Future-Proofing a Landmark Hotel: A Comprehensive Energy Upgrade with Solar

Related project: 600kW Southern Hotel Rooftop & Carpark

The Southern Hotel in Toowoomba, Queensland, is one of the region’s most established full-service hospitality venues. It runs around the clock, with its restaurants, bars, conference facilities, and guest rooms driving annual electricity consumption beyond  1 GWh. Energy is one of its highest operating costs.

Rising grid prices and growing pressure to show sustainability made a clear case for solar. Yet a standard rooftop system would only cut the daytime bill. Evenings, when kitchens and lighting peak, would still draw from the grid at the most expensive time of day. The hotel needed more than panels: it needed an integrated system that could generate, store, and manage its own power. The value of the system comes from how its components work together. Solar generation is strongest during the day, while hotel demand continues into the evening. By storing surplus generation and using it later, the battery helps align energy production with the hotel’s operating profile. EV charging adds another flexible load that can be managed within the same energy system.

The Solution

A 300 kWh STB Centurion battery stores excess daytime generation and releases it through the evening peak. Four on-site EV chargers, two of them fast units that top up a vehicle in under 30 minutes, draw on stored energy, minimizing the added load on the hotel’s connection. The battery and chargers are sized to work together, so a guest plugging in after dark is drawing on energy the hotel captured earlier that day. Inverters manage the flows between generation, storage, and consumption.

The Benefits

The system’s annual production is modelled at 757 MWh, according to DS Energy’s yield estimate, helping reduce the hotel’s reliance on the grid and lower its carbon footprint.  The hotel reports that on-site solar and storage are on track to cover more than 60 percent of its annual electricity use, with the rest drawn from the grid.

That level of self-generation changes the economics. In a sector where energy is one of the largest operating costs, generating power on site means less exposure to wholesale price swings and peak demand charges, and a cost base that is easier to predict year over year. For a business operating with significant and variable energy demand, greater predictability in energy costs can be nearly as valuable as the savings themselves. The system also flattens evening demand by drawing on stored energy, strengthening load management. And its architecture is designed to scale: the storage and EV charging can expand as the hotel’s needs grow.

A Repeatable Model

The Southern Hotel illustrates a broader direction in commercial energy management. Integrated solar, storage, and EV charging are increasingly being considered together as businesses look to manage energy costs, demand and resilience. While the technology has long been ready, what has truly changed is the willingness to view energy as a system to be managed, rather than just a bill to be paid. For complex, mixed-use venues like the Southern Hotel, delivering a custom energy system requires more than just high-quality components; it demands tight integration. By combining Astronergy’s n-type TOPCon modules with the design, engineering and installation expertise of project partners such as DS Energy, the project demonstrates how high-quality module technology can contribute to reliable, integrated energy systems for large-scale commercial applications.