Energy Assessments for Manufacturing Plants

If you have read any of my previous posts, you know that I have a passion for improving energy efficiency in industry. I have spent several years devoting my time and efforts to the unique needs of manufacturing plants.

When comparing energy usage in manufacturing to other areas, such as residential, office, retail, data centers or agriculture we see multiple processes that incorporate various types of energy (thermal, electrical, and cooling) to produce a finished product. Energy use is usually quite significant, opportunities abound and must be properly vetted and prioritized. The use of energy in manufacturing demands a system approach and is usually unique to each manufacturer or plant. Energy savings must be balanced against impacts to the process, reliability of equipment, capital availability, and labor changes. This requires more innovative solutions and more cooperation with plant operations to insure the goals of lowered energy demand, and perhaps increased energy generation, are met. 

You may also know I am an active participant of the Association of Energy Engineers, who have asked me to communicate my approach and knowledge to others that are interested in embarking on energy assessments at their or their customers' plants. Energy Assessments for Manufacturing Plants is a short, interactive course comprised of four, two-hour sessions set over 4 days. Join me and I will share what I have learned in over 16 energy assessments on manufacturing plants, my interactions with vendors and service providers, and my specific experience with energy management systems within a pulp and paper organization. Please contact me with any questions you have concerning this course.  The next opportunity to take the course is late October. 

Things we can all agree on (from an energy perspective at least).

In these times of political upheaval, divided opinions and values, and general unease, it is important to reflect on those things which we can potentially agree are in our best interest. There should be some consensus on evaluating energy demand and supply options that move us toward an overarching better state. This state would essentially be dictated by accurate economic analysis that include all known costs -both direct and indirect ones. Of course the issue is that indirect costs are difficult to estimate and tend to be dependent on politics and some interpretation of scientific data. That leaves us with the direct economic measures which are basically dictated by free market pricing, to the extent a free market exists. We must also incorporate the changes in price in the future due to resource depletion, technology improvements, and perhaps public acceptance. This analysis should lead to an energy future that has lower impacts to the environment and raises our quality of life from a local and global perspective. Here is my list of energy oriented issues that we should agree on. Please feel free to add yours in the comments.

• The use of any energy source requires conversion from a primary energy source such as wind, sun, or fuel to the end energy state which is power, heat, or cooling. Things however get complicated as we include external impacts such as grid and pipeline reliability, real time pricing, demand charges, incentives, and fuel quality.
• Distributed generation of power has distinct advantages that can be economically attractive. It allows for harnessing of already available primary energy sources (sun, wind, waste fuels, waste heat), higher efficiencies due to thermal coupling potential (combined heat and power), reduction of transmission losses, and is known to create higher levels of employment per KW. It also gives the customer more flexibility and control over their energy costs.
• Energy conversion technology continues to improve. Especially renewables like PV and wind, but also organic rankine cycle engines, back pressure turbines, cooling towers, recovery boilers, gasifiers, combined cycle natural gas turbines, etc. Use of energy also is continuously improving (lighting, heat recovery and integration, chillers, compressors, motors, pumps, fans, drives, controls, etc).
• Energy efficiency will always be a worthwhile endeavor regardless of where energy comes from. It has always been to lowest cost option, highest ROI, and most unassailable strategy to reduce energy and environmental footprints, carbon use, and cost. It requires an in-depth analysis of what we are trying to do and how we can effectively do it while keeping risk low and flexibility high. It also demands a solid system to track savings and monitor usage over time to ensure benefits are captured.
• Pandas are cute. And probably energy efficient.

Steam and Water Balances - the Key to Thermal Energy Efficiency and Power Generation

Complex manufacturing operations involve transporting and heating raw materials to the temperature of reaction, separation of the products and byproducts, converting to final products, and recovery of the waste byproducts and waste heat to the extent economically feasible. Over time the race for higher production rates and capacity, more complex product slates, greater emission and effluent constraints, and restrictions on maintenance has outrun the ability of the plant to optimize its energy and fuel usage. Vendors promise that by implementing their software platforms, you can get the optimization desired via proper tracking of energy coupled with pricing information of each energy stream. Unfortunately, this may work well for an existing building with HVAC requirements or a simple industrial process, but is inadequate for industrial systems. Plants that are old and complex, have been changed significantly, over or under designed, and built at a time when energy and water use were less at a premium than they are today have need for energy efficiency fundamental work. In these cases it makes more sense to spend limited resources on a more comprehensive approach.

