This data contains the output from the first Flexible CCS Network Development (FleCCSnet) workshop of stakeholders discussing the development of CO2 networks in the UK. The first was held on the 30 April 2014 at the University of Edinburgh, UK. The purpose of Workshop 1 was to identify and confirm the key questions to be considered in order to understand the most likely impacts of variability in the CO2 sources and variability in CO2 sinks on CO2 transport system design and operation. There were a total of 21 attendees including 7 representatives from PSE, Scottish Power, BP, SCCS, Parsons Brinckerhoff, Element Energy, and AMEC. The dataset consists of two reports. The first report, 'Developing CO2 networks: Key lessons learnt from the first Flexible CCS Network Development (FleCCSnet) project workshop', summarises the workshop findings, which have been used to create a series of scenarios that were investigated by transient simulation. The scenarios developed are described in the second report, 'Developing CO2 networks: Scenarios building on the first Flexible CCS Network Development (FleCCSnet) project workshop'.