Energize Weekly, July 24, 2019
Natural gas, despite growing concerns about its role creating greenhouse gases, continues to provide “quick wins” for carbon emissions reductions and clean air improvements, according to a study by the International Energy Agency (IEA).
In the United States, for example, there has been a 70 percent increase in natural gas-fired generation since 2005, and it now provides a third of the nation’s electricity. Coal-fired generation has dropped to 30 percent from 50 percent during the same period.
The IEA estimated that coal-to-natural gas switching in the U.S. led to a reduction of 200 million tons of carbon dioxide equivalent in 2017 when compared with 2010 and that 1,200 million tons of carbon emissions could be abated worldwide in switching from coal to existing natural gas plants.
The result of such a switch would be to bring global coal demand down by 15 percent, cut power sector emissions 10 percent and total energy-related carbon dioxide (CO2) emissions by 4 percent, the agency said.
On average, coal-to-gas switching reduces CO2 emissions by 50 percent when producing electricity and by 33 percent when providing heat.
Still, some environmental groups, such as the Sierra Club, are beginning to raise concerns that heavy investment in natural gas development will lead to long-term carbon emissions for the industry.
“It is clear that switching between unabated consumption of fossil fuels, on its own, does not provide a long-term answer to climate change, but there can nonetheless be significant CO2 and air quality benefits, in specific countries, sectors and timeframes, from using less emissions-intensive fuels,” the IEA said.
In 2018, global carbon emissions grew by 1.7 percent to a record high of 33.1 gigatons, with the power sector accounting for about two-thirds of the growth in emissions.
By the agency’s estimate, annual emissions have to be brought below 18 gigatons by 2040 to meet its “sustainable development” scenario. This includes a 75 percent cut in coal-related emissions compared to current levels.
Natural gas can play a role in cutting those emission, as well as improving air quality, the IEA said.
Simply running existing natural gas-fired plants in place of coal creates a swift saving of 1.2 gigatons of CO2, depending on fuel prices and regulatory policy, the IEA said. “The vast majority of this potential lies in the United States and Europe,” the report said.
“The clearest case for switching from coal to gas comes when there is the possibility to use existing infrastructure to provide the same energy services but with lower emissions,” the report said. “Given the time it takes to build up new renewables and to implement energy efficiency improvements, this also represents the quickest route to emissions reductions.”
In China, the focus for natural gas has been on the residential and industrial sectors, particularly in urban areas, as part of the country’s push to improve air quality. In India, natural gas may play a similar role.
A switch to natural gas from coal reduces key air pollutants such as coal-based sulfur dioxide and fine particulate matter by as much as 50 percent.
Southeast Asian countries, such as Vietnam and Malaysia, have recently invested in coal-fired capacity to meet growing electricity demands, and natural gas may play a lesser role, the report said.
Natural gas-fired generation, however, is already feeling market pressure from renewables, particularly wind and photovoltaic (PV) solar, which are already the cheapest options for new generation in many markets around the world.
“The volume of electricity generated by gas-fired plants can be squeezed, but they can nonetheless provide important value by guaranteeing flexible and reliable operation of fast-changing power system,” the report said.