What is PowerCrete and where is it used?
Demand for renewable energy infrastructure is growing. The International Energy Agency (IEA) predicts power generation from nuclear sources will be overtaken by wind and solar in 2026. By the end of the decade, the Agency forecasts that global renewable electricity generation will increase by nearly 90% in comparison to what it was in 2023.
The transition to clean energy is gaining momentum around the world and here in the UK. One of the core drivers of adopting renewable energy to power our homes, industries, and businesses is reliable power transmission. The underground cables that transfer electricity around the nation need to effectively manage heat buildup, particularly with the network growing, and engineers need to be able to install them efficiently.
Helping to enhance consistent and reliable electricity transmission is our thermally conductive bedding material, PowerCrete. Specially designed to reduce hot spots and enhance handling ease, PowerCrete is empowering the development of renewable energy infrastructure in the UK.
The need for a superior heat-conducting concrete
When bedding and infilling high voltage (HV) and ultra-high voltage (UHV) cable installations, a 14-1V cement bound sand (CBS) is traditionally used. When compacted properly, the ENA TS 97-1 compliant mix hardens, making it ideal for protecting underground cables from physical damage.
14-1V CBS is a dry mix and needs compacting with a wacker plate, which can be difficult to manoeuvre in confined spaces. If 14-1V isn’t compacted effectively, its capacity will reduce.
What is PowerCrete?
In the switch to renewable energy, infrastructure needs to be as efficient and robust as possible for long-term, sustainable use. PowerCrete is the heat-conducting concrete alternative developed to meet the needs of bedding and infill in HV and UHV cable installations. The high-performance concrete is designed to overcome the common challenge of overheating and provide additional benefits to underground electrical cable protection.
Advantages of using PowerCrete
PowerCrete’s thermal conductivity is superior and has low heat transmission resistance. The heat-conducting concrete mix enables:
- Efficient heat dissipation
- Reduced magnetic field strength
- Lower conductor temperatures for increased power capacity
- High levels of workability
- Smaller conductor sizes to be used
- Use of aluminium or copper conductors
- Thermal resistivity of 0.33 Km/W
The concrete mix also prevents hot spots, making it a robust upgrade over traditional backfill materials.
Challenges of HV and UHV underground cable installation
Where underground space is limited, HV and UHV cables sometimes need to be installed near each other. It’s a common challenge when bringing cables from off-shore wind sources to those on-shore, or improving the power output of a substation in the grid.
The closer the cables are to each other, the easier it is for heat to build up. The potential for hot spots increases, which can lead to damaged cables. Heat build up can also increase resistance placed onto the cables, reducing the total power output the cables can achieve.
Thermal resistivity of heat-conducting concrete
Traditional materials used in HV and UHV cable bedding and infill have a thermal resistivity of between 1.2 Km/W and 2.7 Km/W. The thermal resistivity of PowerCrete is 0.33 Km/W, thanks to our exclusive use of a binder with extremely high thermal conductive properties.
Our specialised concrete mix allows effective dissipation of heat, reducing the likelihood of hotspots and associated issues. Underground cables bedded or infilled with this concrete will continue to run at a safe temperature, keeping electrical transmission efficient.
Aluminium VS copper conductors
PowerCrete doesn’t just enhance electrical transmission and installation efficiencies, but can unlock cost savings, too.
Copper is a metal widely used for underground cable conductors. With superior electrical conductivity and a high current capacity, it’s easy to see why. But copper is an expensive material, and when scaled for use in a large infrastructure project, it can be out of budget.
Aluminium conductors are an effective alternative that can be used in most applications. They’re more affordable than those made from copper - in some cases, copper is five times more expensive than aluminium - making them ideal for managing cost constraints in large renewable projects. While copper has better electrical conductivity than aluminium (by a factor of 1.64), it’s also around three times heavier, meaning aluminium is easier for engineers to handle.
The shift towards aluminium is also because of its lower levels of energy loss. Studies have compared energy losses when using a small copper conductor against a very large aluminium conductor. The former generated the most losses, showing how aluminium could bring about significant savings across both energy and cost.
Thanks to working with both copper and aluminium conductors, PowerCrete gives engineers the flexibility they need when it comes to cost considerations as well as heat loss and handling ease.
High levels of workability
When embedding and encapsulating ducts and cables, for instance, you need a heat-conducting concrete with a free-flowing consistency. We can adjust the workability of PowerCrete to meet the demands of your application. PowerCrete is usually supplied at a consistency of S4/F4, but we can tailor it to meet the specific needs of any project to allow easy placement and compacting for the best finish.
Suitable applications for PowerCrete
Our specialist concrete mix is ideal for HV and UHV underground cable installations across numerous applications, including:
- On- and off-shore wind farms
- Solar farms
- Nuclear power plants and modular nuclear reactors
- Substations
- Subsurface power infrastructure
- Data centres
- Battery storage facilities
PowerCrete in use: Hurst National Grid Sub-Station
In 2020, the National Grid started a seven-year underground rewiring project in South London. Many of the cables relied upon to transmit electricity around the area site have nearly reached end of life and need replacing. PowerCrete was selected as the heat-conducting concrete mix that would house and protect the new HV electricity cables in these deep underground tunnels to deliver enhanced reliability and power.
PowerCrete in use: Offshore Inch Cape Wind Farm Landfall
Critical to Scotland’s renewable energy infrastructure is the Inch Cape Landfall project. It plays a significant role in transitioning the UK to low-carbon energy. At the landfall site, the project needed a robust and thermally efficient solution for cable burial. PowerCrete was chosen for the project, enhancing heat dissipation and structural integrity of the electrical infrastructure.
Power range of thermally conductive bedding materials
PowerCrete is our heat-conducting concrete mix with the lowest rate of thermal resistivity, 0.33 Km/W. Not all applications require such a low level - one of the other mixes in our Power range may be more suitable for your project.
PowerSand
Product type: Sand
Ideal for: Long-distance underground cable routes where future access may be needed
Advantages: Offers stability by accommodating minor ground movements
PowerSand CBS
Product type: Backfill material
Ideal for: Energy, utility, and rail projects
Advantages: Certified and ENA TS 97-1 compliant, and dissipates heat to reduce electrical resistance
PowerSand CBS Extra
Product type: Non-traditional stabilised backfill
Ideal for: Power cable installations
Advantages: Contributes to a reduced carbon footprint, making it a sustainable choice
PowerCrete
Product type: Heat-conducting concrete alternative for bedding and infill
Ideal for: HV and UHV cable installations
Advantages: Superior thermal conductivity, supports conductors of different sizes and materials, and helps to prevent hot-spots
Thermal resistivity comparison
Order PowerCrete
For more information on using PowerCrete to protect underground electrical cables for your application or to place an order, please get in touch with our technical team via: concrete.technical@heidelbergmaterials.com.
