Water Power and Dam Construction. Issue April 2009

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DIARY

Let IWP&DC’s readers know about your forthcoming conferences and events.

For publication in a future issue, send your diary dates to: Carrieann Davies, IWP&DC, Progressive Media Markets Ltd, Progressive House,

2 Maidstone Road, Foots Cray, Sidcup, Kent, DA14 5HZ, UK. Alternatively, email: cdavies@wilmington.co.uk, or fax:+44 208 269 7804

DIARY OF EVENTS

Hydrogeology

Saskatoon, SK, Canada

CONTACT: University of

Saskatchewanm, Canada

Email: cynthia.hanke@usask.ca

http://www.engr.usask.ca/aquitards

14-16 June

1st Int ernational Conference on

Civil Engineering – Towar ds a

Better Future, Coimbra, Portugal

CONTACT: Conference

Secretariat, CI-Premier Pte Ltd,

150 Or chard Road, #07-14,

Orchard Plaza, Singapore 238841.

Tel: +65 6733 2922.

Fax: +65 6235 3530.

Email: cipremie@singnet.com.sg.

http://www.cipremier.com.

17-19 June

4th International Con ference on

The Concrete Future,

Coimbra, Portugal

CONTACT: Conference Secretariat

CI-Premier Pte Ltd

(address details as above).

Email: cipremie@singnet.com.sg.

24-26 June

IHA Congress 2009

Reykjavik, Iceland

CONTACT:

International Hydropower

Association, Fifth Floor West,

Nine Sutton Court Road,

Sutton, Surrey. United Kingdom,

SM1 4SZ.

Tel: +44 20 8652 5290.

Fax: +44 20 8770 1744.

Email: iha@hydropower.org.

www.hydropower.org.

July

20-22 July

Conference on High Strength Steels

for Hydropower Plants

Takasaki, Japan

CONTACT: Prof. Dr. Kohsuke

Horikawa, The Committee for

HSS Conference, Suite 801, Sannoh

2-6-2, Ohta-Ku, Tokyo, Japan

143-0023.

Tel: +81 3 3774 2361.

Fax: + 81 75 581 7776.

info@hss-conference.org. jp.

http://www.hss-conference. org.

27-30 July

Waterpower XVI

Spokane, Washington, US

CO NTACT: HCI Public ations,

410 Archibald Street, Kansas City,

MO 641 11, US.

Email: info@hcipub.com.

www.hcipub.com.

BHA Conference 2009

Liverpool, UK

CONTACT: Ellan Parry, British

Hydropower A ssociation.

www.british-hydr o.org.

26-28 October

Hydro 2009

Lyon, France

CONTACT: Aqua-Media

International Ltd, 123 Westmead

Road, Sutton, Surrey, SM1 4JH

Tel: +44 20 8643 5133.

edit@hydropower-d ams.com.

October

14-15 October

12 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

INSIGHT

HE UK government’s 2006 Energy

Review resulted in an investigation

of tidal power opportunities by its

independent wat chdog, the

Sustainable Development Commission, and

its report in 2007 conclud ed, with con di-

tions, that there is a strong case for a sus-

tainable Severn Barrage, and also potential

for barrages in other locations such as the

Mersey, Wyre and Thames rivers.

The government then launched a two-year

feasibility study, being carried out by

Parsons-Brinkerhoff, to investigate the costs,

benefits and impact of a Severn tidal power

scheme, to determine whether or not it could

support such a scheme, and if so, on what

terms. The study began in January 2008. It

has now gone into a public consultation

phase covering the selection process, the pro-

posed shortlist, and the issues proposed for

further investigation. The decision as to

whether or not to support a Severn tidal

power scheme will be taken following fur-

ther consideration of the issues and a second

public consultation, probably in 2010.

ONG LIST

Ten schemes were put forward following a

Call for Proposals in May 2008, including

barrages, lagoons (land-connected and off-

shore), a tidal fence and a tidal reef. These

proposed schemes were in varying stages of

development, with some us ing tried and

tested technology, and othe rs usi ng tested

structures, but com pletely new materials.

Some proposals were based on embryonic

technologies which have never been proto-

typed or deployed, let alone at the huge scale

proposed. The largest schemes span the

Estuary from Minehead t o Aberthaw (15

miles) while the smallest lie upstream of the

Severn road crossings. Energy outputs also

vary with the largest op tion (the Outer

Barrage) estimated to generate up to 7% of

UK electricity and the smallest roughly the

same as a large fossil fuel power plant.

EASIBILITY CRITERIA

The ten long-listed proposals were assessed

for t heir feasibility. In the context of the

study, feasibility means whether the project

has a realistic prosp ect of being built and

whether it could meet the objectives of the

study. Five key areas were identified as deter-

mining feasibility:

• Technical risk.

• The cost and amount of energy produced.

• Affordability and value for money for the

public sector.

• The environmental impacts.

• Regional level economic and social impacts.

