Crown Capital Management

UK – Drax, the traditionally coal fired power station in North Yorkshire may well claim to be the largest and cleanest of its type in the country, producing between 7 and 8% of Britain’s electricity but since 2003 it has been using an amount of sustainable biomass in an effort to reduce its environmental impact. This work took a big step forward last week when the company unveiled the UK’s first purpose-built biomass rail freight wagon, designed by the team at Lloyd’s Register Rail, and intended to radically improve the logistics required in transporting the fuel.

Drax is one of the world’s largest source of carbon emissions but is converting three of its six electricity generating units to burn sustainable biomass in place of coal with the intention of reducing emissions by some 10 million tonnes of CO2 a year compared to levels today. Obviously such an ambitious project will require improved logistics to ensure delivery of the huge quantities of biomass from ports such as Tyne, Hull and Immingham to the Drax Power Station, near Selby, hence the new wagon which has been built by rolling stock experts WH Davis.

After conversion Drax will generate electricity with biomass as the primary source of fuel making the plant one of the biggest sustainable power generators in the world. The wagons are part of an investment of up to £700 million by the group that includes boiler modifications and new biomass receipt, storage and handling facilities at Drax Power Station, as well as developments further upstream in the biomass supply chain.

The power station’s first biomass converted generating unit began operating in April; a second will follow next year and a third by 2016, crucially dependant on securing contracts for sufficient biomass supplies, with each burning approximately 2.3 million tonnes of sustainable biomass a year.

The properties of the fuel itself are radically different from coal, it is a third lighter but susceptible to rain, a problem solved so far by retrofitting roof components to old, open coal wagons. The differences in weight etc. meant that a complete redesign to produce a totally new type of wagon was necessary. To produce a vehicle capable of carrying the maximum amount of fuel, Lloyds had to squeeze control equipment, pipework etc. into otherwise redundant areas of a traditional hopper wagon whilst designing a viable steel/aluminium roof which could be operated pneumatically. The discharge of the fuel is also controlled by a patented product flow control system.

Work on two prototypes began in January 2013 and presented the design engineers with a number of challenges in achieving the increased wagon capacity within the limits of the Network Rail loading gauge. At 18.9 metres long with top doors stretching 18.2 metres and bottom doors of 3.7 metres, the supersize wagon has a capacity of 116 cubic metres allowing a biomass load weighing 71.6 tonnes. Its volume is almost 30% bigger than any freight wagon currently used in the UK. WH Davis, the last independent British freight wagon manufacturer, met this design specification by working to a measurement tolerance of 5mm, the highest possible and half that normally associated with wagon manufacturing. Ian Whelpton, sales and marketing director of WH Davis said:

“This has been one of the most challenging fabrications we have undertaken, but by working with the wagon designers from the beginning, we have been able to manufacture the required innovations and achieve the significantly increased cubic capacity.”

Drax has ordered 200 wagons, for which it owns the designs, and the first is on display at the National Railway Museum, York until the 12th August 2013. Speaking at the unveiling ceremony, Peter Emery, Drax’s production director said:

“Our transformation to become one of Europe’s largest renewable generators through the use of sustainable biomass means we need new, bigger and better rail wagons. We need to keep the biomass dry, move more of it and speed up the process of delivery. The finished product is an industry-leading design and fulfils all the criteria we set. We may be launching it in a museum but this wagon is no museum piece and will not be surpassed for many years to come.”

The near 30% increase in volume which the designers at Lloyd’s Register achieved during the wagon’s design was just one of a whole set of challenges associated with the completely new design, but these were accepted with alacrity by the team as Richard Gibney, professional head traction and rolling stock, Lloyd’s Register Rail UK confirmed, saying:

“This is the sort of project that designers relish. An opportunity to take a current design and re-imagine the entire concept, taking advantage of what we have learnt from the performance of the existing model, removing some of the inefficiencies and delivering an optimised design.

“As a project, it still presented the team with some unique challenges as we sought to arrive at a design that would meet its objectives yet also conform to all the necessary industry standards. We are proud to have produced a design that fits the brief precisely and will serve our client’s business for years to come.”

The story of the concept, design and construction of the biomass rail wagon can be seen on a specially made video (viewable here).