The unique methodology for managing solar projects through all of their development stages has been created. Publication provides detailed description of the specifics of this methodology and describes its benefits and necessity. The lack of the unified methodology is caused by the fact that there are many service providers, which offer various separate tools and services for solar energy companies. To complicate things even further, most of the available separate services and tools focus on supporting specific stage of solar project development. As result, solar energy companies are forced to use multiple tools within the scope of one project, which also forces solar companies to mix different processes for different stages of the development of a solar project, to comply with tools and services they are using. Overall the lack of unified methodology leads to unnecessary resource spending, making the final costs of solar projects higher, and lengthening payback time, thus making solar energy less attractive. In addition, lack of the unified methodology lengthens time it takes to disseminate the scientific innovations to the solar energy companies. Developed methodology, is the result of long time cooperation between solar installers, solar software developers and researchers. In the process of the methodology development the unique knowledge transfer space was created. This allowed to pinpoint the real needs of a solar energy project development process and discover the solutions to the burning issues. At the moment the developed methodology, is represented as service platform PVStream, and its services are aimed to cover the full scope of the needs for designers and installers in most project cases. The ability to include additional features for modern and unique conceptions provides room for long-term development and relevance of the methodology. The tools and services united by the methodology include: lead generation and proposal tool; financial feasibility analysis; energy efficiency analysis; project design and engineering tool; performance modeling and simulation suite; monitoring and maintenance tool. The methodology allows to manage projects that combine both Photovoltaic and Solar thermal energy sources. Large emphasis is put to building energy efficiency. The project data can be extended as the project develops over time, this makes resulting data more precise and close to customer needs. The usage of such methodology significantly reduces human resources time by automating design, performance modeling, documentation creation and overall project management. Further development and dissemination of the united solar energy project development methodology will make solar energy more affordable and attractive, by cutting the costs of the project development, and cutting overhead costs of solar energy companies.