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Working Paper 8509

TOTAL FACTOR PRODUCTIVITY
AND ELECTRIC UTILITIES REGULATION

by Phi 1i p I s r a i l e v i c h

Working papers o f t h e F e d e r a l Reserve Bank o f C l e v e l a n d
are preliminary materials, circulated to stimulate
d i s c u s s i o n and c r i t i c a l comment. The views expressed
h e r e i n a r e t h o s e o f t h e a u t h o r and n o t n e c e s s a r i l y
those o f t h e F e d e r a l Reserve Bank o f C l e v e l a n d or o f
t h e Board o f Governors o f t h e Federal ReserveeSystem.
The a u t h o r would l i k e t o t h a n k Amy D u r r e l l , who
provided valuable research assistance.

December 1985
Federal Reserve Bank o f C l e v e l a n d

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Introduction

Regulators base electricity prices or rates on the average operating cost

of producing electricity and on a "fair" rate of return on capital for a given
year ' .
There are two shortcomings with this procedure. First, it does not
consider the dynamics of average total costs and its components. Regulations
may influence the incentives of utilities to innovate and overcapitalize as
well as the demand for electricity which, in turn, may influence utility
operating costs.
Second, regulators consider only tangible input factors (capital, labor,
fuel, material) in the calculation of average costs. Intangible input factors
(workers' discipline, managerial skills, returns to scale, for example) are
not considered in the regulatory price mechanism because they have no explicit
and measurable prices and their effect on utility output and costs is
difficult to measure.

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Nevertheless, t h e impact o f i n t a n g i b l e f a c t o r s on c o s t s and u t i l i t y
p r o f i t s may be s u b s t a n t i a l .

Moreover, t h e i n a b i l i t y t o b r i n g i n t a n g i b l e i n p u t

f a c t o r s i n t o t h e r a t e - s e t t i n g process may c r e a t e t h e wrong i n c e n t i v e s f o r a
u t i l i t y t o o p e r a t e i n t h e most s o c i a l l y e f f i c i e n t way.

One s o l u t i o n t o these problems i s t o examine t h e components o f t o t a l
f a c t o r p r o d u c t i v i t y (TFP).

These components i n c l u d e t h e i n d i v i d u a l i n p u t

p r o d u c t i v i t i e s , a r e t u r n s t o s c a l e e f f e c t , and an average c o s t (AC) s h i f t
term.

The i n d i v i d u a l i n p u t p r o d u c t i v i t i e s a r e t h e t a n g i b l e i n p u t

c o n t r i b u t i o n s , t h e r e t u r n s t o s c a l e t e r m i d e n t i f i e s one o f t h e i n t a n g i b l e
f a c t o r s , and t h e AC s h i f t t e r m i n c l u d e s t h e o t h e r i n t a n g i b l e e f f e c t s .

Using

t h i s decomposition, r e g u l a t o r s may o b t a i n a b e t t e r i d e a a b o u t t h e sources o f
AC change.

To measure TFP, economists t r a d i t i o n a l l y u t i l i z e t h e long- run p r i c e o f
c a p i t a l services.

T h i s paper argues t h a t f o r t h e purpose o f r e g u l a t i o n , t h e

shadow r e n t on c a p i t a l , which i s t h e s h o r t - r u n measure o f t h e v a l u e o f c a p i t a l
s e r v i c e s , i s more a p p r o p r i a t e .

T h i s i s n o t a new concept -- r e g u l a t o r s have

used t h e shadow c a p i t a l r e n t measure f o r decades, b u t i t s use w i t h t h e TFP
c a l c u l a t i o n s , which have t r a d i t i o n a l l y employed a long- run c a p i t a l r e n t
measure, i s new.

An u n d e r s t a n d i n g o f t h e d i f f e r e n c e between t h e two n o t i o n s

o f c a p i t a l r e n t h e l p s t o d i s t i n g u i s h a s h o r t - r u n s h i f t i n average c o s t s f r o m a
long- run s h i f t .

I n t h e second p a r t o f t h i s paper, t h e r e g u l a t o r y process i s b r i e f l y
d e s c r i b e d and t h e u s e f u l n e s s o f TFP i n d i c a t o r s t o r e g u l a t o r s i s discussed.
TFP and r e t u r n - t o - s c a l e e f f e c t s a r e e s t i m a t e d f o r seven m a j o r Ohio " u t i l i t i e s

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( w h i c h produce about 90 p e r c e n t o f t h e e l e c t r i c i t y for t h e s t a t e ) o v e r t h e
1964-82 p e r i o d .

The d a t a and t h e i r sources a r e d e s c r i b e d i n Appendix 111.

The t h e o r e t i c a l d i s c u s s i o n of t h e s h o r t r u n average c o s t (AC) s h i f t ' i s

I t i s argued i n t h e f o u r t h

p r e s e n t e d i n t h e t h i r d s e c t i o n o f t h i s paper.

s e c t i o n t h a t d u r i n g t i m e s when r a t e h e a r i n g s a r e h e l d f r e q u e n t l y , a u t i l i t y ' s
i n c e n t i v e f o r p r o d u c t i v i t y i n c r e a s e s may d e c l i n e .

The R e g u l a t o r y Process
A u t i l i t y ' s a c c o u n t i n g p r o f i t , which i s t h e p r i m a r y concern o f t h e P u b l i c

U t i l i t y Commission o f O h i o (PUCO), i s c a l c u l a t e d as:
n=R-OC
where R i s o p e r a t i n g revenue and OC i s t h e o p e r a t i n g c o s t

.

Whenever a r a t e

change i s requested, PUCO c a l c u l a t e s t h e u t i l i t y ' s " f a i r " r e t u r n on c a p i t a l as:
n , = B * r
where r i s t h e " f a i r " r a t e of r e t u r n and B i s t h e r a t e base o r t h e book v a l u e
o f net capital .
The d i f f e r e n c e between t h e a c c o u n t i n g p r o f i t , n, and t h e f a i r p r o f i t ,
n,,

i s t h e b a s i c reason f o r t h e r a t e change; e l e c t r i c i t y r a t e s a r e s e t by

t h e r e g u l a t o r t o equate n w i t h n, on t h e d a t e t h e h e a r i n g i s h e l d .

As

t i m e passes, n may d e v i a t e f r o m n, i f i n p u t p r i c e s , e l e c t r i c i t y demand,
and o t h e r f a c t o r s change, b u t a r a t e change t o re- equate n w i t h n, i s
n o t made u n t i l t h e n e x t r a t e h e a r i n g .

A u t i l i t y r e q u e s t s a p r i c e change

h e a r i n g when i t i s convinced t h a t i t s p r o f i t ,

TI

i s s m a l l e r t h a n n,.

If

PUCO e s t a b l i s h e s t h a t n exceeds a reasonable r e t u r n on c a p i t a l , say sB, t h e n
PUCO.calls f o r a r a t e decrease h e a r i n g .

Such h e a r i n g i s u s u a l l y prompted by

consumer advocates, when n 2 sB i s observed.
adjustment mechanism can be d e s c r i b e d as

This r e g u l a t o r y p r i c e

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P

<

<sB (no rate change)

if

n,

P o < P l5 P,*1.2

if

n

<

P, < Po

if

n

> sB (rate decrease hearing).

n
n,

(rate increase hearing)'

Due to the passive nature of the regulatory process, the last constraint is
observed very rarely. This issue is addressed later in the text. The rate
increase hearing is the most common one. In this case, electricity price
increases from Po to P I .

