Massachusetts-based 621 Energy, LLC builds, owns, operates and services commercial-scale solar photovoltaic systems. We provide a complete range of solar PV solutions including: - Project Development - Turnkey Installation - Financing - Operation and Maintenance - Solar and Energy Consulting Services June 21st is most often the date of the summer solstice, when the sun’s position in the sky reaches its northernmost extreme. This is the longest day of the year and a peak solar power day in the northern hemisphere. In the spirit of the summer solstice, the mission of 621 Energy is to ensure that our solar photovoltaic (PV) systems and those of our clients operate at a peak performance level. The experienced 621 Energy team has developed standards for project management, engineering, product selection, installation, documentation and ongoing monitoring which are designed to meet the requirements of the most discerning customers.