1 | Building Technologies Program eere.energy.gov

Review of the Life-Cycle Cost and National 

Impacts Analyses

Katie Coughlin

Lawrence Berkeley National Laboratory

Liquid Immersed and Medium Voltage Dry-Type Distribution 

Transformers Negotiated Rulemaking Working Group 

Meeting

September 15-16, 2011
2 | Building Technologies Program eere.energy.gov

Steps in the Standards Rulemaking

Framework

Document

Preliminary

Analysis NOPR Final

Rule Date

Screening

Analysis

Engineering

Analysis

Energy Use and 

End-Use Load 

Characterization

Shipments

Analysis

National

Impact

Analysis

Markups for 

Equipment Price 

Determination

Life-Cycle

Cost and

Payback 

Period Analysis

Market & 

Technology 

Assessment

Preliminary 

Manufacturer 

Impact Analysis

Compliance 

Date
3 | Building Technologies Program eere.energy.gov

LCC and PBP Analysis

A & B 

Parameter

Transformer 

Designs

A&B 

Selection

Markups & Total 

Installed Cost

LCC Transformer 

Loading

Electricity 

Cost & Prices

Electricity 

Growth & 

Price Trends

Discount 

Rates

Compliance 

Date, 

Lifetime

Transformer 

Design 

Selection

Simulate 

Load & Price

Discount Rate 

Selection

Annual Operating 

Costs 

Operating Costs 

over the Lifetime 

of the Transformer

Net Present Value 

of Lifetime 

Operating Cost

From: 

Engineering Analysis

From: 

Energy Use and Load 

Characterization 

Analysis
4 | Building Technologies Program eere.energy.gov

• 10,000 transformer installations for each LCC run

• Each installation has an owner and a number of characteristics that 

belong to either the owner or the transformer

• These characteristics are the same for all efficiency levels

• Owner characteristics include

– Geographic location

– Evaluator (yes/no); if yes an A & B value

– Electricity price

– Discount rate

• Transformer characteristics

– Total installed cost

– Lifetime

– Peak load factor (relative to capacity)

– Load simulation -> annual load losses

– Annual no-load losses 

• Transformer design (price, efficiency) selection may change with EL

• The effect of the efficiency level specification is to restrict the 

number of available designs

Mechanics of the LCC
5 | Building Technologies Program eere.energy.gov

• For transformers, efficiency depends on energy losses 

– No-load losses

• Parameterized by loss rate NL

• Occur whenever the transformer is energized

• Annual watt-hours = 8760*NL

– Load losses 

• Parameterized by loss rate LL = load loss at 100% load

• Vary with the square of the load on the transformer

• Load dependence is captured through the loss factor LSF

• The LCC accounts for time-varying electricity costs

– Operating Cost = ∑t

 transformer_loss(t)× electricity_cost(t)

– t is the time period index

– Time period is hourly for utility-owned transformers (liquid-type)

– Time period is monthly for dry-type transformers in buildings

Energy Use and the LCC
6 | Building Technologies Program eere.energy.gov

Example: Cost-Efficiency data and

CSLs for DL1 (50 kVA, 1-phase)

$1,500 

$2,000 

$2,500 

$3,000 

$3,500 

$4,000 

$4,500 

$5,000 

99.00% 99.10% 99.20% 99.30% 99.40% 99.50% 99.60% 99.70%

Manufacturer Selling Price ($)

Efficiency at 50% Load, Temperature Corrected

M5CuAl_sh

M3AlAl_sh

M3CuAl_sh

M2AlAl_sh

M2CuAl_sh

ZDMHAlAl_sh

ZDMHCuCu_sh

SA1AlAl_sh

SA1CuCu_sh

CSLs

CSL 0 CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 CSL 6
7 | Building Technologies Program eere.energy.gov

LCC Transformer Design Selection

Illustrative Example: Sampled designs, Design Line 1, EL5

$0.00

$500.00

$1,000.00

$1,500.00

$2,000.00

$2,500.00

$3,000.00

$3,500.00

$4,000.00

99.00% 99.10% 99.20% 99.30% 99.40% 99.50% 99.60%

Design Data Basecase CSLs CSL 5
8 | Building Technologies Program eere.energy.gov

Another View of Selected Designs 

Example: Design Line 1, Efficiency Level 1

0

100

200

300

400

500

600

700

800

900

1000

0 50 100 150 200 250

Load Losses (watts)

No Load Losses (watts)

Design Load Losses (LL) vs No-Load Losses (NL)

at rated load

Available Designs

Selected Designs, Base

Selected Designs, Standard

Compliance

Compliant

Non-compliant

Residential Buildings
9 | Building Technologies Program eere.energy.gov

Example Results: LCC Savings 

(April 2011)

Box: 25% - 75% 

Whiskers: 5%-95%

-2000

-1000

0

1000

2000

3000

4000

CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 CSL 6

Average LCC Savings ($)

