Drax Power Station

Drax Night Shot

The Drax Power Station has been registering with the Scheme since July 2012 and is being constructed by Shepherd Construction Ltd. The Scheme spoke to Shepherd to find out more about their commitment to considerate construction.

Please can you describe the project you are working on?

Drax Power Station in North Yorkshire is the UK's largest power station, and is set to become the UK's largest single renewable electricity generator through the operation of new biomass facilities constructed by Shepherd Group.

With recent Government targets outlining that 15% of the UK's energy must come from renewable resources by 2020, Drax embarked on an internationally unprecedented path by announcing plans to convert the existing facility to a predominantly biomass-fuelled generator and chose Shepherd Group as its main contractor for the construction works.

The biomass conversion will ultimately see three of the six generating units at the Yorkshire power station converted to burn sustainable biomass in place of coal. The first unit has been running successfully on sustainable biomass since the beginning of April 2013, with the second planned for this year and the third in 2016. Each converted unit will provide enough renewable electricity to meet the equivalent needs of over 1 million homes.

Presented with Drax's bold proposals for biomass receipt, storage and distribution, Shepherd Group's Power and Infrastructure team utilised its global resources, experience and skills to identify the technically viable and ingenious solutions to make this ambition a reality.

Shepherd's pioneering solution encompassed the construction of four extensive biomass storage domes - with a combined total of 450,000m³ of potentially hazardous biomass material storage space. The project has also seen the installation of bespoke infrastructure to facilitate the transportation of high volumes of biomass material across the site.

It clearly shows what can be achieved by British industry not only in terms of Drax's visionary strategy, but in the ability of UK expertise in the Built Environment sector to turn that vision into a world class point of reference for exemplar design and engineering.

State-of-the-art and ground-breaking projects that are critical to national success in industries such as energy, infrastructure, health and education always require the most demanding and, at times, unexpected requirements.

An overwhelming challenge for Shepherd was to implement the transformation concurrently with the plant's essential day-to-day operation.

Working hand in hand with Drax, this project harnesses the multidisciplinary expertise across Shepherd's in-house teams, comprising Shepherd Construction, the technical services specialist Shepherd Engineering Services (SES) and bulk handling specialist Portasilo.


Biomass conversion is complex. It's not simply a matter of swapping one fuel for another and, as a UK-first, this project and the materials used, presented challenges not yet faced on UK soil.

The storage domes - each reinforced with 500 tonnes of concrete - feature pioneering technical solutions to eliminate fire risks surrounding dust generated from the biomass pellets. Combined with the vibrating floor technology, which prevents product degradation, this enables maximum efficiency and 100% reclaim of biomass pellets.

The unprecedented infrastructure needed on site has seen the incorporation of 28 conveyors systems with a combined length of 4km, capable of transporting 2,800 tonnes of biomass per hour, reaching day silos at heights of up to 68 metres.

In addition, a total of 5,680 metres of new rail track has been laid (rising to approximately 6,000 metres including track repair work) to allow the sustainable conversion of the plant, the operation of Drax's specialist network of biomass trains and delivery of construction items. So far there have been 19,061 deliveries since project commencement.

The shift into renewables required the deployment of technical innovation never seen before in the UK power and infrastructure sector, so it was essential that the team undertook a rigorous and open-minded approach to researching and evaluating the best available technology.

Bringing technologies from other countries into the UK presents its own unique challenges, for example, the thin-shell concrete dome storage solution at Drax involved addressing substantial differences in design standards and safety regulations between the USA and the UK.

This demonstrates Shepherd Group's growing reputation as the industry's best-in-class and innovators in the complex global technical market arena.

How have you incorporated the Scheme into your site?

Phil Greer Neil Clarke  Ed Davey MP copyA key part of Shepherd Construction's DNA is to ensure that its presence in the communities in which it operates brings passion, pride, added value and leaves behind a true measurable legacy, for all stakeholders. At the forefront of this is the belief that all working practices and projects undertaken promote inclusivity and accessibility for all.

Fundamental to this partnering ethos is engagement with all stakeholders involved in the project to ensure Shepherd addresses and meets everyone's aspirations. In short, Shepherd cares and is in it for the long run. Close partnering with stakeholders is a necessity and the company believes it is an obligation to lead this interaction.

It is why Shepherd are 100% committed to and believes in the Considerate Constructors Scheme, the principles and requirements of which are at the heart of all of the Company's activities.

The team is proud to have received scores of 9-out-of-10 for environment and safety and 8-out-of-10 for appearance and workforce against the Scheme's Code of Considerate Practice.

This endorsement is testament to the fundamental incorporation of Shepherd's own high standards of work-place health and safety, Quality Assurance, environmental responsibility and excellent working practices across all of its projects.

Key to safety issues on site is the very nature of biomass pellets. Generally made from compacted wood products, moving these pellets results in the generation of dust at all stages of the biomass's journey across the site.

This represents a key safety consideration for the entire workforce which is intrinsically linked to the day-to-day cleaning and maintenance and appearance of the workplace, as well as on-going staff training and the environment.

To achieve such high scores for the on-site environment represents a clear success considering the project is being delivered within an incredibly tight timescale and on a fully-operational site, which brought its own logistical challenges.

Shepherd had to deliver the project in compliance with permits and environmental targets effectively and efficiently; Drax Power Station is regulated by the Environment Agency (EA) under an Environmental Permit. The Environmental Permit covers the whole project and every person working on it without exception.

Failure to comply with the Environmental Permit carries a range of penalties depending on the severity, including a monetary fine and imprisonment with the consequent impact on operating costs, operational restrictions and reputational damage.

The project incorporates an array of world-leading health and safety features from fixed vacuum cleaning systems which ensure control of dust across the site, in addition to more than one mile of dust conveying pipework which has been installed by the team.

