The blackout that hit several parts of the country on Tuesday was due to a fault in the power distribution lines, Energy Cabinet Secretary Charles Keter has said.
Mr Keter said the distribution line from the Olkaria geothermal station -- one of the country's main power suppliers -- to a sub-station in Nairobi, was cut off after its conductors blew, leading to an overload in the system.
And since the power distribution system in Kenya is interconnected, the problem was transferred to several parts of the country, he said.
"The dual line from Olkaria, carried about 250mw each. And after one of the lines failed, the load was transferred to the other line, which, due to the overload, equally collapsed," said the CS.
Speaking in Nairobi, during a tour of the Juja sub-station, where the lines were cut off, Mr Keter, however, said the system had been restored and power redistributed to the affected regions.
"But it is also important to note that this station was built a long time ago," he said.
Several towns, including Nairobi, and shopping centres across the country were thrown into darkness on Tuesday evening, leading to closure of businesses and disrupting services. Some of the traders said they recorded losses due to the outage.
Mr Keter said plans to upgrade and digitise the Juja station were under way to avert a similar occurrence.
The CS spoke as a section of opposition MPs asked the National Assembly to summon him over increased power bills.
Mr Keter had on Monday attributed the increase in charges to an ongoing upgrade of Kenya Power's billing system, denying claims of a change in tariff or backdating of electricity bills.
Gem MP Elisha Odhiambo and his nominated counterpart Godfrey Osotsi dismissed an earlier explanation by the CS, saying it did not add up, as the system upgrade was supposed to lead to efficiency and better service provision and not increased electricity bills.
The MPs also want the Kenya Power managing director Ken Tarus and director-general of the Energy Regulatory Commission (ERC) Robert Oimeke summoned by the parliamentary Committee on Energy for subjecting low-income Kenyans to high electricity charges.
"Kenyans demand a proper explanation from the CS, Kenya Power and ERC," said Mr Odhiambo, a member of the Energy committee.