Apple has been testing both forms of charging as a way of combating the short battery life typically seen in many smartwatches on the market.
The iWatch’s launch date is expected to be sometime in 2014.
According to the paper, the three alternative charging methods are seen as a way for Apple to overcome one of the major complaints about smartwatches.
Of all three charging options, the solar option is the most obvious. The wireless charging method is expected to make use of a magnetic induction charging plate.
As for the kinetic method, it is expected to use a very similar method to that already used in many watches. According to the paper, it will “charge the battery through movement,” the Times said.
“A person’s arm swinging could operate a tiny charging station that pushes power to the device while walking,” it added. Apple is understood to have filed a patent describing such an approach in 2009.
The paper also quoted Nest founder and “one of the fathers of the iPod” Tony Fadell as saying that Apple has been working for years on making a smarter battery. However, according to Fadell, the company had failed to make a breakthrough while he was still working there.
The report also repeated earlier rumours that the device will come with curved glass.