One of the biggest challenges in using a model like HOMER Pro is finding the numbers to put into it. This page is meant to help you find the information you need. If you know of any other helpful sources, please let us know so we can add them. Note that NREL cannot guarantee the accuracy of any data from external sources and does not endorse any manufacturer or retailer.

Electric Load Data

Some of the sources of hourly load data are: 
1) https://openei.org/doe-opendata/dataset/commercial-and-residential-hourly-load-profiles-for-all-tmy3-locations-in-the-united-states
2) http://www.ercot.com/gridinfo/load/load_hist/

Geography

To find your latitude and longitude, check www.multimap.com. Or check the list of world cities at www.infoplease.com/ipa/A0001769.html.

To find your time zone, check www.worldtimezone.com.

Solar Radiation Data

HOMER Pro will accept solar radiation data as monthly averages or as a time series. Time series solar radiation data is most commonly available with an hourly time step, but HOMER Pro can accept any time step down to one minute. One of the best sources of solar radiation data is the TMY2 and TMY3 data sets provided for free by the US National Renewable Energy Laboratory. You can import TMY2 and TMY3 files directly into HOMER Pro's Solar Resource Inputs window.

• NREL provides TMY2 data at http://rredc.nrel.gov/solar/old_data/nsrdb/).
• And TMY3 data at http://http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3/).
• NASA's Surface Solar Energy Data Set provides monthly average solar radiation data for everywhere on earth at https://data.nasa.gov/Earth-Science/Prediction-Of-Worldwide-Energy-Resources-POWER-/wn3p-qsan.
• In the Solar Resource Inputs window if you specify monthly data there is a button labeled "Get Data Via Internet".  If you are connected to the Internet, that button retrieves monthly solar data for the specified latitude and longitude from NREL's and NASA's satellite databases.  Give that a try, it's really handy. If you specify a lat/long outside North America, HOMER refers to the NASA SSE dataset.  So depending on what location you request data for, HOMER might ask you to specify a username for NASA on their SSE website. Please use skip@larc.nasa.gov as your NASA SSE username in HOMER2. NASA recently re-configured their website and eliminated the need to validate specific email addresses. To enter this in the HOMER software, open HOMER2, select File >> Preferences, and enter skip@larc.nasa.gov into the field for NASA SSE username.
• This help file contains a table of monthly solar data for selected worldwide locations.
• The US Renewable Resource Data Center provides US data and maps at http://www.nrel.gov/rredc.
• The World Radiation Data Center provides worldwide solar data at http://wrdc-mgo.nrel.gov. Note that data from this website need a lot of processing to be useful in HOMER.

Wind Speed Data

It can be difficult to obtain measured wind speed data. Proper measurement of wind speed is expensive and time consuming, and average wind speeds can vary markedly over short distances because of terrain effects. For these reasons, it is often necessary to synthesize wind data from estimated monthly average wind speeds.

Many countries have published wind atlases:

• Wind maps for many US states are available at www.eere.energy.gov/windpoweringamerica/wpa/wind_maps.asp.
• The Canadian Wind Atlas is available at www.windatlas.ca.
• The Brazilian Wind Atlas is available at www.cresesb.cepel.br/atlas_eolico_brasil/atlas-web.htm.

A number of other websites provide wind speed data:

• The US Renewable Resource Data Center provides information on wind data at http://www.nrel.gov/rredc www.windustry.com/resources/windmaps.htm.
• The website www.weatherbase.com provides monthly average wind speed data for many cities around the world.
• The Windustry website maintains a list of US wind data resources at www.windustry.com/resources/windmaps.htm.
• The US National Climatic Data Center provides monthly average wind speed data for many US cities at https://www.ncdc.noaa.gov/data-access/quick-links. To convert from mph to m/s, divide by 2.23694.
• The Technical University of Denmark maintains a database of wind characteristics at www.winddata.com.

Renewable Power System Components

Several retailers sell components for renewable power systems . The website www.ecobusinesslinks.com maintains a list of renewable power retailers around the world. A few have very helpful websites providing cost and performance data for PV panels, wind turbines, hydro turbines, batteries, converters, and other system components. Check out:

• Real Goods at www.realgoods.com
• The Alternative Energy Store at www.altenergystore.com
• SolarEnergy.com at www.solarenergy.com
• The Solar Biz at www.thesolar.biz
• The Energy Development Co-operative at http://www.solar-wind.co.uk/

Other sources of cost and performance data for renewable power system components include:

• The California Energy Commission, at www.energy.ca.gov/
• The Renewable Energy Technology Characterizations, a detailed report on the performance and costs of solar, wind, and biomass power systems, available at www.eere.energy.gov/power/techchar.html. This report even includes predictions of future performance and costs out to the year 2030.
• SolarBuzz, which provides price data for PV modules, inverters, batteries, and charge controllers at www.solarbuzz.com.
• An online marketplace for wind turbines at https://windturbines-marketplace.com/.

Generators

• A very useful document covering the technology, emissions, and costs of natural gas-fired reciprocating generators, microturbines, fuel cells, and Stirling engines is the Gas-Fired Distributed Energy Resource Technology Characterizations, available at www.eea-inc.com/dgchp_reports/TechCharNREL.pdf.
• The Distributed Generation Information Center provides summary technical and economic data on reciprocating engine generators, microturbines, and fuel cells, as well as a large library of links, at www.distributed-generation.com.

Emissions

The US Environmental Protection Agency provides emissions coefficients for CO₂, SO₂, and NO_x for US locations at their Power Profiler website at www.epa.gov/cleanenergy/powpro/screen1.html.

The EPA's eGRID website contains even more emissions data, including state-by-state average emissions factors for all the pollutants that HOMER models.

Policies and Incentives

• For information on current net metering policies across the Unites States, see the US Department of Energy web page on the topic at https://energy.gov/savings/net-metering-4
• For a list of renewable energy incentives across the United States, see the Database of State Incentives for Renewable Energy at http://www.dsireusa.org/resources/detailed-summary-maps/net-metering-policies-2/.