The first step to solving this dilemma is not found in sophisticated energy control software, but in starting with the basics - steam and water balances that are developed under typical conditions in various seasons. These balances are built from good process flow diagrams coupled with instrumentation which take accurate and representative measurements of steam and water properties and flows. With a robust and easy to follow model, the balances become the basis for understanding where there are opportunities for saving energy through using recovered heat rather than primary steam or thermal fluid. This then allows for either lower fuel use or increased power generation. A good set of balances can be developed using an existing data acquisition system as long as the sensors have been calibrated and are measuring the required information. If not, new sensors and transmitters must be added to the system and old ones must be calibrated or replaced.

The model results further allow for benchmarking against similar plants, in terms of energy, raw material and water usage per unit of product produced. The use of a model based on good balances can nail down where there are gaps with a benchmark and lead to solutions which involve a number of acceptable and practical methods. It is at this point that discussions with the plant stakeholders - operators, engineers, and leadership is undertaken. While, the best available technology may not be economically feasible, it is likely that lower capital improvement changes with high ROI's will be identified. These include additional heat exchangers which can utilize lower temperature water, insulated tanks which keep varied temperature streams segregated, flash tanks where they are not being fully utilized, condensate return issues, desuperheater and steam trap issues, and repiping of higher temperature water flows to take advantage of this heat in processes that can benefit from them directly. These projects when implemented will reduce operating costs and increase the plant's viability and profitability. Plant staff need to be fully involved to insure that recommendations are practical and will not impact the process adversely.

On the power side, the model results will show how much steam can be saved through appropriate projects, and how this steam translates into power generation. Additionally important are uses of power that could be reduced or eliminated by reducing recycling of water, resizing of pump impellers, and selective implementation of variable frequency drives. Again, buy- in with the plant staff needs to be made before moving further on recommendations. The result of reducing demand and increasing generation will result in a net power sales increase.

The cost for this activity is as you might expect a great deal less than software optimization platforms with supervisory control packages, and it is not a recurring cost. The important difference though is that it will result in projects that have high ROIs and are proven to be effective by benchmark plants, model results, and operating data. Once the plant staff have put these projects in place and the full plant has been sufficiently updated and made efficient, then it may be time to consider optimization software and controls.

The return from this approach is significantly greater than could be achieved from typical software based systems. It has been estimated by various vendors that their energy management software systems will save 1-3% of energy per year. The approach elucidated here will save 5-20% of energy use since it will involve structural changes that will make the process and all energy related aspects more efficient. The savings will be locked in as they are engineering changes which cannot be easily undone by operations staff who may have opposing motivations.

While great software and controls are the ultimate answer to making manufacturing optimized and automated, the first steps of a detailed process flow diagram and energy balance are still both necessary and sufficient to make significant progress in reducing a manufacturing plant's energy and water footprint. These foundation blocks are critical to seeing sustainable and real energy and process efficiency.

Finding Innovative Energy Efficiency Solutions

Energy efficiency is nearly universally hailed as one of the most cost effective ways to achieve a lower carbon footprint and become more sustainable.  Measuring and tracking allows us to track success in this over time.  There is a generally agreed to standard metric for manufacturing plants - energy intensity - which when used properly shows us how well a plant is performing with respect to energy use.  We can agree on this metric and the importance of measuring the factors that affect energy intensity.  We also have great tools to measure, track, statistically analyze, and verify energy savings from various improvements.  However, we can't easily agree on a single methodology that guides the company on the most cost effective route to permanentaly reduce energy intensity.   At least, I haven't seen a universal, plug and play, cookbook - like method which is clear enough that all stakeholders can agree - engineers, operators, financial planners and senior management.

That is because the solution set is large, and plants are too different from each other in terms of raw materials used, the exact process employed, heat and energy production, fuels used for this energy, product slate, production size, hours of operation, age of plant, future production plans, staff expertise and motivation, potential for sale or closure, and other obvious and hidden variables.  This makes it challenging but of course more interesting to find the best solutions.  It takes asystems engineering view, and the ability to innovate.  It demands making use of best practices and technology, but applying this in exactly the right way.  It takes teamwork, collaboration, and ultimately a path that has certain and predictable paybacks.

