Raabe J. Hydro power - the design, use, and function of hydromechanical, hydraulic, and electrical еquipment
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Fig.
1.6.9.
Longitudinal section of the power house at San Fiorano, Italy (owner
ENEL).
Mixed
plant with
2
ternary sets for pumped-storage. Pelton turbine (PT) built by Hydroart, Milan, Italy.
Data:
H,
=
1403
m;
n
=
600
rpm;
P,
=
140
MW. To date the highest
nHP
in a storage P (Drawing
courtesy
ENEL).
Such gears are widely used now as hydromatic drives in cars and with an output
up
to
2000
kW
for
Diesel hydraulic locomotives. Because of their low specific weight, these gears are extremely suitable
for Diesel locomotives. Such locomotives are the backbone of traction power of the unelectrified
lines of the West German federal railroads. With their low specific weight, for a certain limit they
are superior
in
output to Diesel electric locomotives.
1.6.4.
Hydro power plants with respect to their
availability
-
Run-of-river power stations operate fairly continuously and supply base load. Most of
run-of-river power plants have a low reservoir storage capacity and usually low head.
Together with thermal and nuclear power plants, they cover the base load of
an
electric
grid. These sets usually have a speed control (if any), which cares for a small variation of
output within the permitted range of frequency (provided the grid is an
AC
one) and
hence of speed from
nmin
to
n,,.
This is effected by a rather high permanent speed droop defined by
6,
=
(n,,,
-
nmin)/
n
,,,,
(see also Cap.
11.2)
in the range of
6,
=
0,03 to
0,04.
-
Storage plants with a smalI storage volume (weekend reservoir). Usually a chain of
river power plants, which has a certain storing capacity in its terminating highest and
lowest reservoirs. In West Germany, rivers without navigation,
e.g. the Lech or the upper
Danube between
Ulm and Regensburg have such a chain of power stations to cover
smaller peak load demand
(e.g. electric traction power) by the so called "swell" operation.
With this a certain water quantity passes through the chain to the reservoir on the chain's
lowcr en11. From tlicrc on downstream
ccrtain tilrgct rclici has
to
bc
dclivcrcd into the
river.
scc
1
I?
I
.O.IO
an(!
(;~.iit~~lr
[1.75].
1
I;tvirig thc cove1 ing of'pc;11\
lo;ld
ill rni~~rl, tlic set
needs ,l ch;tr;lc:cri.\tic.
ill
which the output drop5 [nor::
vs
sl?ct.d
than
in
a
base load plant.
Hcncc the pcr~nzncnt spceci droop
clip
-
0,02.
At thc Danube this service will quitted.
-
Storagc pl;ints with
;i
lar_ce storagc vol~lmc (annual rcscrvoii). Usu;~lly the upper
reservoir is located in
the mountains to store nielled
snow
anti
ice
(see
Fig.
1.6.1
1).
As
Fig. 1.6.10. Section along a river with head
reservoir
and
flow
equalizing
reservoir at its
ends,
and chain of power stations between for
swell operation.
Fig. 1.6.1
1.
Schematic perspcctive view of combined peak load storage and pumped-storage
plants
Ziller
a:ld
Zemm.
Austria (owner Tauernkruftwerke
AG,
Salzburg). Annual productivity
1072,9
G\\h:
annual i\>ns\:mption by pumping
755
GWh. 1) Schlegeis reservoir, levels at altitudes
h,,,,,
=
17SZ
rn:
11,,
=
1650 m; live storagc volume
rl
Y
=
137.7
.
106
m3
2)
Kosshang powerhouse:
4
ternary xts. Fr;incisiurbincs iFig. 10.3.9; with
H,,,,,
=
672
m
(to date highest head of
a
Francis
turbine
opcr;~tin~. here since 1970) built
by
Sulzcr Escher Wyss Andritz:
,I
=
750
rpm;
P
=
58
b1
W.
2-stage pumps started up filled by Fottinger torque converter. a11 bililt bj Voith.
P
=
62,5
hIW.
3) Stillup rescrvoir:
h,,,
=
1
120 ni;
/I,,
=
1
106 ni;
A
V
=
6,9
-
loh
m3;
4) %layerhofen powcr house,
tl
=
469 nl: cs.,(Onl> turbining)
=
345
MW;
5)
Hiiusling power house (under ereition)
2
ternary
scts with Francis turbines
of
then highcst head
H,,,
=
744
m,
P,
=
180
MW
(see
Fig.
