Saudi Arabia's sovereign wealth fund and the SoftBank Group Corp. of Japan announced plans last night for what would become the world's largest solar power project in the kingdom, developing 200 gigawatts of new solar power capacity by 2030, the Wall Street Journal reports.

Why it matters: If the plan actually comes to pass, well, that's a lot of solar. By way of comparison, the U.S. added a total of 10.6 GW of new solar PV capacity last year, according to a recent industry report. Plus — it also underscores Saudi Arabia's efforts to diversify its oil-dependent economy.

One level deeper: Saudi Crown Prince Mohammed bin Salman and SoftBank CEO Masayoshi Son jointly announced the plan in New York.

• According to the WSJ and other reports, the total costs are estimated at $200 billion, with an initial $5 billion stage beginning construction this year that's designed to bring 7.2 GW online in 2019.

Huge: Bloomberg points out Saudi Arabia only has small-scale solar projects there now. And, Reuters has more good context on the project's projected scope.

• "That would add to around 400 GW of globally installed solar power capacity and is comparable to the world’s total nuclear power capacity of around 390 GW as of the end of 2016," Reuters writes.