Lean Subsea Electric Actuators for Linear Gate Valves

Abstract Offshore resources are a major part of the world's required energy mix and are currently crucial as a source for many materials and goods used in our daily life. The production and processing of these resources mostly relies on heavy-duty machinery and infrastructure that has been proven and running for many decades. Over the years the possible technologies used for the process evolved and equipment became more reliable and compact with longer step-outs. At the same time, electric actuators were deployed to overcome the need for complex hydraulic power supply and to increase monitoring possibilities while minimizing time lags in the system's reaction. During the deployment of innovative technologies, a focus was put on the safety performance of the actuation systems. Due to potential risks to the environment, safety remains a key requirement for upcoming unmanned and autonomous production and processing sites. Linear valves and actuators play a critical role in subsea systems as they allow for lightweight and compact design of infrastructure. The first electric subsea actuators for linear valves were expensive, large, and non-retrievable due to complex safety mechanisms using springs. The current actuators reduced the size by replacing the springs with electric batteries, leading to higher costs to ensure minimum safety integrity level with complex subsea control modules. This dilemma splits the users in two groups: the ones who prioritize safety by springs but have to maintain the environmental risks and OPEX costs of conventional hydraulics; or the ones who prioritize electrification by subsea batteries but limit its application to fewer projects which can afford a much higher CAPEX. An innovative solution to overcome the challenges of the industry, following the state-of-the-art developments, was needed to allow sustainable and future-proof production and processing. This enables viable business models for rising industries such as Carbon Storage and green hydrogen production and transportation. At the same time, the solution had to be designed in a way to reduce cost and increase reliability and protection for the environment. This paper shows the simplest way to electric automated linear gate valves subsea, without compromising safety and efficiency. It explains how a portfolio of lean all-electric subsea actuators was developed and qualified, focused on cost-efficient and reliable operation, by integrating field-proven safety with an easy-to-exchange module and low-power consumption drive, designed to scale up the energy transition.