Northumbria County Council, Tyne Mills Depot


Replacing costly generator power for a cleaner environment

With no access to grid power, Northumbria County Council was running a large diesel generator to support administration offices and other incidental loads at the depot. However, there are many negative factors when running a diesel generator and the customer at Tyne Mills Depot was not only concerned about the extremely costly matter but also the environmental impact it would be having, due to the noise and carbon emissions.

Frequently diesel generators are overrated for the job in hand and spend most of their time running with but doing very little work, the introduction of Hybrid Power Hire’s alternative power solutions will allow for efficient and cleaner power.

It was difficult to gauge what power solution was suitable for the Tyne Mills Depot but before the installation, a 160kVA generator was installed. However, it quickly became apparent that this was grossly overrated for the job at hand. Consequently, by looking at a more suitable solution it could be largely beneficial as fuel consumption and carbon emissions would substantially improve. Furthermore, a 30kVA 60kWhr system was installed, where it worked alongside the existing generator, in place.




An initial period of trial, with the existing 160kVa generator, showed that the table-top assessment was correct and that power consumption was significantly lower than had been previously assumed. The hybrid battery system enabled the generator to be turned off for long periods and had an immediate impact on fuel economy and polluting emissions, as well as addressing night time/ weekend noise.

Following the initial period of assessment, it was clear that a smaller diesel generator was appropriate and the 160kVa set was then replaced with an 80kVa machine, half the size. The result was further reductions in fuel consumption, better emission levels, and better generator installation- a smaller generator well-loaded runs more reliably than a large generator with low load.



The remote monitoring feature, standard to the gridtogo power cube, showed that even during the unseasonably cold weather power demand on the site did not exceed 33kW and averaged 19kW (just short of 12% the 160KVA capacity of the generator). Into the warmer springtime, these power levels would reduce, as the use of heaters diminished.


Taking into account the varying cost of diesel, at worst, resulted in a monthly cost reduction in the order of £1500. The ability to reduce the size of the generator also contributed to cost reductions through the lower rental rates, compared to the larger 160kVA set. These cost savings more than compensated for the uplift in the additional rental cost of the hybrid unit.


By reducing generator size and the introduction of the hybrid unit pushed generator loading to, more than 50% of capacity which resulted in a four-fold improvement in fuel consumption measured in litres burned per kWh generated.


After an initial introduction of the hybrid solution, fuel consumption was reduced by over 20% saving, typically, some 3500kg of CO² in a month. Following the swap of the generator to the smaller 80kVA set, and moving into the warmer spring months, this saving increased to 60% compared to what was being consumed previously. This resulted in significant cost savings, a dramatic cut in CO² production, substantial reductions in pollution and long periods without the noise of the generator.


With the battery system requiring virtually no maintenance and a significant reduction in generator running hours, the costs for maintenance are significantly lowered. What is more, better utilisation of the generator means that it is more reliable.


By reducing the running hours of the generator and utilising the silent battery power at night, the noise pollution was therefore reduced.


By reducing the generator requirements the cost savings and impact on the environment offer a longterm solution.