The UK took a big step towards the electrification of offshore oil and gas platforms on Friday with Scotland’s selection of 13 projects under its pioneering INTOG scheme for deployment of large-scale wind power to the sector, but industry bodies are wary of technical and cost challenges.
A lack of grid connections in remote parts of the harsh North Sea environment makes offshore wind the obvious route for complying with a mandate on reducing emissions from offshore operations, but issues such as costs and the intermittency of wind supply also have to be tackled, the leading trade association points out.
“Platform electrification… can enable near-term oil and gas industry emissions reductions, but there are cost challenges,” a UK continental shelf integration report from industry body Offshore Energies UK said.
Offshore installations require high amounts of uninterrupted energy for their production and drilling operations, as well as the power needed for workers stationed offshore.
A 2019 OEUK report assessed UK offshore platforms’ power demand at about 24 terawatts per year, or 2.75 gigawatts on average. This represented over 5% of UK power demand, accounting for over 10% of total power plant emissions
Offshore rigs today are usually powered by open-cycle gas turbines or diesel-powered generators.
The UK’s North Sea Transition Authority (NSTA) has estimated that power generation for oil and gas infrastructure in the UK generates emissions equivalent to 10 million tonnes per annum of carbon dioxide.
The North Sea Transition Deal signed with the UK government in 2021 committed the industry to reducing greenhouse gases emitted during production by 10% through to 2025, rising to 25% by 2027, and 50% by 2030 — against a 2018 baseline — before hitting net zero by mid-century.
Electrification of power supply is seen as one way to reduce the overall carbon footprint of North Sea UK oil and gas production and help align with these carbon reduction targets.
As many platforms in the North Sea are in the late stages of their production cycle, overhauling their energy source could represent a significant cost burden, the OEUK points out.
Challenges include high brownfield capital expenditure on new infrastructure such as cables on a platform with limited remaining operating life.
An expected 25% demand in decline for power on offshore facilities by 2030 is due to decommissioning, PEUK says.
Size and proximity to other infrastructure are also factors in the costs equation, trade bodies say.
Retrofitting brownfield operations, that were not designed to be electrified, can be technically difficult, with the OEUK stating that “major capital investment will be required”.
“The cost of retrofitting will vary largely between platforms. Platforms that can’t electrify will look at alternative solutions such alternative fuel,” the OEUK told Upstream.
The OEUK also points to regulatory blind spots that can be difficult to navigate when policies are still developing in this area.
The trade body stresses that the INTOG projects have to be connected to the oil platforms before 2030 in order to support the existing carbon reduction targets, but typical development timelines are estimated at eight to 10 years.
From a technical aspect, questions remain as to how much of a platform’s power supply can be delivered by offshore wind, with its intermittent nature, without significant backup.
Gas and diesel-powered systems have been relied on for years as they ensure availability and no interruptions. Generators have been designed to withstand the harsh conditions of the location to high standards of reliability.
Solutions may be offered high-capacity battery storage or simply retaining some gas-generation capacity, as is the case on Equinor’s Hywind Tampen floating wind project in Norway where wind farm-generated power is expected to meet 35% of annual power demand from five platforms in the Snorre and Gullfaks offshore fields.
Equinor states that the solution “will help reduce the use of gas turbine power” employed at the sites.
On the issue of intermittency, the OEUK told Upstream: “Some projects are looking to connect with the grid, providing power continuity. Other projects will only do partial electrification and use gas or diesel turbines as back up.”
The UK has a separate goal to reach an installed capacity of 50 GW from offshore wind by 2030.
The OEUK adds that synergies with wind farms and interconnectors include opportunities to repurpose oil and gas assets.
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