Three Factors to Consider When Adding Solar to New and Existing Buildings

There are three main areas of concern when reviewing common problems and solutions regarding PV solar integration with an existing or new commercial or industrial building: the structural capacity of a building, the roof’s age and condition, and electrical integration.
By Josh Held
September 18, 2018

There are three main areas of concern when reviewing common problems and solutions regarding PV solar integration with an existing or new commercial or industrial building: the structural capacity of a building, the roof’s age and condition, and electrical integration.

structural capacity

For the structural capacity, the first area of analysis is answering these questions: What was the building originally intended for, what is it being used for now, and how does that impact the amount of weight planned for the HVAC and other future roof loads? Each building has been constructed with a specific economic objective and overall function. In some cases, the build objective was minimal protection, just to meet code. In other buildings, there may be a heavy weight load. That dictates the beams, the purlins, and members and other structural components.

When a company is considering adding solar to an existing building, the engineers need to look at how much weight can be added to the roof, based on all of the existing conditions. And they need to create a solar solution that is within the weight threshold. Can it handle a racked system? A ballasted system? Does the company need the lightest system possible to adhere to the structural constraints posed by the site?

Roof age and condition

The next major area to consider is the age and condition of the roof. As an example, in California, 80 percent of commercial roofs are 15 to 20 years old. At that point in a roof’s life cycle, deterioration of the roof’s weatherization is usually significant. A 20-year old roof’s ability to keep water out of the building is compromised.

It is important for the company to synchronize the solar lifespan and the roof lifespan. If the roof is ending its life cycle, the company does not want to add a solar system that would have to be moved in a few years to replace the roof. Before the building owner installs new solar, it is critical to assess and integrate the long-term plan for the building’s roofing system.

It is also important to understand the costs and impacts of installing solar in harmony with each specific roof type. There are a number of options when determining how to maintain or replace a building’s roof that range in cost and life expectancy. For example, many business owners are choosing membrane roofs made from a TPO or EPDM rubberized polymer that have extended life expectancy and large energy-saving attributes. It critical to understand how best to integrate solar attachments to these types of roofing applications to be as non-invasive as possible. There are now options that require no penetration into the roof.

Electrical integration

The last major area of consideration is the electrical integration of a solar system. That refers to how the energy created from a newly installed solar system is integrated into the existing electrical infrastructure of a building. Commercial and industrial buildings typically have customized electrical systems that were engineered for the needs of the original building owner. The specific capacity and components of the electrical system on site directly impacts how new energy can best be integrated. In extreme cases, the existing infrastructure can even limit the amount of power that can be produced and integrated from a newly installed solar system. The best approach to his issue is to use an experienced solar and/or electrical engineer who not only knows the code standards but also has practical field experience with the most cost-effective and ideal integration practices.

Overall, all of these building situations have good solutions that can help a company install the right solar and have it offset up to 100 percent of their electricity costs. The best solution can also add value to the property long-term.

by Josh Held
Josh Held has helped develop and lead installation efforts on more than 20 megawatts of commercial, industrial and residential solar projects throughout the United States. Whether it is understanding and applying solar building code compliance, portraying economic analysis and benefits of solar to consumers, or helping overcome political obstacles holding back renewable energy progress in the United States, Josh has been at the forefront leading the charge for renewable energy initiatives.

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