New research suggests that power companies are dragging their feet when it comes to embracing green energy sources such as wind and solar.
Only one in 10 energy suppliers globally has prioritised renewables over fossil fuels, the study finds.
Even those that are spending on greener energy are continuing to invest in carbon heavy coal and natural gas.
The lead researcher says the slow uptake undermines global efforts to tackle climate change.
In countries like the UK and across Europe, renewable energy has taken a significant share of the market, with 40% of Britain's electricity coming from wind and solar last year.
But while green energy has boomed around the world in recent years, many of the new wind and solar power installations have been built by independent producers.
Large scale utility companies, including many state and city owned enterprises, have been much slower to go green, according to this new study.
The research looked at more than 3,000 electricity companies worldwide and used machine learning techniques to analyse their activities over the past two decades.
The study found that only 10% of the companies had expanded their renewable-based power generation more quickly than their gas or coal fired capacity.
Of this small proportion that spent more on renewables, many continued to invest in fossil fuels, although at a lower rate.
The vast majority of companies, according to the author, have just sat on the fence.
"If you look at all utilities, and what's the dominant behaviour, it is that they're not doing much in fossil fuels and renewables," said Galina Alova, from the Smith School of Enterprise and the Environment at the University of Oxford.
"So they might be doing something with other fuels like hydro power or nuclear, but they're not transitioning to renewables nor growing the fossil fuel capacity."
The author says that many of these types of utilities are government-owned and may have invested in their power portfolios many years ago.
The overall conclusion from the analysis, though, is that utility companies are "hindering" the global transition to renewables.
"Companies are still growing their fossil-fuel based capacity," Galina Alova told BBC News.
"So utilities are still dominating the global fossil fuel business. And I'm also finding that quite a significant share of the fossil-fuel based capacity owned by utilities has been added in the last decade, meaning that these are quite new assets.
"But in order for us to achieve the Paris climate agreement goals, they either need to be retired early, or will need carbon capture and storage because otherwise they're still here to stay for decades."
She says that inertia within the electricity industry is one key cause of the slow transition.
But the news reporting about energy companies doesn't always capture the complexity of their investments.
"Renewables and natural gas often go hand in hand," said Galina Alova.
"Companies often choose both in parallel. So it might be just in media reports we are getting this image of investing in renewables, but less coverage on continued investment in gas.
"So it's not greenwashing. It is just that this parallel investment in gas dilutes the shift to renewables. That's the key issue."
The study has been published in the journal Nature Energy.
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