HORT LIST

The short-listed schemes are all barrage or

lagoon schemes based on relatively well under-

stood hydroelectric technologies with a mix of

existing and new engineering structures. Not

all barrage and lagoon schemes have been

short-listed. Some do not perform well in terms

of the assessment criteria as they show, for

example, extremely high cost of energy pro-

duced. Schemes involving new or untried tech-

nology such as the tidal reef or the tidal fence

options, have not been included, but the UK

government is keen to consider innovative

schemes that may be less environmentally

damaging, and some of those that have been

submitted to the feasibility study, although not

sufficiently developed technically at this point

for more detailed evaluation, may re-appear if

further development, supported by a fund set

up for the purpose, bears fruit.

The short-listed Cardiff-Weston barrage,

with an e stimated const ruction cost of

around £21B (US$30M), is something of a

special case . It would be more than fiv e

Bristol Channel

0 6 miles

Mouth of

the Severn

Swansea

Bridgend

Bristol

Clevedol

Weston-Super-Mare

Burnham-on-Sea

Cardiff

Penarth

Newport

M48

WALES

ENGLAND

Shoots

barrage

Cardiff-Weston

barrage

Shoots barrage

Beachley barrage

Bridgwater

Bay lagoon

Fleming lagoon

Five into Severn may go

The Severn Estuary’s 14m tidal range represents a huge source of predictable (though

intermittent) low-carbon energy. The UK government’s feasibility and consultation

process – which will take several years to come to a conclusion about whether to pro-

ceed with the exploitation of this potential – has compiled a short list of five schemes

selected from ten contenders. Report by Leonard Sanford

Map of Bristol Channel and Severn Estuary showing the short listed proposals

Table 1. The long list

Route Proposals (notes, proposer)

Minehead to Aberthaw Outer barrage (25 TWh/y)

Tidal fence (3.5 TWh/y, an array of tidal stream turbines, Pulse Tidal)

Tidal reef (20TWh/y, rotating turbine modules, Evans Engineering)

Cardiff to Weston Conventional barrage, Lavernock Point to Brean Down (17 TWh/y)

Variant of above with causeway and other facilities (Severn Lakes)

Tidal Fence, (3.5 TWh/y, array of tidal stream turbines, Severn Tidal Fence Gp)

Barrage variant, Cardiff to Hinkley Point (better flood defence, Shawater)

Upper Estuary Shoots, conventional barrage (2.77 TWh/y)

Beachley barrage (Like Shoots but doesn’t cut off River Wye)

Welsh Grounds tidal impoundment (3.0 TWh/y, Fleming Energy)

Tidal lagoons (various, including those proposed by Tidal Electric)

bank of the Estuary with an estimated con-

struction cost of £4B [US$5.7B])

•

Cardiff-Weston (Lavernock Point to Brean

Down) Barrage (8.46GW scheme, com-

monly known as the ‘Severn Barrage’, with

an estimated cost of construction of £20.9B

[US$29.9B ]) being considered for a 2030

timescale.

This technical feasibility assessment is the first

of several such procedures, and will be fol-

lowed by a quantitative study (energy outputs

and CO

savings), levelised cost estimates, and

a qualitative study (environmental, social/

regional and economic effects.

HE SURVIVING CANDIDATES

Beachley is the small es t barrage alignment

considered by the study (625MW) and is

located furthest upstream. This means it

does not impact on the maj or ports and

causes the least, although still potentially sig-

nificant, intertidal habitat loss as it is locat-

INSIGHT

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 13

times the cost of other schemes on the pro-

posed shortlist. Unlike the other options, its

construction could not be funded by the pri-

vate sector alone and taxpayers/consumers

would likely bear a large part of the cost

burden and risk. However, this barrage

could also make a significant contribution

to the UK’s energy goals and will therefore

be studied further. This will allow the scale

of enviro nmental impact and options for

mitigation and compensation to be studied.

EXT PHASE

The next phase of the feasibility study will

make a strategic environmental assessment,

considering the impacts of the various short-

listed schemes – impact on the construction

supply chain, on the energy market and grid,

and on the ecosystem. The consequences of

compliance with environmental protection

legislation and the means of ensuring that

environmental effects could be mitigated

where possible, and compensated for if they

cannot be mitigated, will also be considered.

A further public consultation, pro b a b l y in

2010, will seek views on the evidence gath-

ered and the analysis, and will feed into the

decision on whether a scheme could be

taken forward with government support.

The option not to proceed with any scheme

remains open. If a Severn tidal power pro-

ject does go ahead, the plan ning and con-

senting process may tak e 3-5 yea rs, an d

construction at least a further 5-7 years,

depending on the scheme selected.

EDUCING TEN TO FIVE

The ten proposals were assessed for technical

and commercial feasibility against a number

of criteria, (see above) and the following

schemes were provisionally short-listed:

• Shoots Barrage (1.05GW scheme located

downstream of the new Severn road

cros sing with an estimated construction

cost of £3.2B [US$4.6B])

• Beachley Barrage (625MW scheme further

upstream of the first Severn road bridge

with an estimated cost of construction of

£2.3B [US$3.3B])

• Bridgwater Bay Lagoon (1.36GW

impoundment on the Eng lish side of the

estuary with an estimated construction

cost of £3.8B [US$5.4B])

• Fleming Lag oon on Welsh Grounds

(1.36GW impoundment on the Welsh

ed upstream of the confluence with the River

Wye and might have a reduced effect on that

iver. Some fish mortality is still likely. This

option would have a smaller energy output

than the majority of other schemes – at least

90% smaller than the e stimated output of

the barrage from Minehead-Aberthaw. It is

the cheapest in terms of capital cost and the

unit cost of energy is a little higher than

Cardiff-Weston, and lower than Bridgwater

Bay lagoon. It is, therefore, one of the most

affordable options. There are concerns over

the potential build up of sediment behind a

barrage at Beachley, which may impact on

future maintenance costs and feasibility. This

needs to be studied further. Given the afford-

ability, unit cost and relatively smaller envi-

ronmental and shipping impact, this option

was included in the short-list despite its rel-

atively small energy output.

