Cut out the diesel with this hybrid solution

Crossflow’s Integrated Energy Solutions (IES) is a combined wind turbine, solar pv, battery and diesel back up unit which promises significant cost savings for telecoms operators. By allowing for 100% non-diesel powered uptime, Crossflow believe they can reduce your energy costs by 20-30% while reducing the need for site visits. With a prototype going live in the Caribbean and promising results already, Crossflow offer a new solution for the global telecom towers industry from out of South Wales. 

TowerXchange: Please introduce Crossflow Energy – what is the origin of your unique technology and what problem are you solving for the telecoms sector?

Crossflow IES are specifically designed to deliver clean, reliable energy in remote, off-grid applications. The IES comprises a robust specialised Wind Turbine, and Energy Management System (EMS) to combine multiple energy generation and storage assets to optimise clean power delivery. By incorporating a wind turbine the IES has the capability of delivering 100% clean energy. The Crossflow IES has been successfully commissioned at the Company’s test site in South Wales; we are focused on moving towards achieving a rapid roll-out of the technology, with initial market demonstrators agreed with a key Mobile Network Operator (MNO) Anchor Customer in the Caribbean. At present some 1 million MNO towers rely on diesel generation (entirely or significantly) for network reliability; Crossflow IES units can move such remote locations to 100% clean energy with potential for significant cost savings by MNOs.

TowerXchange: The first question our readers will want to know is ‘how proven is the solution in the field’ – please tell us about the performance of your solution in the field – who is using it and what results have been achieved?

The Crossflow Pre Production Prototype (PPP) IES has been successfully commissioned at the test site in South Wales and we are currently preparing to install the first commercial trial project at a MNO telecommunications tower site in the Caribbean. The empirical data obtained from the PPP IES bears out the Computational Fluid Dynamics (CFD) predictions for the turbine and we are achieving a power curve and efficiencies in line with expectations; we are also able to monitor and operate the IES unit remotely to ensure correct rotor head alignment in relation to wind direction and the various arms of the IES – wind, solar pv, battery storage and stand-by diesel generation – are integrated ensuring continuous clean energy supply to the designated IES load.

TowerXchange: What’s the sweet spot for your solutions in terms of grid availability and the load your solutions can support? How would it handle a tower with multiple tenants?

The IES unit is designed to be able to deliver firm power on a continuous basis and is particularly suitable for remote, off-grid locations, or those where the grid supply is intermittent and unpredictable. The addition of a robust and reliable wind-turbine to the IES unit helps enable the unit to generate 100% clean energy and greatly increases the time interval between service visits and reduces (or in some cases removes) the requirement for diesel replenishment visits.

The initial PPP IES unit is based on a wind turbine rated at around 7kW, but we have also developed the design for a smaller, self-yawing turbine with rated power of around 3.5kW. The IES with the larger turbine would typically be sized to deliver continuous firm power at around 4/5kW (depending on wind and solar irradiation) which should be suitable for MNO telecommunication towers, but could also meet the power requirements of a number of other remote power delivery requirements – avoiding the need to install diesel generation and meeting long-term power requirements at reduced cost. The actual power delivery can be adjusted using sophisticated software modelling techniques to optimise the IES configuration to meet load demand. For remote sites requiring a smaller load the 3,5kW turbine configuration would be considered offering firm power in the 1.5/3kW range. Where wind conditions do not justify installation of a turbine the IES unit can be installed on a solar pv and battery basis.

For towers with multiple tenants there is obviously scope for the installation of two or more wind-turbines and adjusting the size of the solar pv and array and battery storage. We have also done detailed design for a 15kW rated turbine but the ability to ground assemble and erect without use of cranes would be more challenging – we believe that remote assembly and erection without the need for heavy lifting gear and cranes is a key advantage of the Crossflow design.

TowerXchange: How many hours of sunshine and what wind resource is necessary for your renewable energy solution to start to become a viable option? Tell us about the reliability and autonomy of your solution.

We use specific software packages to evaluate the energy profile at each site and the expected components – solar pv, wind and storage. One advantage is that given the modular nature of the IES unit it is possible to adjust the generation and storage components based on actual performance and load requirements to optimise the unit. It should be stressed that as the intention is to provide ‘energy-as-a-service’ the detailed configuration is an issue for the IES owner not the power user who will be expected to enter into a long term power purchase agreement so will have known and predictable costs which are designed to offer a significant discount relative to the cost of diesel generation to ensure continuous power. The PPP IES has been installed and commissioned and we are in the process of detailed analysis and performance testing at present.

TowerXchange: How does the total cost of ownership of Crossflow Integrated Energy System compare with traditional diesel-oriented energy solutions over an eighteen month, three year and five year scenario?

This is a very site specific question as so much depends on the full cost of diesel generation (including losses, transportation costs, service visits et cetera) but we would expect to be able to offer an ‘energy-as-a-service’ package which ensured continuous clean power (with diesel generation back-up) at a cost which would offer power purchasers a cost saving in the region of 20/30% against current fully costed power requirements on a longer term basis. In addition surplus power would be available to support surrounding communities’ power needs for unit charging, internet access and making the move to greater use of electrical power.

TowerXchange: What is your capacity and appetite to offer energy as a service to reduce up-front capital investments?

The Crossflow business approach is based on either direct sale of the IES unit or energy as a service offering where the Anchor Customer is seeking to reduce front end Capex.

TowerXchange: How scaleable is your solution for rapid roll-out and consistent maintenance in areas with less experience of wind energy?

The Crossflow turbine has been specifically designed as ‘robust, agricultural engineering’ and is intended for rapid roll out at multiple sites with remote monitoring and control capability; fundamental to the design is simplicity and long service intervals. The wind turbine is a combined hybrid lift/drag design so operates at relatively low tip speed ratios and cannot overspeed in high wind conditions – the design allows for ‘energy spillage’ in high wind scenarios to allow for ongoing generation in such conditions and ‘end-on’ parking in severe storms to reduce loading. In the case of very extreme weather (hurricanes etc) it is also possible to lower and protect the turbine and bring it back into operation immediately post the event. The majority of service activity would be carried out using locally trained staff. The long service intervals and the potential for 100% clean energy productions are key elements in terms of developing an offering which is capable of providing firm power at lower costs than would be the case for diesel generation supported infrastructure.

TowerXchange: Community power and minigrids are often seen as “next steps” for those providing cell site energy solutions, what is your proposition for rural electrification?

This is core to Crossflow’s business focus and the combination of firm power for Anchor Customers and the spin off benefits of mini- grids is the real focus – we see the use of spare power by communities being symbiotic with the roll out of internet and communication services.