10.3.11)
6)
Zillcrgriindl rescrvoir
11,~~~
=
1850
rn;
hmim
=
1740 m;
AV=
89
-
lo6
m3.
7) Zemnl scheme opera-
ting.
8)
Ziller scheme under
erection.
From
LVidntan11
(1.761.
these plants have, in the main, also to cover peak load demand. their permanent speed
droop is
small
6,
=
0,01
to
0,015.
CVicirnuntl
desribes a recent scheme of this type
[1.76].
-
Tidal power plants: for the usual type of plant made to date
with
one basin, the
availability of its power depends on the date, the moment, and especially on
the
related
position of moon and sun (see
Fig.
1.6.2).
-
Pumped storage plants: these plants meet the daily peak load demand (see Fig. 1.6.12).
Fig. 1.6.12. Variation of grid load of West German power
board
(RWE)
during a winter working day a) base load of
run-of-river sets b) the same for thermal power plants c) peak
load of storage and pumped-storage plants
d)
consumption
by pumping of pumped-storage plants.
1.6.5.
Hydromechanical equipment of outstanding plants
Table 1.6.2 shows a compilation of the important dates and features of the hydro turbo-
machines of some important plants.
Table
1.6.2. Compilation of hydroturbomachinery of large water power plants
Plantlriver (country) Number of sets Head
(m)
Output
(M
W)
D(m)
Kaplan
turbitres
22nd Congress/Volga (USSR) 22
Iron
Door/Danube (Rumania-Jugoslavia) 12
Porto Primavcra (Brazil)
18
JupiaIRio Parani (Brazil)
14
Rocky Reach (Columbia)
11
Tres Marias/Rio S5o Francisco (Brazil)
6
Gezhouba
1
(China)
2
'Table
1.6.2. Continuation.
Palrnar (Uruguay)
Aschach/Drtnubc (Austria)
Orlik/Vultava (Czccho-Slovakia)
Prit~ikoski (Finland)
Solbergfoss (Norway)
Otori (Japan)
Fra?rcis turbines
Itaipu/Kio Paranri (Brazil-Paraguay)
Guri
I1 (Venezuela)
SajanskIYenissei (USSR)
Krasnojarsk/Yenissei (USSR)
Charchill Falls (Canada)
BratskJAngara (USSR)
Ust
IlimIAngara (USSR)
Ilhe Solteira/Rio Paran6 (Brazil)
Tucuri/Tocantin (Brazil)
La
Grande 2 (Canada)
Itaparica/Rio Siio Francisco (Brazil)
Cabora
Bassa/Zambesi (Mozambique)
Grand Coulee
I1I/Colurnbia (USA)
Pelton turbines
Cliivor (Columbia)
Sy Sima (Norway)
Grand
Maison-L'Eau d'Olle (France)
Paute (Ecuador)
Lotru (Rumania)
Silz (Austria)
Lago Delio (Italy)
Roselend (France)
El Toro (Chile)
Idikki (India)
Villarodin-Mont Cenis (France)
Chandoline (Switzerland)
Reil3eck (Austria)
Pumped
storage
plants
Bath County (USA)
Cornwall (USA)
Dinorwic (Great Britain)
Racoon (USA)
Helms (USA)
Grand
Maison-L'Eau d'Olle (France)
Okukiyotsu (Japan)
Wehr (West Germany)
Vianden (Laxemburg)
Montezic (France)
hlalta/Drau (Austria)
Coo
2 (Belgium)
Caplijna (Jugoslavia)
San Fiorano (Italy)
Iliiusling (Austria)
PUT Pumpturbine TS Ternary set
329 457
PUT
350 295 PUT
536 317 PUT
305 382
PUT
531,6 414 PUT
955 152,5 PUT
490 260 PUT
645(max) 257,5 TS with
FT
28? 105 TS with
FT
419,l 230 PUT
1030 208
TS
with PT
275 234 PUT
237 250 PUT
1438.6 105,8
TS
with PT
744(max) 180 TS with FT
2.
Economical and other aspects of hydro power
and
actual examples
2.1.
