The pledge was among a slew of COP28 announcements on Saturday aimed at decarbonising the energy sector - source of about three-quarters of global greenhouse gas emissions - that included expanding nuclear power, cutting methane emissions and choking off private finance for coal power.
"This can and will help transition the world away from unabated coal," said Sultan al-Jaber, the United Arab Emirates' COP28 summit president.
Led by the European Union, United States and UAE, the pledge also said tripling renewable energy would help remove CO2-emitting fossil fuels from the world's energy system by 2050 at the latest.
Backers on Saturday included Brazil, Nigeria, Australia, Japan, Canada, Chile and Barbados.
While China and India have signalled support for tripling renewable energy by 2030, neither backed the overall pledge on Saturday - which pairs the ramp-up in clean power with a reduction in fossil fuel use.
US envoy John Kerry says the world cannot achieve "net zero" emissions without new nuclear reactors. (AP PHOTO)
Backers including the EU and UAE want the renewable energy pledge included in the final UN climate summit decision, to make it a global goal.
That would require consensus among the nearly 200 countries present.
The pledge, a draft of which was first reported by Reuters last month, also called for "the phase down of unabated coal power" and an end to the financing of new coal-fired power plants.
It also included a target to double the global rate of energy efficiency by 2030.
Climate vulnerable countries insisted that the goals must be paired with a deal among countries at COP28 to phase out the world's use of fossil fuels.
"It is only half the solution. The pledge can't greenwash countries that are simultaneously expanding fossil fuel production," said Tina Stege, climate envoy for the Marshall Islands.
While deployment of renewables like solar and wind has been surging globally for years, rising costs, labour constraints and supply chain issues have forced project delays and cancellations in recent months, costing developers like Orsted and BP billions of dollars in writedowns.
Hitting the target for 10,000 gigawatts of global installed renewable energy by 2030 will also require governments and financial institutions to hike investments and address the high cost of capital that has stymied renewable energy projects in developing nations.
Oil and gas firms have signed a charter driven by COP president Sultan al-Jaber to cut emissions. (AP PHOTO)
"The mismatch still exists between our potentiality and our limitations to attract investment," said Najib Ahmed, a consultant at Somalia's climate ministry.
Africa has received just 2 per cent of global investments in renewable energy over the last two decades, the International Renewable Energy Agency said.
More than 20 countries also signed a declaration on Saturday aiming to triple nuclear power capacity by 2050, with US climate envoy John Kerry saying the world cannot achieve "net zero" emissions without building new reactors.
"We are not making the argument that this is absolutely going to be the sweeping alternative to every other energy source," Kerry said during a launch ceremony at COP28.
"But... you can't get to net-zero 2050 without some nuclear, just as you can't get there without some use of carbon capture, utilisation and storage," Kerry said.
Global nuclear capacity now stands at 370 gigawatts, with 31 countries running reactors.
Tripling that capacity by 2050 would require a significant scaling up in new approvals - and finance.
Other pledges took aim at coal, the most CO2-emitting fossil fuel.
France said it would rally a group of countries to ask the OECD to measure the climate and financial risks attached to investing in new coal assets, to deter private financiers from backing projects.
Coal users Kosovo and the Dominican Republic also agreed to develop plans to phase out their coal-fuelled power.
Meanwhile, nearly 50 oil and gas companies including Exxon Mobil signed the Oil and Gas Decarbonisation Charter, an initiative driven by COP president Jaber to cut operational emissions by 2050.
The charter was criticised by environmental groups who said the commitments were merely a distraction from the COP28 process and fail to deal with the emissions caused by burning fossil fuels.
