6th Jan 2016: North Korea claim H-bomb
Many who are involved in the renewable wind sector industry in Scotland and the UK will have been inconvienced by a seemingly obscure measurement station known as Eskdalemuir. A key purpose of the site is to measure sesimic ground vibrations relating to nuclear testing. In 2004 the station registered concern that the installation of wind turbines nearby might impact the sensitivity of the site's detection capabilities and this week the importance of this capability was put on the front page with the news from North Korea claiming to have tested an H-Bomb. The scientists at Eskdalemuir will be working with their colleagues at the CTBTO to verify these claims. Xi are proud of the work we undertook that allowed the development of wind turbines in the area whilst protecting the Eskdalemuir seismic array.
There's a great video by MinutePhysics that explains how the CTBTO works of which Eskdalemuir forms an important part.
27th May 2014: ReNews reports that,
"The Ministry of Defence has withdrawn objections to hundreds of megawatts of proposed wind farms around the Eskdalemuir nuclear test monitoring facility in the south of Scotland."
The 50km radius consultation zone around the Eskdalemuir seismic array
The hills close to the village of Eskdalemuir in the borders of Scotland are home to a seismic monitoring station. The Eskdalemuir Seismic Array (EKA) is a seismic station within the International Monitoring System (IMS) network. It was built to support verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which was ratified by the UK in 1998. As the UK’s designated national authority, the Ministry of Defence (MoD) must ensure that the UK’s responsibilities are fulfilled under the CTBT, by ensuring that the station’s detection capabilities are not compromised.
To protect the EKA from ground vibrations the MoD introduced a 10km radius Exclusion Zone and a 50km radius Statutory Consultation Zone for all wind turbine development. This consultation zone covers an area of almost 8000km2 covering the South of Scotland and the North of England representing around 3% of the UK’s total land area. Within the Consultation Zone a vibration budget was implemented with all existing and newly built wind turbines contributing to an overall vibration level acting on the EKA. That level has now been reached and without mitigation to reduce vibration levels there can be no further wind turbine development in the area.
Working towards wind energy that is compatible with safeguarding the EKA
Artists impression of Xi Engineering's SQT vibration damper for wind turbines
The Xi Engineering team have been heavily involved since 2005 in trying to overcome the challenges of maintaining protection of the EKA whilst allowing development of further wind resource. Xi initially designed an innovative damping system for wind turbines called the SQT. The prototype SQT was found to be extremely effective at reducing the vibrations that prove most problematic for the EKA detection and is potential route to mitigation. In addition to this, Xi have been working with the Eskdalemuir Working Group (EWG), the EWG is headed by the Scottish Government and is made up by the MoD, DECC, wind farm developers, RenewableUK and Scottish Renewables. The EWG are tasked with looking at the issues surrounding the EKA and wind development. In 2013 Xi published preliminary work ‘Initial Study of ground vibration data recorded near Craig windfarm, Phase 0 report - estimate of potential head room in the Eskdalemuir Budget’. This work indicate that there is a likely prospect for headroom to allow further wind farm consents without breaching the vibration threshold at the EKA. Following this, the EWG and Xi are currently working on the implications of these findings in the follow-up Substantive Research Stage One work, with the results of these findings expected in mid April.
Other Sensitive Sites
The Eskdalemuir Seismic Array relies on vibration to operate and is therefore very sensitive to external vibration noise. The EKA is not alone and similar issues can be found with other seismic observatories part of the CTBT network or otherwise. Other sites with sensitive equipment that may be susceptible to ground vibration include telescope observatories, gravity wave observatories (or other scientific facilities using laser interferometry), medical facilities and semi-conductor manufacture facilities. In addition vibration can come from a variety of sources beyond wind turbines, including, but by no means limited to road, rail, and construction piling. With their seismic prediction capabilities, Xi are industry leaders in these issues and would welcome discussing the quantification of ground borne noise in relation to your application. So if you are looking to develop wind turbines within the Eskdalemuir consultation area and would like to learn more about how your development may be impacted, or you have concerns over another seismically sensitive site, please contact us and our specialist team will be happy to discuss.