At first blush, this rate-setting scheme appears sensible.

It seems

,reasonably efficient to allow utilities to pass along operating costs.
However, there are potentially serious problems related to consumer
reactions to rate increases and to the types of incentives given to
utilities. First, rate increases may lower the consumption of electricity,
which may reduce

n

below

n,

and trigger a rate increase, which in turn

may lower consumption and trigger another rate increase and so on. That is,
the proper response to falling utility profits because of lower demand may
not be to raise rates. Second, utilities may be able to effect rate
increases by overcapitalizing, which affects their rate base B. Indeed,
rate increases lower the risk of capital investment below the risk level of
nonregulated industries, clearly giving utilities the incentive to
overcapitalize. Finally, the ability to obtain rate increases because of
operating cost increases originating from productivity declines suggests
that utilities may not have the incentive to raise productivity.

Thus, not all AC increases should be treated equally.

Increases in AC

due to input price increases and to environmental regulation, for example,

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s h o u l d be passed on, w h i l e i n c r e a s e s due t o i n e f f i c i e n t c a p i t a l investment
d e c i s i o n s and i n c r e a s e s t h a t may l e a d t o a long- run d e c l i n e i n u t i l i t y
revenues s h o u l d n o t be passed on t o consumers.

I t should be c l e a r t h a t i t

i s i m p o r t a n t t o be a b l e t o d i s t i n g u i s h among t h e causes of AC change.

In

t h e f o l l o w i n g two p a r t s o f t h e paper, a s e t o f measures t h a t e x p l a i n s t h e
c o s t change as a weighted sum o f d i f f e r e n t economic f a c t o r s , based on a TFP
approach, i s p r o v i d e d .

A Simple T o t a l F a c t o r P r o d u c t i v i t y Measure f o r Ohio E l e c t r i c U t i l i t i e s

We b e g i n t h e d i s c u s s i o n b y r e l a t i n g AC t o o p e r a t i n g revenue.

Operating

revenue i n c l u d e s n e t income and o p e r a t i n g c o s t s :
(1)

R = B*~K
+ LorL

+ F * ~ E+ M * ~ M , where

r K i s t h e r a t e o f r e t u r n on c a p i t a l , computed as r K= w/B w i t h

IT

c a l c u l a t e d as a r e s i d u a l between OC, and R
L, E, and M a r e t h e number o f employees, f u e l (energy) consumption i n

p h y s i c a l u n i t s , and m a t e r i a l , computed as M = ( m a t e r i a l
expense)/r , r e s p e f i t i v e l y used i n t h e p r o d u c t i o n o f e l e c t r i c i t y .

r L , r E , and r~ a r e t h e average p r i c e s o r wage r a t e s f o r t h e
corresponding inputs.

When r, i n ( 1 ) i s equal t o t h e f a i r r a t e o f r e t u r n on c a p i t a l ,
revenue i s equal t o c o s t and n equals w, from t h e r e g u l a t o r ' s p o i n t o f
view.

I n a d d i t i o n , t h e p r i c e o f e l e c t r i c i t y i s equal t o t o t a l average c d s t ,

a c o n d i t i o n we w i l l m a i n t a i n i n t h i s p a r t o f t h e paper.

Later, t h i s

assumption i s r e l a x e d by t a k i n g i n t o account the d e v i a t i o n o f r k from t h e

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f a i r r e t u r n and t h e d e v i a t i o n o f t h e f a i r r e t u r n f r o m t h e long - run c o s t o f
capital.
Changes i n average c o s t s can be decomposed i n t o changes i n i n p u t f a c t o r
c o s t s and changes i n TFP.

A c c o r d i n g t o K e n d r i c k (19731, p. 32, "The TFP

r a t i o i n d i c a t e s t h e r e l a t i o n s h i p between r e a l p r o d u c t i n a g i v e n year t o t h e
r e a l p r o d u c t t h a t would have been produced ( r e a l f a c t o r c o s t ) i f t h e
p r o d u c t i v e e f f i c i e n c y o f t h e f a c t o r s had been t h e same i n t h e g i v e n year as
i n t h e base y e a r . "
Qc

The TFP r a t i o i s : A=Q/Qc,

i s r e a l f a c t o r c o s t i n t h e base y e a r .

where Q i s r e a l o u t p u t and

Taking t h e t i m e d e r i v a t i v e o f

t h e above e q u a t i o n and d i v i d i n g i t by A, one d e r i v e s :
( * " ) i n d i c a t e s p r o p o r t i o n a l r a t e o f change.

AO=QO-QC0
. Where

The d i s c r e t e f o r m o f

O

Q

c

is

measured by t h e Tornqui s t a p p r o x i mation:
QcO=Cs,
iO

(2)

where s , i s t h e c o s t share i n t h e base year o f t h e i - t h i n p u t and i i s t h e
amount o f t h e t a n g i b l e i n p u t f a c t o r employed, such as c a p i t a l (K), l a b o r

( L ) , energy

(E) and m a t e r i a l ( M ) .

S u b s t i t u t i n g ( 2 ) i n t o ( I ) ,t h e TFP r a t e

of change i s measured as a r e s i d u a l growth o f o u t p u t t h a t cannot be
e x p l a i n e d by t h e growth o f t a n g i b l e i n p u t s :
(3)

A" = Q O - I s ,i

O

T h i s TFP measure i g n o r e s t h e impact o f t h e i n t a n g i b l e i n p u t f a c t o r s .

A

b e t t e r TFP measure can be d e r i v e d by e l i m i n a t i n g one o f these i n t a n g i b l e
factors,

O

t h e r e t u r n s - t o - s c a l e e f f e c t f r o m A i n ( 3 ) , l e a v i n g a new r e s i d u a l

denoted as Do as t h e new TFP measure.

This decomposition o f TFP can b e s t be

demonstrated w i t h t h e use o f a c o s t f u n c t i o n f o l l o w i n g G o l l o p and Roberts
(1981).
(4)

L e t t h e c o s t f u n c t i o n be:
C = G ( r L , r ~ r, ~ r , ~ Q,, T)

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where G i s t h e minimal c o s t f u n c t i o n f o r each e l e c t r i c u t i l i t y .
maximizes p r o f i t by o p t i m i z i n g t h e c h o i c e o f i n p u t f a c t o r s .

A utility

Differentiating

( 4 ) i n r e s p e c t t o t i m e one d e r i v e s :

where i = K, L, E and M.

A c c o r d i n g t o Sheppard's lemma f o r a c o s t

m i n i m i z i n g f i r m ( a G / a r i > = i, where i i s i n p u t f a c t o r .

Applying

Sheppard l s lemma t o ( 5 > , one d e r i v e s :
1 dC= C r i + I
-

'

Cdt

c

ri

dri

dt

+aGQ@aQcQdt

aG 1

atc

then:
C0

(6)

= C

sir

0

i

+ Ec,QO

+

Do

I

where Ec,

=

aG Q

i s t h e e l a s t i c i t y o f c o s t w i t h r e s p e c t t o o u t p u t , and

aQ c
Do

=

-aG 1

i s the p r o p o r t i o n a t e s h i f t o f the cost f u n c t i o n over time.

at c

U s i n g t h e e x p r e s s i o n f o r t o t a l c o s t , we can d e f i n e t h e dynamic
r e 1 a t i o n s h i p between average c o s t and i t s components.
O

O

Si nce

AC=C/Q,

O

AC =C -Q , then a c c o r d i n g t o ( 6 ) :

The change i n average c o s t , h o l d i n g i n p u t f a c t o r p r i c e s f i x e d , i s due t o
two f a c t o r s :

E

- 1

If Ec,
Ec,

Do, which i s a dynami-c source o f economic g r o w t h and

, which i s a s t a t i c source o f economic g.rowth o r s c a l e e f f e c t .

