Only a total shift to low-carbon generation can effectively tackle climate change, according to a report published by the UN's Intergovernmental Panel on Climate Change (IPCC). Improving the energy efficiencies of fossil power plants or shifting from coal to gas will not by itself be sufficient.
Globally, greenhouse gas (GHG) emissions continue to grow, reaching a record 49.5 billion tonnes of carbon dioxide equivalent (CO2eq) in 2010.
"There is a clear message from science: To avoid dangerous interference with the climate system, we need to move away from business as usual."
IPPC Working Group III
The energy supply sector is the largest contributor to global greenhouse gas emissions, responsible for approximately 35% of all anthropogenic emissions. In the absence of climate change mitigation polices, energy-related emissions are expected to rise to 55-70 billion tonnes CO2 by 2050.
The stabilization of GHG concentrations at low levels requires a fundamental transformation of the energy supply system, including the long-term substitution of unabated fossil fuels by low-GHG alternatives, such as nuclear, renewables, and carbon capture and storage (CCS).
In the majority of low-stabilization scenarios (430–530 ppmCO2eq), the share of low-carbon energy in electricity supply increases from the current share of some 30% to more than 80% by 2050. In the long run, fossil power generation without CCS is phased out almost entirely by 2100 in these scenarios.
The IPCC report confirmed nuclear energy among the lowest carbon forms of generation, taking into account both direct emissions and lifecycle, ranking alongside wind turbines at 12gCO/kWh. Hydro and solar have emissions of 24gCO2/kWh and 28gCO2/kWh respectively.
Although identified as low carbon options, biomass has total emissions of 220gCO2/kWh and fossil fuels with CCS 160-220gCO2/kWh, much higher than those of nuclear and renewables, although lower than high-carbon generation from gas (490gCO2/kWh) and coal (920gCO2/kWh).
On safety the report noted that fatality rates of non-hydro renewable energy, hydro and nuclear power in developed countries technologies are comparable - and are lower than those of fossil chains.
Ottmar Edenhofer, co-chairman of the IPPC Working Group III which produced the report, commented: "Climate policies in line with the 20C goal need to aim for substantial emission reductions. There is a clear message from science: To avoid dangerous interference with the climate system, we need to move away from business as usual."
The IPCC has now produced three reports for its Fifth Assessment Report, which will be compiled into a Synthesis Report, due to be published in October.
Researched and written
by World Nuclear News