SEATTLE | Fri May 15, 2015 2:18am BST

The first of two Royal Dutch Shell drilling rigs slated for Arctic oil exploration arrived in Seattle on Thursday as environmental activists geared up for days of protests over plans to store the equipment at the city's port.

Shell is planning to use Seattle as a base to store and maintain the rigs and other equipment as it resumes exploration and drilling this summer in the Chukchi Sea off Alaska, where it has not drilled since a mishap-filled 2012 season.

The decision to resume drilling, and the port's decision to allow Shell to lease space in Seattle, has been met with anger by some city leaders and environmental activists who say drilling in the delicate Arctic ecosystem could lead to an ecological disaster.

Environmental groups also contend that weather conditions make it impossible to safely drill in the remote Arctic, a region that helps regulate the global climate because of its vast layers of sea ice.

Over coming days and weeks, protesters are planning dozens of demonstrations, including in boats and kayaks, to try to prevent the rigs from leaving again. At least one city councilman, Mike O'Brien, said he planned to participate.

Activists constructed an approximately 20-foot-tall (6-meter) metal tripod at the entrance to Shell Oil's fuel transfer station in Seattle on Tuesday to try to block access to the rigs.

The Puget Sound region has for decades been a hub for equipment used in energy drilling in Alaska even as some environmental groups and politicians have pushed for the region's economy to move beyond oil, gas and coal and into clean energy.

Seattle Mayor Ed Murray and the City Council have urged the port to reconsider its lease to Shell, and the city's planning department has ruled that the port's agreement with Shell is in violation of its city permit.
The Port of Seattle had asked Shell to delay its plans to move the Polar Pioneer rig to the city on Thursday while it appealed. Shipping company Foss Maritime has also appealed the ruling.

A Shell spokesman said it intended to move ahead with plans to dock the rigs at the port despite the permit questions and protests. A timeline of when Arctic exploration would resume was not yet known, he said.

The other rig planning to dock in Seattle, the Noble Discoverer, was at the Port of Everett and also headed to the city this week.