Innovation is the part of the equation that can drive large gains.  Here is both where the needle - changing energy intensity improvement takes place, but where there is no roadmap.  The question then is how to get there without suitable precedence or the clear ability to replicate a past success.  Innovation in my experience (20+ years of innovation in manufacturing) requires bringing together the right information, people, resources, and spirit of seeking a better way.  It requires a deep set belief that the status quo is not good enough.  It is the melding of good historical and real time data, experience with similar plants and processes,  a sufficient model of the system, and an analysis with focus on discovery and "what - if" scenarios.  

Innovation questions why we do things the way we do them.  For energy efficiency, this is critical, as plants and processes waste energy because we get used to the way things have been.  Saving it requires more attention, along with potential risks and impacts which affect the process as designed by the original design engineers, resulting in off spec products, lower productivity or catastrophes.  Secondarily we think we don't want to spend money on capital projects that aren't primarily aimed at production increases.  Done right though, energy efficiency brings energy savings along with productivity increases, maintenance savings, and an overall better process.  

What's it worth?  I have seen savings to a plant from innovative projects worth millions of dollars per year with ROI's of 30% or more.  These projects include better hot water use, pulp dryer redesign, kiln heating and heat recovery, turpentine collection redesign, steam coil and condensate collection system repiping, fuel blending, covering and dryers, combustion air system control, lighting retrofits, more effective chilling processes, and pumping that is sending the right amount of material to the right place with the least energy. 

How to get started?  1. Bring together committed people from your organization.  Determine what resources you have and what is missing.  2. Find expertise from outside that you can use to leverage your team and help to both innovate and provide solid and proven solutions.  3. Measure and track the important parameters of your process.  4. Work to find innovative solutions that solve more than one thing and affect the entire system in a positive and lasting way.  5. Implement the solutions.  5.  Validate the results.  6.  Extend the success to other projects and plants. 

Energy Efficiency — 3 “Excuses” for Low Adoption

Out of sight, out of mind — venting steam, heating warm water to hot, condensate going to cooling towers are signs of opportunity.

Wind turbines and Photovoltaics have an enviable position in the energy world for a variety of reasons. They are simple to understand by the lay person, don’t directly emit gases or pollutants (if you don’t count their manufacture), renewable, and only require a grid, a defined power purchase agreement and net metering to produce the desired return on investment. They are hip, cool, and look sleak. By contrast, energy efficiency is complex in nature, doesn’t have much cache or even visibility, and is directly coupled to an existing process, plant, or building. This last element is the one that provides the greatest opportunity for high returns on investment (in most cases far greater than any energy generation project could attain), and the greatest risk of failure (each project is necessarily a customized situation and approach). However, the risk is not commensurate with the actual potential for failure. It is generally overestimated by engineers and management because of 3 key issues.

The product or manufacturing process will be adversely affected by the energy efficiency project. This is clearly the chief factor in the process engineer’s head — will the project result in problems which are more expensive to fix then the savings. The energy efficiency engineer should follow the physican’s Hippocratic oath of “do no harm”. This will be the result of thorough analysis of the current situation and the proposed change by all stakeholders — process engineers, operators, building occupants and workers. There needs to be buy in by all parties so that “improvements” won’t be eroded by manual changes in controls, new processes or products, or other predictable outcomes. Everyone must be aligned for energy efficiency to work and produce returns.

The plant or building could be sold, retired, or completely changed before the energy efficiency project is paid for. This is real but often exaggerated due to the emphasis on keeping optionality. It’s in the category of “paralysis by analysis”. Energy efficiency starts reaping rewards as soon as the project is completed, but demands action. Waiting too long will only insure that it doesn’t produce the expected value and that one of the above scenarios does come true. 

Capital for the project must compete with other projects that have more immediate concerns to the company. Energy efficiency can’t compete with more pressing needs like deferred maintenance, improvements to production volume or quality, projects that reduce labor, and environmental/safety needs. But these aren’t really zero sum gain investments. Energy efficiency investments will add to the bottom line directly and could be financed by third parties if desired. Alternatively, using a separate pool of money that is replenished from the savings and incentives produced could be utilized.

Energy efficiency is boring and tedious (you were expecting it to be fun and exciting?). It requires thorough analysis, constant vigilance, working with all stakeholders, and taking deliberate action. On the plus side, it is challenging to bring all these things together and rewarding when it happens. It drives me to push the envelope and find new and innovative energy efficient projects that achieve high returns for the plant and buildings. In every case I have identified and implemented, the rewards are real, the returns better than expected and quite healthy, and the risks were minimized or eliminated.