Introduction
The economical aspect is certainly important in determining whether any hydro power
project comes to fruition. Since nobody is an island, the engineer, the economist or the
politician, whilst seeing a certain project as progress in their own eyes must be aware that
it
may not be so in the mind of the ecologist, sociologist or even the ordinary man affected
by the project.
The mere size of a hydro power project especially the largest ones, and its environmental
and sociological impact turns
it
from a business alone between the engineer and
economist or the business
nlen into a political affair.
What is one man's
meat is another man's poison, and any project has three aspec::
Yours, mine and the facts. Usually engineers and economists
claim to concern themselves
only with facts (but who knows them perfectly
with all their consequences?). Putting aside
the impossibility of reconciling the many conflicting opinions,
it
has to be realized that
most public opinion is
determined not
by
reasoning bur by emotions; e.g. when deciding
on the justification of a nuclear
plant
mans
people associate this with the bomb.
On
the
contrary in the case of a hydro power plant, only an infinitesimal
minority associates this
with the
casualities of dam disasters. of dam-induced earthquakes, spreading of bil-
harziosis, the distress of displaced people,
the calamity of rising ground salination, sinking
water table, rising erosion, interrupted transport of fertilizing sediments and aquatic food
to the detriment of fauna and flora, etc.
This situation should
not seduce the planner to dispose of imaginable objections. He
should meet them with public
consense and by means of studies based on :he actual state
of knowledge. The latter should not fall short of the planner's responsability range.
A
hydro power plant is an investment with relatively high specific initial cost and usually
also high total initial cost. The decision to build a plant has to be based on a reasonable
purpose, since
it
absorbs working power or its monetary equivalent for the relatively long
period of its useful life in the order of about
40
years.
from the capitalistic point of view a hydro power plant is an investment that has to be remunerative.
Once the demand for power and the feasibility of power transmission are given. the investment is
usllally
alwajs lucrative, because of the rising energy demand in the world. Even if the initial cost
of
a
hydro power plant are relatively high especially in the low head range, the balance may be
rc;lcllcd
by
a
rather long depreciation period, revenues by an adequate electricity rate, low operating,
1ll;llllt~I~;lncc and replacement cost, and often by
the
multipurpose
profitability of the plant, such as
iln~rc!''~n\cnt
of
navigation, fishcry, flood protection, storing water for industry, home and farms and
crc;\tic>ll
cjf
lc.i.;urc tones, building access roads and exposing an originally unaccessible and remote
I0
~~.olloi\llcal development.
The
specific initial ccst of a hydro power plant dcpcnds rnai:~ly on thc hc:l<i and size and
hel~cc on thc rotational
speed
or
the
unit. The cost
of
civil en_cinccring works, ;rrchitecture,
powcr tran~rnission line, mcchnnical ar,d e!cctricrtl
equipment
tlcpclltis both on thc head
and on the
type
of
plant (i-c., wllcther river run, pumped storage etc.). The actual state
of
art
is
rcilcctcd
by
discussing the development
of
some important rivers.
2.2.
Economical aspects
of
hydro
power
plants
2.2.1.
General
remark about
feasibility
of
a
project
In general the planning
of
a
hydro power plant has to bc based on the principle that the
plant has
to
bc economically viable. Strictly speaking this means that the cost of the
plant's equipment
(i.e., turbines, alternators, transformers, switchgear, high voltage
transmission,
contrcl rooms)
its
buildings (i.e., barrage, tunnel, pressure shaft, surge tank,
spillway, powcr house)
its
erection and assembly, its ground acquisition, indemnification
and wztcr easement, its maintainance, repair and service during its useful life and the loan
and interest on
it
during its depreciation period (not to forget the salaries for
a
reasonable
board
c;f
directers), must be equal
to
the earning
by
sale
of
energy and other improve-
men
ts.
The inlpleme~ltation of a hydro power plant withdraws available funds, one of the most scarce goods,
from
thc money market for the rather long period of a plant's useful economical life. Raising the
expenses of a plant by borrowing money is the usual practice
[2.1
to
2.31.
Bonds and assurance
provide for
financial safety
[2.5].
2.2.2.
