The companies currently committed to the RE100 campaign will need to spend around $94 billion (£84bn) to hit their 2030 clean targets.
That’s according to a new report from Bloomberg New Energy Finance (BNEF), which says this would be enough funding to procure 172TWh of renewable power and help install 87GW of new clean capacity through power purchase agreements (PPAs).
However, it suggests it is more likely the 125 companies will enlist a variety of different mechanisms to meet the current renewable energy shortfall, including PPAs, certificates, onsite generation and utility contracts.
The current group of RE100 signatories, which includes IKEA, Aviva and BT, consumed around 163TWh of electricity in 2016, more than the entire power consumption of Sweden.
The report predicts their electricity demand will grow to at least 223TWh by 2030, based on historical growth patterns.
BNEF Analyst Kyle Harrison said: “The clean energy demands of these corporations will catalyse billions of dollars in clean energy investment.
“Corporations can have a real say in power market design.”