< 1, t h e n average c o s t w i l l d e c l i n e w i t h t h e r i s e o f o u t p u t . If

> 1 , average c o s t w i l l i n c r e a s e .

I n t h e case o f c o n s t a n t r e t u r n s t o

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scale,

EcQ =

1 , average c o s t i s n o t a f f e c t e d by t h e change i n o u t p u t .

E q u a t i o n ( 7 ) can be d i r e c t l y r e l a t e d t o TFP, d e r i v e d f r o m e q u a t i o n ( 3 ) .

To i l l u s t r a t e t h e r e l a t i o n s h i p between t h e change i n c o s t and t h e change
i n t h e p r o d u c t i o n f u n c t i o n , we proceed as f o l l o w s .

Totally differentiating

t h e c o s t a c c o u n t i n g i d e n t i t y w i t h r e s p e c t t o t i m e , one d e r i v e s :

Then t h e p r o p o r t i o n a l change i n average c o s t i s :

The change i n TFP i s a d i f f e r e n c e between o u t p u t g r o w t h and a d i v i s i a i n d e x
o f i n p u t g r o w t h (see e q u a t i o n ( 3 ) ) , t h e r e f o r e :
( 8 ) -A0 = AC - C s i r ,
O

O

s u b s t i t u t i n g ( 7 ) i n t o ( 8 ) and changing s i g n
(9) A " = ( 1 - EcQ>QO- Do
E q u a t i o n 9 shows t h a t t h e TFP measure i n ( 2 ) has a r e t u r n s - t o - s c a l e b i a s .

The sources o f economic g r o w t h o f t h e seven m a j o r O h i o u t i l i t i e s a r e
q u a n t i f i e d i n t h e dual ( c o s t ) form."
u s i n g an e s t i m a t e o f Ec,

An e s t i m a t e o f D can be made by

c a l c u l a t e d b y G o l l o p and R o b e r t s (1981).

They

found t h a t Ec, v a r i e d between 0.7 and 0 . 9 i n t h e i r sample o f e l e c t r i c
u t i l i t i e s which i n c l u d e d f o u r o f t h e seven m a j o r O h i o u t i l i t i e s .
f o l l o w i n g c a l c u l a t i o n s , we use a v a l u e o f 0 . 8 f o r

EcQ.

For t h e

We f i r s t d i s c u s s

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t h e components o f t h e change i n AC o v e r t i m e .

Four d i s t i n c t p e r i o d s o f

e l e c t r i c i t y p r i c e and consumption b e h a v i o r o v e r t h e 1964-1982 i n t e r v a l were
observed.

W i t h i n each p e r i o d , t h e d i r e c t i o n o f p r i c e s (AC) and s a l e s o f

e l e c t r i c i t y changes were t h e same f o r each u t i l i t y i n t h e sample.
f o u r s u b p e r i o d s a r e 1964-1968, 1969-1973, 1974- 1979 and 1980- 1982.

These
Price

and t o t a l s a l e s f i g u r e s f o r a l l seven u t i l i t i e s a r e p l o t t e d i n c h a r t 1.

I n t h e f i r s t p e r i o d , 1964-1968, t h e average p r i c e o f e l e c t r i c i t y was
f a 1 1i n g and s a l e s were r i s i n g .

I n t h e second and t h i r d p e r i o d s , 1969-1973

and 1974-1979, e l e c t r i c i t y consumption i n c r e a s e d b u t p r i c e s a l s o i n c r e a s e d .
I n 1969-1973 p e r i o d , t h e i n c r e a s e i n s a l e s was g r e a t e r t h a n i n t h e p r e v i o u s
p e r i o d , b u t i n 1974-1979 p e r i o d e l e c t r i c i t y consumption f e l l c o n s i d e r a b l y .
F i n a l l y , i n t h e t h i r d p e r i o d , 1980- 1982, e l e c t r i c i t y consumption d e c l i n e d
f o r t h e f i r s t t i m e i n O h i o ' s h i s t o r y and p r i c e s i n c r e a s e d a t t h e f a s t e r r a t e
than i n t h e previous periods.

The sources o f t h i s b e h a v i o r can be i d e n t i f i e d b y decomposing AC i n t o
t h e c o n t r i b u t i o n s made b y p r i c e changes of t a n g i b l e i n p u t s , b y t h e
r e t u r n s - t o - s c a l e e f f e c t , and by t h e s h i f t o f t h e c o s t c u r v e o v e r t i m e u s i n g
(7).

T h i s i s shown i n t a b l e 1.

I n t h e 1964-1968 p e r i o d , t h e s c a l e e f f e c t

and Do i n d i c a t o r o f TFP were t h e m a j o r c o n t r i b u t o r s t o t h e d e c l i n e o f AC.
W i t h o u t these e f f e c t s , t h e t a n g i b l e i n p u t p r i c e changes would have r a i s e d AC
by 1.5 p e r c e n t , i n s t e a d o f t h e observed d e c l i n e of 1.5 p e r c e n t .

I n the

1969- 1973 p e r i o d , t h e c o n t i n u i n g i n c r e a s e o f s a l e s o f e l e c t r i c i t y l o w e r e d AC
by 1.2 p e r c e n t f r o m t h e r e t u r n s - t o - s c a l e e f f e c t .

Do a l s o r e v e r s e d i t s

e f f e c t f r o m t h e p r e v i o u s p e r i o d , r a i s i n g AC b y 1.2 p e r c e n t .

I n the

1974- 1979 p e r i o d , t h e s c a l e e f f e c t on AC was l e s s t h a n a p e r c e n t a g e p o i n t

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'

Table 1

Sources o f Change o f AC f o r O h i o U t i l i t i e s
Average Annual Rates f o r t h e P e r i o d
1964-68
O

1969-73

1974-79

1980-82

Change i n average c o s t

AC

- 0.015

0.057

0.130

0.120

AC c u r v e s h i f t

Do

- 0.012

0.012

0.029

0.036

Return to scale e f f e c t

(EcQ-l)QO

- 0.018

- 0.028

- 0.007

0.007

Input price effect
o f capital

sK.r;

-0.002

-0.005

- 0.000

0.004

Input price effect
o f 1a b o r

sL.r;

0.005

0.010

0.008

0.010

Input price effect
o f energy

sE.r:

0.000

0.034

0.076

0.041

Input price effect
o f m a t e r i a1

sM.rl

0.01 1

0.018

0.025

0.022

and Do r a i s e d AC by 2.9 p e r c e n t .

F i n a l l y , i n t h e 1980-1982 p e r i o d ,

consumption o f e l e c t r i c i t y d e c l i n e d , f o r c i n g u t i l i t i e s away f r o m t h e o p t i m a l
s c a l e o f p r o d u c t i o n and i n c r e a s i n g AC b y .07 p e r c e n t and Do i n c r e a s e d i t s
c o n t r i b u t i o n t o t h e AC i n c r e a s e by 3.6 p e r c e n t .

