If you're looking for an index that isn't so specialized that it only captures the most niche alternative energy players, then the FTSE Group has a new benchmark out that might make a lot of sense.

The FTSE Environmental Opportunities All-Share Index has been launched. It's made up of 450-plus constituents covering alternative energy, water and waste management companies.

According to FTSE, Russell Investments has already licensed the index for an environmental technology multimanager fund.

The All-Share benchmark's constituents are taken from the FTSE Global Equity Index Series and are included in the index if a minimum of 20% of their revenue comes from environmental markets or technologies.

That differs from most indexes that focus on renewable energy. Those generally favor smaller firms that have at least 50% or more of their revenue—or count renewable energy as their core business—in alternative energy endeavors.

As a result, the FTSE index has as its top-holding German industrial giant Siemens at 4.29%. Suez, a French utilities company, is next at 3.7%. It's followed by another big utility, Spain's Iberdrola.

Four U.S.-based conglomerates are included in the benchmark's top 10: United Technologies, 3M, Emerson Electric and Honeywell International.

Constituents are researched by Impax Group, the specialist environmental investment company, who has partnered with FTSE to develop a range of indexes within the environmental technology space.

"The FTSE Environmental Opportunities All-Share Index will appeal to institutional and retail investors who want to gain exposure to and track the performance of those companies who are transforming their businesses to increasingly source revenues from global environmental markets," said Will Oulton, head of Responsible Investment at FTSE (what a title), in a statement.