Shoots is the largest barrage that could be

taken forward with limited government

involvement in risk and cost bearing. T he

Concrete

structure

housing sluices

and turbines on

a small barrage

such as Shoots

Background to the study

Is a tidal scheme needed?

There is some doubt about how much a tidal scheme is needed. The draft Renewable Energy Strategy

suggests that the scheme may not be essential to meeting 2020 renewables targets and must be

assessed against other alternatives. Parsons Brinkerhoff’s analysis of comparative costs shows that

while Severn tidal power is expensive compared to other renewable sources it could reduce the cost of

meeting the UK’s renewable energy target of supplying 15% of energy from renewable sources by 2020.

Risks and benefits

Careful consideration of the benefits, consequences, risks and costs is needed. The Severn Estuar y,

which could be altered utterly, is an internationally important nature conservation site. Flood risk impacts

have been considered. Some land drainage systems would be affected and might require pumped

drainage as a remedy.

Expected social and economic benefits include £620M (US$887M) to £3.5B (US$5B) injected into local

economies, and new road and rail links that might be needed after 2025 or so.

Finance

It is estimated that all proposals would require some government support through planning and possibly

construction phases owing to their high capital costs and the scale of regulatory risks, particularly on the

environmental side, to be borne by consumers and taxpayers. The private sector could operate any

scheme constructed. For the smaller schemes with an estimated constr uction cost of £2-4 billion the

private sector could reasonably be expected to own, finance and take on most of the construction risk,

provided there is sufficient revenue certainty. However, a larger scheme (such as the Cardiff-Weston

barrage, (£20.9B [US$29.9B], a figure that includes the estimated cost of compensator y habitats) with

annual output of 17 TWh would need government assistance to finance its construction. All proposed

schemes would require revenue support during the financing lifetime (the first 35 years) to remain

competitive with non-r enewable sources. Beyond this period, the schemes could generate power for a low

upkeep cost for the remainder of their estimated 120 year minimum lifespan.

Some schemes could work in combination; for example a lagoon with a barrage further upstream or a

combination of lagoons. Such options will be considered by the feasibility study.

Transmission

A Severn tidal power project would also require investment in new transmission assets, mainly grid

connections, depending on the size and location of the scheme. The balancing of intermittent but

predictable power generation and demand will require consideration, particularly for the larger schemes.

These aspects will be considered in greater detail in the next phase of the feasibility study.

Table 2. Summary of

short-listed proposals

Project Installed Cost

construction capacity

Shoots barrage 1.05 GW £3.2B

Beachley barrage 625 MW £2.3B

Fleming lagoon 1.36 GW £4B

Bridgewater Bay lagoon 1.36 GW £3.8B

Cardiff-Weston barrage 8.64 GW £20.9B

14 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

INSIGHT

unit cost s of energy are the cheapest esti-

mated for all the Severn options. These fac-

tors combine to make it one of the most

affordable. It does not directly impede the

major ports in the Estuary. Initial figures

show that intertidal habitat loss may be

smaller than similar output lagoon options,

although this remains significant, as do cur-

rent estimates of impact on fish. Shoots

shares the sediment risk of the Beachley bar-

rage. Given the relatively low unit costs of

energy and capital cost, this option was pro-

posed for inclusion in the short-list.

ardiff-Weston (Lavernock Point – Brean

Down) barrage could provide 4.8% of the

UK’s electricity (based on estimated demand

in 2020). The sheer scale of the capital cost

is very challenging, estimated at between

£19.6B (US$28B) and £22.2B

(US$31.75B)0, depending on compensatory

measures. Unit cost of energy figures are

well below the co st thresho lds set and are

the second cheapest of all the schemes.

Cardiff-Weston could result in up to an

estimated 20,000ha loss of intertidal habi-

Table 3. Performance of shortlisted proposals against assessment criteria

Note: Minehead to Aber thaw tidal reef (not short-listed) is included only for purposes of comparison

Project Cost of Technical Affordability Environmental impact Regional economic and

energy risk social impacts

Intertidal Summar y Value of construction job

habitat creation par tially offset by:

loss (ha)

Minehead to High High Difficult All of pre-construction risk Unknown Less habitat loss and less Navigation impacts not

Aberthaw and most of construction risk detriment to wildlife than studied. May be less

tidal reef borne by the public sector other options detriment to fisheries.

