Renewable energy has failed to provide energy when Eskom most needed it, CEO Brian Molefe said on Thursday.

Speaking at its quarterly “state of the system” briefing in Cape Town, Molefe said renewable energy is like a very old cellphone. The technology has not yet developed enough for it to perform efficiently and make a meaningful contribution to electricity supply in the country.

He said renewable energy is in practice available from 9am to 3pm, which is not when Eskom needs it. Solar power is only available when the sun shines, which excludes the evening peak in winter. Wind power is at its best in the early hours of the morning and late at night, when Eskom has surplus power.

“To rely on renewables on a day like today is very clumsy,” he said.

He said renewable energy was expected to deliver the 3GW of generation capacity Eskom needed to avert load shedding. It delivered it during the day, but not when Eskom needed it at the evening peak around 6pm.

He said renewable energy will improve in the next 10 years with the development of storage, which will make it available during peak consumption periods. He compared it with old cellphones that have been optimised as technology has advanced.

Molefe said Eskom is forced to buy electricity from renewable projects at a higher cost than its own generation when it has excess capacity of its own. To add insult to injury, it was forced to sign 20-year power purchase agreements, at the end of which the assets will be transferred to Eskom.

At that stage, the technology will be out of date and the assets will be useless. “We will be like somebody who has an old phone, while everybody else has an iPhone,” he said.

Eskom is committed to the success of the renewable programme and will try to ensure that the right technology is being deployed. “At the moment there is a mismatch between what it was supposed to achieve and the reality,” he said.

Molefe said Eskom will nevertheless remain interested in renewables and has allocated R1bn to research on, among other things, renewable energy.

Eskom has already connected 46 out of more than 100 renewable projects to the grid. It had to strengthen the grid for this purpose and is ready to accommodate all projects up to bid window 4.5 of the department of energy’s renewable procurement programme.

According to Eskom’s integrated report, the renewable projects performed at an average load factor of 31% in 2014/2015.