These definitions are for the purposes of the Grid-interactive Efficient Buildings Technical Report Series. They may be defined differently or more generally in other contexts. Grid services Services that support the generation, transmission, and distribution of electricity and provide value through avoided electricity system costs (generation and/or delivery costs); this report focuses on grid services that can be provided by grid-interactive efficient buildings. Distributed energy resource (DER) A resource sited close to customers that can provide all or some of their immediate power needs and/or can be used by the utility system to either reduce demand or provide supply to satisfy the energy, capacity, or ancillary service needs of the grid. Load profile A building's load profile describes when-time of day or hour of the year-the building is consuming energy (typically used to refer to electricity consumption but can also describe on-site fuel use); load shape and load curve are often used interchangeably, but all refer to the timing of energy use. Energy efficiency Ongoing reduction in energy use to provide the same or improved level of function. Demand flexibility Capability of DERs to adjust a building's load profile across different timescales; energy flexibility and load flexibility are often used interchangeably with demand flexibility. Demand response Change in the rate of electricity consumption in response to price signals or specific requests of a grid operator. Demand-side management The modification of energy demand by customers through strategies, including energy efficiency, demand response, distributed generation, energy storage, electric vehicles, and/or time-of-use pricing structures. Grid-interactive efficient building (GEB) An energy-efficient building that uses smart technologies and on-site DERs to provide demand flexibility while co-optimizing for energy cost, grid services, and occupant needs and preferences in a continuous and integrated way. Smart technologies for energy management Advanced controls, sensors, models, and analytics used to manage DERs. GEBs are characterized by their use of these technologies. Generation Services Energy Power plant fuel, operation, maintenance, and startup and shutdown costs Capacity Capital costs for new generating facilities and associated fixed operation and maintenance costs Ancillary Services Contingency Reserves 9 Power plant fuel, operation, maintenance, and opportunity costs associated with providing contingency reserves Frequency Regulation Power plant fuel, operation, maintenance, and opportunity costs 10 associated with providing frequency regulation Ramping Power plant fuel, operation, maintenance, and startup and shutdown costs Delivery Services Non-Wires Alternatives 11 Capital costs for transmission and distribution (T&D) equipment upgrades Voltage Support Capital costs for voltage control equipment (e.g., capacitor banks, transformers, smart inverters)