Cardiff-Weston Low Low Difficult Pre-construction risk entir ely 20000 Major habitat loss and Adds time and cost to main

barrage borne by public sector, potential impact on wildlife four ports access.

to share some construction risk Impact on fisheries and fishing

Shoots Low Low-Med Medium Shared public/private 5000 Lower impact on Upstr eam of busiest ports; still

barrage pre-construction risk. No intertidal habitat and adds time and cost to Sharpness.

construction risk exposure impact on wildlife Impact on fisheries and fishing

Beachley Low Low-Med Easier Shared public/private 3500 Lower impact on inter Upstream of largest ports;

barrage pre-construction risk. No tidal habitat; less damage to adds time and cost to Sharpness.

construction risk exposure migrator y fish Impact on fisheries and fishing

Russell lagoon Medium Low-Med Medium Shared public/private 6500 Significant loss of habitat; May be less detriment to local ports

Fleming Energy pre-construction risk. No impact on fish uncertain but and fisheries than large barrages

construction risk exposure may be less than barrages

Bridgewater Bay Low Low Medium Shared public/private 5500 Significant loss of habitat; May be less detriment to local ports

pre-construction risk. No barrages the River Parrott and fisheries than large barrages

construction risk exposure impact on fish uncertain but

may be less than barrages

Computer realisation of the lock gate of the

Cardiff-Weston Barrage

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 15

INSIGHT

tat with significant damage to wildlife, and

particularly migratory fish species as the bar-

rier would be downstream of the tributary

rivers of the Severn. It may offer tidal flood

protection to the Gwent Leve ls and

Avonmouth. During its operation ships

docking at the regions m ajor ports would

have to pass through loc ks, which would

add time and cost to their operation.

However, the overall regional economic

impact of a Cardiff–Weston barrage is esti-

mated to be substantially positive.

A Cardiff–Weston barrage could be gen-

rating by 2020, e v e n if not fully commis-

sioned. However, this would be a best case

scenario. There would still be a risk that it

would not contribute significantly towards

the 2020 renewables target.

Providing over £2 0B of finance for

Cardiff-Weston, either publicly or privately,

would be very challenging and it is unlikely

that the private sector could carry this risk

alone. Taxpayers /consumers would likel y

bear a large part of the cost burden and risk.

The government will need to consider the

macro-economic and fiscal impact this scale

of spending and risk exposure would have

on a 2020 timeframe. In this context, it may

also be appropriate to consider the feasibil-

ity of the Cardiff–Weston barrage on a

slightly longer timescale, nearer to 2030.

iven the potential broad similari t i e s in

environmental and regional impact, it was

considered appropriate to study the lagoons

that performed well in terms of the short-

listing criteria and ha ve the potential to

work in combinat ion with other options

(thereby producing more energy or energy

at peak times) as the representative options.

These are the Bridgwater Bay lagoon from

the generic lagoons and the Fleming Lagoon

at Welsh Grounds.

They a re estimated to produce broadly

similar energy outputs to each othe r,

although are of sligh tly la rger i nstalled

capacity than the Shoots barrage.

Comparing each lagoon against Shoots

helps inform what difference there is

between the impacts of a lagoon vers us a

barrage. Each performs well on the short-

listing criteria. The Bridgwater Bay lagoon

has the lowest cost of energy out of all the

lagoons and could potentially connect more

easily to the existing electricity infrastructure

at Hinkley Point. While the Fleming lagoon,

located on the Welsh side of the Estuary in

elatively shallow water uses a different form

of wall constru ction, costs are within the

cost thresholds set.

As with all the other ty pes of schemes

(barrages, lag oons, fences, reefs), there

may be the potential to build a lagoon at

different locations but a detailed unde r-

tanding of the technology and impact of

th e lagoon concept gained from studying

tw o schemes further was con sidered nec-

essary for this feasibility study and for sup-

porting a de cision on whether lagoons

could be the preferred opti on.

Leonard Sanford is Deputy Editor of

IWP&DC’s sister publication,

Modern Power Systems. For more

information on this journal, visit

www.modernpowersystems.com

IWP& DC

Top: Sluice and turbine caissons on a lagoon; Bottom: Lagoon overview

Carbon payback

The payback period of carbon costs induced by

the production, transportation and construction

of the materials to be used at the Severn

Barrage project would be less than six months,

according to a recent study published in The

Chartered Institution of Water and

Environmental Managements (CIWEM) Water

and Environment Journal.

The barrage would mainly be formed of

reinforced concrete caissons constructed at

many shore based yards and towed to the site.

It would require over 200 large water turbines

and electrical generators and 166 sluice gates.

The carbon content of producing these

materials, transporting them to plant fabrication

yards, manufacturing and constructing the units

of equipment, and transpor ting the products to

site for final assembly and installation have

been quantified by Charlie Woollcombe-Adams,

Michael Watson and Tom Shaw FCIWEM.

In just over four and a half months the barrage

can be expected to have paid back the carbon

costs incurred from the sourcing of materials,

manufacture of components and their

transportation to the barrage site.

When including the on-site works used to

construct the barrage, this increases the

payback period to five and a half months.

Constructing the Severn Barrage would take

about nine years but power generation could

begin before the barrage is completed as long

as it is ‘closed’. Hence the barrage could begin

its carbon payback when still incomplete and

less than a year of operating at 85% annual

output, it will have paid back the construction-

related costs of the whole project.

Compared with its construction, the annual

carbon cost of its operation is nominal.

