Energy consumption in commercial and industrial buildings is rarely optimised by default. Lighting systems designed in the 1990s operate at three times the lighting power density achievable with current LED technology. HVAC plant runs at fixed speed when variable speed drives could reduce fan and pump motor consumption by 30–50%. Power factor drifts below 0.85 as inductive motor loads accumulate, attracting network reactive power charges that inflate electricity bills without adding any productive work. Compressed air systems leak at rates representing 20–30% of compressor output. An engineering-grade energy efficiency audit finds and quantifies these losses systematically — not by walking the site with a clipboard, but by deploying calibrated measurement instruments, building a submetered load inventory, and analysing the data against recognised benchmarks.
Power Factor Measurement and Correction
Power factor — the ratio of real power (kW) to apparent power (kVA) — reflects how effectively a site converts the current drawn from the network into useful work. A site with significant motor load, fluorescent or discharge lighting, and variable speed drives without line reactors may operate at a power factor of 0.75–0.85 lagging during peak production hours. Most network tariffs in Australia apply a reactive energy charge or a maximum demand charge based on kVA rather than kW once power factor falls below 0.90 — some tariff structures penalise sites below 0.80 with a demand charge uplift that can represent 15–25% of total electricity cost.
Nexus Grid engineers install calibrated power quality analysers at the main switchboard and at key sub-distribution boards for a minimum seven-day monitoring period, capturing 10-minute-interval real power, reactive power, apparent power and power factor data across the full weekly operating cycle. From this dataset, we calculate the reactive power compensation (kVAr) required to lift the site to a target power factor of 0.95 lagging or better. Automatic power factor correction (APFC) capacitor banks — switched by a power factor controller in steps matched to the reactive demand profile — are sized and specified, and the simple payback period from reduced reactive energy and demand charges is calculated using the client's actual tariff structure.
Load Profiling, Maximum Demand and Tariff Optimisation
Maximum demand — the peak kVA or kW drawn from the network in any half-hour interval — is the basis of demand charges in most commercial and industrial electricity tariffs. A single production event that pushes maximum demand 20% above baseline can increase the demand charge component of the electricity bill for the entire month. Nexus Grid's load profiling process identifies peak demand events, their cause and their duration, enabling targeted load management strategies — demand-controlled HVAC setback, production schedule adjustment, or battery energy storage discharge during peak demand windows — to reduce measured maximum demand and the associated tariff penalties.
AS/NZS 3000:2018 Section 2 maximum demand calculations are not limited to new installation design — they are equally applicable as a diagnostic tool in existing buildings where switchboard limitations, network capacity constraints or tariff structure create commercial incentives to reduce peak apparent power. Our audit reports document the measured maximum demand profile alongside the AS/NZS 3000 calculated maximum demand, identifying where the actual demand exceeds diversity assumptions and where switchboard or mains conductor upgrades may be deferred by load management.
NABERS Energy Benchmarking
NABERS Energy — the National Australian Built Environment Rating System — uses normalised energy intensity (measured in MJ/m² per annum for office buildings, or MJ/occupied-room-night for hotels) to assign a one-to-six star energy performance rating. A 5-star NABERS Energy rating corresponds to best practice performance, approximately 30% below industry average; a 6-star rating represents market-leading performance. Nexus Grid engineers prepare the energy data submission format required for a NABERS Energy assessment, calculate the normalised energy intensity from metered consumption data and independently verified occupancy hours, and identify the highest-impact measures for improving the rating.
- Seven-day power quality logging at main switchboard and key subdistribution boards
- Power factor measurement and APFC sizing to achieve 0.95 pf target — payback from network tariff savings
- Half-hourly maximum demand profiling — peak event identification and load management strategy
- NABERS Energy baseline calculation from metered data — gap analysis to target star rating
- Lighting power density survey — fixture-by-fixture comparison against current LPD benchmarks
- HVAC system efficiency assessment — chiller COP, cooling tower approach temperature, AHU fan kW/l/s
- Compressed air system leak detection survey using ultrasonic acoustic imager
- Costed measure register with capital cost, annual saving (kWh and $), and simple payback period
- Prioritised implementation roadmap aligned to capital budget cycles
Audit Reporting and Implementation Support
An energy audit that produces a report without implementation support is a cost, not an investment. Nexus Grid delivers audit reports structured around actionable measures rather than observations, with each recommendation accompanied by a capital cost estimate, an annual energy and cost saving, a simple payback period, and an indicative scope of work. Measures are ranked by payback period — typically from weeks (power factor correction, operational schedule adjustments) through to three to seven years (LED retrofits, VSD installations, chiller replacements) — so clients can sequence implementation aligned to capital budgets and maintenance cycles.
Where energy savings need to be reported against a contractual or regulatory obligation — NABERS commitments under a Green Star project, Energy Savings Scheme (ESS) or Victorian Energy Upgrades (VEU) baseline documentation, or sustainability reporting under GRI standards — Nexus Grid provides the metered baseline data and measurement verification methodology required by each framework. Our engineers remain available during implementation to review contractor proposals, attend FAT and commissioning activities, and conduct post-implementation measurement and verification (M&V) against the IPMVP Option B or C protocols, confirming that projected savings are being realised in practice.