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Posts Tagged ‘CO2’

Johan Sverdrup field, 155 km from shore

Production from Equinor’s important Johan Sverdrup field, which accounts for 755,000 bopd (36% of Norway’s oil production), was shut-in on Monday as a result of a power outage. Production was in the process of being restored on Tuesday.

According to Equinor, the outage was caused by overheating at an electric converter station onshore.

A 2022 BOE post questioned Norway’s push to power offshore platforms with electricity transmitted from shore. This incident reinforces those concerns. Summary:

  • Most offshore platforms produce sufficient gas to support their power demands
  • Assuming gas that is not used to power a platform is marketed and consumed elsewhere, the net (global) reduction in CO2 emissions from electrifying offshore platforms is negligible. (Perhaps there is actually a small increase in net emissions given the power required to transport the gas to markets and the emissions associated with onshore power generation).
  • Offshore power demands are highly variable, especially when drilling operations are being conducted.
  • Gas turbines are reliable, and capable of responding to variable power demand. Excess generation capacity is typically provided.
  • Power from shore increases the cost of platform operations and could decrease ultimate recovery of oil and gas resources.
  • Per NPD, electrification of the shelf will increase electricity prices for onshore consumers and increase the need for onshore facility investment.
  • Gas turbines or diesel generators are still necessary to satisfy emergency power needs at the platforms.
  • Long power cables are vulnerable to damage (accidental or intentional), as are onshore power stations.

I hope the investigation of this incident considers some of these broader electrification policy issues.

Equinor diagram: The purple cable shows power from shore to Johan Sverdrup phase 1, established in 2018. The yellow power cable shows power from shore to Johan Sverdrup phase 2 and the Utsira High area solution, from 2022. The orange cable shows power from shore to the Sleipner field centre and connected fields from late 2022. Black cable shows existing power cables at Sleipner field centre and to the Gudrun installation.

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Culzean facilities

Total has announced plans to install a 3 MW floating wind turbine 2 km west of the Culzean platform, 220 km off the coast of Scotland. This turbine, expected to be fully operational by the end of 2025, will supply around 20% of Culzean’s power requirement. This project is interesting from an R&D standpoint, but makes little sense otherwise. Here’s why:

  • Culzean is a gas condensate field that is capable of meeting 5% of the UK’s gas demand. There is thus ample produced gas to reliably and economically power the platform.
  • Gas will be required to meet 80% of the power requirement even after the wind turbine is operating.
  • In light of installation, maintenance, and decommissioning costs for the floating turbine, the cost of the intermittent wind power will no doubt be much higher than the cost of the power generated by platform gas.
  • Some tax benefits may be associated with adding the wind turbine, but this won’t affect the real costs, other than to perhaps make them higher.
  • In addition to affecting profitability, higher operational costs could reduce the ultimate recovery of gas and condensate from the field.
  • Gas not consumed at the offshore facilities will be marketed and consumed onshore, so there is essentially no net reduction in global CO2 emissions.
  • As JL Daeschler reminds me, the floating turbine complicates operations and could create safety issues: obstruction for helicopters and supply boats to avoid, trenching and installing power cable in a spare “J” tube, and feeding power to an electrical distribution system in accordance with standards and platform specifications. As JL notes, “I think we have plenty to do offshore already!”
  • And what if there are mooring failures and the turbine drifts toward the platforms? Turbine blade failures?
  • Bottom line: adding costs and risks for no apparent benefit.

See a related post on platform electrification in Norway.

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