Note – this article was originally published on chesterenergyandpolicy.com
The Open PV Project was an ambitious undertaking which could have a profound effect on Solar Energy and analysis in the future. Unfortunately, NREL’s Open PV Project is no longer available. However, photovoltaic (PV) installation is available from Lawrence Berkeley National Laboratory’s Tracking the Sun report.
While solar power continues its accelerated adoption in the U.S. market, the National Renewable Energy Laboratory (NREL) tracks photovoltaic (PV) installations nationwide. As the sector evolves, this tool provides invaluable access to public data.
The Open PV Project, run and operated by NREL, tracked and made such publicly available solar data and provided vital information for any stakeholders across the solar energy industry. The dataset is undoubtedly massive, so a first glance proves intimidating. However, digging through Quora for the most common type of questions about the solar industry provides the ideal opportunity to walk through the data for anyone (even those who aren’t experts in solar) on how to take advantage of such a valuable resource.
The Open PV Project was a collaborative effort between government, industry, and the public that compiled a database of available public data for photovoltaic (PV) installation data for the United States. Data for the project was voluntarily contributed from a variety of sources including solar incentive programs, utilities, installers, and the general public.
NREL’s data represented the best crowdsourced resource to identify the country’s solar installations, both large and small. NREL, one of the laboratories under the umbrella of the U.S. Department of Energy, offered this information to the public to help people, government entities, and industry to understand past and current trends of the U.S. PV industry.
Keeping the data complete, up-to-date, and accurate was critical for The Open PV Project to retain its value, so NREL noted that data was collected from all contributors willing to offer data– including state-run incentive programs, utilities, PV businesses and installers, solar advocacy organizations, consumers, and more.
Photo Source: National Renewable Energy Laboratory
In collecting this completed dataset, NREL encouraged contributors to include as much information as they have and find relevant, with categories including (but not limited to) the following:
Not every entry includes data for each category– the only data fields required to be filled out are date installed, size, location, and total installed cost (before any incentives).
To prove how useful this dataset can be, I’ll now answer some of Quora’s most pressing questions on the solar industry using just the information found on The Open PV Project. For those unfamiliar, Quora is an online question-and-answer resource where community members can seek out answers from experts to any question, with the top answer often ending up the top result on Google when someone asks the same question.
Equipped with the invaluable information from The Open PV Project, we can now provide the solar industry answers demanded by the Quora community:
This question is exactly the type that The Open PV Project was built to answer. By downloading the full dataset and filtering so only the residential installations are shown, we were still left with over 908,000 entries from the original 102,000,000 entries, but where are those residential installations focused? By sorting the 908,000 residential installations by state, we got the following top 10:
|State||Installation Count||Total Capacity (MW)|
California was head-and-shoulders above the rest of the country with almost 600,000 residential solar installations for over 4,000 MW. Other states in the Southwest join California in the top 10 of residential solar, including Arizona, Nevada, and Texas. The Northeast joins as the other region of the country highly represented, with large solar installation counts in Massachusetts, New York, New Jersey, Connecticut, and Pennsylvania.
We must consider, though, that some of these states might only fall in the top 10 because they are populous states. To check for that, we could factor in each state’s population to find the top 10 states in per capita installations:
|State||Population Divided by Residential Installation Count||Solar capacity (kW) per Capita|
As this list shows, many states are represented in the top 10 when calculated on a per capita basis. Even though California is so populous, they are still kings based on one residential solar installation for every 69 residents. However, Texas, New York, Maryland, and Pennsylvania fall out and are replaced with Delaware, Washington DC, New Mexico, and New Hampshire, who are each doing more with their smaller populations.
Answering this question shows how publicly accessible datasets like The Open PV Project represent an opportunity to quash misinformation. Assuming this question is asking why the deserts of the American Southwest, with their abundant sunshine, are not being utilized for utility-scale solar power, then a quick analysis shows that there in fact are plenty of solar panels in these areas.
The Southwest almost always refers to Arizona and New Mexico and can also include California, Nevada, Utah, Colorado, Texas, and Oklahoma, depending on the context and who you ask. Given these states, a quick analysis of the data shows the following count of utility installations across the Southwest states:
|State||Number of Utility Installations||Total Capacity (MW) per Capita||Oldest Installation|
Based on this, we can see that most of the states do indeed utilize their solar resources on a utility scale, and in fact they’ve done so for going on a decade or longer. But the person who asked this question is correct to ask why more isn’t being done, particularly in Utah and Oklahoma where no utility installations of solar are recorded.
