Jun 182009
 

image Next to Lighting, Motors are the second best area for saving money in your facility. Did you know that electrical costs account for approximately 95% of your motor’s lifetime costs? Drives and speed controls provide further savings when motors are run for long hours with light loads. This all adds up to big savings when it comes time to look energy improvements.

Pumps and fans represent a major portion of the electrical load in a commercial building. Motors used in HVAC and Refrigeration systems can account for 30% of the total load.  Any time you have motors operating 2,000 hours or more in your facility it would be wise to replace them with NEMA Premium motors. Even if they aren’t running this long, it may still make economic sense to update if you have high utility rates, high motor repair costs, if your utility offers rebates to upgrade.

Motor Savings

Annual savings from specifying NEMA Premium motors

Horsepower Standard Eff. Rating NEMA Eff. Rating kWh Savings Cost Savings

10

89.5

91.7

1200

$60

25

92.4

93.6

1554

78

50

93.0

94.5

3820

191

100

94.5

95.4

4470

223

200

95.0

96.2

11755

588

Based on enclosed fan cooled motor (1800 rpm), 8000 hours annually, 75% load,
and $0.05/kWh electric rate. (Courtesy of the Department of Energy)

You can calculate your own energy savings and develop a wn motor management plan by using the tools found on the MDM website.

Motors Decisions Matter is a national campaign designed to improve the way motor repair or replace decisions are made by promoting the financial and performance benefits of sound motor management policies. MDM aims to increase awareness of motor management opportunities; boost demand for NEMA Premium® motors and best practice motor repair; encourage the market to engage in motor planning; and, enable various stakeholders to collaborate nationally to enhance local effectiveness.

Start with the 1*2*3 Spreadsheet. This spreadsheet takes your basic data inputs (nameplate data, cost of energy, purchase and repair costs, and operating hours, incentives) and calculates energy costs, capital investment, life cycle cost, annual savings, net present value and simple payback. This allows you to make a decision to replace the motor immediately, repair, or replace upon failure.

With this information in hand, it can make it easier for the ‘boardroom’ to implement energy-saving capital projects.

Drives

Adjustable Speed Drives are suggested when the rated load is delivered less than 40% of the time or the average output is less than 60%.

Mark Jewell in the August 2008 issue of Engineered Systems writes,

In addition to saving energy, drives can offer greater control over motor speed, which can prolong motor life and reduce maintenance costs. Drives can also increase productivity by empowering more precise control of process operations, which can result in higher product quality. In certain applications, the installation of drives can enable load-shedding strategies that can benefit from demand-response programs, which are playing an increasingly important role in maintaining grid reliability in the face of steadily growing electricity demand.

Rebates & Incentives

In the Minnesota, both Xcel Energy and Moorhead Public Service offer rebates.

Xcel Energy Motor Efficiency Program – Xcel offers rebates ranging from $4-$18.50/HP depending on whether you are replacing, or upgrading a motor and the motor’s efficiency. They also offer $30/HP incentive for Drives. See their website or download the program brochure for more details.

Moorhead Public Service uses the Bright Energy Solutions program, which offers incentives from $4-$15/HP depending on the NEMA Premium motor’s size. The program has rebates for pumps and $40/HP for Variable Frequency Drives. See the Bright Energy Solutions website for more details.

 

References

  • Opportunities for Motors And Drives by Mark Jewell, Engineered Systems, August 2008
  • Show Me The Motor Money! by Mark Jewell, Engineered Systems, November 2008
  • Motors Decisions Matter – “contains information you can use to develop a motor management plan that meets your company’s needs. The information can also lead to partnerships with your local sales & service center, vendor, utility or other energy-efficiency representatives who may offer added support.”
  • The Database of State Incentives for Renewables & Efficiency. “DSIRE is a comprehensive source of information on state, local, utility, and federal incentives and policies that promote renewable energy and energy efficiency. Established in 1995, DSIRE is an ongoing project of the NC Solar Center and the Interstate Renewable Energy Council funded by the U.S. Department of Energy.”