For further details, visit www.ciwem.org

16 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

SOUTH AMERICA

thought that they had heard the last of Garabi, as previous attempts

to reach a development agreement have floundered because of fears

that the Uruguai River is already too heavily dammed. It is believed

that thousands of people would have to move and 33,000ha of land,

much of it agricultural, will be flooded but the prospect of securing

2800MW of additional generating capacity could prove tempting

to the two governments concerned, both of which have rapidly

growing economies and demand for electricity.

Argenti ne President Cristina Kirchner Ferna ndez has t alked of

Garabi as a means of promoting closer ties with Brazil. Speaking at

a meeting on the project with Brazil’s President Luiz Ignacio Lula da

Silva, she commented: “If we deepen the integration process, if we

[capitalise on] the complementary nature of our industries, we’re

going to sort out our differences. We are going to sort out our dif-

ferences, because the deeper our integration the less reason there will

be for some nay sayers, some minorities, who keep hoping that we

can’t deepen Mercosur”, referring to the regional trade organisa-

tion. Mercosu r has repeatedly sought to promote closer regional

integration through cross-border power projects, including new

hydro schemes.

That South America’s two biggest economies and traditional rivals

are considering closer hydro sector cooperation is further evidence

of the slow but steady improvement in international relations in the

region. The swing to the left in the political landscape may have made

some difference but most South American leaders do not share the

socialist and nationalising zeal of Venezuela’s Hugo Chavez or

Bolivia’s Evo Morales. Brazil’s Lula and Argentina’s Kirchner

OWER sector integration in South America has long attract-

ed support from some of the continent’s most prominent

leaders, yet political differences and have delayed progress

to date. However, a combination of successful cooperation

in the hydro sector and the election of a raft of left leaning govern-

ments in recent years once again offer the prospect of a truly conti-

nental power pool that would allow hydroelectricity to be marketed

across the continent where it is most needed.

Perhaps the most outstanding example of cross-border power sector

cooperation in the region is the 14GW Itaipu project on the Parana

River on the border between Paraguay and Brazil. Operational since

1991, the scheme has just enjoyed its most productive year yet on the

back of exceptionally high rainfall. Output for 2008 reached a stag-

gering 94,685GWh, helped by the installation of two additional

715MW Francis turbines in the past three years.

Itaipu provides 19% of all power consumed in Brazil and its suc-

cessful development and operation has encouraged Brasilia to inves-

tigate the possibility of tapping more of the hydroelectric potential

in its borderlands. The most prospective o ption at present is the

Garabi scheme on the Uruguai River on the border with Argentina.

The latter already operates two binational projects, the 3200MW

Yacyreta scheme with Paraguay and the 1890MW Salto Grande ven-

ture with Uruguay. In January, Brasilia and Buenos Aires signed a

preliminary agreement to develop the Garabi scheme, but this will

not necessarily lead to actual construction, as the project has been

on the drawing board for more than three decades.

Environmental non-governmenta l org anisations may have

Despite widespread cross-border problems, South America has more than its fair share

of major bilateral hydro schemes. Itaipu remains one of the region’s largest hydro

ventures, but what other schemes are on the cards? Neil Ford reports

Conflict and cooperation

in South America

but other foreign f irms may be deterred f rom investing in future

hydro and other infrastructural projects in the country.

ROGRESS ON

ADEIRA

While Ecuador’s hydro industry faces an insecure future, the pace of

dam construction in Brazil has certainly picked up, partly on the back

of the Madeira scheme in Rondonia State, which is the biggest hydro

scheme currently under development anywhere in South America.

Located on the Madeira River close to the Bolivian border, it comprises

the 3330MW Jirau and 3150MW Santo Antonio projects. In February,

BNDES agreed to provide a $3B loan to Jirau, equivalent to more than

two-thirds of total project costs of $4.38B. Jirau is being developed by

consortium comprising French firm GDF Suez (50.1%), Brazilian

power companies Eletrosul (20%) and Chesf (20%), plus Brazilian

construction firm Camargo Correa (9.9%), which collectively won a

30-year concession to develop and operate the scheme in May last year.

BNDES has already agreed to provide a $2.55B loan to the San

Antonio development consortium of power companies Furnas and

Cemig, construction firms Odebrecht and Andrade Gutierrez, plus

banks Santander and Banif. Construction will be carried out by a

wide ranging consortium c alled Consorci o Constr utor Santo

Antonio (CCSA), which comprises Odebrecht, Andrade Gutierrez,

Alstom Hydro Energia Brasil, Areva Transmissao and Distribuicao

de Energia, Siemens, Andritz Hydro, Voith Hydro and Bardella.

A $318M contract to supply electromechanical equipment, includ-

ing twelve bulb turbine generators, to Santo Antonio was awarded

to Andritz VA Tech Hydro (now Andritz Hydro) in November.

Promoting the technology on offer, an Andritz spokesperson com-

mented that the 72MW bulb units “are particularly suitable for low

heads a nd thus for hydroelectric projects that utilise large water

flows, such as in the Madeira River. These units provide high effi-

ciency, since they remain entirely submerged in the water, thus being

capable of handling large water flow variations”.