Additionally, the Shepherd team has carried out the training and induction of 5,241 staff on the project ensuring that the existing health and safety standards remain a legacy of the project going forward.

In order to reduce health and safety risks, and to ensure the quality assurance of the site with such a large number of staff, Shepherd fully utilised its SES Prism off-site fabrication facility.

By ensuring the maximum amount of construction off-site and use of the latest Shepherd BIM modelling software, Shepherd dramatically reduced the labour time, manufacturing space and material wastage on the Drax premises as well as the health and safety risks.

As a national industry leader, it gave the Shepherd team great pride to take on a challenge at this vital facility.

What were the key challenges?

To ensure compliance with the Environmental Permit, Shepherd drove continual environmental improvement through the operation of its Integrated Management System accredited to ISO 14001:2004.

Shepherd assessed all environmental aspects and evaluated their significance including; emissions to air, release to water, waste management, contamination of land, impact on communities, use of raw materials and natural resources and other local environmental and community issues.
Where these issues impacted on Shepherd business functions and construction activities, they were recorded on the Project Significant Environmental Aspects Register and further developed into a robust Project Environmental Plan, which was reviewed and approved by Drax, Shepherd's verification body BSi and Drax's external verification body, Lloyd's Register Quality Assurance (LRQA).

With regards to the health and safety aspects on this project which were many and varied, from confined space through to and including working at height (in some cases over 75m high) Shepherd ensured that an overall project risk assessment was undertaken to identify all potential risks. This then allowed the company to prepare project specific risk assessments that included site specific controls to prevent the hazard from occurring. Throughout this process Shepherd engaged fully with both the client and its supply chain to ensure a collaborative effort in preventing health and safety risks from occurring.

This was further supported by developing and running a project specific cultural behavioral safety program that was attended by the client, employees and supply chain which further enhanced the team's commitment to safety in project delivery.

The fire and explosion risks presented by biomass are significant and are clearly illustrated by recent incidents at Avedore Poer Plant, Copenhagen (Dong Energy) and Tilbury Power Station, UK (RWE Npower).

These incidents demonstrate the emerging status of biomass specific technology and emphasise the need for rigorous interrogation of both the strategic design approach and detailed design solutions at the earliest stage in a project's gestation and throughout.

All elements of the system had to minimise air-borne dust and product degradation, provide fire produce protection, incorporate a high level of automation and guarantee operational reliability.

And in addition to this, the key technical challenge with this project was quite simply, scale.

The size of the project is unprecedented in terms of biomass storage capacity, transfer rates and staffing levels within a fully-operational site.

How did you overcome these?

Drax Eco Store from Stack 002The facilities being delivered are certainly not an 'off the shelf' solution; they have required innovation at every stage by Shepherd Construction, SES and Portasilo, as well as the supply chain.

With 800 people currently on site, rising to 900 for the first two handovers, approximately 210,000 hours per month are spent on the project.

As of December 2013, a total of 3,441,333 man hours have been worked on site with an Accident Frequency Rate of 0.14, which is a significant achievement for the team.

This project has required the Shepherd team to challenge itself and put its intelligence to the test every day whilst ensuring every aspect contributes to the client's performance objectives.

With all of the air-inflated four domes capable of holding 450,000m3 of biomass material - it was key that all aspects of the processes installed on site work perfectly in sync.

An example of all this multifaceted approach is the world-first fire prevention schemes that Shepherd implemented after analysing the safety systems in existing biomass plants across the world.

To develop the final system, Shepherd worked closely with suppliers, Air Products, to install the on-site Nitrogen generation and CO2 storage plant. While nitrogen is used as a suppressant to stop fires starting in the first place, CO2 would be used in the eventuality of a blaze.

The result is a bespoke system offering both preventative and immediately reactive protection as well as added security.

As mentioned, working in such a confined space required an emphasis on logistical management.

Shepherd has installed 7,000 tonnes of primary steel; 100km of primary containment (from baskets to ladder racking and trunking); 400km of power and lighting cables alone; more than 3,000 luminaires; 9 air compressors and 307km of commercial & industrial cabling.

To ensure maximum productivity, Shepherd engaged the SES PRISM off-site fabrication facility, where a total of 8,000 man hours were utilized, significantly reducing the labour time which would have traditionally have had to be done on-site.

As a result, 22 prefabricated switch rooms, 697 prefabricated integrated services modules, 28 prefabricated services risers were completed off site.

Another 1.7km of pipework and 13km of electrical containment was fitted on modules at PRISM and 2,286 prefabricated brackets were assembled, again off-site, reducing time, space and wastage as well as the health and safety risks of labour on site.

Can you give other examples of good practice on the project?

The operational challenge of managing a potentially hazardous and confined site has required an incredible amount of collaboration between all three Shepherd operating companies and the client from day one.

Potentially one of the biggest innovations has been the way all parties have come together to work as 'Team Drax'.

With Shepherd Construction, SES and Portasilo working together with the client and the supply chain, everyone has bought into it, representing a perfect example of Shepherd's collaborative team culture.

Team Drax is not just a logo, a banner or a slogan. It has become a way of life.

There is a dynamic to the project which is driving towards completion and this makes the environment very intense. Because of the speed of the build and the size of the components, staff can physically see progress every day on a massive scale.

Any other comments?

It says a lot about Shepherd as a UK-leading company that success and project delivery is being achieved in such a strict and challenging environment, yet the company's responsibility to the safety and quality assurance of the site remains at the forefront of its strategic thinking.

This project marks a key milestone both for Drax and for Shepherd. It shows what can be achieved by British industry not only in terms of Drax's visionary strategy, but in the ability of UK expertise in the Built Environment sector to turn that vision into a world class point of reference for exemplar and ground-breaking design and engineering.

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