transmission & distribution
Bridging the Brazilian power gap1 January 2010
The development of Brazil’s power infrastrucure has broken several world records. The next one will fall in 2012 when the world’s longest HVDC interconnector comes on line.
The complex of hydroelectric plants being built on the Rio Madeira totals 6.5 GWe in capacity, mainly from the 3.3 GW Jirau dam and the 3.15 GW Santo Antônio dam. They are situated near Porto Velho in the northwest of Brazil close to the confluence of the Madeira with the Itenez and Baures rivers.
Its power output is destined mainly for delivery to São Paulo, Brazil’s most populous city, in the far south east of the country. To carry the electricity from Porto Velho to São Paulo requires the construction of an entirely new transmission link. It will consist of 2x600 kV DC bipole lines each of 2375 km and when finished will be the longest HVDC connector anywhere in the world.
Development of Brazil’s infrastructure
The Rio Madeira power line is a part of the expansion of Brazil’s system, designed with two main objectives – electrification of some less developed areas, and the reduction of GHG emissions by increasing the reach of green power from the country’s hydroelectric resource.
The Madeira river is a major waterway in South America, approximately 3380 km (2100 miles) long and the longest tributary of Amazon. The enormous Madeira River complex, in the tri-border region of Peru, Bolivia, and Brazil is, as well as a keystone of Brazil’s economic well-being, an anchor project in South America’s Integrated Regional Infrastructure for South America (IIRSA) tranche of projects. It would transform the Madre de Dios-Beni-Mamoré-Itenez-Madeira river system into a major corridor for energy production and raw material export. The proposal includes the construction of four hydroelectric dams, most importantly the Santo Antônio and Jirau dams in Rondônia, Brazil. Together, these two dams would produce a projected 6450 MW of hydroelectricity, 8% of Brazil’s capacity and equal to half of the electricity produced by the Itaipu dam in the Brazilian state of Paraná, the world’s second largest hydroelectric power plant after Three Gorges.
It is powered by a gigantic water resource. The Madeira receives the drainage of the north-eastern slopes of the Andes from Santa Cruz de la Sierra to Cuzco, the whole of the south-western slope of Brazilian Mato Grosso and the northern slope of the Chiquitos sierras. In total, the catchment area is
850 000 km2, almost equal in area to France and Spain combined. The mean inter-annual precipitations in the great basins vary (from 750 to 3000 mm) but the upper Madeira basin as a whole receives 1705 mm per year with extremes of 500 mm and more than 7000 mm. At its head, the Madeira on its own is still one of the largest rivers of the world, with a mean inter-annual discharge of 17000 m3/s, that is, 536 m3/yr, approximately half the discharge of the Congo River in Africa.
The new link is a major part of a more general plan to strengthen the Brazilian transmission network in the Amazonian basin and extend its reach into areas of the country not yet electrified or only connected to fossil fired power stations. For example the Tucurui-Macapa-Manaus interconnection line, part of the ‘Light for all’ programme of the National Electric Energy Agency of Brazil (ANEEL), is currently under construction. Hopes are high that it will be accepted as a UN Clean Development Mechnaism project. The objective of the line is to extend the interconnected system of Brazil’s grid to the regions of Manaus, Macapa and the villages on the left bank of the Amazon. Fossil fuels, mainly coal, are what generates most of their current supply of electricity.
In July 2007 the plans to construct two dams for hydroelectric power on the Madeira River were approved by the Brazilian government. There was, and still is, opposition from environmental groups which are concerned about the impact that the construction could have, citing threats to fish species migration, deforestation, and pressure on conservation areas and on the territories presently occupied by indigenous peoples.
Most of the Madeira output will be transmitted through two identical 3150 MW HVDC bipoles from the northwest to the southeast of Brazil, allowing integration with the SIN (National Interconnected System). In the São Paulo area a proportion of the power will be distributed via a back-to-back link to the local AC network.
