The summer surge: How to keep energy bills cool when temperature rise

A CEO's Guide to Managing Summer Energy Peaks with Solar + Storage

The Seasonal Spike That Hits Every Business

Every Australian summer, the same story unfolds: temperatures rise, air- conditioning units strain, and the national grid groans under the pressure. According to AEMO data, during the 2024-25 summer season:

Wholesale energy prices hit $246 per MWh during peak intervals - a 37% increase from the prior year. Queensland and NSW both recorded new five-year highs for daily peak loads, exceeding 10,500 MW. Average commercial power bills rose 22-28% compared to winter 2024.

For large businesses, those numbers translate into six-figure seasonal cost shocks. The summer period has become one of the most expensive and volatile quarters in the energy calendar - and the trend is accelerating.

The Commercial Cost of Heat

Heat directly inflates consumption. Every 1°C rise in temperature lifts HVAC energy demand by 3-5% and refrigeration load by 6-10%.

Take a logistics warehouse with a $600,000 annual power bill. A 20% summer uplift pushes an extra $120,000 of electricity costs of which around $40,000 is typically driven by short, high-demand intervals that attract network penalties.

These are not unavoidable expenses; they're inefficiencies caused by unmanaged peaks.

How Solar + Storage Neutralise Summer Peaks

Solar generation peaks during the same hours as grid tariffs - roughly 11 a.m. to 5 p.m. Batteries then extend that self-supply period, allowing stored solar energy to cover evening operations and offset demand charges.

Across a typical summer quarter, a 500 kW solar array paired with a 500 kWh battery can reduce grid imports by up to 40%, delivering between $85,000 and $110,000 in avoided energy costs. Network demand charges often fall by another 25-35%, meaning systems of this size usually recover an additional 0.8-1.2 years of payback compared to solar-only installations.

Why CFOs Should Care: Demand Charges as Silent Inflation

While most executives focus on kilowatt-hour rates, nearly half of a commercial energy bill in summer comes from demand charges - the highest 15-minute load interval across the billing cycle.

A manufacturing plant with a 1 MW peak load might pay roughly $180 per kilowatt in annual demand tariffs - that's $180,000 per year regardless of how much energy it uses overall. Installing a 400 kWh battery to reduce just 20% of that peak would save around $36,000-40,000 per year, often paying for itself in less than three years under a lease or PPA model.

Case Study: Cold Storage Facility, Brisbane

A 7,000 m2 refrigerated warehouse in Brisbane implemented a 650 kW rooftop solar system and 600 kWh battery under an Agile Energy PPA. Before installation, the site drew about 1,200 MWh per year.

After commissioning, the results were immediate:

Summer grid draw dropped 41%, and peak demand fell from 480 kW to 270 kW.

Annual savings reached $162,000, including $48,000 in avoided demand penalties.

Solar uptime during the heatwave months exceeded 99.6%, and refrigeration systems saw a 9% reduction in compressor runtime during January alone.

For the operator, the system didn't just cut energy costs - it improved thermal stability, product integrity, and resilience during grid volatility.

The Macro Trend: A Hotter, Pricier 2026 Ahead

AEMO and the Bureau of Meteorology both forecast an extension of the El Niño pattern into 2026, bringing 5-10% more cooling degree days and an additional 2-3 GW of commercial demand pressure across the grid.

Price volatility is likely to persist, with forward contracts already trading above $250-300 per MWh for next summer. In response:

Around 40% of Australia's top 200 industrial users now generate at least part of their own power. 23% have added or committed to on-site storage within the past 18 months.

The direction is clear: energy independence is becoming a competitive differentiator, not a sustainability gesture.

The most powerful shift is financial. Businesses no longer need to outlay capital to access resilience. Under an Agile Energy PPA, the system is fully funded by Agile and the customer simply buys the generated electricity at a fixed rate. This model can cut a site's annual energy costs by 35-45%, equating to $80,000-$120,000 in immediate cash savings for a 500 kW system. For CFOs, it's effectively a cost-neutral hedge: long-term price certainty without upfront CAPEX.

Get Summer Ready with Agile Energy!

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