Living and Working Off the Grid - Cedarvale Health and Lifestyle Retreat 

(New South Wales, Australia)

Like all off-grid communities, Cedarvale wants continuous renewable power while minimizing its use of diesel generators. Ecoult provided Cedarvale with a fast-charging UltraFlex battery solution designed for continuous use in partial state of charge – perfect for periods when solar power is limited. The battery manages variations in demand and fluctuations in solar input. And on those rare occasions when the generator is used, UltraFlex charges at a high rate so the generator can operate at its full rated output – where it is most efficient.

Background

Cedarvale Health and Lifestyle Retreat is a thriving business in the breathtakingly beautiful Kangaroo Valley, about two hours south of Sydney. The off-grid retreat prides itself on its renewable power system, which includes a solar array and a micro-hydro generator. These two sources provide just about the right amount of energy to power the site.

However, the site’s peak energy-demand periods coincide with breakfast and dinner (and associated showers and spa treatments), which take place just before and just after the bulk of the day’s solar power is available. It was clear that an energy storage solution could offer significant benefits to the site and its owners.

Ecoult UltraFlex - Off the Grid - Cedarvale Health and Lifestyle Retreat

UltraBattery-assisted renewables can power an off-grid resort.

Client challenge

Before Ecoult installed UltraFlex, Cedarvale had been relying on a micro-hydro generator with a set of batteries for storage. However, those batteries were not suited to constant cycling, and had reached the end of their life. The site was becoming increasingly dependent on a back-up diesel generator whenever the micro-hydro was not producing enough power. The owners decided to install a 10 kW solar array, and were looking for a set of smoothing and shifting batteries to help regulate the site’s power.

Figure 1 shows a typical day’s operation prior to UltraFlex being installed. Whenever demand exceeded the supply of the micro-hydro system, the diesel generator was called upon to make up the difference. The site owners were keen to find a battery solution that was itself sustainable and recyclable while having the capability to maximize the site’s renewable power use and supply the site with smooth power despite the fluctuating renewable supply.

Figure 1: System prior to UltraFlex installation
Figure 1: System prior to UltraFlex installation

Solution provided

UltraFlex was the perfect solution, easily meeting the variability between generation and demand and suffering no ill effects from weeks of cycling with no refresh or float periods.

Once UltraFlex and the 10 kW solar array were installed, diesel use dropped dramatically. During the first summer after installation, the diesel generator was used only for a few hours throughout the entire season. On winter days diesel is sometimes used for a brief period just after sundown.

The customized solution, developed by Moruya-based installer Bunya Solar with engineering assistance from Ecoult, was to install a nominally 48 V, 20 kW peak power UltraFlex energy storage system, with power flows managed by a Selectronic SP Pro inverter.

The load on the Cedarvale site is relatively unpredictable, as different groups of guests rotate through the property in varying numbers and with different showering and relaxation habits (spa treatments, etc.). However, the energy storage needs of the site were found to be perfectly served by a single UltraFlex.

The presence of a relatively constant 4 kW micro-hydro supply provided a reasonably reliable baseload supply, which is somewhat unusual for an off-grid site. This was exploited to provide significant battery charging overnight, making it possible to greatly decrease diesel use even on relatively overcast days.

Ecoult has developed specialized run algorithms so that, in the vast majority of cases, when renewable power is insufficient, UltraFlex can meet demand for extended periods rather than the diesel generator having to come online.

Hence, cloud cover events can be managed and, in general, the evening peak load can be catered for by UltraFlex and micro-hydro together.

Figure 2: Once UltraFlex was installed, it easily managed site variability. The diesel generator is now an infrequently used backup, used only for brief periods on some winter evenings and almost never in the warmer months.
Figure 2: Once UltraFlex was installed, it easily managed site variability. The diesel generator is now an infrequently used backup, used only for brief periods on some winter evenings and almost never in the warmer months.

UltraFlex: Designed for the Client

Ecoult developed UltraFlex to offer a mid-range, commercial and industrial, fully remotely monitored and controlled battery energy storage system to suit the multiple applications and environments our clients brought to us.

Powered by the extraordinary UltraBattery, invented by CSIRO, it offers high charge and discharge power rates, constant cycling for weeks continuously with no rest or float periods, DC–DC efficiency of more than 91%, and world-beating recyclability and sustainability.

UltraFlex truly is the best of both worlds. It can outperform, out-cycle and outlast other chemistries in most fast-cycling and variability management applications, plus it has the ability to provide the daily deep discharge of the world’s best off-grid lead-acid batteries.

Ecoult UltraFlex - Off the Grid - Cedarvale Health and Lifestyle Retreat