John Farrell, a senior researcher on the New Rules Project at the Institute for Local Self-Reliance, has published an interesting animated map at the website “Energy Self-Reliant States” to project solar grid parity in cities across the United States. Solar grid parity refers to the point at which electricity from solar power is less costly than electricity from the existing grid. The animated map predicts that it will be a city in California to be the first solar grid parity city; specifically, San Diego in the year 2013. According to the figures presented, “In just 7 years, 1 in 6 Americans living in major metropolitan areas could lower their electricity bill by installing solar –without any incentives.” Farrell notes that he drew his conclusions with the following data:
“We used the following assumptions in the construction of this animated map: 1.) The cost of solar in 2011 is $4.00 per Watt installed. 2.) Grid electricity price is the average residential retail rate reported by PVWatts for the core city of the metropolitan area. 3.) The cost of solar decreases by 7% per year. 4.) The grid electricity price increases by 2% per year.”
Take a look at the animated map here and click the “animate” button or input the year you want to see figures for. For instance, by inputting the year 2015, the map shows that grid parity will only be evident in two cities: San Diego and New York. However, by 2020, the map shows that 17 cities will have solar grid parity with 6 cities achieving that status in California.
There are issues to ponder, however, when considering the accuracy of the chart’s conclusions. Some critics have argued it doesn’t seem to fully account for local incentives and tax benefits that affect prices. In addition, one might take issue with the projected utility rate increase, which possibly falls short of the national historical average and there is reason to believe costs will increase far more than outlined by the graph’s numbers. That being said, the map is an interesting perspective on when the rising-grid-cost and falling-solar-cost curves will intersect in cities.