* Risk of power cut unless SAfricans save energy
* Voluntary power savings miss target
* SAfrica least energy efficient nation in Africa
By James Macharia
JOHANNESBURG, April 2 (Reuters) - South Africa's energy minister said on Thursday the country was still in the grip of a major power crisis despite being able to keep the lights on since a series of blackouts early last year.
Voluntary energy savings had failed to meet the required levels, and the country was risking new power cuts, the Minister of Minerals and Energy, Buyelwa Sonjica said in a statement.
State-owned utility Eskom [ESCJ.UL, which provides 95 percent of the country's power, has rationed electricity since early last year, but has not cut power since last April.
Sonjica said Africa's biggest economy was suffering from a perilously low electricity reserve margin or spare capacity.
"The recent lack of blackouts has led to the assumption that our energy situation has been resolved," Sonjica said.
"Unfortunately this is far from the truth. We are in trouble unless we all begin to take responsibility for our habits of energy wastage."
Two years ago, Sonjica urged South Africans to save 10 percent of their electricity usage every year for the next five years but so far energy savings were way below that, she said.
Sonjica said a healthy electricity reserve margin was about 17 to 20 percent, to ensure that sudden changes in demand or supply and power-plant maintenance do not cause blackouts.
Eskom said in January the reserve margin was about 8 percent, and has said its long term target is 15 percent.
She said following the success of the Earth Hour over the weekend, and with winter fast approaching, she wanted South Africans to save power to ensure stable electricity supply.
Lights went out in homes across the globe on Saturday for Earth Hour 2009, a global event designed to highlight the threat from climate change.
Sonjica said the Earth Hour initiative would promote awareness that the country still faced a serious energy crisis because South Africa's record on energy conservation was poor.
"South Africa is one of the least energy efficient nations in the world and the least efficient in Africa," she said.
"We also hold the number 11 spot on the top 20 greenhouse gas emitters list and are responsible for 42 percent of Africa's emissions. Every kilowatt of electricity you use produces 1 kg of carbon dioxide; one of the main greenhouse gases."
Critics say the energy crisis that dented South Africa's growth and investor-friendly image was caused by the government's failure to invest in new power generation plants, coupled with surging demand led to the power crisis.
Mines, some smelters and big industrial operations have been receiving about 90 to 95 percent of their power requirements since the blackouts in January last year.
The government offered a mea culpa, saying it ignored warnings from experts to build new power plants. It has warned that the crisis could last until 2013, but added that plans to host the 2010 Soccer World Cup should be unaffected.
Eskom plans to spend 343 billion rand ($37.19 billion) on a five-year investment programme, to boost power generation.
(Reporting by James Macharia, Editing by Peter Blackburn)