Efficiency Level

Design Line 1: Liquid-immersed, 50 kVA, 

1 Phase, 125 kVA BIL

Average LCC Savings

median average

-4000

-3000

-2000

-1000

0

1000

2000

3000

4000

CSL 1 CSL 2 CSL 3 CSL 4 CSL 5 CSL 6 CSL 7

Average LCC Savings ($)

Efficiency Level

Design Line 7: Dry-type, 75 kVA, 3 Phase, 

10 kVA BIL 

Average LCC Savings

median average
10 | Building Technologies Program eere.energy.gov

• Detailed results for 13 Design Lines are extrapolated to full 

set of equipment kVA ratings

• Use the 0.75 scaling law, with adjustments so that the 

efficiency vs. kVA curve is continuous at each representative 

unit

• The NIA generates national-level results for each equipment 

class (LVDT, MVDT, LI)

– Shipments are forecast shipments for each kVa

– Calculate aggregate dollar costs, benefits and energy savings

• National Impacts are dependent on the combination of ELs 

that are used to construct a draft TSL

• The NIA results posted Aug. 23 are for a set of draft TSLs 

which may be modified

• Further downstream analyses (e.g. emissions impacts) also 

depend on the details TSL

Mechanics of the NIA
11 | Building Technologies Program eere.energy.gov

Example: Efficiency vs. kVA

Rep Unit Rep Unit

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

97.00

97.50

98.00

98.50

99.00

99.50

100.00

10 100 1000

Efficiency (%)

kVA

Medium-Voltage Dry-Type, 96-150 kV BIL, 3-Phase

Base

1

2

3

4

5
12 | Building Technologies Program eere.energy.gov

Design 

Line

Base 

(2007 FR)

Draft Trial Standard Level

1 2 3 4 5

1 99.08 99.16 99.22 99.25 99.31 99.50

2 98.91 99.00 99.07 99.11 99.18 99.46

3 99.42 99.51 99.54 99.57 99.61 99.73

4 99.08 99.16 99.22 99.25 99.31 99.60

5 99.42 99.51 99.54 99.57 99.61 99.69

Draft TSLs posted August 23 2011

Design 

Line

Base 

(EPACT ‘05)

Draft Trial Standard Level

1 2 (NEMA 

Premium)

3 4 5 6

6 98.00 98.47 98.60 98.60 98.80 98.93 99.44

7 98.00 98.47 98.60 98.60 98.80 98.93 99.44

8 98.60 99.14 99.02 99.25 99.32 99.44 99.58

Design 

Line

Base 

(2007 FR)

Draft Trial Standard Level

1 2 3 4 5

9 98.82 98.99 99.12 99.28 99.38 99.59

10 99.22 99.40 99.50 99.53 99.60 99.67

11 98.67 98.81 98.94 99.06 99.13 99.50

12 99.12 99.30 99.39 99.46 99.53 99.65

13A 98.63 98.76 98.85 98.92 99.10 99.48

13B 99.15 99.31 99.38 99.43 99.49 99.58
13 | Building Technologies Program eere.energy.gov

Example Annual Savings and Cost 

Results (April meeting)

-$2.0

-$1.0

$0.0

$1.0

$2.0

$3.0

2016 2026 2036 2046 2056 2066 2076 2086 2096

Billions of 2010 Dollars

Liquid-Immersed - CSL3 

-$0.4

-$0.2

$0.0

$0.2

$0.4

$0.6

$0.8

$1.0

2016 2026 2036 2046 2056 2066 2076 2086 2096

Billions of 2010 Dollars

Dry-Type - CSL3 

-$2.0

-$1.0

$0.0

$1.0

$2.0

$3.0

$4.0

2016 2026 2036 2046 2056 2066 2076 2086 2096

Billions of 2010 Dollars

All Transformers - CSL3 

Operating Cost Savings Equipment Cost Net Savings
14 | Building Technologies Program eere.energy.gov

• Example: All liquid immersed transformers (Design Lines 1-5)

Summary of Cumulative National 

Energy Savings Impact (Aug 23)

Draft Trial Standard Level

Base 1 2 3 4 5

Transformer Shipments 2015-2044 

(Billion KVA) 1.95 1.91 1.89 1.89 1.89 1.77

Equipment Cost ($Billions) 63.08 -7.47 -10.08 -9.44 -10.61 -33.85

Operating Cost (Savings in ELs) 

($Billions) 83.72 11.20 16.16 18.07 22.65 35.25

Cumulative Source Savings 2044 

(Quads) 0.691 1.01 1.13 1.44 2.25

Net Present Value at 3% Discount Rate 

($Billions) 3.73 6.08 8.63 12.04 1.40

Net Present Value at 7% Discount Rate 

($Billions) -0.164 0.10 1.00 1.741 -6.51
15 | Building Technologies Program eere.energy.gov

