The second CCS summer school to be organised by our Italian members Sotacarbo took place last week at their headquarters in Carbonia, Sardinia, with the aim of introducing students in energy research to CCS technologies. From the Clean Coal Centre, Geoff Morrison and I were both attending as speakers for the school, as well as presenting an associated workshop on improving coal plant efficiency as a precursor to CCS. This one-day event included presentations of the Centre’s latest work on plant upgrading, advanced materials for raising steam temperatures, and progress in CFB efficiency.
Sotacarbo are a coal research centre with a particular interest in CCS, as this historical mining region of southwestern Sardinia sits on top of the Sulcis basin: a geological formation with strong potential for carbon storage. Besides the option of storing CO2 within the deep-lying coal seams (possibly as a means to enhance coal bed methane recovery), a substantial saline aquifer formation lies deeper still, and around half the basin extends offshore. Having already taken measurements to establish baseline CO2 levels in the area, Sotacarbo are planning a CO2 injection project and an underground analysis laboratory in one of the disused mines in order to fully characterise the storage potential of the site. The CO2 itself would come from a 350 MW capture plant also planned for the region, probably at the site of Enel’s existing coal plant nearby. While several technologies have been proposed for this capture plant, there is particular interest in the pressurised oxyfuel technology developed by Italian company ITEA which has so far been tested at a 5 MWt scale.
Several talks and various visits to Sotacarbo facilities introduced us to some of this work going on in the region, while the rest of the programme gave a well-balanced overview of the status of capture, transport, and storage technologies, as well as approaches to project cost analysis and public engagement. Many of the talks emphasised the widespread consensus from organisations such as the IEA and IPCC that substantial instalment of CCS will be necessary to achieve any reasonable cap on atmospheric CO2 concentrations. Some informative back-of-the-envelope calculations presented by one speaker highlighted the fact that last year’s emissions of 40 Gt/yr of CO2 amount to another 2.5 ppm increase in atmospheric CO2, giving us very limited time to keep within the IEA’s target of a 50 ppm maximum rise. Hopefully some of the novel capture technologies discussed, such as chemical and carbonate looping or membrane-based capture systems, will be able to help accelerate the sluggish uptake of CCS. Nevertheless, Geoff’s overview of current demonstration projects showed that progress is already being made, with big capture plants in North America nearing completion, the recent bonus of 300m in EU funding to the UK’s WhiteRose project, and the huge emerging potential for fitting capture to China’s fleet of coal-to-chemicals plant. Last week also saw the news of the CCS retrofit at a 600 MW coal plant in Texas moving into a construction phase.
I skipped some of the school to visit Enel’s 700 MW plant on the nearby coast at Portoscuso; a must-see for fluidised bed enthusiasts due to the 350 MW CFB boiler which was the largest in the world when completed in 2005. The fuel flexibilty of fluidised bed combustion allows the unit to fire 15% biomass (by calorific value) and a proportion of the high sulphur local coal, whilst meeting emissions requirements without downstream deSOx or deNOx. The older of the two units is a pulverised coal boiler which may be in line for replacement by the planned capture plant.
The school finished with a visit to a museum dedicated to the disused Sebariu coal mine which shares Sotacarbo’s site, giving a reminder of the long history of the industry in this region. A sizeable network of tunnels has been reconstructed around the original shaft, with equipment and images showing the progression from manual mining to the machinery used when the pit closed in the 60s. The last coal mine remaining in the region is also set to close in the next few years, regardless of the CCS project, due to the unfavourable economics of mining the relatively poor quality coal found here. However, the region must surely be one of the most appealing coal-mining regions in the world, where even the imposing industrial complex at Portovesme does little to mar the beautiful coast line, and fresh seafood is plentiful. Plenty of reasons for students to sign up for the school next year.