Cutting offshore emissions: Oil and gas platform electrification

The idea is straightforward to cut offshore carbon emissions: replace the open cycle gas turbines used to generate a platform’s continuous power and heat with an electricity supply. Platform electrification offers the opportunity for perhaps the most straightforward early win in the effort to support the delivery of the UK’s net zero target.

The world needs answers to cut greenhouse gas emissions and there is the opportunity to capitalise on the synergies which exist within the UK’s burgeoning offshore wind sector, with potential to share infrastructure as well as expertise and knowledge. The concept of platform electrification reduces the carbon footprint of the oil and gas business, while extending asset and field life and improving operational economics. Our recent report for the Oil and Gas Authority (OGA) has shown that technical solutions including, using both AC and DC systems, are mature and relatively low risk.

Electrification – a game changer

The savings gained from platform electrification may simplify the equipment needed offshore, however, these savings alone, compared to using turbines, are unlikely to make the electrification business case. Platform retrofits would also typically be high cost, although requirements would vary between assets and locations. The option of running a cable from the shore to the platform is a major investment because oil and gas operations tend to be far from shore, between 150–350 kms. If you tried to send a continuously stable power over such distances under water, it would never be cost effective and is difficult to achieve, especially as a longer field life is fundamental to cover the pay-back period for the cable investment. A cost reduction that would positively impact the capex, would be to plug into an existing subsea electrical interconnector or share electrical infrastructure with a nearby offshore wind farm. Wherever the circumstances are right, platform electrification should be considered, especially for new projects.

Power to the platforms

Equinor’s Johan Sverdrup field in the Central North Sea, came on-stream in October 2019 and is already producing 350,000 barrels per day. By powering the field almost entirely by hydroelectric power from shore, they have managed to slash emissions to just 0.67 kg — or four percent of the world average — per barrel produced. This means the field will avoid emissions of more than 620,000 tonnes of CO2 every single year.

This field highlights the real life application of hydroelectric power, where a large new development can be the hub for further electrification in other neighbouring fields. Once you’ve made the investment to send power offshore, it’s a matter of incremental investments to distribute that power elsewhere in the area. Add to this a Norwegian government that is committed to reducing its offshore emissions – about a third of national emissions; you have the winning ingredients for positive change. By 2020, the Norwegian parliament has decreed that licensees in the Johan Sverdrup field must establish a power-from-land solution in the area, which is ideal in cutting carbon emissions, especially for a country with a clean-energy mix from hydropower.

Together, longer or larger

Electrification doesn’t stack up for all platforms. Looking at economies of scale, doing this on an individual asset basis may not be the best approach. One way forward is for existing operators to join forces, sharing the investment required over several platforms.

As touched on earlier, fields with a short life span are pretty much ruled out as it could take four to five years to implement electrification, before starting to realise a positive return on investment. What is more promising are fields with a longer life span, as well as areas with a high growth potential, for example, in the North Sea, electrification shouldn’t be ruled out for the under-explored area in the West of Shetland. These larger fields have less than a 40–50 year lifespan and offshore wind might make the sums add up if it’s located within 50kms or so. An oil and gas facility could leverage low-carbon power from the wind farm when the wind is blowing, while having security of supply from cable to shore when there is no wind. It is clear that greater collaboration between the oil and gas and wind industry is needed. The development of more onshore and offshore wind farms, such as floating wind farms, have the capability of placing offshore wind power generation at the heart of oil and gas production in deeper waters.

Lloyd's Register secured two major UKCS projects with the Oil and Gas Authority (OGA) for the UK Continental Shelf (UKCS), for the provision of Regional Exploration Maps and Regional and Field Support Engineering Services to help the OGA independently assess remaining undiscovered resources and improve geotechnical understanding. Read full details of the project win.

This is article four in a series of posts dedicated to our project for the OGA. Read the previous article.

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