APPENDIX J. ESTIMATION OF UTILITY AND ENVIRONMENTAL

RESULTS FROM NEMS­BT OUTPUT

TABLE OF CONTENTS

**J.1 Allocation**  **of Input**  **Electricity Savings**  **by Census**  **Division and**  **End Use......................**  **J­2**

**J.2 Choice**  **of Impact**  **Multipliers........................................................................................... J­2** 

**J.3 Regression**  **Smoothing of**  **NEMS­BT Outputs.................................................................**  **J­5**

**J.4 Estimation**  **of Interpolating**  **Functions from**  **Savings Multipliers** 

**.................................... J­6** 

**J.5 Environmental**  **Impacts**

**.................................................................................................... J­8** 

LIST OF TABLES

**Table J.1.1**  **Shares of**  **National Savings**  **by Census**  **Division Used**  **in NEMS­BT**  **.......................J­2**

**Table J.1.2**  **Heating and**  **Cooling Share**  **for PTHP**  **Equipment by**  **Census Division**  **....................J­2**

**Table J.2.1**  **Comparison of**  **Savings with**  **Different Multipliers**  **with Total** 

**Generation.............................................................................................................J­3**

**Table J.2.2**  **Final Implied**  **Multipliers by**  **Equipment Class**  **and Trial**  **Standard**

**Level .....................................................................................................................J­4** 

LIST OF FIGURES

**Figure J.3.1**  **Example of**  **Regression Smoothing**  **Fits for**  **Fossil­Fired and**  **Total**

**Installed Capacity**  **(200X case**  **for PTHP).............................................................J­6** 

**Figure J.4.1**  **Response (Interpolating)**  **Functions for**  **Selected Generation** 

**Outputs, PTHP**  **Case for**  **2025...............................................................................J­7**

**Figure J.5.1**  **Response (Interpolating)**  **Functions for**  **Carbon Dioxide,**  **PTHP**

**Case, for**  **Years 2015,**  **2020, 2025**  **and 2030.........................................................J­8** 

**J­i**APPENDIX J. ESTIMATION OF UTILITY AND ENVIRONMENTAL

RESULTS FROM NEMS­BT OUTPUT

**The effects**  **of proposed**  **energy conservation**  **standards for**  **packaged terminal**  **air**

**conditioners (PTACs)**  **and packaged**  **terminal heat**  **pumps (PTHPs)**  **was analyzed**  **using a**  **variant**

**1a of**  **National Energy**  **Modeling System**  **(NEMS) model,**  **called NEMS­BT. Because**  **the size**  **of**

**national energy**  **savings as**  **a result**  **of the**  **proposed standards**  **for PTACs**  **and PTHPs**  **are so**  **small**

**relative to**  **the size**  **of the**  **entire electric**  **utility sector,**  **DOE used**  **an estimation**  **method involving** 

**regression smoothing**  **and interpolation.**  **This appendix**  **describes the**  **major elements**  **of this** 

**method.**

**To run**  **a simulation**  **in NEMS­BT**  **model, the**  **space­cooling load**  **in the**  **commercial**

**building module**  **is reduced**  **annually according**  **to the**  **electricity savings**  **estimated by**  **the**

**National Energy**  **Savings (NES)**  **spreadsheet model**  **(see Chapter**  **11 of**  **the TSD)**  **for each**  **trial**

**standard level**  **(TSL). The**  **electricity savings**  **increase over**  **time as**  **PTAC and**  **PTHP equipment** 

**are replaced**  **with more**  **efficient equipment**  **meeting the**  **proposed conservation**  **standards.**

**The magnitude**  **of the**  **electricity decrement**  **that would**  **be required**  **for NEMS­BT**  **to**

**produce stable**  **results out**  **of the**  **range of**  **numerical noise**  **is greater**  **than the**  **highest TSL**  **under**

**consideration. Therefore,**  **to estimate**  **results for**  **the TSLs**  **evaluated here,**  **a series**  **of NEMS­BT** 

