GDF Suez has sold 50 percent of its Portuguese thermal and renewable power holdings at time when electricity consumption is rebounding in the hard-hit country.

The French energy company announced Monday it had sold a half share of its 3,300-megawatt Portuguese subsidiary National Power International Holdings B.V. to Japanese trading house Marubeni as part of efforts to reduce debt.

GDF Suez President Jean-Francois Cirelli said in a statement the deal represents "the first long-term partnership with Marubeni in Europe and enables the group to consolidate its presence in Portugal and pursue the ambition to develop its European renewable energy activities."

The affected assets comprise about 17 percent of the power generation capacity in Portugal -- a vital part of the basic power infrastructure in the country.

They include stakes in a balanced set of coal- and gas-fired thermal power plants with a capacity of 2,400 megawatts, and renewable assets (mainly wind) with a capacity of 900 megawatts.

The French and Japanese companies will co-manage the power plants, providing for their "seamless and efficient operation," resulting in a reduced debt load of nearly $800 million for GDF Suez this year, with a further $400 million reduction in 2014, Cirelli said.

Meanwhile, Marubeni is looking to increase its global holdings in renewable energy and came only a day after it announced it was spending $150 million for a 25-percent stake in the Ireland's Mainstream Renewable Power.

In Portugal, Japanese investment comes as the recession-plagued country is finally seeing a halt to a steep decline in its electricity demand during the last two years.

Grid operator Redes Energeticas Nacionais said consumption rose in July for the third time this year -- up by 3.3 percent over the same period last year following similar rebounds in March and April, the Portuguese news agency Lusa reported.

REN President Rui Carterton said the increased power demand indicated "the worst of the economic downturn has passed.

"What we have observed is that the level of negative changes began to soften for three or four months," he said. "We cannot conclude from energy consumption that the economy is in recovery, but we can conclude that the deterioration of the situation was almost stagnant."

Portugal has 4,460 megawatts of installed wind power, employing thousands in a country where unemployment is nearly 18 percent, but is frequently oversupplied and needs to export the power to foreign markets due to its own flagging demand.

The Marubeni investment came shortly after the Portuguese wind power consortium ENEOP -- which this year secured $400 million to develop the third and final tranche of a 1,200 megawatt project - said it plans to export 50 percent of its 2013 output.

ENEOP President Anibal Fernandes told Lusa there is still room for a further 500 megawatts of future wind generating capacity in the country, which his consortium would consider developing.

But because Portugal was forced to place a moratorium on feed-in tariffs for new developments as part of last year's $103 billion European Union bailout, as well as a continuing squeeze on project financing, the tranche will probably be the only significant expansion of its wind power capacity in the short and medium terms, Windpower Monthly reported.