The ESCOs in the Duquesne (Pittsburgh) region also offer another option when switching electricity - choosing if a customer wants a certain percentage his or her electricity to be generated via renewable sources (most use wind and/or solar).
Here I have graphed another time series (Oct 2010 - Jul 2013), this time comparing the average rates of plans that have renewable generation. Plans offered in the Duquesne region offer 2%, 12%, 20%, 50%, and 100% renewable options.
1 - On average, renewable plans through ESCOs are competitive to Duquesne's price to compare (PTC). While the 100% Renewable plan was initially higher than the PTC, it stayed consistently lower for over a year (Apr 2012 - May 2013).
2 - As expected, the lower the percentage of renewable generation, the cheaper the tariff. The average rate for 50% renewable plans, however, strayed from this trend - it was the lowest rate offered between May 2012 - Dec 2012. I will follow up with research into why the 50% plan has not been offered since.
This graph only shows renewable fixed plans offered in the Duquesne region, but many more factors go into a customers decision to switch electricity to a more competitive electricity supplier: fixed vs variable plans, introductory rates, and cancellation costs.