So why exactly is Project GRAID so important to National Grid? Simply put, the building of the National Transmission System or NTS was started in the late 1960s and was given a 40 year design life. Over 60% of these assets will be beyond this point by the end of 2030. The large diameter pipelines between sites are managed through a combination of in-line inspection using Pipeline Inspection Gauges or PIGs and cathodic protection. High pressure installations are not currently in-line inspected due to the complex pipework geometry which the PIGs cannot negotiate.
It is this very environment that GRAID is designed for, being able to drive under its own power (so not propelled by the gas flow) around sharp bends, inclines, declines and diameter changes in the pipework.
It is also very costly to purge a high pressure installation of gas in order to inspect the inside of a pipe in atmospheric conditions which is why GRAID is also designed to operate up to 100barg which is far higher than the actual pressures it will experience in the pipe.
Getting into the pipe is only half of the battle, because once there GRAID needs to be able to take useful readings of wall thickness which will need to be combined with other sources of data and fed into a model to derive a health score for that particular installation. This information will ultimately feed into National Grid’s submission to OFGEM in terms of how much investment is needed on our sites for the following 8 years (between 2021 and 2029).
So GRAID has quite an important job to do!