Solar Farm DC Collection: Optimizing Energy Harvest

Project Overview

A utility-scale solar developer commissioned a 50MW photovoltaic power plant in California's Mojave Desert. The project covered 300 acres with over 125,000 solar panels arranged in approximately 4,200 strings feeding 200 central inverters. With string runs ranging from 50 feet to over 500 feet, the DC collection system design had significant impact on project economics and energy yield.

Unlike AC power distribution where voltage drop is a recommendation, DC voltage drop in solar installations directly reduces energy production and project revenue. Every percentage point of voltage drop represents power that is generated by the solar panels but lost as heat in the wiring before it can be converted to AC and sold to the grid. For a 50MW project operating for 25+ years, even small improvements in DC collection efficiency translate to millions of dollars in additional revenue.

The engineering challenge was to optimize conductor sizing across thousands of string home runs while balancing installation cost against lifetime energy losses. This case study demonstrates the systematic approach used to develop an economically optimal DC collection design.

System Configuration

Voltage Drop Optimization Strategy

Rather than using a single wire size for all strings (which would either waste copper on short runs or lose energy on long runs), the engineering team developed a distance-based conductor selection matrix:

Economic Analysis

Optimize Your Solar Project

Planning a solar installation? Our DC voltage drop calculator helps optimize string sizing and conductor selection for maximum energy harvest.