Some of the world’s biggest brands are converting plastic waste into fuel.At this vast landfill in Indonesia, excavators are tearing into stinking mountains of garbage, looking for bubble wrap, take-out containers and single-use shopping bags.All this trash is then processed and used as fuel to power a nearby cement plant. It’s cheap fuel – but it comes with a high price on the environment, some academics and scientists told Reuters. A number of consumer product giants and cement companies are promoting the approach as a win-win for the planet.They say converting plastic to energy keeps it out of landfills and oceans while allowing cement plants to move away from burning coal – a major contributor to global warming.The cement industry is responsible for 7% of the world’s carbon dioxide emissions. Reuters has identified nine collaborations launched over the last two years between various consumer goods giants and major cement makers. They include:Coca-Cola, Unilever, Nestle and Colgate-Palmolive.On the cement side are top producers including Holcim Group and Solusi Bangun Indonesia – or SBI. These projects span the world, from Costa Rica to the Philippines. The project in Indonesia is funded by Unilever, SBI, and the local government.The plastic-derived fuel is known as Refuse Derived Fuel, or RDF. Ita Sadano is the Business Development Manager of Solusi Bangun Indonesia: "I believe this is significantly helping to reduce plastic waste because RDF is an alternative fuel that we've been looking for. But as we all know, we don't exclusively (recycle) plastic waste, but we prefer plastics because they contain more energy." Critics say there’s little green about burning plastic to make cement A dozen sources with direct knowledge of the practice told Reuters the process emits harmful air emissions.Some say it amounts to swapping one dirty fuel for another.63-year-old Dadan bin Anton owns a roadside shop near the cement plant in West Java. "What bothers me so much about the air pollution is the dust, which we can clearly see. "So much dust, but we can't measure it. For instance, it's littering all over our floor." Unilever, Coca-Cola, Colgate and Nestle did not respond to questions about the environmental and health impacts of burning plastic.Cement companies SBI, Cemex, Republic Cement and Holcim’s Geocycle unit told Reuters their partnerships with consumer goods firms are aimed at addressing the global waste crisis and reducing their dependence on traditional fossil fuels.Axel Pieters, the chief executive of Geocycle, the waste management arm of Holcim, one of the world’s largest cement makers, and partner with Nestle, Unilever and Coca-Cola, said that burning plastic in cement kilns is a safe, inexpensive and practical solution that can dispose of huge volumes of this trash quickly.In Indonesia, local environmentalists say they are alarmed that cement plants could become the fix for a nation flooded with plastic waste.Yobel Novian Putra is an Associate with the Global Alliance for Incinerator Alternatives: "It's like moving the landfill from ground to the sky, which make it invisible... It's transforming domestic waste problem into a toxic waste problem." Less than 10% of all the plastic ever made has been recycled, in large part because it’s too costly to collect and sort. Plastic production, meanwhile, is projected to double within 20 years.Exactly how much plastic waste is being burned in cement kilns globally isn’t known.