Dairy's Best Practices for Saving Energy
It is time to talk about best practices for the dairy processing industry. But I am not an engineer and I can’t get too technical, like recommending that you lower your refrigeration system’s minimum head pressure set point or telling you that you should lower your boiler steam generation pressure to match your process requirements.
Instead, I’ll take it from a different angle. From my perspective, the No. 1 best practice in dairy processing is to know your industry and your operations in detail. The more you know, the better decisions you can make.
According to the U.S. Census Bureau, the dairy processing industry spent $726 million on electricity and another $731 million for fuel in 2008. With a combined total expenditure of nearly $1.5 billion for energy per year, efficiency is a golden opportunity.
Electricity is used throughout dairy processing operations, with a dominant portion being used for cooling and cold storage. Fuels, of course, are combusted for the heat that is used for processing and cleaning. According to the recently released dairy-focused Energy Star Guide for Energy and Plant Managers, 18% of electricity is used for lighting and HVAC (heating, ventilating, air conditioning), 40% is for machine drive applications and 31% for cooling, freezing and cold storage. With respect to fuel, 80% is used for process heating and the creation of steam in boilers.
Understanding where energy is consumed signals where one should pursue best practices that will yield the greatest return in energy savings. The Energy Guide is a great place to get a deeper understanding of potential energy savings in a dairy processing environment.
The Energy Guide for dairy plants was drafted by staff at Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, Calif., with insight and feedback from a number of industry insiders. The guide is available at no charge from IDFA’s website (www.idfa.org). The Energy Guide for dairy is the latest in a series that includes food industry guides for corn milling and fruit and vegetable processing. The guides are similarly organized in that they provide some great background, data and information about the respective industry. Each outlines the processing methods and takes a close look at the industry’s energy consumption.
Where dairy processors use energy
Did you know that it takes 538 Btu to freeze a pound of ice cream? Or that a whey evaporator will consume 3,881 Btu per pound of dry whey? Or that the pasteurization of fluid milk uses 92 Btu per pound? This is the level of detail that you’ll find in the guide. But more importantly, it will help you see that those 92 Btu used in fluid milk pasteurization represent nearly 30% of the energy intensity of fluid milk, which gives it significance.
The guide does a good job of breaking down the approach to better energy management by dividing plants into systematic areas such as steam, motors, pumps, refrigeration, compressed air, lighting and HVAC systems, and then provides specific suggestions or measures that can be followed to gain efficiency. It also provides some useful appendices which help the reader with everything from identifying basic energy-efficiency actions for plant personnel to a checklist on how to team up to save energy.
Finally, there is an appendix of support programs, which among other things, identifies programs where individuals can get free energy assessments including those performed by the U.S. Department of Energy’s Industrial Assessment Centers (IAC).
That brings me to two other best practices. First, don’t go it alone — make it a team effort. Second, get as much free or pre-existing help as possible. The IAC program is geared toward small- and medium-sized manufacturing facilities, which have fewer than 500 employees and annual sales of less than $100 million. The on-site assessments are provided at no-cost, using faculty and staff from 24 universities around the country.
If your business is too large to qualify for the IAC program, you may want to consider the DOE’s Save Energy Now program, which focuses on large plants’ process heating, steam, pumps and compressed air systems.
DOE’s best practices program
In addition, DOE runs a best practices program to improve the energy intensity of the U.S. industrial sector through a coordinated program of research and development, validation, and dissemination of energy-efficient technologies and practices, aptly named BestPractices. The BestPractices website (www1.eere.energy.gov/industry/bestpractices)
has a number of useful tools, including publications, software tools, training opportunities and databases. The database section includes 247 past dairy industry IAC assessments dating back to 1982. The assessments are searchable by Standard Industrial Classification or North American Industrial Classification System codes and include data on current energy usage and costs, recommended reductions in usage and recommended actions to achieve the reductions along with costs and payback periods.
Last but not least, Wisconsin’s Focus on Energy program (www.focusonenergy.com) drafted a Dairy Processing Energy Best Practices Guidebook in 2006. It is available online at no cost at http://tinyurl.com/d84z3w2. The 72-page guidebook has more than 20 detailed best practices with nearly a dozen that address refrigeration alone. The practices are well written and easy to follow, which makes this publication an excellent resource.
To reiterate, when pursuing best practices, don’t try to do it alone and don’t try to reinvent the wheel when there is so much information and assistance available. I hope that this column has pointed you in the right direction.