fea sibility study for optimisation of land drainage bby...
TRANSCRIPT
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asibility Stb
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e of the land. of wind energea in Dithmaras a result it cminantly supptigation area iower were reiency. The anuse in sustaina
Objectives at the coastsand to guaransystem of dpass the di
ainage is reqer level diffechanges in cotening of thewhich leads
climatic chanral drainage ough the uses results in grapidly.
& Stattegger (e– New Result
(2010), ISSN 0
tudy for Oby Using
Marie Naul
nstitute for Hychnische Univoastal Enginee
oasts secures tto guarantee adeep and cliof natural dr
presents an inhe drainage asnalyse sustainwable energy.
of drainage meFor this reaso
gy were carrierschen. It wascould be showlied by a windin Dithmarsch
eviewed for fenalysis indicaable drainage
secures the ntee a produitches and chke. Sluices
quired since terences. Nowoastal morphe sluice time s to a highernges such as(Maniak et ae of coastal great financi
eds.): ts in Coastal R0928-2734, IS
OptimisatRenewab
lin1 & Thor
ydraulic Enginersität Braunsering, Hambu
the drainage oa productive aimatic changerainage. A co
ntervention wissociations sinnable solution. ethods shows on, analyses oed out over a s found that thwn that the end energy planthen in Northereasibility andated that elecsystems.
drainage of uctive agriculhannels that are preferrethe sluice gawadays naturhology whereat low tide ar risk of flos the rise of al. 2005). A cpumping sta
ial burdens f
Research SBN 978-3-98
tion of Lable Energy
sten Albers
neering and Wschweig, Germurg University
of the marsh ragriculture. Ches such as thonventional sith a high en
nce the cost ofns in order to
that wind-drivof the energy period of threhere is a relat
nergy demandt. In addition rn Germany. T
d evaluated onctric wind pu
the marsh relture. Therefleads the w
d as drainagates close at hral drainage e the slope oand the amouooding since
the sea leveconventionalations represfor the draina
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and Drainy
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Water Resourcemany
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region along thanges in coahe sea level rsolution, replanergy demandf energy is incoptimise the
ven pumps aredemand of a
ee years in thetion between
d of a coastal a feasibility sThree alternatn the basis ofumping system
egion along fore in the hi
water to eithege structureshigh tide respusing sluice
of the outer dunt of water the run-offs
el will also lel solution, susents an inteage associati
nage
es,
gy, Germany
the North Seaastal morpholorise will leadacing sluices
d. This resultscreasing rapidland drainage
e highly relevpumping state coastal regiothe investigapumping stattudy was carrtives to use wf calculationsms were hig
the North Seinterland the
er sluices or s since no apectively opes is becomdeep is reducdischarge th
fs are not suead to degrauch as pumpiervention witions since th
a as ogy d to
by s in dly. e in
vant tion ons
ated tion ried
wind s of hly
ea as part e run-offs pumping
additional en at low ing more ced. As a
hat passes ufficiently adation or ing water th a high
he cost of
128
A new cthis purppumpingdocumenareas inrepresenthe wateanalyse renewab
InvestigDithmarGermanyhinterlansluices ofloods freconomiFor the catchmein more Steertlocmanagempumpingconditionthe nearb
Figure 1:
2 AnAs windthe energcarried ocounty D
concept for opose, wind eg stations. Tnted. For exn The Nethents hydro power discharge i
sustainable ble energy.
gation Arearschen is a coy (figure1). nd the run-ofor pumping sfrom inland ic sector of thfeasibility stnt area of 1.2detail. Due
ch is reducedment of this g station Hilln in form ofby sites.
Investigatio
nalysis of end energy was gy demand oout in more Dithmarschen
optimisation energy repre
The historicaample wind-erlands sincwer that coulis increased bsolutions in
a ounty on theThe coast ar
ffs are drainestations in ordischarges ahis region. tudy, the pum200 ha and thto changes
d and therefarea has to blgroven weref water level
on Area in Dit
nergy demaidentified as
of a pumpindetail over an.
