PARIS — As the world's political leaders debate ways to alleviate poverty in Africa, industrialists are moving ahead with their own designs for pan-African development - including the building of the world's largest hydroelectric dam at a bend in the Congo River, between Kinshasa, the capital of the Democratic Republic of Congo, and the Atlantic Ocean.

Called Grand Inga, this giant dam will cost $80 billion to build and will have twice the installed generating capacity of the current record-holder, the Three Gorges Dam in China. Grand Inga would produce enough electricity to serve all of the more than 500 million Africans who currently go without.

While it remains to be seen whether recent leaps in transmission technology are sufficient to carry electricity over Africa's vast distances and physical barriers like the blistering sands of the Sahara, power-hungry countries as far away as Egypt and Nigeria are interested in Grand Inga's potential supply.

"This is a Marshall Plan for Africa," said Gerald Doucet, secretary general of the World Energy Council, the overseer of the project, which is being developed with Westcor - a consortium of power companies from neighboring countries including Namibia, Angola and South Africa - and with international power and engineering giants, including ABB of Sweden, E.ON of Germany, EDF of France, Union Fenosa of Spain and SNC-Lavalin of Canada.

Grand Inga is one of a growing list of large dams under development or serious discussion in Africa, where private investors and development banks are re-examining the potential of "big hydro" to help counter a worsening power shortage.

The World Bank and its lending arm, the IFC, along with the African Development Bank, private investors, power companies and, increasingly, Chinese hydroelectric concerns are the major players.

The amount of hydropower under construction in Africa jumped 53 percent from 2004 to last year, according to the Hydropower & Dams World Atlas and Industry Guide, an industry reference journal. But environmental watchdogs and other nongovernment organizations say that, unlike oil and gas development, the planning process for hydropower lacks transparency and the number of dams under development in Africa is difficult to pinpoint.

Armed with a wealth of experience in constructing large hydro dams, Chinese companies are signing on to projects in many African countries, often as elements of infrastructure investment packages in oil-producing countries. For example, China plans to build and finance a $1.5 billion, 2,000-megawatt plant in the Mambila Plateau in Nigeria, in a deal that also includes Chinese imports of the country's oil and rights to exploit four oil blocks.

Apart from Chinese projects, the World Bank recently approved a $360 million package of loans and guarantees for Bujagali, a 250-megawatt hydro plant on the Nile at Lake Victoria in Uganda that will cost $799 million to build. Uganda, with the fastest growing population in East Africa, has regular rolling blackouts and only one percent of the rural population has access to electricity.

The World Bank also made a $297 million grant to refurbish two existing hydropower plants on a site near Grand Inga last month, as part of a $500 million package co-financed with the African Development Bank to repair damage and silting that occurred over the past decade, during Congo's civil wars.

"Interest in the importance of hydropower has been slowly re-emerging over the past five years," said Philippe Benoit, Inga project manager at the World Bank.

Large dams became controversial in the 1980s and 1990s as environmental and civil rights organizations focused attention on issues like the damage done to rivers, watersheds and aquatic ecosystems, poorly designed resettlement strategies, failure to share economic benefits with affected communities, weak government controls and corruption.

Compensation claims from past projects linger. For example, 50 years after the Kariba Dam was built on the Zambezi River, in what is now Zambia, 57,000 people who were resettled to make way for the dam are asking the World Bank and other parties for compensation because their new agricultural lands are less productive, according to the International Rivers Network.