The i m p a c t o f o t h e r i n t a n g i b l e f a c t o r s on AC was n e g a t i v e i n t h e f i r s t
p e r i o d (DO<O).

T h i s was p o s s i b l y due t o improvements i n e a r l i e r - i n s t a l l e d

t e c h n o l o g i e s and t o t h e i n t r o d u c t i o n o f more e f f i c i e n t generators..

In later

p e r i o d s , f e w e r new g e n e r a t o r s were i n s t a l l e d , c a u s i n g a slowdown i n t h e
d e c l i n e o f AC.

I n t h e 1970s, most O h i o u t i l i t i e s were b u i l d i n g n u c l e a r

p l a n t s , which p o s s i b l y l i m i t e d r e s o u r c e s f o r t h e improvement o f u t i l i z e d
facilities.

T h i s p o s s i b i l i t y , p l u s t i g h t e r r e g u l a t i o n s on a i r qua1 it y may

have caused e i t h e r t h e d e c l i n e o f TFP (DO>O) or t h e i n c r e a s e i n AC.

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C a p a c i t y U t i l i z a t i o n , R e g u l a t o r y Lag, and a SRAC s h i f t .

I n t h i s s e c t i o n Do i s decomposed f u r t h e r i n t o a c a p a c i t y u t i l i z a t i o n
e f f e c t and a r e g u l a t o r y l a g e f f e c t .

The r e g u l a t o r y l a g a r i s e s because r a t e

r e q u e s t s a r e made o n l y a f t e r c o s t s have changed enough t o w a r r a n t a r a t e
increase.

Thus, r e g u l a t o r y l a g , t h r o u g h c a p i t a l r e n t s and revenues, a f f e c t s

b o t h AC and TFP e s t i m a t e s .

I n t h e p r e v i o u s s e c t i o n , TFP was c a l c u l a t e d u s i n g

t h e l o n g - r u n assumption o f c o s t and revenue e q u a l i t y .
i f t h e u t i l i t y pays t h e long- run p r i c e , p k , o f c a p i t a l .

T h i s assumption h o l d s

I t can be measured

u s i n g t h e Christensen- Jorgenson (1969) r e n t a l p r i c e index, b u t because t h e
p r i c e o f c a p i t a l i s s e t by t h e r e g u l a t o r as t h e f a i r r a t e of r e t u r n on
c a p i t a l , i t may n o t be equal t o t h e long- run p r i c e o f c a p i t a l P k .

Thus, o u r

e s t i m a t e s o f AC and TFP w i l l be i n c o r r e c t i f P k does n o t equal t h e f a i r r a t e
o f return.

I n t e r e s t i n g l y , i t t u r n s o u t t h a t these c a p i t a l p r i c e d i s c r e p a n c i e s

r e f l e c t economic measures o f c a p a c i t y u t i l i z a t i o n .

A detailed explanation o f

t h i s phenomenon, p r o v i d e d by Berndt and Fuss(1982>, i s presented below.

The k e y n o t i o n i n t h e Berndt- Fuss approach i s t h e f i r m ' s c a p a c i t y l e v e l o f
output.

The c a p a c i t y l e v e l o f o u t p u t Q* i s c h a r a c t e r i z e d by t h e t a n g e n t i a l

p o i n t o f t h e long- run average c o s t (LRAC) curve and t h e s h o r t - r u n average c o s t
(SRAC) c u r v e .

If t h e o u t p u t p r i c e i s h i g h e r than t h e LRAC a t p o i n t Q*,

f i r m w i l l o p e r a t e i n t h e r e g i o n Q*<Q i n o r d e r t o maximize p r o f i t s .
case, t h e company o v e r u t i l i z e s i t s q u a s i - f i x e d c a p i t a l .

the

I n this

If t h e p r i c e o f t h e

o u t p u t i s lower than t h e LRAC a t p o i n t Q*, then t h e f i r m w i l l o p e r a t e a t t h e
l e v e l Q<Q* i n o r d e r t o m i n i m i z e l o s s e s .
u n d e r u t i l i z a t i o n o f quasi- fixed capital.

This w i l l l e a d t o t h e
Capacity u t i l i z a t i o n , according t o

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B e r n d t and Fuss, can then be measured by q = ( Z k 1 P k ) , where Z k i s t h e
expected shadow r e n t a l p r i c e o f c a p i t a l .

Thus t h e problem o f measuring

c a p a c i t y u t i l i z a t i o n becomes one o f measuring t h e shadow p r i c e o f c a p i t a l .
B e r n d t and Fuss(1982,p.

28) argue " . . . t h e

As

v a l u e o f s e r v i c e s f r o m stocks o f t h e

q u a s i - f i x e d i n p u t s should be a l t e r e d r a t h e r than t h e i r q u a n t i t y . "

A t the

o u t p u t l e v e l Q*, t h e shadow p r i c e o f c a p i t a l i s equal t o t h e long- run p r i c e o f
c a p i t a l , Z k =P k , and t h e r e f o r e , q = l .

Nevertheless, i f the f i r m increases

i t s o u t p u t above Q*, a d d i t i o n a l u n i t s of c a p i t a l would i n c r e a s e SRAC, meaning
t h a t t h e f i r m o v e r u t i l i z e s i t s c a p i t a l and t h e r e f o r e i s w i l l i n g t o pay more
f o r i t s q u a s i - f i x e d c a p i t a l t h a n t h e market p r i c e , Z k > P k , and q > l .

To make t h i s t h e o r y o p e r a t i o n a l , o p e r a t i o n a l i z e t h i s t h e o r y , one needs a
measure f o r t h e c a p i t a l r e n t , Z k .

Hul t e n (1983) argues t h a t t h e r e s i d u a l

income accounted as a d i f f e r e n c e between revenue and v a r i a b l e c o s t p e r u n i t o f
c a p i t a l i s an e s t i m a t e o f Z k , which i s t h e payment f o r a u n i t o f c a p i t a l a t
time t.
Zk't'

-.

= P ( t > *Q(t> - C r i ( t > * i ( t ) ,

K( t )

where i = L,E,M

I n t h e s h o r t r u n , the f i r m minimizes r e s t r i c t e d v a r i a b l e c o s t s c o n d i t i o n a l
on v a r i a b l e f a c t o r s p r i c e s , t h e amount o f q u a s i - f i x e d c a p i t a l , and o u t p u t :

where i

=

L, E, M, and P k ( t > i s a " long - run " r e n t per u n i t o f c a p i t a l s t o c k

( t h e t parameter i s o m i t t e d i n t h e f o l l o w i n g f o r convenience).

P k , as

opposed t o Z k , i s t h e o p p o r t u n i t y r e n t f o r t h e a1 t e r n a t i v e use o f t h e
c a p i t a l stock.

I n t h e case o f nonconstant r e t u r n s , t h e e q u a l i t y P k

=

Zk

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would be a t t a i n e d a t t h e l e v e l o f o u t p u t where t h e LR c o s t i s t a n g e n t i a l t o
t h e SR c o s t , which i s n o t n e c e s s a r i l y t h e minimum p o i n t o f s h o r t - r u n c o s t s
(see M o r r i s o n and B e r n d t ) .

The d i f f e r e n c e between P k and Z k h e l p s t o

f o r m u l a t e t h e r e l a t i o n s h i p between s h o r t - and long- run average c o s t .