The
electricity rate
In
a
free market the electricity rate depends on the demand. Therefore
it
is usual for energy to be
much cheapcr duril?g the hours of low demand, (e.g. nlght) than during the peak load hours (usually
during the
da;~). Usually certaili power stations are designed to meet base load demand, others to
meet peak load derrand. .4s the duration of peak load demand is shorter than that of base load and
as
thc
cost
uf
a
plant has to be covered by revenues during a certain depreciation period, the
electricity rate depc~icls malnly on the duration of
full
Ioad service per year (see Table
2.2.1).
Setting
*
5
the electricity rate implies cvaliiation of the plant's uses
(2.6
to 2.101. On the other hand in a free
market cconorny, the electricity rate
has to cover the initial cost inciusive of interest, and the
P'
operatins, maintenance ar~d repair. In a multi purpose plant this has to be set with due consideration
of
earnings duc to other benefits, see Table
2.2.1
and
[2.11
to
2.171.
k
3
i
2.2.3.
The
specific investment
cost
per installed
kW
>I
The specific investment costjinstailed
kW
is also an essential factor in planning. Even if this depends
on local circumstances, in general, it is
lo~vered by increasing the power installed, and for
a
given
plant with a certain number of sets of a given type
(e.g. Francis turbines of
a
certain specific speed
and head),
it
is also lo\verzd by increasing the speed and hencc the specific speed of the set. For the
small
number of sets \vhich are normally involved, any economic benefit due to quanti:y production
-by increasing
:he number of sets may
be
excluded.
On the contrary for sets which are usually of large size, increasing the number of
sets increases also
the number of large machine members to be fabricated on large machine tools only available in
limited
numbcrs. Moreovcr
it
increases the number of accessories, manifolds, control mcchanism, the
concrete forms
nccessrlry for the draft tube, spiral casing and pit. Hence usually the specific cost is
luwered by lowering the number of sets in a certain plant.
Table
2.2.1.
Energy production cost of today, according to Bohn.
comparison of Hydroelectricity Thermoelectricity Nuclear power plant
rates
Duration of service Lower Upper Lower Upper Mean value
~er year (hours) limit limit limit limit
Typical figures of hydro power:
Cabora Bassa, Mozambique:
2
100
M
W;
8000
h/year
;
0,002
US
$/kwh
lnga
1
+
11, Zaire:
1 760
M
W;
6800 h/year; 0,0024 US $/kwh
ItaipG, Brazil
:
12
870
MW;
5000 h/year; 0,014 US
$/kwh
West German Lech:
20
M
W;
4700
hlyear; 0,02 US $/kwh
Trends in electricity rates:
Year Hydroelectric
multi Hydroelectric
purpose scheme (irrigation,
plants for energy
storing, navigation, production only
protection against
inundation) without
weighing these purposes
Thermal plant Nuclear Year
using pit coal plant
(subsidized by
government, here
West Germany)
Once the fabrication of large machine parts on site is excluded, the lower limit for the number of sets
results from the transport facilities in the factory and on the roads near the site. In the special case
of a plant in
a
rather broad valley, requiring a large submergence into dificult ground, increasing
the number of sets may lower the specific cost. This may apply in the mean head range of 10 to
30
m.
For a given power installed, a certain number of sets of definite type, the specific cost per
kW
decreases with increase in head up to
H
=
800 m, because the resulting increasing pressure difference
on the rotor vane makes the plant more compact.
Hence tida! power plants with the lowest heads down to
H
=
1,5
m (in the case of the Sovjet Russian
plant Kislogubskaja in the Mersenj Bay of the Ice Sea) are the most expensive in specific cost
reaching in former reports a figure of
10000 US$/kW in the case of Fundy Bay. Nevertheless in a
recent study of
A.
Douma,
G.
D. Stewart
(Annapolis Straflo turbine will demonstrate Bay of Fundy
tidal project, issued by
Sulzer Escher Wyss), the so-called
B9
project of the Fundy Bay with
3800 MW was suggested to have
a
specific cost of only
960
US
S/kW.
From about 800
m
heacf on upwards the specific cost rises with the head. Then the power station
ustially
is
fed from a reservoir in a remote mountainous area. This requires the building of long and
oflen
difficult
access roads with longer tunnels (up to
15
km) and pressure shafts or penstocks.
To givc further details about specific cost some actual examples
of
hydro power plants
arc
lllentioned in the following.