**simulations is**  **performed using**  **higher values**  **for the**  **input electricity**  **savings. These**  **simulations**

**establish the**  **relationship between**  **the NEMS­BT**  **output variables**  **(electricity generation**  **by fuel,** 

**installed electricity**  **generation capacity,**  **and emissions)**  **and the**  **electricity savings**  **inputs. For** 

**each output**  **variable, a**  **regression model**  **is estimated**  **to represent**  **an average**  **response across**  **the**

**series of**  **simulations. Impacts**  **are obtained**  **using predicted**  **values from**  **the regression**  **models**

**corresponding to**  **the (smaller)**  **levels of**  **savings corresponding**  **to TSLs.** 

**As discussed**  **in Chapter**  **14, the**  **utility and**  **environmental impacts**  **from an**  **amended**

**energy conservation**  **standard on**  **PTAC equipment**  **can be**  **expected to**  **be different**  **from a** 

**standard on**  **PTHP equipment.**  **Separate sets**  **of runs**  **with the**  **NEMS­BT model**  **were made**  **for**

**each type**  **of equipment**  **to distinguish**  **these effects.** 

**a DOE’s**  **EIA approves**  **of the**  **name NEMS**  **to describe**  **only an**  **official version**  **of the**  **model without**  **any**

**modification of**  **the code**  **or data.**  **Because the**  **analysis of**  **PTAC and**  **PTHP energy**  **efficiency standard**  **entails some** 

**minor code**  **modifications and**  **the model**  **is run**  **under policy**  **scenarios that**  **are variations**  **of DOE/EIA**  **assumptions,**

**the name**  **NEMS­BT refers**  **to the**  **model as**  **used here.**  **(The Building**  **Technologies [BT]**  **program is**  **one of**  **the major** 

**program offices**  **within DOE’s**  **Office of**  **Energy Efficiency**  **and Renewable**  **Energy. The**  **Building Technologies** 

**program is**  **responsible for**  **promulgating energy**  **efficiency standards**  **for the**  **buildings sector**  **mandated under**  **the**

**2005 Energy**  **Policy Act**  **and earlier**  **federal legislation.** 

**J­1**J.1 Allocation of Input Electricity Savings by Census Division and End Use

**Although the**  **utility and**  **environmental impacts**  **are national**  **in scope,**  **the NEMS­BT** 

**model operates**  **at a**  **census division**  **level. Lacking**  **sales information**  **for PTAC/PTHP**  **equipment**

**by census**  **division, an**  **allocation of**  **savings was**  **made on**  **the basis**  **of population.**  **The shares** 

**used to**  **distribute the**  **savings across**  **census divisions**  **are shown**  **in Table**  **J.1.1. The**  **shares are** 

**held constant**  **for the**  **forecast period**  **through 2030.** 

Table J.1.1 **Shares of**  **National Savings**  **by Census**  **Division Used**  **in NEMS­BT** 

**Census Division**  **Share (%)** 

**New England**  **11.2%**

**Middle Atlantic**  **14.1%**

**East North**  **Central 16.0%** 

**West North**  **Central 6.8%** 

**South Atlantic**  **18.4%**

**East South**  **Central 6.0%** 

**West South**  **Central 11.2%** 

**Mountain 6.5%** 

**Pacific 16.0%** 

**For PTHP**  **equipment, energy**  **efficiency standards**  **will yield**  **electricity savings**  **for both** 

**heating and**  **cooling. Based**  **on the**  **building energy**  **use simulations**  **described in**  **Chapter 7**  **of this** 

**TSD, an**  **estimate of**  **savings between**  **heating and**  **cooling was**  **developed for**  **each census** 

**division. The**  **simulation results**  **were weighted**  **by state**  **population estimates**  **corresponding the** 

**locations employed**  **in the**  **analysis. The**  **relative shares**  **between heating**  **and cooling**  **vary**

**slightly across**  **trial standard**  **levels for**  **PTHP. As**  **the shares**  **for two**  **of the**  **trial standard**  **levels**

