Gas platforms and offshore windfarms could work together to maximise gas production and renewable electricity generation offshore, according to a report from the Oil and Gas Authority in the UK.
The concept of gas-to-wire (GTW) involves using the gas produced from gas fields to generate electricity offshore and then transmit it to shore via spare capacity in subsea cables used for offshore windfarms.
“Due to the intermittence of wind, annual use of the associated power infrastructure is typically 40%. This spare capacity presents an alternative route for electricity generated offshore from gas fields or even from undeveloped discoveries and stranded gas resources,” said the Oil and Gas Authority (OGA).
“By installing offshore power generation facilities, operators could export electricity via established windfarm infrastructure instead of exporting gas to shore by pipeline. As a relatively flexible and fast responding form of power generation, it could play a useful role in balancing the electricity grid as supply and demand fluctuates.”
The OGA report, EIS Gas to Wire: UK SNS, looks at the technical considerations and potential benefits from GTW in areas such as the southern North Sea and the east Irish Sea. Both are unique in featuring established offshore gas production facilities and infrastructure alongside large existing and planned offshore windfarms.
In addition to generating additional electricity offshore, other benefits from gas and renewables collaboration include potentially reducing operating costs by pooling logistics and establishing guidance for effective co-existence within the same geographic area.
While individual elements of GTW are already proven (such as offshore gas production, gas-fired power generation, subsea power transmission), work is still required to bring the concept to market.
The UK southern North Sea (SNS) and east Irish Sea (EIS) are established production basins. Since the 1960s, numerous gas fields have been brought on stream following extensive infrastructure development. A more recent development has been the installation of large offshore windfarms in the vicinity of these gas fields.
The addition of offshore electrical infrastructure (including substation platforms and subsea cables) to export windfarm power to shore has, in effect, extended the UK’s national grid into the SNS and EIS.
The UK now generates more electricity from offshore wind than any other country in the world. Installed capacity, chiefly in the SNS and EIS, is currently at 6.8 GW, an increase of 1.7 GW since 2016 and is set to increase to 10 GW by 2020.
This ‘ullage’ (spare capacity) in this power infrastructure presents a potential alternative route for monetising nearby gas reserves, be that from currently producing fields or in stranded resources. By installing offshore power generation facilities, operators could export electricity via established windfarm infrastructure instead of exporting gas to shore by pipeline.
The OGA continues to support the East of England Energy Group (EEEGR) cross-industry work group which aims to promote gas and renewables synergies, while also collaborating with colleagues in the Oil and Gas Technology Centre (OGTC) and the Netherlands Organisation for Applied Scientific Research (TNO) who are considering similar concepts.
OGA area manager Eric Marston said, “Gas-to-wire has the potential to both help maximise the UK’s remaining gas resources while also boosting electricity generation offshore, with associated benefits for both gas producers and windfarm operators. We continue to see interest from a number of developers and operators seeking to commercialise this opportunity.”
EEEGR chief executive Simon Gray said, “For the last 18 months we have had a number of our members considering this sector. When we first looked at this opportunity, the barriers to market seemed too difficult to overcome. However, the legislative difficulties now seem to be surmountable, the technology achievable and the market more willing to consider this as a real opportunity.”
MP for Waveney Peter Aldous said, “This initiative with the gas and offshore wind industries working together is very much to be welcomed.
“Gas and offshore wind are vitally important component parts of the UK’s energy policy and significant advantages are to be gained from the two sectors collaborating in this way. These include the potential to reduce operating costs, ensuring that offshore infrastructure is fully utilised and balancing the grid at times that windfarms are not producing electricity. This partnership illustrates both the continuing strategic importance of the southern North Sea and how the UK is the global focal point for innovation in the power generation sector.”