Saudi Arabia and Japanese conglomerate SoftBank set out plans to deploy 200GW of PV in the Middle Eastern kingdom by 2030.

The massive solar build – equivalent to roughly double the entire global capacity additions seen in 2017 – will cost $200bn, SoftBank CEO Masayoshi Son told reporters in New York, where he unveiled the plans.

The initiative will be backed by Softbank’s Vision Fund technology investment vehicle, with a first 7.2GW phase costing $5bn, Son said.

Saudi Crown Prince Mohammed Bin Salman told the event sealing a memorandum of understanding that the solar build plan marked “a huge step in human history”.

The MoU would cover extensive local equipment production and energy storage, the partners said.

The scale of the planned expansion would be matched only by China, which already has more than 130GW of solar in place.

Oil-rich – and sun-blessed – Saudi Arabia has pursued an increasingly ambitious renewables programme, including wind and solar tender rounds designed to propel it to 9.5GW of renewable energy capacity by 2023.

Its energy minister described renewables as “a new engine of growth” when he launched the programme in early 2017.

However, some analysts urged caution over even that 9.5GW goal – small beer compared to the target outlined today – pointing out that the kingdom had a track record of false starts in the clean energy sector.

SoftBank has emerged as an increasingly active player in global renewables under Son, a strong advocate for clean energy who has already taken the telecoms-led group into the Indian solar sector.