Alstom Hydro is providing a further 19 bulb turbines from its

engineering plant close to São Paulo in Brazil, and describe these

units as “indicated for low fall, high flow rivers, which is the case

with the Madeira River. The reservoir, in the case of bulb type tur-

bines, requires a smaller area thus minimizing socio-environmental

impacts.” According to the company, bulb type turbines have been

far less popular in South America than in Europe or North America

in the past, so it appears to consider Santo Antonio an excellent

opportunity to promote the techn ology more widely across the

region.

The first of Jirau’s 44 turbines are scheduled to come on stream

in 2013, with the first San Antonio turbine due to produce electric-

ity one year earlier. Electricity from both halves of the Madeira ven-

ture will be widely marketed once a new 2375km transmission line

is completed. The interconnector is to be developed in seven sections

by companies licensed by national power sector regulator, Agência

Nacional de Energia Elétrica (Aneel), following the completion of a

contract tender in December. Successful bidders secured the con-

tracts with bids ranging from $6.2M up to $69.5M, depending on

the length and technical difficulty of each section.

Environmental opposition to the entire Madeira scheme has been

huge, both within Brazil and in neighbouring Bolivia. Critics fear that

the river’s very diverse fish life could be affected, while the malaria

risk could increase as mosquitoes thrive in the new reservoir that will

be created. In addition, thousands of people have been displaced. The

companies involved in dam construction have already run into prob-

lems and the Jirau consortium was fined $208,000 in February for

destroying about 47 acres of primary rainforest in a nature reserve

that lay outside its concession. It has also been fined $3.35M for

killing an estimated 11 tons of fish by using dynamite. Environmental

NGOs fear that the entire ecosystem of the western Amazon Basin

could be affected by the project as a whole.

Newly merged French conglomerate GDF Suez already has

6.9GW of installed cap a c ity in B ra z i l and i s currently developing

new dams elsewhere in the country, including the 1087MW Estreito

and 241MW Sao Salvador plants on the River Tocantins in north-

Fernandez are far more pragmatic in their economic policies and their

refusal to challenge the power of foreign companies in all sectors has

disappointed their more hard line counterparts further north.

The clash of political ideologies has most recently been seen in the

hydro sector in the dispute over Brazilian firm Odebrecht’s operations

in Ecuador. Since gaining power in January 2007, Ecuador’s President

Rafael Correa has pledged to reduce poverty and curtail private sector

influence, thereby gaining the support of the radical governments in

Venezuela and Bolivia. Last September, a dispute between the gov-

ernment and Odebrecht saw the army seize control of the Baba, San

Francisco and Toachi-Pilaton hydro schemes, all of which are being

– or have been – developed by consortia led by the Brazilian firm.

San Francisco came on stream in May 2007 with 230MW of gen-

erating capacity but the government complained that it was not as

reliable as had been promised. Quito demanded that the firm return

a payment made for completing the run of river project nine months

early and provided a list of improvements that it insisted were

required to both turbines and dam infrastructure. While it is diffi-

cult to assess the validity of Quito’s complaints, Odebrecht appears

to be the victim of the government’s determination to take a firm

stand on private sector concessions and distance itself from contracts

awarded by the previous government.

Although the firm took the lead on the development of the project,

it only held a minority stake in the Hidropastaza joint venture that

operates San Francisco, with Ecuador’s state owned utility

Hidroagoyan owning the remaining equity. The joint venture holds a

30 year concession to operate San Francisco and was awarded all three

hydro licences by the previous administration. The fate of the other

two projects, which are still under development, is not yet known.

The con tractual dispute has also affected relation s betwee n

Ecuador and Brazil. When ordering the army takeover, Quito

stopped payments to Brazi l’s national develo pment bank, Banco

Nacional de Desenvolvimento Economico e Social (BNDES), which

had provided a $243M loan to help fund San Francisco, turning the

country’s hydro sector i nto the focus of a heated diplomatic

exchange. Brasilia withdrew its ambassador to Ecuador last

November bu t he return ed in January after payments to BNDES

were resumed. The long term fate of Odebrecht’s operations in the

country, which are valued at a total of $800M, remains uncertain

WWW.WATERPOWERMAGAZINE.COM APRIL 2009 17

SOUTH AMERICA

Construction underway at the Sao Salvador

project on the Tocantins River, Northern Brazil

18 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

ern Brazil. The former is being de veloped by Consorcio Estreito

Energia (Ceste), which is a consortium of GDF Suez offshoot Suez

Energy South Am erica Particpacoes, Alcoa Al luminio, Camargo

Correa Energia and Companhia Vale do Rio Doce (CVRD). Ceste

was awarded the concession in 2002 and subsequently allocated the

main construction contract on the project, worth $324M, to a joint

venture of OAS and Impregilo of Italy.

A price tag of $395M has been put o n Sao Salvador, which is

being constructed by the French firm’s subsidiary, Tractebel Energia.

After years of delays, the Brazilian organisation responsible for

licensing hydro schemes, Instituto Brasileiro do Meio Ambiente e

dos Recursos Naturais Renováveis (Ibama) granted a four year con-

struction licence for the project, while Tractebel already holds a 30-

year operating permit starting in 2011, which it acquired with a bid

of $2.58B. The French firm revealed in late November that it had

already completed much of the construction work on the dam.