**were very**  **close to**  **each other**  **(TSL 2**  **and TSL**  **6), the**  **shares for**  **TSL 6**  **were used**  **develop**

**heating and**  **cooling savings**  **inputs for**  **NEMS­BT. The**  **heating and**  **cooling shares**  **by census** 

**division are**  **shown in**  **Table J.1.2.** 

Table J.1.2 **Heating and**  **Cooling Share**  **for PTHP**  **Equipment by**  **Census Division** 

**Census Division**  **Cooling Heating** 

**New England**  **35% 65%** 

**Middle Atlantic**  **42% 58%** 

**East North**  **Central 41%**  **59%**

**West North**  **Central 51%**  **49%**

**South Atlantic**  **73% 27%** 

**East South**  **Central 69%**  **31%**

**West South**  **Central 80%**  **20%**

**Mountain 59%**  **41%**

**Pacific 59%**  **41%**

J.2 Choice of Impact Multipliers

**To gain**  **some understanding**  **of the**  **how NEMS­BT**  **would respond**  **to various**  **magnitudes**

**of savings,**  **a “reference”**  **time series**  **of savings**  **was initially**  **selected from**  **the NES**  **spreadsheet**

**model. This**  **reference series**  **was selected**  **as the**  **savings that**  **would result**  **from highest**  **level of** 

**TSLs for**  **PTHP equipment**  **with cooling**  **capacity great**  **than 10,000**  **Btu/h (i.e.,**  **representative**

**cooling capacity**  **of 12,000**  **Btu/h for**  **standard sizes**  **PTHPs as**  **shown in**  **Chapter 11).**  **As**

**described in**  **Chapter 7,**  **the energy**  **savings for**  **this equipment**  **category are**  **estimated**

**J­2 approximately**  **40 percent**  **higher than**  **the equivalent­sized**  **PTAC equipment.**  **NEMS­BT was** 

**run for**  **this stream**  **of savings,**  **as well**  **as for**  **higher multipliers**  **(designated here**  **with a**  **suffix X),** 

**including 2X,**  **5X, 10X,**  **20X, 100X,**  **200X, and**  **300X. It**  **was judged**  **on the**  **basis of**  **graphical**

**output and**  **comparison of**  **trends among**  **the output**  **variables, that**  **the numerical**  **noise from**  **the**

**model was**  **overwhelming the**  **impact of**  **the savings**  **decrement for**  **the smaller**  **multiplier factors** 

**b up**  **to 20X. Table**  **J.2.1 compares**  **the savings**  **decrement applied**  **to the**  **model under**  **various**

**multipliers and**  **how the**  **magnitude of**  **the savings**  **compares with**  **total electricity**  **generation in** 

**2c EIA’s**  **Annual Energy**  **Outlook (AEO2007)**  **reference case.** 

Table J.2.1 **Comparison of**  **Savings with**  **Different Multipliers**  **with Total**  **Generation**

**2015 2020**  **2025 2030** 

**Multiplier Total**  **Generation (TWh)**  **4,392 4,722**  **5,038 5,397** 

**1X Savings**  **(TWh) 0.039**  **0.076 0.103**  **0.125**

**% of**  **total generation**  **0.002% 0.004%**  **0.005% 0.006%** 

**100X Savings**  **(TWh) 3.9**  **7.6 10.3**  **12.5**

**% of**  **total generation**  **0.19% 0.38%**  **0.51% 0.62%** 

**200X Savings**  **(TWh) 7.8**  **15.2 20.6**  **25**

**% of**  **total generation**  **0.39% 0.75%**  **1.02% 1.23%** 

**300X Savings**  **(TWh) 11.7**  **22.8 30.9**  **37.5**

**% of**  **total generation**  **0.58% 1.13%**  **1.53% 1.85%** 

**Based on**  **this testing,**  **a decision**  **was made**  **to use**  **the higher**  **multipliers in**  **the range**  **of**