To

r e p r e s e n t t h i s r e l a t i o n s h i p , we f o l l o w t h e H u l t e n approach w i t h some
modification.

F i r s t , we d e r i v e a s h i f t i n t h e SRAC curve.

For t h a t purpose, we need t o

define the p a r t i a l d e r i v a t i v e o f the r e s t r i c t e d variable cost w i t h respect t o
capital:

The d e r i v a t i o n o f e q u a t i o n (11) i s p r e s e n t e d i n Appendix I. A s i m i l a r
e q u a t i o n was d e r i v e d by H u l t e n f o r o n l y one v a r i a b l e component.
short- run e q u i l i b r i u m , marginal cost equals p r i c e :
logarithmically differentiating

(lo),

(aS/aQ>

=

In a

P, and

we f i n d ( t h e d e r i v a t i o n i s s i m i l a r t o

t h a t o f (6) and presented i n Appendix 11):

The o n l y t e r m l e f t undefined i n (12) i s a s l a t .
S

I t can be expressed as

a f u n c t i o n o f t h e TFP change A", h a v i n g a l l i n p u t f a c t o r s f i x e d

Denote SRAC as a

=

SIQ.

(1):

Then a =S - Q .
O

O

O

To d e r i v e t h e s h i f t o f theaSRAC,

we assume i n p u t p r i c e s a r e c o n s t a n t i n ( 1 2 ) , ( t h i s d e f i n e s s h i f t o f t h e r e a l

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SRAC), t h e n

where

= S-PQ,
and by r e a r r a n g i n g terms,

(13)

oO=-A"

+ PQ-S- (QO-A"-KO) .

The second t e r m i n e q u a t i o n (13) i s a c a p a c i t y u t i l i z a t i o n measure.

If the

u t i l i t y o p e r a t e s a t t h e c a p a c i t y l e v e l , revenue equals c o s t (PQ=S>, and t h e
shadow p r i c e o f c a p i t a l i s equal t o long- run p r i c e o f c a p i t a l ( P k = Z k ) .
Therefore, a t c a p a c i t y , t h e SRAC change
0

o f LRAC ( - A ) .

(0")

i s d e f i n e d s o l e l y by t h e s h i f t

Otherwise, t h e s h i f t i n t h e SRAC ( b e s i d e s , t h e LRAC s h i f t ) i s

d e f i n e d by t h e change i n t h e o u t p u t - t o - c a p i t a l r a t i o e x c l u d i n g t e c h n o l o g i c a l
change A",

a d j u s t e d by t h e r a t i o o f p r o f i t t o c o s t .

The sense o f t h e second term o f e q u a t i o n (13) i s i l l u s t r a t e d on F i g . 2,
O

assuming A =O.
Q,,

Say a u t i l i t y w i t h t h e SRAC curve

which i n d i c a t e s an o v e r u t i l i z a t i o n of c a p i t a l .

(KO, P k ) produces o u t p u t
I n o r d e r t o increase

p r o f i t s , t h e u t i l i t y should i n c r e a s e i t s c a p i t a l s t o c k , which would s h i f t t h e
SRAC curve t o t h e r i g h t .

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F i g . 2.

$

S h o r t - r u n C o s t s , Long- run C o s t s , and C a p a c i t y U t i l i z a t i o n

I

O

I n t h i s case, KO>O, Q =O, and (PQ-S>>O i m p l y t h a t t h e r i g h t w a r d s h i f t o f t h e
SRAC c u r v e w i l l l o w e r average c o s t s ( o O < O assuming A O = O ) .

S i n c e P and Q a r e

f i x e d , t h e d e c l i n e i n average c o s t s w i l l r a i s e t h e p r o f i t - t o - c o s t r a t i o
(PQ-S)/S.

T h i s i s d i f f e r e n t f r o m e q u a t i o n ( 1 3 ) where t h i s r a t i o i s assumed

f i x e d a t p o i n t Z,.

Thus e q u a t i o n ( 1 3 ) u n d e r e s t i m a t e s t h e average c o s t

d e c l i n e i n t h i s case.

On t h e o t h e r hand, t h i s r a t i o measured a t p o i n t Z 1

would o v e r e s t i m a t e t h e change i n o . "

S i m i l a r l y , i n t h e case o f n e g a t i v e

p r o f i t s , t h e decrease i n c a p i t a l would l o w e r a v e r a g e c o s t s and a f i x e d
p r o f i t - t o - c o s t r a t i o ( a t t h e b e g i n n i n g o f t h e p e r i o d ) would o v e r e s t i m a t e t h e
cost decline.

B e s i d e s t h e s h i f t f r o m So t o S 1 , t h e r e i s a s h i f t i n t h e LRAC, w h i c h
i s measured by A",

( i . e . t h e v e r t i c a l s h i f t i n SRAC as opposed t o t h e

h o r i z o n t a l one d i s c u s s e d above).

T h i s i s i l l u s t r a t e d on F i g . 3 .

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F i g . 3.

Ib

-

Average Cost Change Due t o V e r t i c a l and H o r i z o n t a l S h i f t s i n SRAC.

Lf?AC0
L RAC

I

I

I

I

I

Output

Costs i n F i g . 3 have i n c r e a s e d f r o m So t o S, due t o t h e change i n
capaci t y u t i 1i z a t i o n and capi t a l - o u t p u t r a t i o .

But, due t o t h e advancement i n

t e c h n o l o g y (AO>O), c o s t s have d e c l i n e d from S , t o S2.

The second t e r m i n e q u a t i o n (13) v a r i e s o v e r t h e business c y c l e f o r
unregulated industries.

I n a p e r i o d of economic expansion, t h e c o m p e t i t i v e

f i r m o v e r u t i l i z e s i t s c a p i t a l because of an i n c r e a s i n g p r o f i t - t o - c o s t r a t i o
making o0 p o s i t i v e ( c o n s i d e r i n g AO=O>. I n t h i s case, t h e p r o f i t - t o - c o s t
r a t i o i n c r e a s e s and more o u t p u t i s produced p e r u n i t of c a p i t a l (QO-KO).

In a

p e r i o d o f economic downturn, o u t p u t w i 11 d e c l i n e toward Q* ( Q O < O > w i t h a
d e c r e a s i n g o u t p u t - t o - c a p i t a l r a t i o (QO-KO)<O, making o 0 n e g a t i v e .

Finally,

a t t h e t r o u g h , Q m i g h t be below t h e o p t i m a l l e v e l w i t h n e g a t i v e p r o f i t and AC
w i l l i n c r e a s e (oO>O) i f o u t p u t c o n t i n u e s t o d e c l i n e .

When economic r e c o v e r y

r e t u r n s , o u t p u t i n c r e a s e s and (QO-KO>>Oand AC w i l l s t a r t t o d e c l i n e .

I n most o f t h e e x i s t i n g TFP s t u d i e s , t h e c a p a c i t y u t i l i z a t i o n e f f e c t i s
n o t considered ( i . e .

o i s equated t o TFP).

I n such a case, TFP has a

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capacity u t i l i z a t i o n bias.

The d i r e c t i o n o f t h e b i a s f o r u n r e g u l a t e d

i n d u s t r i e s most l i k e l y c o i n c i d e s w i t h t h e business c y c l e .

