Large-scale deployment of renewable energy resources, both utility-scale and distributed, create reliability concerns for electrical power system operators. The weather-dependent, non-dispatchable nature of renewable resources decreases the ability of operators to match supply with demand. Concurrently, distributed energy resources, defined as small-scale loads, generation sources, and storage systems, are becoming ubiquitous within modern electrical systems. This literature review presents the grid services that utilities use to alleviate power systems reliability concerns, particularly those caused by renewable resources, and how aggregations of residential-scale distributed energy resources can be used to provide these services.By aggregating distributed energy resources en masse to provide grid services, grid operators can concurrently improve reliability while ensuring high penetration levels of renewable resources. Academic researchers have developed the theoretical methods for achieving these objectives. Standards bodies have created open communication frameworks for linking these resources with grid operators. And, large-scale utility programs have demonstrated the potential for providing grid services using aggregations of these resources. This manuscript presents a review of the literature, methods, and standards that have created the foundation for distributed energy resources to help decarbonize electrical power systems.