**100X through**  **300X. While**  **these multipliers**  **are large,**  **they still**  **do not**  **yield large**  **perturbations**

**to the**  **base case**  **simulation. For**  **example, as**  **Table J.1.1**  **indicates, even**  **at 100X**  **in the**  **year 2025** 

**the total**  **savings decrement**  **applied to**  **the model**  **represents only**  **about 0.5**  **percent of**  **total**

**electricity generation.** 

Final Implied Multipliers by Equipment Class and Trial Standard Level

**Subsequent to**  **the production**  **of the**  **NEMS simulations**  **described in**  **the previous**  **section,**

**some revisions**  **were made**  **to the**  **final set**  **of energy**  **savings estimates**  **for the**  **NOPR. In**  **addition,**

**for purposes**  **of estimating**  **utility and**  **environmental impacts**  **for standard­size**  **equipment, the** 

**two size**  **equipment classes**  **(equal or**  **less than**  **10,000 Btu/h**  **and greater**  **than 10,000**  **Btu/h) were** 

**combined. To**  **adjust for**  **these changes,**  **the difference**  **between the**  **final savings**  **estimate (by** 

**b The**  **numerical noise**  **stems, in**  **part, from**  **the fact**  **that a**  **precise balancing**  **between the**  **demand and**  **supply sides**  **of**

**NEMS is**  **not always**  **achieved, given**  **the iterative**  **nature of**  **the solution**  **process.**

**The reader**  **should note**  **that the**  **values of**  **the multipliers**  **used here**  **are solely**  **dependent on**  **the initial**  **(and arbitrary)** 

**choice of**  **a particular**  **PTAC/PTHP product**  **and a**  **specific trial**  **standard level**  **(TSL) for**  **that product.**  **The NEMS** 

**BT simulations**  **were performed**  **prior to**  **the final**  **selection of**  **TSL’s and**  **so the**  **1X multiplier**  **does** not **correspond to** 

**any specific**  **TSL for**  **a product**  **category in**  **previous sections**  **of the**  **report. However,**  **it was**  **judged that**  **the savings** 

**decrements (in**  **TWh) tested**  **in NEMS­BT,**  **shown in**  **lower portion**  **of Table**  **J.2.1, were**  **in the**  **relevant range**  **of**

**magnitudes to**  **yield stable**  **and robust**  **predictions by**  **the model**  **and so**  **additional runs**  **using different**  **multipliers**

**were deemed**  **unnecessary. For**  **use in**  **the predicting**  **the impacts**  **from the**  **set of**  **final TSLs,**  **the savings**  **decrement**

**from any**  **TSL was**  **converted into**  **an appropriate**  **multiplier by**  **scaling in**  **proportion to**  **the values**  **shown in**  **the first** 

**row of**  **Table J.2.1.**  **This procedure**  **is explained**  **more fully**  **below. This**  **same scaling**  **was used**  **for both**  **PTHP and** 

**PTAC equipment,**  **with the**  **savings for**  **PTHP equipment**  **allocated to**  **cooling and**  **heating.**

**J­3 c** **equipment class**  **and trial**  **standard level)**  **and the**  **savings from**  **the initial**  **“reference” time**  **series**

**(PTHP, >10,000**  **Btu/h, at**  **TSL 7)**  **was represented**  **as a**  **scale factor.**  **The scale**  **factor essentially** 

**adjusts the**  **savings from**  **particular equipment**  **class and**  **TSL to**  **be consistent**  **with the**  **reference**

**series and**  **thus consistent**  **with the**  **interpolation procedure**  **described above.** 

**The first**  **column in**  **Table K.2.2**  **displays the**  **scale factors**  **for each**  **equipment class**  **and**

**d TSL. The**  **remaining columns**  **display the**  **implied multipliers**  **from the**  **three simulations** 

**performed with**  **NEMS­BT for**  **either PTACs**  **or PTHPs**  **(using their**  **designations of**  **100X, 200X,** 