For t h i s reason,

comparison o f o 0 across u n r e g u l a t e d companies m i g h t be s a t i s f a c t o r y .
N e v e r t h e l e s s , comparing TFPs ( u n a d j u s t e d f o r c a p a c i t y b i a s ) o f r e g u l a t e d and
u n r e g u l a t e d i n d u s t r i e s has a s e r i o u s problem (such comparison was done, f o r
example, b y G o l l o p & Jorgenson [19801>.

The d e v i a t i o n o f revenue f r o m c o s t i n

r e g u l a t e d i n d u s t r i e s i s a f f e c t e d more by t h e frequency o f hearings t h a n t h e
business c y c l e ; i t was observed i n Ohio t h a t t h e d i s t r i b u t i o n o f h e a r i n g s does
n o t f o l l o w t h e business c y c l e ; s i m i l a r o b s e r v a t i o n s were made on t h e U.S.
l e v e l (see Braeutigam and Q u i r k l19841).

Thus TFP e s t i m a t e s should be

d i f f e r e n t b e f o r e and a f t e r r a t e h e a r i n g s even when t h e t r u e TFP does n o t
change because Z k v a r i e s around r a t e h e a r i n g s .

For t h e same reason, TFP

comparisons across u t i l i t i e s i n d i f f e r e n t s t a t e s can be m i s l e a d i n g because o f
the differences i n the regulatory lags.

Therefore, f o r t h e proper TFP

measure, t h e r e g u l a t o r y l a g should be t a k e n i n t o account.

Besides measuring t h e c a p a c i t y u t i l i z a t i o n e f f e c t , e q u a t i o n (13) can be
used t o measure t h e r e g u l a t o r y l a g e f f e c t on TFP.

For t h i s purpose, a shadow

p r i c e o f c a p i t a l Z k should be compared w i t h t h e f a i r - return - on - capi t a l i n d e x
d e f i n e d by PUCO.

I f t h e shadow p r i c e o f c a p i t a l i s n o t equal t o t h e f a i r

r e t u r n , t h e n two parameters would be changed by r e g u l a t o r s : t h e shadow p r i c e
o f c a p i t a l and revenues.

These changes can be d e s c r i b e d as f o l l o w s .

Let the

f a i r r e t u r n on c a p i t a l be ( Z k + G k ) , where Gk i s s i m p l y t h e d i f f e r e n c e
between Z k and t h e f a i r r e t u r n .

Then, a c c o r d i n g t o e q u a t i o n (1 ) , t h e

c o r r e s p o n d i n g revenue i s (PQ + GkK).

S u b s t i t u t i n g t h e new p r i c e of c a p i t a l

and revenue f i g u r e s i n t o e q u a t i o n ( 1 I ) , one de;ives:

( a s / a ~ ) =p k -

( z ~ + G ~and
) P~K-Z,K-G~K=S-PQ-G~K.

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C o r r e s p o n d i n g l y , under t h e new c o n d i t i o n s :
a s l a t = PQ+GkK A" and t h e t e r m PQ Q i n e q u a t i o n (12) i s s u b s t i t u t e d b y
S
S
S
(PQ+GkK>QO. T h e r e f o r e , e q u a t i o n (1 3) can be r e w r i t t e n as
O

The l a s t t e r m on t h e r i g h t i n t h e above e x p r e s s i o n i s a r e g u l a t o r y l a g e f f e c t
on t h e change i n TFP.

Note t h a t i t e q u a l s z e r o when G k i s equal t o z e r o ,

t h a t i s , when t h e shadow p r i c e o f c a p i t a l i s equal t o t h e f a i r r e t u r n on
capital.

F i n a l l y , n o t i n g Q O - K O - A O = C ~ i i O - ( C ~ i > Kwhere
",
i=L,E,M,

and

r e w r i t i n g A" i n i t s s t a t i c and dynamic components (see e q u a t i o n [ 9 1 > , e q u a t i o n
(14) can be r e w r i t t e n a s 7 :
(15)

o0 = (Ec,-1

)QO+DO+

(CS,

i "-(Cs, )KO).PQ-S+GkK , where i=L,E,M.
S

Since a l l t h e parameters i n e q u a t i o n (15) can be c a l c u l a t e d ,
computed as a r e s i d u a l .

Do can be

I n t h i s s t u d y , P k and G k f o r u t i l i t i e s were n o t

e s t i m a t e d and thus t h e D values d e r i v e d f r o m e q u a t i o n (14) (which would be
d i f f e r e n t f r o m D values d e r i v e d i n e q u a t i o n ( 7 ) ) a r e n o t a v a i l a b l e .

How F a i r i s t h e F a i r Rate o f Return R e g u l a t i o n ?

I n t h e f i r s t p e r i o d , 1963-1969, u t i l i t i e s r a r e l y r e q u e s t e d r a t e h e a r i n g s
(see t a b l e 3 ) , which suggests t h a t t h e i r r e t u r n on c a p i t a l was g r e a t e r o r
equal t o t h e f a i r r e t u r n (as d e f i n e d by PUCO), t h a t i s , Gk<O The AC d e c l i n e
d u r i n g t h i s p e r i o d c o n t r i b u t e d t o u t i l i t y p r o f i t s w i t h o u t t h e need f o r
mandatory e l e c t r i c i t y p r i c e i n c r e a s e s (see t a b l e 1 ) .

Thus, d u r i n g t h e f i r s t

p e r i o d , u t i l i t i e s were i n t e r e s t e d i n maximizing TFP growth because i t was
translated into profit.

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According to a popular view developed by Joskow (1974), an electricity
regulator is an extremely passive agent.

Price changes should be triggered by

a request from utilities or consumer advocates.

Utilities, however, have a

much better knowledge of their present and expected profit than consumer
advocates. Consumer advocates are more concerned with price increases than
with utility profits.

In the first period, electricity prices were declining,

which would make consumer advocates hesitant to request an even lower price
decreases.

Thus, utilities were in a position to gain extra profit given the

passivity of the reguEtor-.

As a result, during the first period, an

extremely long regulatory lag occurred. In the second period, 1969-1973, A C
increased slightly, which triggered a modest increase in the frequency of
heari ngs .

In the third and fourth periods, the situation was very different.

Fuel

prices started to increase very quickly, due to the Arab oil embargo 8 , as
we1 1 as to other input Tactors, such as inflation.
utility operating costs.

These were shocks to

For a given electricity price, such operating-cost

increases drove utility profits below the fair return. Utilities promptly
.responded to this shock by requesting electricity price increases that, in
most cases, were granted.

The frequency of hearings increased sharply as

utilities had trouble keeping up with the effects of these shocks. Moreover,
a decline in productivity ( D O > O > contributed to the rise in AC. The
productivity decline could have been due to a number of intangible factors,
some of which are under a utility's control.

Therefore, the decline in TFP

might have been due to a lack of incentives provided by the regulatory process
during the last two periods.
is illustrated below.

The hypothetical argument for such a possibility

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Assume t h a t p r i c e Po ( i n f i g u r e 4) i s t h e e q u i l i b r i u m .
i n p u t - p r i c e i n c r e a s e , LRAC moves up t o p o i n t PI.
loss per u n i t o f output.
i n c r e a s e o f (PI--Po).

Due t o a s h a r p

A r e a PoABPl i s t h e

I n t h i s case, u t i l i t i e s w i l l be g r a n t e d a p r i c e

Such a p r i c e s e t t i n g p r o c e s s i n g e n e r a l t a k e s a

year, f o l l o w i n g a u t i l i t y ' s request.