After questions about the prevalence of different types of solar installations, the other most common inquiries are those asking about the costs. This question gets straight to the point, asking if solar installations are expensive.
Such a broad question cannot be answered with a simple yes or no, but The Open PV Project provided us with the necessary data to describe cost trends. Focusing on the three most common installation types– residential, commercial, and utility– the range of total system costs are shown in the following table:
|Installation Type||Cheapest Installation||Most Expensive Installation||Average Installation|
|Total Cost||Description||Total Cost||Description|
|Residential||$400||0.05kW system installed in 2014 in AZ||$3,940,000||364 kW system installed in 2010 in CA||$33,525|
|Commercial||$1,161||0.51 kW system installed in 2014 in NH||$63,000,000||14,100 kW system installed in 2012 in NJ||$397,102|
|Utility||$11,500||0.9kW system installed in 2012 in OR||$152,200,000||27,600kW system installed in 2009 in FL||$15,641,802|
On mobile devices, view this table horizontally
Overall, residential systems appeared the least expensive and utility the most expensive. Such a trend is unsurprising, as residential systems are typically the smallest, with commercial installations somewhat larger and utility-scale solar by far the largest. To gain further insight, we could have looked at the cost per watt information in the dataset:
|Installation Type||Cheapest Installation||Most Expensive Installation||Average Installation Cost per Watt|
|Cost per Watt||Description||Cost per Watt||Description|
|Residential||$0.75||4.8 kW system installed in 2009 in FL||$30.00||1.07 kW system installed in 2015 in CA||$6.00|
|Commercial||$0.76||309 kW system installed in 2015 in CA||$29.83||21 kW system installed in 2010 in MA||$5.80|
|Utility||$2.34||3700 kW system installed in 2013 in RI||$14.94||4.2 kW system installed in 2009 in OR||$6.74|
On mobile devices, view this table horizontally
Based on the more informative cost-per-watt numbers, we can see that residential and commercial systems tend to be about the same price, as they use the same rooftop solar technologies. Utility-scale installations, though, are somewhat more expensive because they are not simple rooftop installations, but rather full-fledged power generating sites that must include additional features– cooling considerations, transmission and distribution systems, etc. However, those additional features reportedly do lead to higher utilization rates and capacity factors, meaning the ultimate cost for electricity generation is more economic for utilities than for residential or commercial operations. However, all types of solar are already cheaper than new fossil fuel generation projects in many parts of the United States.
Not only did The Open PV Project elucidate the affordability of installations, but we could also plot the data over time to see how prices have evolved.
As is evident from the scattering of data points, much goes into the determination of a solar installation’s cost– factors such as size, location, installer, and unique aspects of the rooftop. Thus, coming up with a one-size-fits-all answer to “How expensive are solar installations” is difficult. But the trend lines do demonstrate that, on the whole, the cost per watt of solar is consistently falling across these three most common sectors. The dataset would also let you separate data to see what trends pop up across different regions, time periods, rebate programs, and more. But I can’t have all the fun on my own, so dive into the data on https://emp.lbl.gov/tracking-the-sun for your own analysis.
But in short: solar installations do have significant upfront capital costs, but those prices are dropping and becoming cheaper than other conventional energy generation sources. For residential and commercial installations, solar typically pays for itself in six to eight years through energy savings, with all savings after that point pure profit.
Ending with a narrower question, this person wanted to specifically know how much a 2 kW solar system would cost. To answer the question we could have focused on all entries of the dataset within 10% of 2 kW, of which there 32,788 installations (88% of which are residential, so we can also narrow our view into those entries since the person asking is likely asking about such residential systems).
Graphing the total system costs of residential solar installations between 1.8 kW and 2.2 kW gave the following:
Unsurprisingly, given our previous findings, the costs have been trending downward but remain spread over a wide range. Across data from The Open PV Project, the price range of ~2 kW residential solar installations extends from $1,800 (1.8 kW system installed in 2015 in California) to $62,608 (2.1 kW system installed in 2010 in Arizona). On average, 2 kW residential solar systems cost $13,968. To demonstrate how that’s changed over time, though, note that from 2000 through 2009 the average 2 kW system cost was $17,317 and that average cost over 2010 through 2018 fell to $12,540.
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