The contracts for the interconnector have been split between two separate construction groups. The first bipole and the back-to-back link are to be supplied by a consortium consisting of two companies in the Abengoa Group, Inabensa S.A (Spain) and Abengoa Construção Brasil Ltd (Brazil), and it has awarded contracts worth over $540 million to ABB to deliver the technology. ABB will supply the power equipment for three HVDC substations. Two substations are to be situated one at each end of the new power highway at Coletora Porto Velho and Araraquara, serving one of the bipoles. The third station will be an 800 MW back-to-back link to transmit power to the surrounding asynchronous 230 kV AC network in the south east of Brazil. The three stations are scheduled for completion in 2012. The 3150 MW capacity rectifier station, which is in the 500 kV AC line that connects the hydroelectric plants, will operate at AC/DC, 500/600 kV, while the 2950 MW inverter station will operate at DC/AC, 600/500 kV.
IE Madeira is responsible for the second 600 kV HVDC bipole, and has awarded the supply contract, worth approximately US$400 million, to Areva T&D. Areva’s contract includes all the equipment, engineering, erection supervision, pre-commissioning and commissioning of the Porto Velho (Rondonia) collector substation in the northwest and the Araraquara II substation in Sao Paulo, which are to be delivered for commercial operation in April 2013.
The new link will be the second 600 kV HVDC transmission connector in Brazil, the Itaipu project built in the mid '80s being the first. The Itaipu connector transmits power from the huge Itaipu dam, until recently the world's largest, on the Brazil-Paraguay border to São Paulo and consists of two transmission lines built by ABB in 1984 and 1987, and is still one of the world’s highest-voltage DC power transmission systems currently in operation. Power is transmitted at very high voltage to minimise transmission losses, which are largely heat losses proportional to the square of the transmission current. ABB pioneered HVDC transmission technology more than 50 years ago and remains a world leader in the technology.
The transmission project, and the associated hydropower projects on the Madeira river including the 3.15 GW Santo Antônio plant and the 3.3 GW Jirau project, are part of the Brazilian government’s growth acceleration programme (PAC) launched in 2007 on a very wide front. It is a mix of tax incentives and public and private investment in the country’s infrastructure with the aim of improving its economic growth by an additional 0.5% per year.
W hy HVDC?
‘HVDC technology is ideally suited for the efficient transmission of renewable energy generated in remote areas, such as hydropower’ said Peter Leupp, head of ABB’s Power Systems division. ‘With the Itaipu project celebrating 25 years of successful operation this year, ABB is proud to continue partnering Brazil in its ongoing efforts to strengthen the country's power network.’
HVDC is more expensive to build but has lower losses and a smaller footprint than AC transmission systems, and is able to stabilise intermittent power supplies that might otherwise disrupt the grid. For these reasons, it is the technology of choice for long-distance transmission projects to deliver electricity from remote generation sources to the load centres. .
Not everyone is in favour
The same line of argument being put forward in favour of this and similar connected schemes – that the Madeira river project would transform the Madre de Dios-Beni-Mamoré-Itenez-Madeira river system into a major corridor for energy production and raw material export – is being put forward by objectors as the main cause of irreparable damage. The scheme, they say, would also increase the capacity for transporting soybean, timber, and minerals to Pacific ports through the installation of navigation locks and dredging to open the river channel, and to connect with highways being built in the Peruvian and Bolivian Amazon.
Environmentalists have therfore been campaigning with great energy to stop the development, saying that the two dams are being built without regard for the environmental consequences, even though the dams will flood land in both countries. It would result in a potential 500 % growth of soybean transport from the current annual seven million tons to 35 million tons exported. Grupo André Maggi, the largest soybean producer in the world, has already received a loan from the International Finance Corporation of the World Bank (in 2004) of US$30 million to expand soybean production, which is one of the leading causes of deforestation in the Brazilian Amazon.
Many suspect that the project sponsors are after something more ambitious: opening the upper Madeira to navigation by fitting the dams with locks. The extra cost would be small, and lower transportation costs would encourage farmers to plant much more soya and grain – at the expense of the remaining rainforest.
The contribution of the Bolivian Andes represents 25% of the discharge of the entire upper Madeira basin.
Carbon trading specialist Zeroemissions estimates that on the 25 year project some 1 280 000 CERs will be generated per year. When the line concession period concludes it will become the property of the government of Brazil. It is presently in construction and is scheduled to be brought into operation in October 2011.