**and 300X).**  **For example,**  **after combining**  **the size**  **categories for**  **PTHP equipment,**  **the actual** 

**multipliers for**  **TSL­7 were**  **52, 104,**  **and 156.**  **Because the**  **savings for**  **TSL 1**  **through 6**  **are**

**smaller than**  **those for**  **TSL 7,**  **the implied**  **multipliers are**  **larger than**  **those for**  **TSL 7.** 

Table J.2.2 Final Implied Multipliers by Equipment Class and Trial Standard Level

**Implied Multipliers** 

**Scale**

**Factor NEMS** 

**BT**

**("100X") NEMS** 

**BT**

**("200X") NEMS** 

**BT**

**("300X")**

**Equipment Class** 

**Standard Size**  **PTACs**

**TSL**

**– 1,2,4**  **0.100 1,000**  **2,000 3,000** 

**TSL**

**– 3**  **0.224 446**  **893 1,339** 

**TSL**

**– 5**  **0.397 252**  **504 755** 

**TSL**

**– 6**  **0.611 164**  **327 491** 

**TSL**

**– 7**  **1.379 73**  **145 218** 

**Non­Standard Size**  **PTACs**

**TSL**

**– 1,2,4**  **0.031 3,266**  **6,533 9,799** 

**TSL**

**– 3**  **0.050 1,984**  **3,968 5,951** 

**TSL**

**– 5**  **0.078 1,290**  **2,581 3,871** 

**TSL**

**– 6**  **0.152 657**  **1,315 1,972** 

**TSL**

**– 7**  **0.209 478**  **957 1,435** 

**Standard Size**  **PTHPs**

**TSL**

**– 1**  **0.192 520**  **1,039 1,559** 

**TSL**

**– 2,3**  **0.404 248**  **495 743** 

**TSL**

**– 4,5**  **0.591 169**  **339 508** 

**TSL**

**– 6**  **0.749 134**  **267 401** 

**TSL**

**– 7**  **1.919 52**  **104 156** 

**Non­Standard PTHPs** 

**TSL**

**– 1**  **0.039 2,586**  **5,173 7,759** 

**TSL**

**– 2,3**  **0.053 1,877**  **3,755 5,632** 

**TSL**

**– 4,5**  **0.091 1,102**  **2,205 3,307** 

**TSL**

**– 6**  **0.147 682**  **1,365 2,047** 

**TSL**

**– 7**  **0.206 486**  **973 1,459** 

**d The**  **scale factors**  **can also**  **be viewed**  **as interpolating**  **values relative**  **to the**  **set of**  **NEMS­BT impact**  **runs. Thus,**  **for**

**example, if**  **an impact**  **upon a**  **particular variable**  **from the**  **“1X” case**  **in the**  **original set**  **of simulations**  **was**

**interpolated to**  **be a**  **value of,**  **say, 0.10,**  **then the**  **impact for**  **TSL­3 for**  **standard size**  **PTAC equipment**  **would be** 

**0.224 x**  **0.10**

**= 0.022.** 

**J­4**J.3 Regression Smoothing of NEMS­BT Outputs

**Even at**  **the selected**  **multiplier levels**  **shown in**  **Table J.1.1,**  **the simulations**  **with**

**NEMS­BT produces**  **considerable year­to­year**  **variation that**  **appears to**  **be caused**  **by numerical** 

**noise from**  **the model**  **solution. This**  **variation appears**  **to affect**  **the outputs**  **related to**  **specific**

**generation fuel**  **and technologies**  **more so**  **than total**  **generation or**  **total installed**  **capacity. For**  **the**

**utility impact**  **assessment, it**  **is more**  **important to**  **identify distinct**  **trends in**  **the utility**  **sector**

**adjustment process**  **rather than**  **year­to­year variation**  **that may**  **or may**  **not be**  **spurious results** 

**from the**  **model solution**  **process.**

**To reduce**  **the potential**  **effect of**  **numerical noise**  **from NEMS­BT**  **simulation, a** 

**smoothing regression**  **was estimated**  **for each**  **of the**  **model output**  **variables. The**  **output variables** 