of land drainesents one aal importanc-driven watece the 15th
ld be utilizedby a high lyin order to o
e North Sea rea consists ed off in a syrder to pass and to main
mping statiohe sluice Steof the coast
fore gravity dbe improvede used as a l differences
thmarschen, N
and of a pus being highl
ng station ana period of t
nage by usinappropriate ae of using w
er pumps havcentury. An
d within the ping polder. Toptimise the
coast of the of polder su
ystem of ditchthe dike. Th
ntain an effi
on Hillgroveneertloch withtal morpholodrainage bec
d and sustainfirst estimatiof high and
Northern Germ
umping statly relevant fod the energythree years i
ng renewablealternative aswind energyve been usednother possiprocess of a
Therefore the land draina
federal stateurrounded byhes and chan
his water manicient agricu
n with a pumh a catchmentogy the slopcomes insuffable solutionion of the pu
d low tide are
many
tion and suor drainage my supply of an the coasta
e energy is ths a possible
y for the drad in order toible renewacascading dr
e main objectage in coast
e Schleswig-y dikes as flnnels that leanagement is
ulture which
mping capact area of 6.30e of the outficient. For tns were analumping timee assumed to
pply of winmethods (IPAa wind energ
al regions of
Naulin
herefore reque energy resoainage of tho drain the lable energy rainage systetive of this sttal regions
-Holstein in flood defenceads the water
important torepresents
city of 160 k00 ha are invter deep of tthis reason, tlysed. The daes since the bo be almost
nd energy AT 1989), angy plant (WEthe North S
n & Albers
uired. For ource for e land is low lying
resource em where tudy is to by using
Northern es. In the r to either o prevent the main
kW and a vestigated the sluice the water ata of the boundary equal for
nalyses of EP) were
Sea in the
Feasibility
EnergyIn order producticonsumpanalysedDeich- uof the C(LKSH 2in Schles
Figure 2:
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Comparisonof Schleswitill 2007)
ults show seaas well as ofber a very lowf the mean annd amounts lly during this recorded. ing the monton 28 % of t
y Balance wults of the fidemand of as it is not pg station sincsuch as hou
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with Monththe distributan energy ba
oastal pumpinwere provid
elverband Dif Agriculturee the productiin.
n of energy deig-Holstein (A
asonal fluctuf the producw energy dennual need is39 % of thehe months JIn the same
ths October the annual de
with Hourlyirst energy ba pumping sossible to cce there is a urs. For this energy demariod of threeentage of enthe percentag
mand the datanage associa
Land Drainag
ly Data ion in time o
alance with mng station wided for the pithmarschene Schleswigion of wind
emand of a puAverage month
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e mean annuJanuary till e time periodtill Decembeemand respec
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umping stationhly values of
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he basis of mwind energyether the wion in wind stemporal re
mping stationm 2005 untily of a pumpimaining energ
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ation Hillgrore, the wind andwirtschafinvestigated
n and wind enthe annual de
tribution of tigure2). Durues of 3 % toing summer
During winterost half (46tion of wind y demand amuction.
monthly datay productionind energy sspeed with siesolution of n and the en 2007. The ing station thgy is that has
the coastal pielverband D
a pumping sd out. Therefo
a period fromoven by the data were taftskammer Sfor the coast
nergy productiemand/ produc
the energy dring summero 5 % and inthe producti
r time highe%) of the energy is al
mounts 32 %
a show the an. From thessupply woulignificant chthe calculat
nergy producmain goal o
hat can be ds to be taken
pumping statDithmarschen
station and thore the electrm 2005 till 2drainage as
aken from anSchleswig - tline of the N
ion along the wction for the y
demand of a r time from n total a percion of wind
er values are mean annualso slightly l
% and the win
annual distribse results of ld be sufficihanges in shotion is increction of a Wof this analydirectly covefrom the loc
tion Hillgrovn. In order to
129
he energy ric power 2007 was ssociation n analysis
Holstein North Sea
west coast years 2005
pumping April till entage of energy is reached.
al energy arger (33
nd energy
bution of f monthly ent for a
orter time eased and
WEP were ysis is to ered by a cal power
ven were o consider
130
a varian220 kW constantconstantIn reality
Figure 3:
nce in pumpto 660 kW. I
t value, viz. t value is equy the pump c
Electrical p2005, 2006system
ing power tIt should be 220 kW or
ualized to thecapacity is di
power supply 6 and 2007 di
the total engnoted that fo660 kW for e rate of the ivided into se
of a pumpingifferentiated in
gine power or the followeach calcularequired pumeveral pumps
station with an energy supp
of the pumping calculatiation. This cmp capacity s which are o
a constant pumply by a WEP
ps was rangions the pumcould be an depending ooperated as r
mp capacity oP (800 kW) a
Naulin
ged with valumping power i
overestimatin the catchm
required.
of 220 kW forand by the lo
n & Albers
ues from is set to a ion if the
ment area.
