The company is to produce a 154-metre rotor for the machine, up from 136 metres on the original model. The blades will be made from carbon fibre, same as before.
A spokesperson for the manufacturer told Windpower Monthly that a prototype of the new model is expected to be up and running in Chinese waters next year.
The company believes that the new turbine will be better suited to Chinese offshore conditions, where winds are lighter than in Europe. The new turbine will have an IEC class of Ib compared with the previous model's Ia status.
United Power installed a prototype of the initial 6MW offshore turbine on the beach of Weifang in east China's Shandong province in 2012. The company has not installed any more of the model since, and has no concrete orders at present, the spokesperson said.
The turbine is variable-speed and uses a doubly-fed induction generator.
The company also confirmed that it is still working on a design for a 12MW turbine, but said that this is still at the concept stage, with no concrete plans to produce a prototype.