1)
Punlpcd storage plant with pump-turbines
for
the generation
of
railroad traction
I)"\\'"
(16%
Hertz). Langenprozelten, owner Rhein-Main-Donau
AG,
Munich, Fed.
Rep.
ofGcrlnany, completed in
1977.
Head
H
=
300
m,
2 pump-turbines of
75
MW
each
with
a
booster Francis turbine of 30
kIV/
each for starting pumping. Spccific cost
400
US
S/k
W.
2)
Low head run-of-river power station with small c~:tput Gcislin~ on the upper Danube,
owner
Rhein-Main-Donau
AG,
Munich, Fed. Rep. of Germany. Completcd in
1953.
Head
H
=
5,9
m.
3 Kaplati turbines
of
8,5
MW
each. Specific cost 1400
US
$/kW.
3)
The most powerful hydro power (and power) plant
of
the world with spillway for
58000
m3/s,
built on rocky ground, used as quarry for concrete. 800 km long,
1200
kV
DC transmissiori lirtc for 13000
hlCV
power block. "Itaipi~" on the river
Parani
near where it forms the frontier between Brazil and Paraguay both of which share the
output. 18 Francis turbines of
71
8
M
W rated output each (12 900 total) at
a
rntcd head
of 110
In to
be
completed between 1985 and 1990. Estimate
of
specific cost: In 1975:
160
US
S/kLV;
in 1979: 1000
US
$/kW; in 1954: 1500
US
$/kW. Two
+
600
kV
DC
trans-
,
lum.
mission lines, 1600
km
enlarge this about 40%. Builder: I~iternational conso-t'
4)
The largzst power plant with
a
higher head range (300 m) with the largest annual
power production of
343 TWh
(I
TWh
=
109kWh) up to 1980 (then followed by La
Grande, Hudson Bay) located in the "Taiga" of the Labrador plateau with annual
average temperature of
-
2"C, at a distance of 1200 km from the nearest consumer
(Moiitreal), transmission by 735
kV
AC.
This plant is 200 km from the nearest railroad
station. "Churchill Falls", Labrador, Canada, 11 Francis turbines of 483 MW each
(5330
MW
total) at
FI
=
312 m head. Operated by Churchill Falls Labrador Corporatim
(CFLC).
Specific filst cost 200
US
$/kW including the 1200
km
long
AC
135 kV trans-
missioti
line.
Completed in 1970.
In
Table 2.2.2, the costs of thc above 4 plants are subdivided into the shares due to civil
engineeriilg works, reservoir, power house, mechanical and electrical equipment ctc.
From this
it
can be seen that these shares depend on the head as well as on the type of
plant. For
esamplc in a low head run-of-river power station the spillway requires 35%
Table 2.2.2. Cost of compotlents for several types of hydro power plants*).
1) Pumped storage plant Langenprozelten, Federal Republic of Gcrmany built by Rhein-Main-
Donau
AG
Munich:
H
=
300
m:
P
=
2
-
75
blW.
Parts
Percentage of total cost
Upper
storngc basin
Pressure
slia
ft
without reinforcement
Power
house (Underground type)
Tail
race basin
Retaining basin
Power house architecture and intake structure
'I
otal civil engineering
Pump-turbines,
2
sets
Main valves, valve-operated booster Francis turbines for speeding up
water
filled
machine to pumping mode, needing up to
40%
of rated
power. which cannot
be
supplied from limited Federal Gerrnan grid for
tractive power with single
phasc
AC
and 16%
Hz.
Piping
Lining of pressure shaft
Trash rack rake, intake gate, cooling
system
Cranes. elevators
Total mechanical equipment
Table
2.2.2.
Continuation.
Alterriators (for tractiori po\vcr with single ph;isc
;1C
of
lh?~
Flcrtir.
since 1905 in Germany for reduction of corn~nutator spark~ng, \\hen
using high voltilge supply froill ovcrhc.;id wirc and t;;insformcr rcgu-
lation). 13,5
%
~ransformcrs 2,73
%
Switch plant and distributing board
10,25
%
Total electrical equipment 26,48'/0
-
2) Low head run-of-river po\vcr plant Geisling on the upper Danube, Rhein-Main-Donau
Miinchen:
/I
=
5,')
m;
P
=
3 .
8,5
blW;
D
=
525
111.