r the years cal power
Feasibility
For the ppower cuWEP theusing thdata werstation BAs an exof 220 kthat the eof WEP pumping660 kW.220 kW
3 FeaIn order and/or heconomistation wtransfer
Figure 4:
AlternaThe firstturbine possibiliwaterboais well apower owith hou86 % de
y Study for Op
production ourve relates e model Enere power curre measured
Büsum in Ditxample the rkW for the yeenergy demasupply was
g station. Fu. As a resultpumps and 7
asibility Stuto analyse d
hydro poweric efficiencywith WEP, (2and (3) casca
Sketches of
ative 1: pumt alternativeand the pumity to receiveard Bremischapproved. In f 560 kW av
urly data shoepending on t
ptimisation of L
of wind energwind speed trcon E 48 wi
rve of the mod by the Gerthmarschen. results in formears 2005 tilland of the pus calculated urthermore, int the mean a72.1 % for 66
udy for Dradifferent drair were reviey for the slu2) reservoir wading draina
f the alternativ
mping statie is composemps there ise energy fromher DeichverBremen the
verages 50 %wed for the the pumping
Land Drainag
gy the data wto the electriith 800 kW wodel E 48 horman Meteor m of the elecl 2007 are sh
umps can be pfrom 83.7 %n this calcul
annual power60 kW pump
ainage Metinage methoewed for feuice Steertlowith wind-d
age system us
ves analysed in
ion with Wed of a pums an electricm the power rband am ree energy sup% of the annusite in Dithm
g capacity ca
e
were estimateical power owind turbineourly data ofrological Se
ctrical supplhown with mpredominant
% (2006) up lation the pur supply by ps.
thods Usingods using renasibility and
och in Dithmdriven pump sing WEP an
n the feasibili
WEP mping stationc power transupply syste
chten Weserply of a WEual demand
marschen a han be expecte
ed using a poutput of a W
e was appliedf the mean wrvice Deutsc
ly of a pumpmonthly value
tly supplied bto 89.8 % (2
ump capacitythe WEP wa
g Renewabnewable enerd evaluated marschen as with a mech
nd hydro pow
ty study (with
n combined nsfer. Durinem. This alte
rufer for the EP (600 kW)(DVR-Brem
higher wind eed since the
ower curve oWEP. As an ed. As input dwind speed wcher Wetterd
ping station wes in figure 3by a WEP. In2007) of they was rangedas estimated
ble Energy rgy three alteon the basifollows (fi
hanical (a) orwer.
h M = motor a
with a WEPng windless ernative is alpumping sta) for the pum
men 2008). Aenergy supplycapacity of t
of a wind turbexample of aata of this cawere used. Tdienst at the
with an engin3. The diagran total the pe
e annual need from 220 kd between 86
ernatives to is of calculagure 4): (1) r electrical (
and G = gener
P. Between periods the
lready realiseation Wasserhmps with a toAs the energyy from abouthe WEP (80
131
bine. The a possible alculation The wind e weather
ne power ams show ercentage ed for the kW up to 6.5 % for
use wind ations of pumping
(b) power
ator)
the wind re is the ed by the horst and otal rated y balance
ut 72 % to 00 kW) is
132 Naulin & Albers
higher and the surface roughness of the terrain affects the wind to a lesser extent. For the catchment area of Steertloch the total required pump capacity was estimated to about 600 kW. This equates a possible wind energy supply from approx. 75 % which represents 240 MWh. Moreover, there is a remaining energy production of 2,400 MWh by the WEP.
Alternative 2: reservoir with wind-driven pump As the second alternative the feasibility of a reservoir with wind-driven pumps was examined. It is noted that a mechanical power transfer between the wind turbine and the pumps is not feasible since mechanical pumping systems only achieve a maximum of 10 kW as rated capacity (Gasch & Twele 2005) which falls below the value of the required pump capacity of 600 kW. With an electrical power transfer the alternative 2b corresponds to alternative 1 including an additional reservoir. By means of the reservoir there is the advantage of adopting the operation of the pumps. Since the water can be stored in the reservoir the pumping times are adjustable to periods with sufficient wind energy supply. For the existing reservoir of the sluice Steertloch the storage volume was calculated by an elevation model covering the data of the bathymetry and the terrain with the software ESRI ArcView. Between the water levels -1.5 mNN and 0.0 mNN the storage volume was estimated to 425,000 m³. With a design discharge of 12.6 m³/s the storage time amounts 9.3 hours. This alternative offers the use of control and feedback control systems where the operation of the pumps can be adjusted to the wind energy supply. Therefore the wind energy supply is estimated as a greater value than in alternative 1, viz. greater than 75 %.
