LOW ORDER DEFLAGRATION
Original Article Written by Wind Energy Network
Low Order Deflagration - why its introduction into the commercial offshore industry will preserve biodiversity and save developers money.
The recent media storm following Joanna Lumley’s stop sea blasts campaign www.stopseablasts.org and direct plea to offshore wind developers and the licencing regulator highlights the need to look at alternative means of UXO disposal.
The ability to reduce the damage done by UXO clearance comes on the back of significant advances in the application of deflagration technology which has, until now, only been the preserve of specialist military operations.
UXO disposal operations remain virtually unchanged since the end of WWII, principally detonating a large donor charge next to the target UXO. This donor charge detonation causes the UXO to function as designed and the resultant high order detonation results in the tell-tale plume of water at the surface and loud audible blast. Propagation of the blast noise can then cause irreversible damage to cetaceans and sea creatures many kilometres away from the blast epicentre.
Mitigation measures in the form of bubble curtains have very questionable effectiveness, particularly against large UXO targets. High order explosions also see the release of numerous toxic chemicals into the water which could enter the food chain and can cause liquefaction of the seabed potentially causing downstream construction headaches for developers.
REDUCED WATER NOISE
The recent DBEIS trials undertaken by the National Physical Laboratory and Loughborough University have proved conclusively that deflagration technology can reduce underwater noise from UXO disposal to a mere fraction of what would be experienced from the traditional high order method. A small charge, whose explosive content is measured in grams not kilograms, delivers a very high-temperature plasma jet into the UXO, burning the explosive fill and contents before bursting open under the build-up of internal pressure. The UXO and its contents once declared safe by the EOD Specialist can then be safely removed and recovered using ROV or divers and later disposed of at a licenced environmental recycling plant. This whole process takes no longer than the current high order process, is safer and will ultimately cost less than the very aggressive high order methodology.
Industry officials from some influential organisations have cited this methodology as being unproven and potentially dangerous whereas the reality is that it is anything but. Deflagration has been used in the military for nearly 20 years with 17 nations’ navies using this capability to undertake thousands of safe and effective underwater EOD operations. In commercial applications, operational safety is assured by using only trained and accredited EOD specialists to undertake this operation. By using only relatively small charge systems in comparison to High Order disposal, deflagration is an almost ‘surgical’ operation in terms of making a UXO safe.
Thankfully forward-looking offshore wind developers do see deflagration as being progressive technology and see the enormous benefits of reducing noise and distress to our marine inhabitants in offshore wind construction. Encouragingly, some operators now see deflagration as the default methodology for UXO clearance. As we increase our offshore wind footprint to meet the future energy needs of our planet, it should not be at the expense of the natural world which we all have a duty to protect.