We explore the interplay of competition and environmental policies to address the question of whether ‘green’ antitrust has beneficial effects in terms of both environmental and consumer welfare performance. We focus on two environmental policy tools, an emission tax and an emission standard, and explore three particular configurations: competitive `green’ R\&D, collaborative `green' R\&D in the form of a joint lab, and the benchmark case of no `green' R\&D. Firms compete in the product market by selling a homogeneous product, either by setting prices (Bertrand competition) or quantities (Cournot competition) while facing convex costs.  We show that `green antitrust' can unambiguously improve the effectiveness of environmental policy without undermining the interests of either consumers or producers, establishing a `win-win-win' outcome. 

Key words:`Green' R&D, emission tax, environmental standard, `green' antitrust, R&D cooperation, joint lab, convex costs.

Code JEL: L13, L4, Q55, Q58.