Now, c o n s i d e r t h a t t h e u t i l i t y c o u l d

have i n c r e a s e d i t s TFP t o p a r t l y o f f s e t t h e i m p a c t of t h e p r i c e h i k e , so t h a t
i n s t e a d o f i n c r e a s i n g c o s t t o t h e P, l e v e l , i t w o u l d have i n c r e a s e d c o s t s
o n l y t o t h e P2 l e v e l (and c o r r e s p o n d i n g l y r e q u e s t p r i c e Pr i n s t e a d o f
PI>.

I f s t a b l e i n p u t p r i c e s a r e e x p e c t e d i n t h e n e x t y e a r , t h e u t i l i t y may

n o t be w i l l i n g t o i n c r e a s e i t s TFP.

I n s t e a d , t h e u t i l i t y would r a i s e t h e

p r i c e t o P I , and i n t h e n e x t y e a r , i t would l o w e r t h e c o s t p e r u n i t o f
o u t p u t b y A".

I f o u t p u t r e m a i n s t h e same, i n t h e second y e a r t h e u t i l i t y
O

would r e g a i n t h e l o s s o f t h e p r e v i o u s y e a r , w h i c h was due t o h a v i n g A =O.
N e v e r t h e l e s s , i f o u t p u t i n c r e a s e s , t h e g a i n i n t h e second y e a r ( f r o m
O

s u p p r e s s i n g A =O i n t h e f i r s t y e a r ) w i l l exceed t h e l o s s e s .

This s i m p l i s t i c

example i l l u s t r a t e s t h e l a c k o f i n c e n t i v e s f o r u t i l i t i e s t o i n c r e a s e t h e i r TFP
under t h e s e c o n d i t i o n s .

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TABLE 2 :
YEAR:

FREQUENCY OF PUCO RATE HEARINGS

% OF U T I L I T I E S REQUESTED RATE INCREASE

R a t e c a s e s f i l e d ; m a t e r i a l p r o v i d e d by PUCO.

Source:

FIGURE 4.

1

Two- Year P l a n

I
I

Quantity

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Conclusion

Input prices and productivity changes are two major sets of factors
affecting utility operating costs. While input prices are little affected by
a utility, its productivity changes are mostly the result of its long- and
short-term planning. Yet PUCO grants equal significance to both sets of
factors in their process of electricity price determination. As a result, the
present regulation may not provide an adequate incentive for a utility to
lower its cost by means of raising its TFP level.

In this paper, three types of factors determining shifts in the SRAC curve
were considered. Each of these factors (technological change--D, return to
O

scale effect--E c Q , and capacity utilization effect--equation C141) is a
Q

result of different activities and should be weighted differently in the price
determination process.

It was indicated that, contrary to common practice, TFP measurement
without consideration of the capacity utilization and regulatory lag effects,
is inadequate for comparing regulated and unregulated sectors.

The most controversial of these three factors is technological change (D)
because the determinants of D are poorly understood.

Nevertheless, economists

are making initial strides in understanding this factor. For example, Gollop
and Roberts (1983) developed a method to consider pollution control bias in
the determination of technological change. Obviously, more work is needed in
this direction to give regulators valuable tools for measuring different
economic and managerial activities.

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-

23

-

FOOTNOTES

1.

For t h e d i s c r i p t i o n o f t h e " F a i r " r a t e o f r e t u r n , t h e

Hope case i s

o f t e n c i t e d i n t h e l i t e r a t u r e : " Rates, w h i c h e n a b l e s t h e company t o o p e r a t e
s u c c e s s f u l l y , t o m a i n t a i n i t s f i n a n c i a l i n t e g r i t y , t o a t t r a c t c a p i t a l , and
t o compensate i t s i n v e s t o r s f o r t h e r i s k assumed
Hope N a t u r a l Gas Co.,

2.

320 U.S.

...". Fed.

Power Comm'n v .

591 (1944):

20 p e r c e n t i s an upper boundary f o r an anual p r i c e i n c r e a s e e s t a b l i s h e d

by PUCO.

3.

F o r d e t a i l s on t h e T o r n q u i s t a p p r o x i m a t i o n , see Cowing, e t . a l . (1981)

4.

These u t i l i t i e s a r e :

O h i o Power, C i n c i n n a t i Gas and E l e c t r i c ,

C l e v e l a n d E l e c t r i c I l l u m i n a t i n g , Columbus and S o u t h e r n O h i o E l e c t r i c , D a y t o n
Power and L i g h t , O h i o Edison, and T o l e d o E d i s o n .

5.

I n case o f constant r e t u r n s t o scale, t h i s p o i n t i s always a t t h e

m i n imum o f SRAC.

6.

T h i s p r o b l e m i s s i m i l a r t o t h e q u e s t i o n o f whether t o measure s h a r e s

for D i v i s i a i n d e x a t t o r t+l p e r i o d .

The T o r n q u i s t a p p r o x i m a t i o n s u g g e s t s

an a v e r a g e s h a r e o f t w o p e r i o d s .

7.

The e x p r e s s i o n f o r Q0-K0-A" can be d e r i v e d as f o l l o w s A 0 = Q 0 - C s , i O

for i = K,L,E,M
Q0-K0-A" = C s , i

o r -Q + C s , i 0 - (1-s,)K0=-K0-A"
O

O

-

(Cs,)KO f o r i

=

L,E,M

f o r i = L,E,M,

then

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8.

O h i o utilities consume coal, which had a much less severe price

increase than oi 1 fuel.

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C a p i t a l Asset V a l u a t i o n to A d j u s t f o r V a r i a t i o n s i n U t i l i z a t i o n , "
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Inc.
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F i r m , " I n t e r n a t i o n a l Economic Review, V o l . 25, No. 1 ( F e b r u a r y , 1 9 5 4 ) .
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Power G e n e r a t i o n , " J o u r n a l o f P o l i t i c a l Economy, v o l . 84, no. 4, P a r t 1
( A u g u s t , 1976), 655- 676. The U n i v e r s i t y o f Chicago.
C h r i s t e n s e n , L.R. and D a l e W. Jorgenson.
"U.S. Real P r o d u c t and Real F a c t o r
I n p u t , 1929- 1967," The Review o f Income and Wealth, S e r i e s 16, Number 1 ,
(March, 1970).
Cowing, Thomas G . , J e f f r e y S m a l l , Rodney E. Stevenson. " C o m p a r a t i v e
Measures o f T o t a l F a c t o r P r o d u c t i v i t y i n t h e R e g u l a t e d S e c t o r : The
E l e c t r i c U t i l i t y I n d u s t r y " i n T.C. Cowing and R . E . Stevenson, Ed.,
P r o d u c t i v i t y Measurement i n R e g u l a t e d I n d u s t r i e s , Academic P r e s s , 1981.
Denny, M i c h a e l , M e l v y n Fuss, Leonard Waverman. "The Measurement and
I n t e r p r e t a t i o n o f T o t a l F a c t o r P r o d u c t i v i t y i n Regulated I n d u s t r i e s ,
w i t h an A p p l i c a t i o n t o Canadian T e l e c o m m u n i c a t i o n " i n T.C. Cowing and
R . E . Stevenson, Ed., P r o d u c t i v i t y Measurement i n R e g u l a t e d I n d u s t r i e s ,
Academic P r e s s , 1981.
G o l l o p , F.M., and D.W. Jorgenson. "U.S. P r o d u c t i v i t y Growth b y I n d u s t r y ,
1947-1 973, i n New ~ e v e r o p m e n t s i n P r o d u c t i v i t y ~ e a s u r e m e n t and
~ n a l y ss,i
( W . K e n d r i c k and B.N. Vaccara, e d s ) , N B E R , ' U n i v e r s i t y o f C h i c a g o P r e s s ,
C h i c a g o , I l l i n o i s (1980)
G o l l o p , Frank M . , and Mark J . R o b e r t s . "The Sources o f Economic Growth i n
t h e U.S. E l e c t r i c Power I n d u s t r y , " i n T.C. Cowing and R.E. Stevenson,
Ed., P r o d u c t i v i t y Measurement i n R e g u l a t e d I n d u s t r i e s , Academic P r e s s ,
1981, p p . 107-143.

