The U.S. average hovers around 20%-- though that's bolstered by wider areas where resources like hydropower come into play, whereas of course DC is an urban environment. Do you know how the 12% figure compares with other cities of DC's size? 

Kellie, DC appears to be using the same false accounting used by many other cities (and states) to double the amount of renewable resources actually providing power to the district.

The law is clear:

"The Retail Electric Competition and Consumer Protection Act of 1999 requires the Public Service Commission of the District of Columbia (“DCPSC”) to report...the amount of electricity sold in the District that comes from renewable sources..."

Its explanation of DCPSC's compliance with the law is a convoluted, unintelligible mess, however, and that seems to be the point - through obfuscation, to exaggerate the amount of renewable electricity being consumed in DC.

The overall quantity of electricity coming from renewable sources, unfortunately for DC and other districts engaging in this deception, is not that difficult to determine: it's exactly the same as the grid to which its connected, plus any renewable electricity generated within district limits. So-called "renewable energy credits," or RECs, do not count - and here's why.

Imagine a track and field event where the winner of a certain competition wins a gold medal - she crossed the finish line first. However, the runner in 4th place, due to personal challenges, was unable to train before the event. So organizers have decided to allow the winner to sell the "attributes" of winning the event in the form of a certificate, a "Triumph Certificate", if you will. By buying these attributes, the 4th place finisher will go in the record books as the winner. She is permitted to claim being the winner, to hang the certificate on her wall, accept endorsements for vitamin pills, appear in motivational videos, etc., and profit from her false accomplishment without the possibility of prosecution. There is no doubt who actually won the event, of course, so the true winner also accepts endorsements for training devices, etc., to profit from her real accomplishment.

In an identical manner, this is how DCPSC is double counting its clean energy consuumption with RECs - the only difference being public ignorance of energy, combined with obfuscation ("Tier 1 and Tier 2 certificates", etc.) permits DCPSC to get away with it.

Interestingly, the author of the report lets the truth slip out here:

"...the suggested fuel mix for the District appears to reflect an overall renewable energy component of over 12% of the total energy sold in the District — in contrast to the PJM System Mix of roughly 6%."

Again, DCSPC's fuel mix is exactly the same as PJMs, the only difference being any renewable energy generated from within. But then the report reveals

"It should be noted that the DCPSC has not independently verified the fuel mix representations made by the suppliers."

Translation: "We use half as much renewable energy as we say we do from outside the district, and we don't verify what's generated inside." Bottom line: DCPSC is using half as much renewable electricity as it claims, and though some may be fooled by its report, nature is never fooled.