GIS technology allows us to query, analyze and visualize information in an incredible number of ways, and as with all technology these days it is evolving rapidly.

Using Geographic Information Systems to find Solar Sites

Nate Sylvester | TRC


What is GIS (geographic information systems) Technology and how does it work?

In its simplest form, GIS technology is the marriage of databases of information and maps, but it is much more than information on a map.  GIS technology allows us to query, analyze and visualize information in an incredible number of ways, and as with all technology these days it is evolving rapidly.  The goal of any technology is to make things easier, faster, cheaper, etc. and GIS technology allows us to make sense of mountains of information in a matter of minutes.  To put it another way, GIS technology answers complex questions - like “what is the developable area of my property?” or “which counties have the highest potential for solar development?”  These are difficult questions but GIS technology enables us to answer them, quickly, using powerful queries, analysis, and visualization techniques.  As mentioned above, GIS technology is constantly evolving.  The availability of useful information in a “GIS ready” format is increasing every day.  Couple that with advances in web-based applications that allow any user to interact with a geographic information system and you have the ability to answer almost any question in no time.


How can GIS Technology accelerate the process of finding suitable solar sites that avoid wetlands/protected land/other issues?

I’ve boasted that GIS technology can be used to answer almost any question and I stand by that. Let’s rephrase the question above to, “where is a site suitable for solar development that avoids wetlands/protected lands/other issues?”  Before we can answer that question we need more information.  First, we need to define “suitable.”  This definition can vary, as some developers may prefer forested lands, while others may target fallow agricultural lands.  The better we define the definition of suitable the better the results will be of the search.  For this example let’s use the following criteria to define suitable:  

  • Large, relatively flat, non-forested upland.

  • Close to existing utility substations and transmission lines that can receive the power generated by the proposed development, without a significant cost to upgrade.

  • Minimum of 100 ac. and maximum of 3 landowners

  • Not within, or adjacent to:

    • Sensitive habitats

    • 100-year-flood zones

    • Conservation lands

    • Or known cultural resource sites

Now that we have a better understanding of what we are looking for, the GIS professional can get to work.  The first step is to compile the all of information needed to answer our question.  This information can be in any number of formats; paper, “GIS ready” files, or live map services.  As mentioned above, this information is more available and easier to use than ever, and only getting better.  An experienced GIS professional can distill all of this information, make it easy to visualize and make it available through an interactive webmap.  A developer can quickly see which areas are suitable and which are not.  The process described above can be completed in as little as a day depending on the area of interest.  


How can GIS Technology reduce solar project timelines and costs?

We’ve already established that locating potential sites for solar development using GIS technology can be accomplished in very little time, but there are other ways GIS technology can streamline the process.   Let’s assume that we have used GIS technology to locate a potential site that meets the criteria stated above.  What’s next?   Let’s find out how many panels we can install and where they can be installed. Also knowns as micro-siting.  

Obviously, you want to install as many panels on your site as you can, but most likely your site has wetlands, streams, steep slopes, shallow bedrock areas, or other areas that are not suitable, or less desirable for solar development.  Right of the bat your 200 acre site only has X acres that you can put panels on.  Using GIS technology you can quickly determine the area of your site that you can actually install panels.  

An experienced GIS professional will seek out and utilize all available information that might help refine the potential development area. Some examples;

  1. LiDAR:  increasingly available and a gold mine for micro-siting.  Used to create slope layer and identify potential wetlands and drainages

  2. USGS Elevation (if LiDAR unavailable):  Used to create slope layer

  3. NWI/State Wetlands layers

  4. NHD (hydro layers)

  5. Sensitive habitat layers (i.e. vernal pools, IWWH, etc.)

  6. SSURGO soils (bedrock, hydric soils, etc.)

  7. Electric Transmission Infrastructure

  8. Current Aerial photography

The result of this process is a layer, or overlay of the areas on the site where panels can be installed based on desktop micro-siting.  This overlay can be sent to the solar design engineers so they can begin the process of laying out the racks and determining the generation capacity of the site.  Often this micro-siting step is not done and solar design engineers cover the site in panels and inflate the potential generation capacity of the site.  Micro-siting gives a realistic estimate of the value of a solar development BEFORE expensive field staff or engineers get involved.  This is done quickly and inexpensively using GIS technology.


What are some of the problems, delays, and surprises solar developers can encounter if they use out-of-date maps, or inexperienced GIS analysts?

The abundance of GIS data available now is both a blessing and a curse.  Obviously more data are better, it allows us to be better informed about potential roadblocks to development.  The fact that these datasets are updated frequently is also a good thing.  However, if an inexperienced GIS professional inadvertently uses stale data, or does not know where to look to find the right information, what might seem like a suitable site may contain a sensitive habitat that is not suitable for development.  It is up to the GIS professional to make sure that they have found all of the pertinent datasets for analysis, AND that they have the most current version.  A developer does not want to show up at and agency or public meeting with a proposed project that is located in a sensitive habitat or conserved property.  There are many ways that stale, incomplete datasets, or errors in analysis can cause problems or delay a development project.  As always, experience counts.


Who are the major players in the GIS field at this time and how would a solar developer go about finding them?

Many solar development companies have their own in-house GIS staff to assist with the development of projects, while others use consultants with GIS expertise to assist.  The field of GIS is very broad and while there are many firms that have very skilled and experienced GIS professionals it is important to find one with experience in solar development.  That experience includes understanding which information matters most.  As an example, one of the best ways to find optimal sites quickly is to filter candidate locations based on interconnection suitability. This sort of evaluation requires systems studies and planning services, the ideal consulting firm (like the one I work for) has that expertise in-house. Experienced permitting staff can be helpful if special preservation zones or habitats are uncovered and assessments are needed to determine their impact on solar development.

An ideal firm will have engineering, environmental, and GIS expertise all under one roof.  It is extremely helpful if the consultant has access to multidisciplinary teams that can support solar development.  


What should you look for in a prospective GIS vendor and what should you ask them?

A consultants experience in solar development, and access to an in-house multidisciplinary team are important, and you should definitely ask about those things.  In addition, a good consultant should have as many questions for you as you do for them in order to define what you think is a suitable site.   A good consultant should also be able to describe how they are going to leverage GIS technology to help you, which data sources they are going to use, what applications they are going to build for you, and how long they think it will take.  If they tell you that it is going to take more than a few days to do anything, be skeptical.  That is the power of GIS technology to quickly answer complicated questions in this day and age.

Nate Sylvester, GISP
Nate Sylvester has over 12 years of experience managing GIS systems in the environmental consulting field.  He has extensive experience working with clients to develop solutions for acquisition, management and analysis of geographic data for large projects.  Project types include: solar development siting and permitting, wind farm permitting and construction, electric transmission and gas pipeline permitting and construction, site remediation, and FERC hydroelectric project licensing.  

Nate is an expert in applying today’s GIS technology to all phases of a project, from the early planning stages all the way through post-construction monitoring.  Nate holds a B.A. in Environmental Science from the University of Maine at Farmington, and a Post Baccalaureate Certificate in Geographic Information Systems from Penn State University.  Nate is a Certified Geographic Information Systems Professional (GISP) and serves as the National GIS Coordinator at TRC.

The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag

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