Alternative 3: cascading drainage system using WEP and hydro power The third alternative is composed of a cascading drainage system using wind energy and hydro power. Therefore at first the water is pumped by a WEP into a high lying polder. From the higher polder the water can be drained by gravity and at the same time hydro power can be gained by powering a generator with the discharge of the water. As a type of generator, pumps as turbines can be applied since the boundary conditions of a changing flow rate and a low head have to be considered. Compared to the wind energy production with a total of 2,600 MWh the production of hydro power with 240 MWh is rather low.
4 Results Besides the review of technical feasibility the alternatives were evaluated on the basis of calculation of their economic efficiency. The costs have been estimated considering the investment and operating costs as well as the tariffs for wind energy and hydro power due to the Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz/ EEG). In order to give some example of the expanses the investment costs of a WEP comparable to the model Enercon E-48 (800 kW) amount to 1.2 million euro. The investment costs of the pumping system were neglected since these values are the same for each alternative. The operating costs mainly consist of energy costs which average up to 310,000 euro/year with an electricity tariff of 15 cent/kWh for a conventional pumping station. For wind energy the tariffs following EEG 2009 are summed up to 160,000 till 170,000 euro/year for a period of 20 years. The tariffs of hydro power result in a maximum of 30,000 euro/year. Table 1 shows the results in terms of the annuities for the different pump capacities of 220 kW and 660 kW. It can be seen that alternative 3 with the cascading drainage system using hydro power is not economic. By contrast the alternatives using energy of a WEP for a pumping system are profitable. In comparison with a conventional pumping system annual costs of up to 47,000 euro/year can be saved.
Feasibility Study for Optimisation of Land Drainage 133
Table 1: Results of evaluation of economic efficiency in terms of annuities considering investment, operating coast as well as tariffs for wind energy and hydro power after EEG (2009) for a period of 20 years
Pump capacity Alternative 0: Conventional
pumping station
Alternative 1: Pumping station
with WEP
Alternative 2: Reservoir with WEP
pumping system
Alternative 3: Cascading drainage using hydro power
220 kW -16,000 euro/year +20,000 euro/year > +20,000 euro/year -337,000 euro/year 660 kW -48,000 euro/year -1,000 euro/year < -1,000 euro/year -338,000 euro/year
5 Summary Wind energy was identified as being highly relevant for drainage methods, therefore analyses of the energy demand of a pumping station and the supply of wind energy were carried out over a period of three years in the coastal regions of the North Sea in Dithmarschen. It was found that there is a relation between the investigated quantities and as a result it could be shown that the energy demand of a coastal pumping station could be predominantly supplied by a wind energy plant. Three alternatives to use wind and/ or hydro power were reviewed for feasibility and evaluated on the basis of calculations of economic efficiency. The analysis indicates that electric wind pumping systems are highly appropriate for use in sustainable drainage systems and from the economic point of view the annual costs can be reduced by a factor of 48 compared to conventional pumping systems.
References DVR-Bremen (2008): Bremischer Deichverband am rechten Weserufer. Personal communication with Mr.
Döscher and Mr. Dülge at May 30th 2008. Gasch, R. & J. Twele (2005): Windkraftanlagen,. Teubner Verlag, Wiesbaden, 540 S. IPAT - Internationale Projektgruppe für angepasste Technologien (1989): Der Einsatz von Windpumpsystemen
zur Be- und Entwässerung. Fachbereich Internationale Agrarentwicklung der TU Berlin. Berlin, 219 S. LKSH - Landwirtschaftskammer Schleswig-Holstein (2008): Windenergie XX Praxisergebnisse 2007,, 98 S. Maniak, U., A. Weihrauch & G. Riedel (2005): Die wasserwirtschaftliche Situation in der Unterwesermarsch
unter der Einwirkung der Klimaänderung. In: Schuchardt, B.& M. Schirmer (Hrsg.): Klimawandel und Küste, Die Zukunft der Unterweserregion. Springer Verlag, Berlin und Heidelberg, S. 79–100.
Acknowledgement The work has been carried out as part of the first authors diploma thesis at the Hamburg University of Technology in collaboration with the water board Deich- und Hauptsielverband Dithmarschen. The supervision and provision of data by the latter is gratefully acknowledged. Moreover, special thanks for additional support goes to DVR Bremen, Enercon, Köster Heide, KSB, BSU and FHTW.
Address Marie Naulin Technische Universität Braunschweig, Leichtweiss-Institute for Hydraulic Engineering and Water Resources Beethovenstrasse 51 a 38106 Braunschweig, Germany