ArcLight Capital Partners, LLC is a private equity firm specializing in buyout investments in the energy sector. The firm prefers to invest in power generation; production; midstream; transmission; and distribution.

In the power generation sector, it invests in power plants and related assets including gas, coal, hydro, wind, geothermal, and other renewable sources of energy. For production sector investments, the firm invests in extraction and production of oil, natural gas, coal, and related products. Within the midstream sector, it focuses on gathering, processing, storage, and transportation of oil, natural gas, coal, and related products. In the transmission sector, the firm invests in interstate and intrastate gas and electric transportation systems. Within the distribution sector, it invests in electric and gas distribution companies and related businesses.

The firm primarily invests in companies based in North America, Western Europe, Australia, and New Zealand. It typically invests between $10 million and $300 million in its portfolio companies. ArcLight Capital Partners, LLC was founded in 2001 and is based in Boston, Massachusetts with additional offices in New York, New York; and Luxembourg, Luxembourg.