Valve Magazine - Spring 2012

ACTUATORS&CONTROLS
Solar-powered Valve Actuation: An Update

The use of solar power in industrial and municipal valve actuator applications goes back several decades; however, technological advances in solar power efficiency and storage mean that today, it has become a practical, dependable alternative for many isolated locations.

In the early days, solar power was
used in noncritical applications that
required low power consumption, prima-
rily to supply monitoring of valve-related
and process data at remote locations. As
solar power technology evolved, applica-
tions expanded along with the sophisti-
cation of the technology.

ENERGY CONSUMPTION

A key factor of whether or not to consider solar power for an application relates to available energy and consumption. Two examples would be a 36- inch valve or gate operating at 1,000 psi on a crude oil pipeline and a 96-inch sluice gate in 25 feet of head water at a remote dam site. The two would require about the same force and amount of energy to operate. In both these cases, users would find bringing utility power to the sites cost prohibitive, which triggers the process to consider solar power.

In these scenarios, the pipeline company needs to be able to close the valve in an emergency in response to environmental and safety concerns. The water utility needs to maintain an appropriate level in its reservoir through the winter, which means changing the outlet gate position as the lake level rises or falls. Both applications need to sense process conditions, transmit information, move a load and do it all off grid. Solar power can be more cost effective in such cases and requires less maintenance than gas or diesel generation systems if the loads can be managed.

High in the Andes Mountains between Argentina and Chile, 14 valve sites are connected by fiber optic cable to the pipeline command center. Solar panels provide power for the station during the summer months and a turbine wind generator takes over during the winter. A control building houses the communication equipment and the hydraulic power unit (lower right). The 16-inch pipeline is buried, but the hydraulic actuator mounted on the valve extension can be seen above grade (lower left).