Home Web information Are you planning to install solar panels in your home? A New NIST Web Tool Can Help

Are you planning to install solar panels in your home? A New NIST Web Tool Can Help


A software tool developed by NIST, called Present Value of PhotoVoltaics, analyzes the economic and environmental impacts of rooftop solar technology.


B. Hayes/NIST

Whether it’s to live more sustainably, save money, or both, many people are considering adding solar panels to their homes. Homeowners consider a number of factors, including the type of solar panel that’s best for them, when deciding if the investment is worth it.

Now, an online software tool from the National Institute of Standards and Technology (NIST) can help answer owners’ questions. The software is called [PV]2 — Present Value of PhotoVoltaics — and analyzes the economic and environmental impacts of rooftop solar technology. The tool can help homeowners and even installers when evaluating rooftop solar PV systems.

Photovoltaics is a semiconductor material that converts sunlight into electricity. They are made up of individual cells that form solar panels. But how can owners know if the technology is right for them?

To help answer this question, [PV]2 uses a method called life-cycle cost analysis, which assesses the total cost of a structure, project, or product over time. It takes into account various costs and can identify the most profitable options in the long run.

The idea for the tool came from NIST economist Joshua Kneifel when he was considering installing solar panels on his own home a few years ago. “Solar installers provided basic cost and savings information based on simple and sometimes non-transparent assumptions. I wanted to determine if installing solar power was a better investment than just investing that money instead, and no tool available at the time could do that,” Kneifel said.

He performed his own calculations using an Excel spreadsheet, but found that the format was not translatable for the average person. “I determined that there was a lack of a tool that a homeowner or solar installer could use to get an independent, standards-based economic analysis of an actual quote to install solar power in a specific home. I wanted to provide all the necessary detail, considering all potential complexities, while simplifying the experience for the user in an digestible way,” Kneifel said.

When users access [PV]2 on the web, they first encounter a landing page that introduces them to the online tool. The page includes links to a user guide that provides a quick tutorial on how the tool works.

The tool does most of the calculations and analysis, so users only need two pieces of information: an actual solar quote – an estimate of a solar installer’s costs – and an electricity bill. If a user doesn’t have these, they can enter a sample quote and utility bill from the landing page to get a rough estimate.

After pressing the start button, users need to go through six steps, such as entering their address or zip code, electricity price on their bill, solar panel system information and any monetary incentive for which they are eligible. Users do not need to know all of this information; some steps contain default information based on the latest research and data. Information entered by users is not stored on a server or on the web application, Kneifel said, thereby protecting the privacy of a user’s personal data.

“Once a user has completed these steps, they press the finish button and get a breakdown of the costs, electricity savings and carbon footprint associated with the photovoltaic system. Charts are also included and everything can be downloaded in a spreadsheet or PDF,” Kneifel said.

[PV]2 uses the Economic Valuation Engine (E3), an application programming interface (API) developed in collaboration with [PV]2 by experts from NIST’s Office of Applied Economics.

“The new concept is to provide a generic API that could be used as a ‘back-end’ compute engine for multiple ‘front-end’ tools, such as a web application,” Kneifel said. “This simplifies and speeds up future development of new tools and minimizes maintenance time and costs for existing tools. The Solar Assessment Tool was a perfect use case to validate and show the capabilities of the Generic Economic API and how it can be leveraged by other tools that assess long-term projects that require a life cycle perspective. life. For example, any building or facility related project aiming for energy efficiency, sustainability or resilience could use E3 for economic analysis.

The web application was beta tested before being released to the general public and has received feedback from beta testers, such as solar installers, homeowners who have recently installed solar panels, homeowners who have considered but not yet installed solar panels and other tool developers. [PV]2 can also be useful for solar installers who need to provide a transparent and independent economic analysis of solar panels. “The hope is that the layman can use this web application to do the same analysis I did to feel comfortable with my solar energy investment,” Kneifel said.

This is the initial version of the tool and new features are under consideration; users are welcome joshua.kneifel [at] nist.gov (provide an answer) to further improve the tool.