Climate change was hard to miss in 2019. Alongside the global climate strike and the United Nations Climate Action Summit in September, there was a swathe of commitments by countries and companies to a net zero carbon pathway. The UK, France and Sweden are now amongst the countries that have set themselves this objective. Meanwhile, big corporate names like Amazon.com, Daimler and Duke Energy – one of the largest electricity companies in the US – trumpeted their own net zero carbon commitments.
What does net zero mean? Simply put, stabilizing global average temperatures at any level means net manmade greenhouse gas emissions have to come down to zero, with any emissions offset by removing carbon. The earlier that happens, the lower the ultimate rise in temperatures. According to the scientists at the Intergovernmental Panel on Climate Change, getting to net zero by 2070 should limit the rise to 2 degrees Celsius, but for the more ambitious 1.5 degree target, the world would need to be carbon-neutral by 2050. Busting the carbon budget will mean higher and sharper temperature rises, and more extreme physical impacts on people and the planet.
The pathway to net zero is perhaps easiest to see in the electricity generation sector. Alternatives to coal and gas generation exist, and while in the past they relied on subsidies, the cost reductions in renewable technologies have been so dramatic that they are often the most economical option even with no subsidy at all. The UK’s latest offshore wind auction saw some prices drop under the £40/MWh (megawatt hour) level – less than half the price that has been promised for energy from the country’s latest new nuclear plant.
Renewable energy already makes up almost three-quarters of net new electricity capacity globally every year, but that investment will have to scale up again to fully decarbonize the sector. Around 200GW (gigawatt) is currently being installed annually, but that’s likely to need to rise to 500-600GW to get to net zero by 2050. Intermittency also has to be tackled, through some combination of using diverse sources of renewables, energy storage, and zero-carbon baseload power like nuclear energy.