Carlyle Group Inc. is looking to increase investments in clean energy while retaining its traditional-energy holdings and working with them to curb their environmental impacts.

Rather than speeding up the sale of those companies, Carlyle believes it can generate more benefits to the planet—and higher returns to its investors—by helping its oil and natural gas businesses reduce their carbon emissions, said Carlyle global infrastructure group Chair Macky Tall, whose purview includes energy and power.

“Some people would say just divest,” Mr. Tall said. “We don’t think that’s enough.”

As an example, Mr. Tall cited Colombian oil-and-gas producer SierraCol Energy, which he said has cut its emissions by a third since Carlyle acquired the company roughly two years ago. Carlyle-backed energy producer Compañía Española de Petróleos SA, or Cepsa, in Madrid plans to invest as much as €8 billion, equivalent to roughly $8.6 billion, in clean-energy businesses such as biofuels and electric vehicle-charging stations as well as wind- and solar-power projects, with a goal of reducing its emissions by 55% within eight years, Cepsa said in March.

“We are taking steps to more than halve the emissions of a very large, integrated energy company,” Mr. Tall said.

Macky Tall, Carlyle Group global infrastructure group chair

Photo: CARLYLE GROUP

The initiatives are part of a broader effort by Carlyle to better capitalize on investment opportunities created by the shift to clean energy. The Washington-based firm recently combined its energy and infrastructure strategies under Mr. Tall. It also hired former Canada Pension Plan Investment Board executive Avik Dey, who in 2016 led the formation of a renewables strategy for CPP Investments. The pension investment manager as of March 31 had assets totaling 539 billion Canadian dollars, equivalent to $420.5 billion. Mr. Dey will lead Carlyle’s overseas energy investments alongside co-head Bob Maguire, a Carlyle veteran.

Mr. Tall recently spoke to WSJ Pro Private Equity about the newly integrated group and the firm’s push to reduce emissions across its portfolio. The interview has been edited for clarity and length.

WSJ Pro: How does Carlyle aim to benefit from combining infrastructure and energy investments into one group?

Mr. Tall: What I’m most pleased about is that this platform allows us to be even more active in this very important energy-transition [theme]. Within the platform, we really have the full spectrum of energy investments, from the very low-carbon renewables assets to the other end of the spectrum, which is [oil-and-gas] upstream, midstream and downstream. We can contribute to the energy transition both by investing and bringing more low-carbon energy on one side and, on the other, by using our skill set and expertise to accelerate decarbonization of traditional energy assets.

WSJ Pro: Why isn’t Carlyle seeking to exit oil-and-gas assets more quickly as other private-capital firms are doing?

Mr. Tall: If you divest [one such] asset in your own portfolio, you have less carbon emissions but the asset is still producing that carbon somewhere else. If you keep that asset and put money into it, you work with management of the business and you set a realistic plan to decarbonize it, then you have moved the needle, you have contributed to the 2050 net-zero targets that an increasing number of countries and corporations are setting for themselves, including Carlyle.

WSJ Pro: What sorts of actions are Carlyle’s portfolio companies taking to reduce carbon emissions?

Mr. Tall: One example, the case of SierraCol, we’ve reduced gas flaring and replaced oil-fired power generation with hydroelectric power. We are also constructing a 40-megawatt solar plant adjacent to the [company’s] oil field, which will generate additional renewable energy to power the operations and a waste-heat recovery project. [In general], there’s a long list of concrete things you can do.

Write to Luis Garcia at luis.garcia@wsj.com