"Last year, almost twice as many green bonds as expected were issued, and in the first quarter of 2017, issuance stood at $21.76 billion, up nearly 42 percent from the same period last year. What’s more, a new report by the Organization for Economic Co-operation and Development (OECD) estimated that the green bond market could increase to $4.7 trillion to $5.6 trillion in outstanding bonds by 2035, with annual issuances of $620 billion to $720 billion."

[COMMENTARY] With investors appetite for green bonds rising sharply and outstripping demand, green bond yields often command relatively lower yields. As lower yields frequently mean reduced interest costs to companies it increases the attractiveness for companies to issue them vis a vis regular bonds. It’s a win for companies and a win for ethical investors.
6 benefits to companies that issue green bonds, by Rochelle J. March, May 5, 2017, GreenBiz, USA.