. " E n v i r o n m e n t a l R e g u l a t i o n s and P r o d u c t i v i t y Growth:
The Case o f F o s s i l - F u e l e d E l e c t r i c Power G e n e r a t i o n . " J o u r n a l o f
P o l i t i c a l Economy, v o l . 91, no. 4 ( A u g u s t , 1983), pp. 654- 674.
H u l t e n , C h a r l e s R. " P r o d u c t i v i t y Change, C a p a c i t y U t i l i z a t i o n , and t h e
S o u r c e s o f E f f i c i e n c y Growth," Working Paper 137, (June, 1983), t h e
B u r e a u o f Labor S t a t i s t i c s .
Joskow, Paul L. " I n f l a t i o n and E n v i r o n m e n t a l Concern: S t r u c t u r a l Change i n
t h e Process o f P u b l i c U t i l i t y P r i c e R e g u l a t i o n , " The J o u r n a l o f Law and
Economics, v o l . 17 ( O c t o b e r , 1974), pp. 291- 328.
K e n d r i c k ; J . W. " Postwar P r o d u c t i v i t y Trends i n t h e U n i t e d S t a t e s ,
1948- 1969," NBER General S e r i e s 98 ( 1 9 7 3 ) .

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M o r r i s o n , C. J . and E. R. B e r n d t . "Short- Run Labor P r o d u c t i v i t y i n a Dynamic
Model," J o u r n a l o f Econometrics, 16, (1981), pp. 339-365. N o r t h H o l l a n d
P u b l i s h i n g Company.
Solow, R o b e r t M. " T e c h n i c a l Change and t h e Aggregate P r o d u c t i o n F u n c t i o n , "
The Review o f Economics and S t a t i s t i c s , V o l . 39, (August, 1957) pp.
31 2-320

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Appendix I

-

27 -

The D e r i v a t i o n o f E q u a t i o n (11)

We p r o v e t h a t

=

Pk - Zk

aK
From e q u a t i o n

(lo),

we d e r i v e

i s t h e marginal r a t e o f t e c h n i c a l s u b s t i t u t i o n (MRTS) . I n t h e SR,
aK
o u t p u t i s a f u n c t i o n o f q u a s i - f i x e d c a p i t a l and o f v a r i a b l e i n p u t s , which
where

depend on g i v e n c a p i t a l :
Q =fCK, L(K>, E(K), M ( K ) l f f ( X )

Rates o f t e c h n i c a l s u b s t i t u t i o n can be d e r i v e d h o l d i n g o u t p u t f i x e d , w i t h
corresponding inputs combination X*:

where i

=

variable.

L, E, M.

\ single
For t h e p r o o f , we have t o d e r i v e MRTS f o r any

Consider l a b o r t o c a p i t a l MRTS t h e n from t h e above e q u a t i o n f o r i =

I n t h e SR:
a f ( X * > = ZK and a f ( X * )
aK
ai

=

ri.

Then s u b s t i t u t i n g ( 1 . 2 ) i n t o ( 1 . I > ,

Q.E.D.

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Appendix 11.

D e r i v a t i o n o f equation (12).

Based on t h e s h o r t - r u n c o s t f u n c t i o n (10) we d e r i v e e q u a t i o n ( 1 2 > , as f o l l o w s :
ds = as d ~ +
dt
aK d t
= (Pk-Zk)K*KO

c % dri
ar,

dt

-

% + as d ~
at

a~

dt

+ C i * r * r O - & + PQ*QO t h e n , d i v i d i n g
at

both sides by S

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Appendix 111
Revenue ( E l e c t r i c o p e r a t i n g revenue) r e p r e s e n t s t o t a l o p e r a t i n g revenues f r o m
the sale o f e l e c t r i c i t y .
Output ( E l e c t r i c s a l e s ) r e p r e s e n t s t h e t o t a l k i l o w a t t hours o f e l e c t r i c i t y
s o l d t o a l l r e s i d e n t i a l , commercial and i n d u s t r i a l customers i n c l u d i n g s a l e s
f o r r e s a l e.
Fuel O p e r a t i o n Expense r e p r e s e n t s t h e t o t a l c o s t o f f u e l used e x c l u s i v e l y f o r
p r o d u c t i o n o f e l e c t r i c energy.
Average Cost of f u e l per m i l l i o n Btu, r e p r e s e n t s t h e t o t a l c o s t o f f u e l
consumed f o r e l e c t r i c g e n e r a t i o n d i v i d e d by i t s t o t a l B t u c o n t e n t .
M a t e r i a l Expense was d e r i v e d f r o m E l e c t r i c O p e r a t i n g Expenses minus t a x e s ,
l a b o r and f u e l expense.
M a t e r i a l P r i c e Index.

Handy-Whitman c o s t ( i n d e x of U t i l i t y P l a n t M a t e r i a l s .

Rate Base i s computed as a sum o f Net U t i l i t y P l a n t and t h e Change i n Working
C a p i t a l . T h i s computation i s c o n s i s t e n t w i t h a r e g u l a t o r y d e f i n i t i o n o f t h e
r a t e base.
Return on c a p i t a l i s computed as a r a t i o between O p e r a t i n g Income and t h e r a t e
Base.
Net U t i l i t y P l a n t r e p r e s e n t s t h e h i s t o r i c a l c o s t , l e s s accumulated
d e p r e c i a t i o n o f t h e t o t a l f i x e d u t i l i t y p l a n t and equipment.
Change i n Working C a p i t a l r e p r e s e n t s t h e amount o f cach o r l i q u i d a s s e t s a
company must have t o meet c u r r e n t c o s t s u n t i l . r e i m b u r s e d by i t s customers.
O p e r a t i n g Income r e p r e s e n t s t o t a l o p e r a t i o n revenues earned f r o m e l e c t r i c
s e r v i c e s minus t o t a l o p e r a t i n g expenses.
Number o f Employees i s e l e c t r i c department employees where each p a r t - t i m e
worker i s counted as o n e - h a l f o f a f u l l - t i m e employee.
Labor Expenses i s d e f i n e d as t o t a l s a l a r i e s and wages charged t o e l e c t r i c
o p e r a t i o n and maintenance p r o d u c t i o n .
Wage Rate i s measured as l a b o r expenses d i v i d e d by t h e number o f employees.
Number o f employees and l a b o r expenses were d e r i v e d f r o m " F i n a n c i a l S t a t i s t i c s
o f S e l e c t e d E l e c t r i c U t i l i t i e s . " The r e s t o f d a t a were d e r i v e d f r o m Cornpustat
Co .