**are measured**  **as the**  **differences between**  **the (AEO)**  **reference case**  **and the**  **energy efficiency** 

**standards case.**  **The formulation**  **of the**  **smoothing regression**  **was a**  **simple quadratic**  **function of** 

**time (in**  **years) with**  **the following**  **form:**

2 Y(T)

**=** a1 **x** T **+** a2 **x** T **+** u Eq. K.1

**where**

Y

**= Output**  **variable for**  **time period**  **T (difference**  **from reference**  **case)**

T

**= Time**  **in years,**  **T**

**= 0**  **in 2011,**  **T**

**= 1**  **in 2012,**  **etc.**

a1,a2

**= estimated**  **regression coefficients** 

u **= random**  **disturbance term.** 

**The regression**  **specification is**  **such that**  **the fitted**  **(predicted) value**  **of the**  **variable is** 

**forced through**  **the origin**  **in the**  **year the**  **prior to**  **the implementation**  **of the**  **standard (2011).**  **By**

**forcing the**  **impact to**  **be zero**  **in 2011,**  **this procedure**  **generates estimated**  **impacts that**  **typically**

**could be**  **expected to**  **change in**  **a systematic**  **fashion beginning**  **in 2012.** 

**Figure J.3.1**  **illustrates this**  **procedure for**  **the differences**  **in total**  **installed capacity**  **and the** 

**three types**  **of fossil**  **fuel capacity.**  **The particular**  **case shown**  **is for**  **the PTHP**  **equipment at**  **the**

**200X level**  **of savings.**  **Clearly, NEMS­BT**  **indicates a**  **very smooth**  **path of**  **differences in**  **total**

**generation capacity**  **as shown**  **in the**  **top left**  **panel of**  **the figure.**  **(In this**  **case, the**  **regression**

**smoothing would**  **not be**  **necessary.) For**  **fossil steam**  **plants, however,**  **for at**  **least 5**  **individual**

**years there**  **are rather**  **large deviations**  **from the**  **trend regression**  **line. In**  **several cases,**  **the**

**NEMS­BT simulation**  **indicates that**  **the overall**  **downward trend**  **is reversed**  **for periods**  **as long** 

**as 2**  **years.**

**The deviations**  **from the**  **fitted trend**  **line are**  **more pronounced**  **for combined**  **cycle plants.** 

**Nevertheless, over**  **the entire**  **forecast period,**  **the downward**  **trend in**  **the capacity**  **of these**  **plants**

**is very**  **apparent from**  **the graph.**  **The approach**  **in this**  **analysis is**  **to abstract**  **these very**  **short**

**term deviations**  **from what**  **appears to**  **be a**  **stable long­term**  **trend. Finally,**  **for combustion** 

**turbines, the**  **deviations from**  **a smooth**  **downward trend**  **are relatively**  **small.**

**The use**  **of the**  **quadratic specification**  **is most**  **apparent here**  **as the**  **decline in**  **capacity**

**accelerates during**  **the latter**  **portion of**  **the forecast**  **period.**

**J­5**T o t a l G e n e r a t i o n

­16 ­14 ­12 ­10

­8 ­6 ­4 ­2 0 2 2010 2015 2020 2025 2030Difference(GW)

NEMS­BT

Fitted Fossil Steam

­10

­9 ­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 0 2010 2015 2020 2025 2030Difference(GW)

NEMS­BT

Fitted

Combined Cycle

­3.5

­3 ­2.5

­2 ­1.5

­1 ­0.5

0 0.5

2010 2015 2020 2025 2030Difference(GW)

NEMS­BT

Fitted Combustion Turbine

­8 ­7 ­6 ­5 ­4 ­3 ­2 ­1 0 1 2010 2015 2020 2025 2030Difference(GW)

NEMS­BT

Fitted

Figure J.3.1 **Example of**  **Regression Smoothing**  **Fits for**  **Fossil­Fired and**  **Total Installed** 