GDF Suez is also one of the most likely developers of a series of

new hydro schemes in Peru. The government has published plans

for ten new project s, including the 1355MW Inamba ri and

1379MW Paquitzapango ventures, both of which Lima would like

to be brought on stream by 2014. More rapid progress on award-

ing concessions and contracts is required if this tight deadline is to

be achieved. The French company’s most likely competitor in Peru

is Eletrobras but it has been reported that GDF Suez’s subsidiary,

Suez Energy Peru, is restricting its interest to three dam proposals in

the south of the country which would primarily be developed to

supply the mining indus try. Lima has a lready revealed that

Electrobras is expected to bid for five projects, which would have

combined generating capacity of 1570MW.

MPSA HYDRO SECURES DEALS IN THE NORTH

Endesa Chile is currently the dominant investor in the Colombian

hydro sec tor, where it operates the 1163MW Guavio, 541MW

Betania, 324MW Guaca and 276 MW Paraiso projects. However,

the biggest hydroelectric venture currently under development in the

country, the 844MW Porce III hydro scheme, is being developed by

Colombian power company EPM (Public Companies of Medellin)

in Antioquia City in Los Andes region in north of the country

Most power generation equipment on the project is being designed

and supplied by Impsa Hydro for EPM. Impsa Hydro delivered the

first of four Francis turbines to the project in January, with the others

due to follow during the course of this year. The turbines, which are

being developed at Impsa’s factory in Mendoza, Argentina, are each

rated at 211MW and all are expected to come on stream by mid-

2010. Output is expected to average 4300GWh a year

The Argentine firm has established itself as a m a j o r equipment

supplier to the hydro sector in South America, providing turbines

for use on the 270MW Dardanelos and 312MW Simplicio schemes

n Brazil, plus the 150MW Acaray project in Paraguay, but it is in

Venezuela that it has become involved in larger projects, supplying

the 498 MW Macag ua I and 22 30MW Tocoma schemes. Despite

Venezuela’s commitment to state ownership of key assets, the Chavez

government is more than willing to award engineering and con-

struction contracts on new dams to foreign firms. However, given

the war of words that has dominated relations between Caracas and

ashington in recent years, it is noteworthy that it is Latin American

rather than US firms that secure deals.

Impsa Hydro has already begin to install some equipment at the

Manuel Piar hydroelectric power plant on the Tocoma scheme.

Following a competi tive tender, it secured a turnkey contract in

January last year to supply electromechanical equipment to state

owned power company CVG Electrificacion del Caroni (Edelca) for

the scheme, including ten turbines each rated at 223MW, making

them the largest Kaplan units in the world. The turbines are to be

located on the Caroní River, about 15km downstream from the Guri

dam, in Bolívar State of southeastern Venezuela.

The Andean Development Corporation (CAF) has provided a mas-

sive $900M to help finance the venture, in two tranches of $300M in

2004 and $600M in 2008, although the government of Venezuela puts

the total cost of the project at $3.06B. CAF agreed to back the venture

to “increase the efficiency and reliability of the Venezuelan National

Electricity System…improve the electricity supply in this member coun-

try and promote development of regional energy infrastructure.”

Venezuela already sources 75% of its electricity from three exist-

ing hydro projects on the Caroní River: the Guri, Macagua and

Caruachi schemes, so CVG Edelca will increase its dependence on

the river even more once Manuel Piar is completed in 2014. By that

date, 16,130MW of generating capacity will be installed on the river,

although no more dams ar e planne d for the lower river basin. In

January this year, th e Inter-American Development Bank (IADB)

awarded the government of Venezuela a $14M loan to improve

water management in the Caroní Basin in order to maximise hydro-

electric production on the four hydro projects and improve living

conditions for local communities.

UTLOOK

South America’s emerging economies are likely to be required to at

least minimise their greenhouse gas emissions when the successor

agreement to the Kyoto Protocol is drawn up over the next three

years. Further hydro schemes on the continent’s many large rivers

could therefore help to provide low carbon, base load generating

capacity, but the key to ensuring their successful operation is main-

taining high levels of environmental protection at and around dam

sites, and implementing any possible measures to mitigate negative

impact of large dam construction. As a result of global warming, the

international community seems more than prepared to accept large

dam projects as an environmentally acceptable means of producing

electricity but this should not be taken to suggest that they are intrin-

sically environmentally responsible.

The governments of South America can also use such large pro-

jects to promote power sector int egration, both w ithin do mestic

markets and across the region as a w hole. Jirau, Sa nto Antonio,

Tocom a and Garabi would all benefit from having access to a

number of national markets in order to ensure their long term com-

mercial success. Particularly where several gigawatts of generating

capacity are located in a single location, it is often prudent to have

several transmission lines to provide access to different markets, so

hydro schemes can drive power sector and even more general eco-

nomic integration of the kind that has been discussed ever since the

South American states gained independence, but towards which so

little progress has thus far been made.

SOUTH AMERICA

IWP& DC

The Itaipu project, on the border of Paraguay and Brazil

THE HYDROPOWER

LEADER

S T R A T E G Y

M A N A G E M E N T

C O N S U L T I N G

E N G I N E E R I N G

C O N S T R U C T I O N

mwhglobal.com

312.831.3515

MWH, the wet infrastructure leader, builds, improves and retro ts

hydropower projects to provide clean, renewable energy. By

maximizing available sources of clean energy, we help clients

optimize the use of natural resources with sustainable techniques.

