Power / Energy Management

Background  USA has 6% of worlds population - Uses 33% of energy consumed  In 1946 we used 30*10 15 BTU  In 1980 we used 90*10 15 BTU (Industry used 36% of this)  In 1990 we used 120*10 15 BTU  Since the 1970's Companies have associated Energy Conservation with Cost Reductions 1. Lucent - Since % per year growth with -2% per year energy costs (savings) 2. TRW - Between , Energy cost down 19%

Do An Energy Audit on Plant to Determine Areas to Save Energy

Energy Audit Compile Energy Data About Each Building Zone Start Energy Savings Actions in Highest Cost Zone

From Highest Cost Zones First See Below For Types of Action Steps

Utility Rates  Commercial - usually highest  Residential  Government - usually lowest Rates Consist of: 1. Energy Charge 2. Fuel Adjustment Charge 3. Taxes 4. Demand Charge 5. Power Factor Penalty

Customer Type Meter Reading KWH Used Energy Charge (- Demand) Demand Charge Power Factor Fuel Adj. Tax

Energy Charge Rate is dependent on:  Commercial, residential Government  Time of Day (Peak Demand Periods)  Total Amount Used (get break after use a predetermined amount)

Ways to reduce these costs:  Run on off peak times  Energy storage in off peak times  Energy Audit  Computer controlled "Alternative load- control" * Computer control systems or zones help to eliminate peak use and optimize power use thus reducing costs. Control Diagram on Next Slide

1 Demand Charges (Item "a" on the bill) This is a payment to the utility for their ability to supply customer's peak requirements. This can be as much as 40-45% of the bill. They measure the highest use during some period (usually a 1/2 hour period) then bill upon this highest use.

Demand Charges Ways to reduce these costs:  Make peak loads during "off-peak- load hours"  Shed peak loads  Balance power loading (with computer control)  Produce your own power during peak Ref: C. F. Paxton, "Solving Resistance Welding Problems with Mini- and Micro-Computers" Welding Journal, August Balanced Load Unbalanced Load

. Power Factor Penalty (Item "b" on the bill) Power factor is the ratio of real power to apparent power or kW/kVA, where kW or kilowatts are measured with a wattmeter and kVA or kilovolt-amperes are measured with a voltmeter and ammeter. A power factor of one or unity is ideal. A power factor of less than one means that a portion of the current being drawn through the power lines is not actually being used by the machinery to produce work.

Ways to reduce these costs  Decrease reactance in secondary a) Smaller loop in secondary b) Less magnetic material within loop  Install series capacitors on machines or shunt capacitors in plant  Use 3 phase machines wherever practicable