**Capacity (200X**  **case for**  **PTHP).**

J.4 Estimation of Interpolating Functions from Savings Multipliers

**The development**  **of utility**  **and environmental**  **impacts focused**  **on specific**  **years from**  **the**

**NEMS­BT simulations:**  **2015, 2020,**  **2025 and**  **2030. For**  **each output**  **variable (e.g.,**  **coal­fired**

**electricity generation),**  **the predicted**  **values from**  **the trend**  **regression were**  **extracted for**  **each**

**savings multiplier**  **level (100X,**  **200X, and**  **300X). A**  **subsequent linear**  **regression was** 

**performed using**  **these values**  **for the**  **dependent variable**  **and the**  **values of**  **the saving**  **multiplier**

**as the**  **independent or**  **explanatory variable.**  **The y­intercept**  **of this**  **regression is**  **forced through** 

**the origin.**  **This restriction**  **ensures that**  **the predicted**  **value of**  **a NEMS­BT**  **output variable**  **is**

**zero when**  **the savings**  **multiplier is**  **zero. Predicted**  **values for**  **non­zero multipliers**  **are calculated** 

**by taking**  **the estimated**  **regression coefficient**  **(slope) times**  **the value**  **of the**  **savings multiplier.** 

**Figure J.4.1**  **shows several**  **examples of**  **this estimation**  **approach. The**  **magnitude of**  **the**

**energy savings**  **multiplier is**  **plotted on**  **the x­axis**  **against the**  **total reduction**  **in generation** 

**capacity for**  **the year**  **2025. The**  **results shown**  **are based**  **on three**  **simulations for**  **PTHP**

**equipment. The**  **fitted 2025**  **values from**  **the smoothing**  **regression of**  **the NEMS­BT**  **output are** 

**shown in**  **the large**  **solid (black)**  **diamonds. In**  **the case**  **of total**  **generation capacity,**  **the linear** 

**regression line**  **is closely**  **aligned to**  **the three**  **points corresponding**  **to the**  **100X, 200X,**  **300X**

**J­6**Total Generation

­40 ­35 ­30 ­25 ­20 ­15 ­10

­5 0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(TWh) Coal

­40 ­35 ­30 ­25 ­20 ­15 ­10

­5 0 0 50 100 150 200 250 300 350

Saving MultiplierDifference(TWh)

Natural Gas

­16 ­14 ­12 ­10 ­8 ­6 ­4 ­2 0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(TWh) Nuclear

0 5 10 15 20 25

0 100 200 300 400

Savings MultiplierDifference(TWh)

Figure J.4.1 **Response (Interpolating)**  **Functions for**  **Selected Generation**  **Outputs, PTHP** 

**Case for**  **2025**

**savings multipliers.**  **Within this**  **range of**  **savings, the**  **plot demonstrates**  **the impact**  **on total** 

**capacity predicted**  **by the**  **model is**  **basically proportional**  **to the**  **magnitude of**  **the savings.** 

**For the**  **other generation**  **types shown**  **Figure J.4.1,**  **the responses**  **deviate from**  **strict**

**proportionality. For**  **example, for**  **coal, the**  **response at**  **the 200X**  **is greater**  **than either**  **the 100X** 

**or 300X**  **levels. The**  **approach taken**  **here essentially**  **produces a**  **weighted average**  **of the** 

**responses across**  **these various**  **savings multipliers.** 

**The predicted**  **value of**  **a NEMS­BT**  **output variable**  **for a**  **given standards**  **level is** 

**interpolated along**  **the regression**  **line estimated**  **for that**  **variable. The**  **savings from**  **a**

**particular standards**  **case is**  **first converted**  **into a**  **savings multiplier**  **using the**  **relationships shown** 

**in Table**  **J.2.1. Thus,**  **for example,**  **if the**  **trial standard**  **level for**  **a particular**  **product yields**  **a**