Our focus: conservation and control of the world’s irreplaceable

resource — water. Our goal: Building A Better World.

A R O U N D T H E W O R L D

20 APRIL 2009 INTERNATIONAL WATER POWER & DAM CONSTRUCTION

DESIGN

THIOPIA

’

S HYDRO POWER COMMITMENT

The Federal Democratic Republic of Ethiopia is a land-locked repub-

lic in the ‘Horn of Africa’. The current republic was formed after the

fall of the ‘Derg Regime’ in 1991. The country has a population of

approximately 78 million.

Ethiopia is a country whose location and high mountainous areas

provide a vast hydroelectric potential that is estimated to exceed

40,000MW. After the ‘Derg’, the government of Ethiopia made its

first priority that of overcoming the environmental, financial, and

technical obstacles necessary for the implementation of several major

hydroelectric developments. To alleviate Ethiopia’s present shortage

of generating capacity, EEPCO’s financial resources were focused

on the early completion of the Tekeze hydro power project.

Innovative modific ations were made during the construction

period to expedite the completion of Tekeze Dam, such as a modi-

fied river diversion scheme, staged dam construction, and the staged

impoundment of the reservoir.

EKEZE CONTRACTORS

The Tekeze project is be ing funded entirely by the Federal

Democratic Government of Ethiopia. The total project construction

HE Tekeze Dam is located on the Tekeze River in the

Northern Tigre Region of Ethiopia. The Tekeze and

Atabara Rivers originate in the Simien mountains of

Ethiopia. Each of these Rivers are little known but are key

tributaries to the 6650km long Nile River. They are also separate

from the White and Blue Nile tributaries. Since ancient times, the

Nile has supported the many civilizations that surround it. The Blue

Nile combined with the Tekeze/Atabara Rivers provide most of the

water and silt in their seasonal runs to the Nile. Most of the rainfall

(89%) arrives with the East African Monsoon during the months of

July, August, and September.

The White Nile is the longest tributary and rises from the Great

Lakes region of central Africa, with the most distant source in south-

ern Rwanda. The White Nile flows north through Tanzania, Lake

Victoria, Uganda and southern Sudan, then meets up with the Blue

Nile in Khartoum, the capital of the Sudan. The Tekeze River orig-

inates in the Northeastern slopes of the Simien Mountains, then

flows out of Ethiopia and into the Atbara River which later joins the

Nile River at a point approximately 322km downstream of

Khartoum, such that it feeds into the Merowe Reservoir.

El.1049 average dam height July 2007

Low block

el.1031 spillway

Upstream

rubber

waterstop

350mm

Stoplog

groove

Gallery P Grouting pipes

983

985

959.50

971.00

Temporary openings, deleted

Stoplog groove

1065

1025

1,039.2

Max. overtopping flood

1300m

/sec

August 9

2007

Dam status as July 2007 flood season Finished dam Feb 2009 Tekeze dam crown cantilever section

Maximum operating

surcharge 1144.00

11145.00 dam crest

1140.00 normal maximum pool

El. 1115 projected

@ end of 2009

End of 2008

el. 1086.60

3,178 million m

LLO wheel gates

LLO radial gates

Mol 1096.00

1031.70

971.00 tailpond

971.00

957.00

957.00 dam base

953.59 sump

959.50

Active storage 5,343 million m

Dead storage 3,967 million m

Dam axis

Gallery 1105

Gallery 1025

Gallery 985

Cantilever centre line

Compensation bypass

HB valve

971.00

–

1058.00

Hydro power in Ethiopia – the staged

construction of Tekeze Arch Dam

Upon completion at the end of February 2009, the Tekeze Concrete Arch Dam in Ethiopia

became the highest dam on the African Continent. Here James R Stevenson and Mihret

Debebe provide further details of the staged construction and filling sequence for the dam,

while summarizing and updating the status of the power projects currently underway in

the Federal Democratic Republic of Ethiopia by the Ethiopian Electric Power Corporation

Table 1: Project contracts

Lot No. Description of the Works Contractor

Consultant Final Design Engineering Montgomery Watson Harza

and Construction (MWH) with Energoprojekt

Management (Serbia)

Initial Design Advanced Feasibility Studies Howard Humphreys & Partners

initial dam design layouts Coyne et Bellier

and civil works arrangements Rust, Kennedy & Donkin

Lot 1A Advance Infrastructure Berta Construction (Ethiopia)

Works – Site Access Road

Lot 1B/2/3 Major Civil Works (including CWGS Joint Venture

camp, dam, powerhouse, (China & Ethiopia)

tunnels & offices) Primary Civil Contractor

Sinohydro – CWHEC of China

Dam Contractor – CGGC of China

Lot 4/5 Powerhouse Mechanical China Wanbao Engineering

Equipment Powerhouse Corporation (CWBEC) of China

Electrical Equipment

Lot 6 Substation Plant and JPPC & CCC (China)

Civil Works

Lot 7 Overhead Transmission Lines JPPC (China)

Figure 1 – Sections through the

Tekeze Dam crown cantilever