The district heating network at Sleaford would distribute free heat and hot water to local organisations, such as schools and sports clubs, bringing a big financial boost to them while lowering carbon emissions, but first Vital Energi would have to overcome the significant obstacle of running district heating pipework beneath the river Slea.
“This was a fantastic community scheme which will now see local organisations benefit from low-carbon heat and hot water and we are delighted to have helped deliver such a technically challenging project.”
Steve Webster Contracts Director - Vital Energi
The £155 million straw bale powered Sleaford Renewable Energy Plant is capable of providing electricity to 65,000 homes and Vital Energi were charged with the task of designing and installing the district heating network.
The facility will burn an estimated 240,000 bales of straw per year to produce electricity and the surplus heat which would be wasted in a traditional power plant will, instead, be used to provide free heat for the community buildings.
This was a project which would be vitally important to the community as local community buildings would receive free heat and hot water which would have an estimated value of over £2 million during the 25-year contract.
Sleaford promised several large challenges which included significant trenching while keeping disruption to shops and residents to a minimum. The network would include a 950m trench on Boston Road, one of the busiest in the area, which would also accommodate a 63mm waste water utility service.
The largest technical challenge on the Sleaford project was that the pipework would have to cross the river Slea and while Vital had done over-water crossings in the past, this was the first instance where they would place a pipe under a river.
After close liaison with the local authorities, Vital Energi installed 2.4km of pipework to connect the local leisure centre, bowls club, football club, North Kelvesten District Council and William Alvery school join the network.
The length of the trench work would see Vital liaising closely with highways and also local residents and businesses who would feel the effects of these essential works which included a 950 metre trench on Boston Road, one of the towns busy access roads. All trenchwork was subsequently reinstated to highways standards.
Phase 2 of the project presented Vital Energi with one of its biggest challenges ever, as the district heating main would now be extended from the Leisure Centre to the North Keveston District Council offices and William Alvey School with the river Slea between the two sites.
After thoroughly exploring all possible options, Vital Energi opted for a directional drilling technique. Using a pneumatic rock auger which drilled two 325mm diameter steel sleeves at a depth of 3m under the river bed, which allowed the District Heating pipework to be placed below the river. The under-river section would measure 26 meters in length and proved to be a secure and cost-effective way of crossing the river.
The depths of the excavation called for extensive shoring to ensure the project, allowing operatives to work in the safest environment possible.
While logistically and technically challenging, through creative design, experience and careful planning the project progressed according to plan and by opting to put the pipework under the river it ensured there was no unsightly above ground pipework.
This project, which will see £2 million of free heat and hot water distributed to local community buildings will have a huge positive impact on the community over the next 25 years.