If there is any single private equity company that could be described as a sustainability leader, it is probably KKR.

The company attracted attention in dramatic fashion in 2007 when it bought the Texas-based energy supplier TXU and promptly announced that it would be scrapping all but three of the 11 new coal-fired power stations that had been planned, investing instead in wind power alternatives. KKR founding partner Henry Kravitz said at the time: “We have developed a new vision with management of how we can turn TXU into a more innovative, customer-centric, environmentally friendly company.”

It was the moment when NGOs such as Environmental Defence switched from being combatants to being partners.

For KKR, it was still an equation about value. It hadn’t suddenly caught tree-hugging fever. The company had accepted the arguments about big changes coming in how climate change would affect energy production – at a time when few in the US wanted to hear that message.

Now KKR has distinguished itself further by taking an active management approach to a broader range of its portfolio companies. It has become one of the few private equity companies to produce an environmental, social and governance report.

It also has a “green portfolio” website that details the work it has done on a number of its companies. It provides a set of analytical tools to help portfolio companies assess and track improvements and use the website to report progress.

To date, it estimates that the green portfolio initiative has saved 345,000 tonnes of carbon, reduced waste by 1.2m tonnes and, most importantly from the point of view of some investors, saved $160m in costs.

When the company chooses to make an investment, it develops a 100-day plan on key goals to realise the value of the investment. If ESG issues are identified as being important in driving value, they are built into the planning process at this stage.

For instance, according to KKR’s ESG report, the 100-day plan for its investment in Oriental Brewery included programmes to reduce energy use and greenhouse gas emissions.

One of the defining moments for KKR came when it acquired Alliance Boots. At that time, the availability of cheap credit was seeing a number of such well-known names falling into private ownership – and many observers were wondering whether such deals would mean an end to those companies’ corporate responsibility and sustainability programmes.

Richard Ellis, CSR director at Alliance Boots, says this definitely was not the case with KKR. “Before the acquisition, I personally assumed there was huge scepticism in the private equity world on this agenda. But since then, I have found that so long as you’re able to treat sustainability as a normal business discipline, these are very smart people who get it.”

Ellis says the move into private equity ownership has resulted in no change to Alliance Boots’ corporate responsibility programmes. KKR, he argues, sees the long-term value of sound management of this area. He says: “I think the Boots example has been influential, with KKR committed to sharing best practice across its portfolio companies.”