CSU Extension recently unveiled our interactive 2018 Solar Payback map of home solar arrays in Colorado rural electric association service territories, and there is a lot of data there to analyze. Perhaps the most meaningful map layer is called “Payback with 3% Electric Rate Inflation”. This shows how quickly a household could get its money back after buying a solar array to offset its electricity use. The map shows a clear geographic trend of shorter solar payback periods in southern Colorado compared to central or northern Colorado. This can be explained in part by the higher solar insolation received in the southern part of the state. The result is that solar panels in southern Colorado generate more electricity than their northern counterparts, and households in southern Colorado will therefore need smaller systems to offset electricity use.
Yet solar insolation is only one piece of the puzzle. The layer showing “Residential Rates” is similar to the payback layer in that there is a fairly distinct difference in rates between southern, central, and northern Colorado. In general, rates are higher in the south. High rates contribute to quicker payback periods as savings are greater.
In addition, although higher solar insolation means smaller system sizes, costs per watt of installed solar are not even throughout the state. Arrays in less populated parts of the state aren’t served regularly by solar installers, so the cost of a 4.4 kW array in San Isabel Electric Association service territory is estimated to exceed the cost of a 4.7 kW array in Poudre Valley Electric Association service territory, for example.
The “Rebates” layer is less important than it used to be, as fewer utilities offer rebates for solar. In fact, only three rural electric cooperatives offer true rebates (Holy Cross, San Miguel, and Mountain Parks). These coops are found in different geographic regions of Colorado.
So what do all these map layers mean for Coloradans interested in going solar? It means that those that live in a rural electric association service territory in which a combination of strong solar insolation, high rates, and low costs per watt are going to see the quickest returns on investment. The REA territories with the quickest and slowest returns on investment for home solar arrays are:
Quickest Return On Investment (ROI):
- San Luis Valley Rural Electric Cooperative
- San Miguel Power Association
- La Plata Electric Association
- San Isabel Electric Association
- Gunnison County Electric Association
- Yampa Valley Electric Association
- Poudre Valley Electric Association
- C. Electric Association
- Delta Montrose Electric Association
- White River Electric Association
For more information and to play around with the layers on our interactive map, visit our Maps page.