Agricultural Irrigation Pump Variable Frequency Drive

Provisional Standard Protocol Proposal

Regional Technical ForumApril 16, 2013

Protocol SummaryEligibility [see Protocol document]

Baseline Single speed pump for irrigation without VFDUpgrade Install VFD set to automatic control mode, remove or disable

baseline control mechanism

Best Practice Savings Estimate1. Collect three years of pre metering and one year of post metering on individually

metered pump motors or on circuits where upgraded motor load is easily disaggregated (e.g., sharing circuit with small electric motors for center pivot, sharing circuit with another pump with known operating hours).

2. Adjust annual baseline kWh values to reflect hardware measures on the irrigation system, for all years prior to the hardware measure implementation.

3. Determine average annual kWh pre and post installation.4. Savings = [Average Annual Baseline kWh] – [Post Installation Average Annual Baseline

kWh]

Simplest Reliable Savings Estimate5. Pre metering for three years6. Savings = [Average Annual Baseline kWh] x [Average Project Savings %]

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Available Best Practice Data• Utility billing data from pre and post metered pumps.– Two years of pre-VFD data (average annual kWh provided)– One year of post-VFD data

• Data disposition– 95 projects at 7 utilities – Dates, installed between February 2010 and June 2011.– Motor Size, 30 HP to 500 HP– Project Cost, $5,000 to $79,000

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Available Best Practice Data (cont)• Analysis

– For each site, computed the annual savings and the savings as a percentage of baseline kWh.

– Considered the unweighted (all projects equal) and weighted (by baseline kWh) average savings percentage.

Savings as a Percentage of Baseline kWh unweighted weightedestimate 27% 25%n 95precision @ 90% confidence 17% 27%

lower bound 23% 18%upper bound 32% 32%

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Available Best Practice Data (cont)

-50% to -40%

-40% to -30%

-30% to -20%

-20% to -10%

-10% to 0%

0% to

10%

10% to

20%

20% to

30%

30% to

40%

40% to

50%

50% to

60%

60% to

70%

70% to

80%

80% to

90%

90% to

100%

02468

101214161820

Count of Projects by % Savings

Savings Range

Num

ber o

f Pro

ject

s

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Available Best Practice Data (cont)

0 100 200 300 400 500 600

-60%

-40%

-20%

0%

20%

40%

60%

80%

100%

% Savings

Pump Motor Power Rating (HP)

Savi

ngs

(% o

f bas

elin

e)

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Discussion• Since precision at 90% confidence is greater than 10%, the protocol

should be categorized as “Provisional”.• Possible measure interaction in dataset (e.g. irrigation hardware

measures).– Proposed protocols allow for additional measures on same metered circuit if

estimated savings are accounted for.• Proposed protocols allow for multiple equipment on meter and rely on

operator estimation of operating hours for significant equipment.• Year-to-year variations in operating conditions (crop type, acreage,

weather, etc.) are not accounted for at any individual site.– This “measurement error” is expected to average to zero for the population.– Crop type and acreage will be collected during provisional period.

• Eligibility limited to 30 to 500 HP motors, based on dataset. Can this be extended to 20 HP motors?

• The percent savings may reduce over time.– This will be something to watch for when making the determination to go to

“Proven” category.

RTF Proposed Motion:

“I _________ move that the RTF approve the Agricultural Irrigation Pump Motor Variable Frequency Drive Standard Protocol in the “Provisional” category, with “Active” status, and a sunset date of April, 2018.”