One of the biggest challenges in our fight against climate change is reducing greenhouse gas (GHG) emissions from the energy sector.
Approximately 87% of current global primary energy supplies (and 67% of electricity generation) come from the fossil fuels coal, oil and gas. Worse still, energy-related GHG emissions are projected to rise by over 50% by 2030, mainly due to rapid developments in China and India.
Much research in recent years has shown that no single technology or strategy will be sufficient to curb rising emissions. Instead, we will need to use every tool we can to develop a portfolio of solutions.
Carbon capture and storage (CCS), or geosequestration, is one such tool. It will be a key factor in meeting the challenge of climate change.
Indeed, numerous studies by the International Energy Agency (IEA), the Intergovernmental Panel on Climate Change and many governments around the world see CCS as an essential technology for reducing emissions.
How does CCS work?
The first step in CCS is to capture carbon dioxide (CO₂) from large industrial sources, such as power stations. This is carbon dioxide that would otherwise be emitted into the atmosphere.
This CO₂ is then compressed and transported to a suitable site for injection. These sites are typically porous rock formations more than 800 metres underground, with impermeable rocks above that ensure CO₂ remains stored over time.
Identifying suitable sites with adequate volumes of porous rock and secure seals or traps is a vital part of a CCS project. Detailed exploration and modelling work is required to satisfy proponents, bankers and regulators that the site will be secure and that the carbon dioxide is then trapped for thousands or millions of years, preventing it from leaking into the atmosphere.
Once approved, CO₂ storage sites are continuously assessed and monitored to ensure leakage does not occur. CO₂ storage is considered to be safe and very low risk by industry and researchers.
This process mimics the way CO₂ is stored naturally in geological formations. By capturing and storing CO₂, CCS can prevent up to 90% of a power station’s CO₂ from reaching the atmosphere.
CCS is already happening
Over 50 million tonnes of CO₂ are already being geologically stored annually in projects around the world, in countries such as Canada, Norway and Algeria. Numerous projects are also being planned in the USA and in Europe.