North Lone Oak Way 5.7kW Grid Tied Solar System in Northern Arizona

North Lone Oak Way Grid Tied Micro-Inverter System

The Lone Oak Way System includes 20 panels (20 Micro-Inverters) in 2, 20 amp circuits.

The North Lone Oak Way system is a Grid Tied System that utilizes 20 Enphase M250-60, micro-inverters paired with Canadian Solar CS6K-285M, 285W solar panels. The 250W rated output of each M250-60 matches well with the 261W PTC output of the panels. The nameplate of the panels indicates the Standard Test Condition (STC) output of the panels, 285W. This is the output measured at 1000 Watts per square meter irradiance (sunlight at sea level shining directly on the panel) at 25°C (77°F). These are somewhat idealized conditions. The National Renewable Energy Laboratory (NREL) established the Photovoltaics for Utility Scale Applications (PVUSA) Test Conditions, or PTC, for a more realistic approximation of what the panels will produce. These conditions have a cell temperature of 45°C (113°F), ambient temperature of 20°C (68°F), and a wind speed of 1m/s (2.2mph) cooling the panels.

The crew from Prometheus Solar installing the Solar Panels and Micro-Inverters at North Lone Oak Way. The rails are mounted to flashings secured under the shingles, and the branch circuits are fed into the attic through a SolaDeck Combiner, with flashing as well. This provides secure mounting and roof penetration without compromising the integrity of the shingled roof.

A 20A circuit of the M250 micro-inverters can contain a maximum of 16 units. The North Lone Oak Way system employs 2 circuits of 10 inverters and will produce about 8,825kWh over the course of a year. The monthly kilowatt hour production is plotted in the graph at the bottom. There are some trees to the southwest of the system, which could cause shading. The Micro-Inverters make it so that shading one panel only affects the power from that panel. The power from any other panel is not affected.

Connection of the North Lone Oak Way Solar System to the Utility Grid. The Enphase Envoy Monitoring system is mounted inside for this system.

All Enphase Micro-Inverter systems engineered by Independent Energy Innovations incorporate a Envoy Monitoring System. Some systems combine at the grid connection. This system has the Envoy and combiner inside, close to where the branch circuits enter the house. This allows for a single home run to the AC disconnect and meters. The Envoy monitors each inverter connected in the system, and conveys the status and production information to the manufacturer’s servers. This information is available to the consumer, installer, and manufacturer, providing effortless warranty replacement for the customer. If an inverter in the system fails, the manufacturer is alerted, via the Envoy, and sends a replacement to the installer.

At the location of the North Lone Oak Way system, accounting for equipment inefficiencies, wire loss, typical environmental conditions, and the available solar resource, the kWh production of the the system is plotted, for each month.

A Grid Tied system, like this, currently costs approximately $16,000.00. After the 30% Federal Tax Credit, and the $1,000.00 State Tax Credit, the initial cost of the system is a little over $9,500.00. If the electricity rates continue in their current trend, this system will pay for itself in little more than 6 years.