An energy company is any business involved in producing, processing, transporting, or selling energy to consumers and other businesses. That covers a wide range, from oil giants pulling crude out of the ground to local utilities delivering electricity to your home to newer firms building solar farms and battery storage. The Global Industry Classification Standard, used by investors worldwide, defines the energy sector as companies engaged in exploration, production, refining, marketing, storage, and transportation of oil, gas, and coal, plus the firms that supply equipment and services to those operations. But in everyday usage, “energy company” extends well beyond fossil fuels to include electric utilities, renewable developers, and retail electricity providers.
Oil and Gas Companies
The most recognizable energy companies operate in oil and gas. This industry is split into three segments based on where a company sits in the supply chain. Upstream companies extract crude oil and natural gas from underground reserves. Midstream companies move and store those raw materials through pipelines, tankers, and storage terminals. Downstream companies process crude oil and natural gas into finished products like gasoline, diesel, jet fuel, and petrochemicals used in plastics and manufacturing.
Some of the world’s largest corporations by revenue are oil and gas companies. Saudi Aramco tops the list with $480 billion in revenue in 2024 and a market capitalization of $1.66 trillion. ExxonMobil brought in $349.6 billion, and Chevron posted $202.7 billion. These companies often operate across all three segments, handling everything from drilling wells to selling refined fuel at gas stations. PetroChina, China’s state-backed oil giant, rounds out the top tier with a $290 billion market cap.
Electric Utilities
Electric utilities generate, transmit, and distribute electricity to homes and businesses. Power plants produce the electricity, high-voltage transmission lines carry it over long distances, and local distribution networks deliver it to your meter. Transformers at substations step voltage up for efficient long-distance travel, then step it back down for safe use in buildings.
Some utilities handle the entire chain. These vertically integrated utilities own their power plants, transmission lines, and distribution networks. Others only operate the distribution system and purchase electricity on the wholesale market from independent power producers or other utilities. Either way, the local utility is typically the company responsible for physically connecting you to the grid.
Utilities come in three ownership structures, each with different priorities. Investor-owned utilities aim to generate returns for shareholders, recovering costs and earning profit through the price per kilowatt-hour they charge. Municipal and publicly owned utilities serve broader public policy goals and don’t need to satisfy private investors, which can make them more flexible on issues like adopting solar energy. Electric cooperatives are owned by their customers and focus on keeping rates low, though they’re often the most sensitive to anything that might push prices up.
Retail Energy Providers
In some states, you don’t buy electricity directly from the utility that owns the power lines. Instead, you choose a retail energy provider. This setup exists in deregulated (or “restructured”) markets, where the utility delivering electricity to your home is separate from the company generating or selling it. Retail choice was designed to create competition among suppliers, ideally driving prices down.
It also gives you options beyond price. In states with retail choice, you can pick a supplier that sources a larger share of its electricity from renewable sources like wind or solar. The local utility still maintains the wires and handles delivery, but the retail provider determines where the electricity comes from and what you pay for it.
Renewable Energy Companies
A growing segment of the energy industry focuses on wind, solar, hydropower, and other low-emission sources. Some renewable energy companies develop and operate large-scale power plants that sell electricity into the wholesale market. Others manufacture the hardware, like solar panels or wind turbines. GE Vernova, a relatively new standalone company spun off from General Electric, focuses on nuclear and wind energy and already carries a market capitalization of $237 billion despite revenue of $38 billion, reflecting investor expectations for growth in clean power.
Renewable developers often compete with traditional utilities for a role in the grid. For investor-owned utilities, distributed solar can be a tension point: rooftop panels reduce the amount of electricity a utility sells, which can cut into revenue. Publicly owned utilities and cooperatives face the same math but without shareholder pressure, so they tend to be more open to integrating renewables even when it reduces their sales volume.
Energy Storage Companies
Energy storage is one of the newer categories in the industry. These companies build and operate large battery systems that sit on the power grid, charging when electricity is cheap or abundant and discharging when demand (and prices) rise. This practice is called price arbitrage, and it’s the primary use for 41% of all utility-scale battery capacity in the U.S. Another 24% of battery capacity is primarily used for frequency regulation, which keeps the grid running at a stable 60 cycles per second.
Storage companies fill a gap that traditional generators can’t. Solar farms produce the most electricity midday, but demand often peaks in the evening. Batteries bridge that mismatch, and they respond far faster than a gas turbine can ramp up. As more wind and solar come online, energy storage companies are becoming essential infrastructure partners rather than niche players.
How Energy Companies Are Regulated
Energy companies operate under layered oversight. At the federal level, the Federal Energy Regulatory Commission (FERC) regulates the interstate transmission of electricity, natural gas, and oil. That includes wholesale electricity sales and the movement of natural gas and oil through interstate pipelines. FERC does not, however, set the prices you pay on your monthly bill.
Retail electricity and natural gas prices fall under state public utility commissions. These state regulators approve the rates utilities charge consumers, review plans for new power plants or transmission lines, and ensure utilities meet reliability standards. If you’re in a deregulated state, the state commission also oversees the rules governing competition among retail providers. This split means an energy company operating across state lines may answer to FERC for its wholesale operations and to multiple state commissions for its retail business.
What Ties Them All Together
Despite covering very different activities, energy companies share a common thread: they convert natural resources into usable power and move it to the people and businesses that need it. An oil company turns crude into gasoline. A utility turns coal, gas, wind, or sunlight into electricity and sends it through wires to your home. A retail provider packages that electricity into a plan you can buy. A storage company holds energy until the moment it’s most valuable. The industry is broad enough that two energy companies can have almost nothing in common operationally, yet both exist to solve the same fundamental problem of getting energy from where it’s produced to where it’s consumed.