Wind, solar and hydro will have to shoulder four fifths of the global power supply by 2050 to meet carbon targets
By Gerard Wynn
Rapid growth in zero carbon energy including renewable power seems assured, as the world faces escalating climate threats and a policy response including higher carbon prices and taxes.
The energy supply sector is the largest contributor to global greenhouse gas emissions, meaning that policies to tackle climate change will inevitably turn to energy, and in particular electricity where larger and easier carbon cuts are expected.
Renewable and nuclear energy already account for nearly a third of global electricity supply.
That share is increasing as a result of rapid growth in wind, hydro and solar power, which accounted for just over half of the new electricity‐generating capacity added globally in 2012.
It will have to increase much more by 2050, to more than four fifths of the global power supply, if the world is to hit more ambitious targets to cut carbon emissions, according to the Intergovernmental Panel on Climate Change (IPCC).
“The stabilization of greenhouse gas concentrations at low levels requires a fundamental transformation of the energy supply system,” their report said.
The IPCC reviews the latest published science on climate change every five to six years. Sunday’s report was the last instalment of the latest report, focusing on policy options to cut emissions, and compiled by some 235 authors.
They found that countries should roughly halve global carbon emissions by 2050, compared with present levels, which are still rising, to avoid the most dangerous climate change.
They said that “business as usual” was not an option, given expected temperature rises of 3 to 5 degrees Celsius without efforts to curb emissions, implying dangerous sea level rise, floods and droughts.
Low carbon energy presently accounts for a smaller share of all energy, including heat and transport as well as electricity, at about 17% (compared with 30% for electricity), the IPCC report found.
The report estimated that share should rise to 60% of all energy by the middle of the century, to have a 50% change of staying below more dangerous levels of global warming.
That implied steady annual growth in renewable energy over several decades.
The IPCC report calculated the level of low carbon energy including nuclear and renewable power needed to limit the rise in atmospheric levels of carbon dioxide to particular levels.
To have a 50% chance of limiting warming to 2 degrees Celsius above pre-industrial levels, greenhouse gases should stay below 530 parts per million (ppm) in the atmosphere, compared with around 450 ppm or more now, and rising rapidly.
The vertical axis in the IPCC figure below shows the required share of low carbon sources in total energy (left chart) and electricity supply (right), for any given atmospheric level of greenhouse gases, as shown on the horizontal axis.
The IPCC found that total, additional investments required in the energy supply sector by 2050 to be around $190 billion to $900 billion per year, to limit the global average temperature increase below 2°C.
That included investments in energy efficiency as well as low carbon sources, and was in addition to expected total global investment in the energy supply sector at $1,076 to $1,350 billion per year.
But it did not include fuel savings from investing in efficiency, compared with continuing as normal, and did not include other benefits from diversifying away from fossil fuels, such as avoided climate change, better air quality and improved energy security.
The report found that renewable energy would entail additional costs to help balance electric grids, because wind and solar power were intermittent and can involve weather forecasting errors.
Such balancing costs include building back-up generating capacity, and investing in wider electricity transmission networks.
But these costs were not a deal breaker, the IPCC report found, adding up to 30% to generation costs from wind turbines.