**decrement of**  **0.038 TWh**  **in 2020,**  **the savings**  **multiplier would**  **be calculated**  **as**

**0.5 (=**  **0.038/.076). For**  **total generation,**  **the estimated**  **response coefficient**  **is ­0.115**  **(e.g., the** 

**slope of**  **regression line**  **in the**  **top left**  **panel Figure**  **J.4.1). Thus,**  **the estimated**  **impact on**  **total**

**generation in**  **2025 from**  **this specific**  **trial standard**  **level would**  **be 0.5**  **x ­0.115** 

**= ­0.0575**  **TWh.**

**The entire**  **estimation process**  **was performed**  **separately for**  **PTAC and**  **PTHP equipment.** 

**As described**  **in Chapter**  **14, the**  **response coefficients**  **for total**  **generation, for**  **the same**  **total**

**savings decrement,**  **was somewhat**  **different for**  **PTAC versus**  **PTHP equipment.**  **The impact**  **on**

**installed generation**  **capacity is**  **significantly higher**  **for PTAC**  **equipment as**  **compared to**  **PTHP**

**equipment.**

**J­7**J.5 Environmental Impacts

**The general**  **approach for**  **estimating the**  **impacts on**  **the utility**  **sector was**  **also used**  **to**

**develop an**  **environmental assessment**  **in terms**  **of changes**  **in emissions.**  **Annual values**  **of the** 

**emissions for**  **NO**

**x ,**  **mercury, and**  **carbon dioxide**  **were extracted**  **from the**  **relevant tables** 

**produced by**  **NEMS.**

**Similar to**  **examples shown**  **in Figure**  **J.3.1, the**  **projections of**  **emissions from**  **2012**

**through 2030**  **were smoothed**  **using the**  **quadratic function**  **in time**  **discussed above.**  **Response**

**functions were**  **then estimated**  **at five­year**  **intervals between**  **2015 and**  **2030.**

**Figure J.5.1**  **shows the**  **estimated response**  **(or interpolating)**  **functions for**  **carbon dioxide** 

**emissions for**  **PTHP equipment.**  **In general,**  **total carbon**  **emissions are**  **approximately**

**proportional to**  **the level**  **of the**  **saving decrement**  **(for the**  **savings decrements**  **shown in** 

**Table J.2.1**  **corresponding to**  **100X, 200X,**  **and 300X).**  **The scale**  **of the**  **y­axis is**  **held constant** 

**for each**  **of the**  **plots and**  **so the**  **clockwise rotation**  **of the**  **slopes across**  **the years**  **2015 through** 

**2030 reflects**  **the increasing**  **reduction in**  **emissions over**  **selected years.** 

Carbon Dioxide Emissions (2015)

­50 ­40 ­30 ­20 ­10

0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(MMT­CE) Carbon Dioxide Emissions (2020)

­50 ­40 ­30 ­20 ­10

0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(MMT­CE)

Carbon Dioxide Emissions (2025)

­50 ­40 ­30 ­20 ­10

0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(MMT­CE) Carbon Dioxide Emissions (2030)

­50 ­40 ­30 ­20 ­10

0 0 50 100 150 200 250 300 350

Savings MultiplierDifference(MMT­CE)

Figure J.5.1 **Response (Interpolating)**  **Functions for**  **Carbon Dioxide,**  **PTHP Case,**  **for Years** 

**2015, 2020,**  **2025 and**  **2030.**

**J­8**REFERENCES

**1. U.S.**  **Department of**  **Energy. Energy**  **Information Administration.**  **National Energy**  **Modeling**

**System: An**  **Overview 2003.**  **(DOE/EIA­0581(2003), March**  **2003.**

**http://tonto.eia.doe.gov/reports/reports_kindD.asp?type=model%20documentation.**

**2. U.S.**  **Department of**  **Energy/Energy Information**  **Administration (DOE/EIA),**  Annual Energy

Outlook 2007

**, February**  **2007. Washington,**  **D.C. DOE/EIA­0383(2007).** 

**J­9**