The Calvert Cliffs nuclear power plant is licensed by the federal government for another decade. Its owner, though, is planning investments in preparation for a potential license renewal that would last into the second half of this century.

Constellation Energy, which owns the nuclear plant near Lusby in Southern Maryland, is spending $100 million to upgrade equipment and electrical systems. The investment highlights the Baltimore-based company’s aspiration to keep the plant’s two 1970s-era reactors operational for years to come.

After a flurry of nuclear power plants were completed in the U.S. in the 1970s and 1980s, interest in the energy source soured after the 1979 partial meltdown of a nuclear reactor at Three Mile Island in Pennsylvania. Over the last decade, several plants have been shut down for economic reasons.

But there’s been a reversal in recent years. Although not a renewable source like solar and wind energy, nuclear does not produce carbon emissions and is considered far more environmentally friendly than fossil fuels, which make up the vast majority of the U.S. power grid.

The arrival of artificial intelligence technology — which requires constant power — has only increased demand for nuclear energy from companies like Constellation, the largest nuclear operator in the country.

“With prudent energy policies and customer demand for clean and reliable energy, there is an opportunity for hundreds of millions of dollars of additional investment at Calvert to upgrade the plant and ensure that it can power Maryland for decades to come,” Constellation president and CEO Joe Dominguez said in a statement Tuesday.

Constellation, headquartered at Harbor Point, spun off of Exelon in January 2022 as a publicly traded company. Its stock price was initially valued at $45, but has skyrocketed since, peaking at $352 last month.

Calvert Cliffs Clean Energy Center (previously named Calvert Cliffs Nuclear Power Plant) is one of a dozen nuclear plants across the country operated by Constellation. The licenses for its two reactors, which are awarded by the U.S. Nuclear Regulatory Commission, expire in 2034 and 2036. Licenses can be renewed for up to 20 additional years.

Each year, Calvert Cliffs temporarily shuts down one of its two reactors. During the roughly 18-day outage, hundreds of workers refuel and complete necessary maintenance on the shut-down reactor. During a scheduled annual outage this month, upgrades to the nuclear plant will begin, the company said.

The upgrades could pave the way for additional capital improvements at the Calvert Cliffs plant. That could increase electricity production by roughy 10% — a substantial amount, given that the plant, by itself, provides about 40% of Maryland’s power generation.

Constellation’s decision to spend $100 million on the only nuclear plant in Maryland comes as state officials search for ways to generate more electricity in-state, a response to skyrocketing energy bills facing many residents.

Last week, top lawmakers in Annapolis rolled out a package of bills designed to amp up the state’s electricity generation. Maryland imports about 40% of its electricity, and that dynamic has complicated the state’s efforts to decarbonize its power grid and ensure lower-cost electricity.

A big part of the plan, which is backed by Senate President Bill Ferguson and House Speaker Adrienne Jones, involves paving the way for new power plants in Maryland, possibly one fueled by natural gas.

The package also aims to encourage new nuclear power plants. That could come through approvals of new reactors, a process that would take many years.

But at a Friday news conference, Sen. Brian Feldman, chairman of the Education, Energy and Environment Committee, also pointed to the potential to turbocharge output from Calvert Cliffs. The Montgomery County Democrat expressed confidence that the private sector is interested in developing new power generation in Maryland, and pointed to steps in one of the energy bills that would cut red tape to make it easier to approve new projects.

“We’ve heard from them, and they’ve said: If you do some things here to remove some of those regulatory problems, we’re going to be much, much more interested to come into the state of Maryland,” said Feldman.

Baltimore Banner reporters Adam Willis and Pamela Wood contributed to this article.