To coincide with OTC 2014 in full swing in Houston this week, we’re kicking off our offshore blog series with the benefits of Direct Current (DC) transmission for exploration and production, and how it can be harnessed by particular applications to meet wider industry challenges.
First and foremost, DC will make offshore activity more economically viable – a vital factor as we are now forced to explore further offshore as ‘easy to access’ resources are depleting. Boosting the overall operational efficiency of transmission and increasing range and step out, DC reduces the cost of power delivered to, and on, offshore applications including drill ships, semisubmersibles and FPSOs. In addition, CAPEX is further reduced owing to the relatively small amount of copper cable required to transmit DC compared to Alternating-Current (AC).
Drill-ships naturally lend themselves to DC, owing to the large amount of existing DC loads (namely drilling). They are the most mobile breed of offshore drilling units and while they are quick to deploy, they do require a consistent, clean supply of energy for dynamic positioning and propulsion to move between multiple locations, making DC power systems for drill ships a most attractive proposition. Drill ships, therefore, will be one of the first offshore applications to really utilise such systems on board, due to the hugely simplified installation and increased power density of the power and propulsion equipment. This includes transformer-less solutions, high speed generators and reduced amounts of switchgear.
Semisubmersibles, while less flexible in terms of location, are cheaper to construct than drill ships and DC still has the potential to significantly reduce CAPEX costs and increase efficiency of deployment by eliminating transmission loss on the switchboard, improving dynamic performance and reducing overall generator maintenance on board.
DC can also be used to increase optimization of the power system for Floating Production, Storage and Offloading vessels (FPSOs). The benefit of high speed generators (increased power density) and reduced cabling requirements will dramatically reduce the CAPEX cost of new build FPSOs. The supply of specialist power generation, processing equipment and integrated automation systems also ensures far higher levels of reliability while achieving increased fuel efficiency.
Drill ships are one of the first offshore applications to utilise DC transmission for exploration and production.
As the industry meets this week at OTC, consider the benefits and implications DC technology could have on your offshore operations and business. Even though DC technology for some applications may not be commercially ready for a number of years, the industry needs to start moving now. Greater technological development, research and industry joint venture will help make deep and ultra-deepwater offshore exploration and production more sustainable and economically viable, while reducing the perceived financial risk associated with this activity. This can only be good news for oil and gas companies and, most importantly, their investors.
Following what we have explored above, my colleagues will present a paper alongside partners at OTC about modular DC electrical power systems design for subsea fields at 3:50pm Thursday, May 8. To hear more about this, visit with our experts at GE’s booth: 3163.