• Changes to the definition of efficiency levels used in the LCC, 

or draft TSLs required for national impacts analyses, result in 

changes to the LCC and NIA results

• The input data and methods do not change

• Given a set of criteria for specifying draft TSLs, results can be 

provided to the committee as needed

– For example, minimum LCC, maximum energy savings, 

technology criteria

• Suggestions on how to summarize the data are welcome

Analysis Results
16 | Building Technologies Program eere.energy.gov

Liquid-immersed Transformers: 

Price-Load Correlation

• Hourly production price is correlated with the hourly system load

– Scatter plot of the hourly price (vertical axis) and hourly load (horizontal axis)

– Bin the data according to ranges of the load (stripes)

– Within each bin, price = average value + random increment

• Regional system load data define how many hours per year the load is in each bin 

0

50

100

150

200

250

0 20000 40000 60000 80000 100000 120000 140000 160000

Lambda $/MWh

Load MWh
17 | Building Technologies Program eere.energy.gov

• The hourly transformer load is correlated with 

the hourly system load

Liquid-immersed Transformers: System 

Load – Transformer Load Correlation

1

3

5

7

9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Individual Load Bin

Aggregate Load Bin

0.000-0.005 0.005-0.010 0.010-0.015 0.015-0.020

1

3

5

7

9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Individual Load Bin

Aggregate Load Bin

0.000-0.005 0.005-0.010 0.010-0.015 0.015-0.020 0.020-0.025

Residential Buildings

Commercial Buildings
18 | Building Technologies Program eere.energy.gov

• The loss factor estimate is based on the rule-of-thumb

LSF = k × LF + (1-k) × LF2 with 0 ≤ k ≤ 1

• This equation is always true for some value of k between zero and 

one

• Use data to calculate a set of values (LF, LSF, k) and estimate a 

distribution for k

Dry-Type Transformers: Loss Factor 

Calculations

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

parameter k

frequency

Low LF Medium LF High LF
19 | Building Technologies Program eere.energy.gov

• The monthly responsibility factor (RF) defines the contribution of 

transformer load losses to the building peak demand

• Expect the RF to be correlated to some degree with the load factor LF

– Low load factors imply temporally-variable loads and less predictable 

RF

– High load factors imply flat loads and higher, more predictable RF

• Use hourly building data to calculate a set of values (LF, RF) and 

define a distribution function that provides the probability of RF given 

a value for LF

Dry-type Transformers: 

Responsibility Factor Calculations

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.2 0.4 0.6 0.8 1.0

Load Factor

Responsibility Factor
20 | Building Technologies Program eere.energy.gov

• The Department uses data to 

develop estimates of A and B 

values for transformer owners

• The A and B data capture current 

market purchase decision criteria

• A = NPV of no-load losses

• B = NPV of load losses

Customer Choice Model 

(2) A and B Values

• Liquid-immersed

• Data from previous analysis, supplemented by recent utility purchase bids

• Data cluster around two values of the ratio B:A

• Dry-type 

• Derive A and B values from marginal electricity prices for commercial and industrial 

customers (ref. IEEE PC57.12.33/D8 Draft Guide for Distribution Transformer Loss 

Evaluation)

y = 0.23x + 0.00

R2 = 0.91

y = 0.45x + 0.02

R2 = 0.61

0

1

2

3

4

5

0 2 4 6 8 10 12 14

Load Losses (B) $/W ( 2010$)

No-load Losses (A) $/W (2010$)

Line 1

Line 2

Linear (Line 1)

Linear (Line 2)

Distributions of B Parameters versus A Parameters for 

Liquid-Immersed Transformers
21 | Building Technologies Program eere.energy.gov

• Energy price projections to 2035 based on EIA/AEO 2010 Reference Case

• AEO High Growth and Low Growth (AEO2010) cases run as a sensitivity

• Electricity price forecasts to 2075 are developed from the average rate of 

change over the period 2020-2035

Electricity Price Forecasts

80%

85%

90%

95%

100%

105%

110%

115%

120%

Real Price Relative to 2007

2005 2010 2015 2020 2025 2030 2035

Year

Reference Case High Growth Low Growth
22 | Building Technologies Program eere.energy.gov

• Energy price projections to 2035 based on EIA/AEO 2011 Reference Case

Electricity Price Forecasts

80%

85%

90%

95%

100%

105%

2005 2010 2015 2020 2025 2030 2035

Real Price Relative to 2008

Year

Reference Case High Growth Low Growth
23 | Building Technologies Program eere.energy.gov

Survival and Retirement Functions

Mean Lifetime: 32 years 

Average: 32 Years

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

3.5%

4.0%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 5 10 15 20 25 30 35 40 45 50 55 60

Transformer Retirement Rate (%)

Transformer Survival Rate (%)

Transformer Reliability

Transformer Retirements