Infrastructure investments take many forms. They differ particularly in terms of sectors, project phases and strategies and allow a wide variety of risk/return profiles. Examples are transport and traffic infrastructure (e.g. toll roads or railways), publicly regulated energy and water supply, communication infrastructure (e.g. mobile or satellite communications) and renewable energies. Social infrastructure includes hospitals as well as educational and cultural institutions. Depending on the project phases, there are newly implemented greenfield projects and brownfield projects that build on infrastructure that has already been developed.