.
- Energy Allocation Tool, which allows General Mills to account for every BTU being consumed in different systems, such as lighting, compressed air, refrigeration, HVAC, hot water, and each processing unit’s steam or gas usage. A sample of the tool’s outputs is available here.
- Energy Loss Improvement Tools, which calculate energy-savings potential of specific energy-use systems and suggest best practices and projects that can be replicated from other plants. More details on these tools are available here.
- Manage Energy as an Ingredient—Daily Management of Energy Usage System, which summarizes data from multiple energy meters and organizes the information into actionable dashboards. A screenshot that captures the system’s output and more detail on its capabilities are available here.
General Mills measures the impact of its energy management plan by tracking energy intensity improvement and cost savings since the plan was first implemented. The company tracks energy intensity reduction versus a Fiscal 2012 baseline that adjusts for the impact of weather and production mix using real energy metering values. General Mills also tracks energy cost savings relative to a business-as-usual scenario of no improvements being made.
As of the end of Fiscal 2015, the program has resulted in an impressive:
- $13.5 million in annual energy savings
- 11% energy intensity (Btu/pound) reduction
- 100,000 metric tons CO2e reduction
- 1000+ implemented energy projects
- Development of internal proprietary energy CI processes and tools
- An energy engineer recognized with the 2013 and 2014 Association of Energy Engineers International Young Energy Professional of the Year awards and 5 regional awards in 2014/2015
- Midwest Region Corporate Energy Management award in 2015
General Mills Energy Allocator Tool which classifies and records energy consumption in their facilities.
Energy Loss Improvement Tool used in General Mills facilities.
General Mills' Energy Management Process for its facilities.
General Mills' Gas Metering Strategy to lower energy consumption.
This is General Mills strategy for managing energy as an ingredient, which allows General mills to analyze data in a more holistic way than otherwise possible.
