Electrical
Equipment to Reduce Energy
Consumption & Demand
Thoughtful selection
of transformers and motors can greatly reduce electricity consumption.
Small efficiency
improvements are very effective. Typical efficiencies range from
95% to 99%; a 1% improvement can reduce waste by one-half. When
selecting transformers, consider load factor; with high load variation,
transformers are mostly lightly loaded, and should be selected for
low core losses. With higher load factors, transformers with low
winding losses save more.
Specify transformers
for lowest life cycle cost, not just capital cost. The EPA's Commercial
and Industrial Transformer Cost Evaluation Model (CITCEM) and Distribution
Transformer Cost Evaluation Model (DTCEM) software can be freely
downloaded to aid life-cycle analysis. While capital cost premiums
are quite high (20% to 50%), payback periods range from one to four
years.
Select motors
under 10 horsepower to be 5% more efficient than EPACT requirements;
or designated as “Premium Efficiency” by the Consortium
for Energy Efficiency. Larger motors should be selected for lowest
life-cycle cost, which typically favors very high efficiencies.
(Motor capital and life-cycle cost analysis is straightforward with
software such as MotorMaster.) With capital cost premiums ranging
from 0% to 30%, payback time varies from zero to three years.
Cautions
- Consider
power harmonics when selecting transformers.
- Ensure motors
over 10 horsepower serving varying loads are suitable for variable-speed
drives.