Parts
Percentage
of total cos:
Architecture
of power house 3,s
%
Civil cngincering work head watcr reservoir 20,s
%
Total architccturc and civil engineering 24,6
%
3 Turbines (Kaplsn turbines) 23,9
%
Cranes 0,648
%
Stop logs 1,07
%
Intake trash rack
0,435
YG
thrash rack rake
0,912
%
Covers for grids etc. 0,152 YO
Transportation of trash 0:054
%
Workshop for assembly and repairs 0,736
O/b
Total mcchanical equipment 27,907
%
Spillway stccl structure 12,2
%
Civil engineering for spillway including stilling basin 21,2
%
Architecture of spillway 0,457
'10
Electrical equipment of spill\vay
0,766
O/o
Total spill\vay equiment 34,623 YO
Electric installation 0,335
%
Alternator and exciting devices 9,2
%
Switchyard 2,16
%
Transformer 0,683
%
Telephone operating plant 0.16
%
Emergency alarm plant 0,030
%
inventory
0,31
%
Electrical equipment 12,870
%
3) Plant Itaipu, Rio Parana (Brazil, Paraguay):
P
='I
8 .715
M
W;
H
=
82,9-
126,7
m;
DC
tr;tnsmission 1200 kV over 800
km.
Estimated cost in
1979
in millions of
US
$:
lnfrastruct ure
Civil engineering work
Diversion of river
Barrages, intakes
Spillways
Power house architecture
.
Mechanical and electrical
equipment
Administration,
engineering
and
supervision
lntcrcsts during construction
(10
years)
Total
4)
1'1;1nt-Cliurchil! Falls. I.;ibrrtdor,
C:inad;t,
Churchill Rivcr:
I1
=
312111;
P=
11
.483
MW.
Funds rcquirctl for
Rsscrvriirs
Powcr plant
and
gcncrritors
Switchyard
arid
transmission
Pcrmanen t support
facilities
Tcmporary facilities and services
P4anngcment and cnginccring
Escalation
Con
tingcncy
Direct construction cost
Intcrest during construction 189
IZdrninistr:it.ion, overheads, rniscellancous
8
2
-
'fotal
936
Pcrccntagc
of
total cost
12,3
%
17,9%
107
%
2,7%
8,8
%
3,3
%
10,9
%
4,3
%
--
71,0%
F-~nds crigin:t!ly available:
Equity paid
8
3
7,7
%
I\lIortgagz bonds
690
64,3
%
Retained earnings during construction 150 14,O
%
Bank financing zvailable
150
l4,O
%
-
Total
--
1073
*)
For
detailed informrtt;ons on item
I)
and
2)
the author is greatly indettcd to Mr.
J.
Grijt~er,
superintendent
of
Elec!romechanic Equipment. Rhein-htain-Ilonau
AG,
Miinchen, Fcdcral Republic of Germany. Informations
on
itan
3)
from differcrt Brazilian
and
West German sources. Informations on itern
4)
from a special
publication of
Churchill Falls Lahrador Corporation,
New
Foundland, Canada.
of
cost, in a medium head giant plant like ltaipli only
4,5
%.
But there instcad of the gates
anti
the power house in the low head plant, the barrage appears which takes
17%
of the
cost. This seems to be comparable with
21
%
needed in a low head plant for civil
engineering
work ai the head water reservoir
mainly
consisting in the erection of side
dikcs,
wl~ici~ functio~~ as
a
dam just as the barrage does at Itaipu.
2.2.4.
Eco~lomic zppraisal of
the
projects2)
2.2.4.1.
The
present
value
method
To establish the economic feasibility of
a
project, the assets and liabilities which occur
during its
plannins, construction and useful life have to be accounted for. By way of
comparison, the cash flow of the project has to be
exprcsseh by its present values.
A
hydro-power project is
an
investmen!. To realize it, the owner has
to
invest capital at
a
certain interest rate. This involves his intention to obtain monetary benefits during the
usefill life of the project. The latter generally differs from the pay-off period, determined
by
the moment
at
which the sum of cash flow surmounts the sum of investment.
2,
l'his subchaprsr was stimulated
by
a
lecture Prof.
E.
A4osunji
held about this topic
in
November
1981
in Haus
der Technik in Essen, Federal Republic
of
Germany.
On
this occasion the author would like
to
thank
Prof.
E.
~Uosotrji
for having reviewcd this section.