By Guy De Launey
BBC News in Phnom Penh
People who live in Phnom Penh are used to the odd power cut, but the past few months have really tested their patience.
Generators are filling Phnom Penh's pavements
Two or three times a day an enormous groan can be heard on the streets of the city, as the electricity goes off once again.
It was not always this way. At the start of the decade Phnom Penh enjoyed a stable power supply for the first time in 30 years.
Over the past 12 months, however, candles and battery-powered lights have once again become essential items for home and business alike. The blackouts have lasted for up to four hours at a stretch.
For many businesses the power cuts have come at the worst possible time: the height of the tourist season. Just when there are scores of customers to be had, the shops and restaurants have been plunged into humid darkness.
Internet cafes are frequently unable to offer anything other than blank computer screens. Travel agents complain of missing out on sales because their booking systems are down. The fact that they are hot and sweaty as well just adds insult to injury.
The heart of the tourist district, the riverfront, has been plunged into darkness on a regular basis, making dining by candlelight a necessity rather than a choice.
With tourism the the country's second-biggest industry, this kind of poor impression is set to cause damage that goes far beyond individual businesses.
"It's a disaster," says Giorgio Arcasi from behind the bar in his riverfront restaurant, Pop Cafe.
"I can't buy ice cream any more, because after one day it melts. It's so bad for business. In April or May, if you don't have a generator you'll have to close."
It is both a blessing - and something of a surprise - that the blackouts have struck during the relatively cool months. Towards the middle of the year, temperatures soar above 40 degrees on a daily basis, and air conditioners place an even greater strain on the power supply.
Many people have decided that the situation is more likely to get worse than improve, and shops selling generators have been enjoying something of a boom. Machines of all shapes and sizes now add to the pavement clutter, and clatter away during the blackouts.
Electricite du Cambodge, the state-owned organisation responsible for power generation, has been unable to respond to the problems.
Its deputy director general, Yim Nolson, admits that there was no spare capacity in a system which should ideally have a 15% power reserve.
He believes that a rise in fuel prices has prompted businesses that usually rely on their own generators to switch to mains electricity, creating a demand the system could not meet.
This view evokes little sympathy from Cambodia's main industry, the garment sector. The country's power costs are among the highest in the region, dulling the competitive edge of factories fighting for orders against China and Vietnam.
Small businesses are feeling the strain as the tourists sweat
"Electricity costs represent 30% of our total expenses," one garment factory manager told BBC News.
"It eats all your profits, and we don't have any control. They can cut the electricity whenever they want. So you have to have a generator, and this adds a lot of costs."
Power problems have undoubtedly played a part in deterring would-be investors from coming in to Cambodia.
Both the cost and reliability of supplies compare unfavourably with neighbouring countries like Vietnam and Thailand - and the picture gets even worse outside Phnom Penh, with less than a fifth of the country as a whole has power.
Electricite du Cambodge admits that power station breakdowns have played a part in the electricity shortages. There have been accusations that poor maintenance and a lack of spare parts have made the situation worse.
A new power station is due to come on line by the middle of the year, but Yim Nolson thinks that any extra capacity will be absorbed within months.
It seems the groans, and the clattering emanating from the generators are set to continue.