Residential Micro Grid Design using HOMER Pro

With the increasing focus on renewable energy and energy independence, microgrids are gaining traction as a sustainable and cost-effective solution for residential and commercial power systems. This project explores the design, optimization, and economic feasibility of a residential microgrid using HOMER Pro, a powerful simulation tool for microgrid modeling.

The goal of this project was to design a cost-effective, energy-efficient microgrid for a household in Fairfield, Victoria. The system integrates:

• Solar PV System – Primary renewable energy source
• Battery Storage – Energy backup and peak load support
• Diesel Generator – Backup power in standalone mode
• Grid Connection – To supplement power when needed

The design aimed to evaluate the system’s performance, cost-effectiveness, and renewable energy penetration under both standalone (off-grid) and grid-connected modes.

The microgrid was designed to meet the following key criteria:

•  Cost-Effectiveness – Minimize the Net Present Cost (NPC) while maximizing renewable energy usage.
• Renewable Penetration – Increase the share of energy supplied by solar PV.
• Energy Reliability – Ensure continuous power supply through battery storage and backup generation.
•  Grid Interaction – Optimize energy export and import to reduce dependency on grid power.
• Fuel Consumption – Reduce reliance on diesel generators to lower operational costs and environmental impact.

The project followed a structured approach:

• Energy Consumption Analysis – Collected and processed household load data, analyzing daily and seasonal demand variations.
• Solar & Climate Assessment – Used NASA solar irradiance and temperature data to evaluate PV performance across different seasons.
• Microgrid Configuration – Designed a hybrid system with solar PV, battery storage, and a diesel generator for backup.
• Dispatch Strategy Simulations – Simulated multiple dispatch strategies in HOMER Pro to determine the most optimal control strategy.
•  Economic & Technical Optimization – Compared system costs, fuel usage, grid sales, and renewable penetration to select the best-performing setup.

Since real-time household energy data was unavailable, we used energy consumption data from a similar home in Victoria. The data analysis revealed:

• Peak electricity demand occurs in the evening, between 6 PM and midnight.

• Lower consumption in winter (July–August) due to gas heating, while higher demand in summer(December–January) due to air conditioning.

• Solar irradiation and temperature variations affect PV generation, leading to seasonal efficiency changes.

By leveraging NASA weather data, we assessed solar availability to determine optimal PV system sizing.

Figure – Monthly average load in Fairfield, Victoria

Figure – Irradiation data obtained from NASA at Fairfield, Victoria

Figure – Temperature data obtained from NASA at Fairfield, Victoria

The hybrid microgrid consists of:

• 1 kW Solar PV Array – Primary renewable source

• 6 x 12V AGM Batteries – Energy storage for nighttime and cloudy days

• 2.5 kW Diesel Generator – Backup power for standalone operation

• 1.5 kW Growatt Inverter – DC-to-AC conversion

• 1.5 kW Bi-directional Converter – Battery charging and grid interaction

Using HOMER Pro, we simulated four dispatch strategies to identify the best power management approach:

•  Cycle Charging – Runs the generator at full capacity, storing excess energy in batteries.
•  Load Following – The generator runs only when demand exceeds solar + battery supply.
• Combined Dispatch – A hybrid of Cycle Charging and Load Following for better efficiency.
• HOMER Predictive – Uses forecasting to optimize battery charging and generator use.

Each scenario was analyzed based on:

• Renewable Energy Penetration (%) – How much of the load is supplied by solar.
• Fuel Consumption (L/yr) – Diesel usage over the system’s lifetime.
• Net Present Cost (NPC) ($) – Total cost, including capital, maintenance, and operational expenses.
• Grid Sales (kWh/yr) – Excess electricity exported to the grid in grid-connected mode.

Standalone Mode: The Cycle Charging strategy was the most cost-effective, with an NPC of $13,871.36, but had higher fuel consumption. Load Following had the highest renewable penetration (94.6%) but was more expensive.

Grid-Connected Mode: Both Cycle Charging and Load Following had similar results, with 64.4% renewable penetration and 57% grid sales, minimizing energy waste.

After optimization, the following components were selected:

• 3 x 330W Jinko Solar PV Panels
• 1.5 kW Growatt MIC Inverter
• Honda Heavy Duty 2.5kW Generator
• 6xXTM Deep Cycle AGM Batteries

These components provide a balance of cost, efficiency, and energy security, ensuring reliable power with high renewable energy penetration.

This project demonstrates how microgrids can enhance energy security, reduce costs, and maximize renewable energy utilization. Using HOMER Pro, we effectively optimized component sizing and dispatch strategies, making informed decisions for a real-world renewable energy system.

Future Work & Real-World Applications

• Scaling up the system for commercial applications
• Integrating AI-based energy forecasting
•  Exploring battery storage alternatives (e.g., Li-ion vs. AGM)

By implementing optimized microgrid solutions, we move closer to sustainable and resilient energy systems, reducing dependence on fossil fuels while ensuring energy affordability.