The current interest in CNG is because there are lots of places where there apparently is a lot of natural gas, and the current direct cost of getting it out of the ground is fairly low. (Ignoring all the trivial details generally grouped together as "environmental impacts," and whatever else is necessary to sell the idea.)
A problem for those who see it as a place to make a profit is that current production supports all the current uses for it, and pulling up more of it would create a supply glut, which would drive down prices, and make even the current production unprofitable.
It is thus "necessary" to find more ways to use it, and to convince enough people that it's "better" so that enough more people will "buy" into it to keep the price up.
CNG is sufficiently "cleaner" than coal to justify conversion of electric generating plants, and the cost could be fairly low in many places. Handling transport, storage, and use of CNG in a stationary plant does not pose many technical problems or risks, if sources aren't too far removed from the plant.
Other generating plants that are deeply integrated with existing coal extraction, shipping, and storage systems could face very high costs for a conversion, so it needs to be a case-by-case decision unless they can convince the people using the electricity to just turn everything off(?).
Many of the plants that would be too expensive to convert to CNG could be cleaned up quite dramatically by applying known upgrades to existing equipment to achieve much cleaner handling and burning of coal, but costs for that also depend on what's there already.
The lower energy density of most "alternate fuels" makes them competitive with existing usage only for a fairly few special purposes, mostly not including general purpose vehicles.
The reason that nearly all "electric" autos are hybrids is that the is NO CURRENT WAY to STORE electric energy in the quantities and at a density that permits an electric vehicle to have a reliable useful range (ignoring load capacity completely) without some kind of backup system.
A home solar supply can use common lead-acid batteries for storage, but for the amount of storage required a useful auto would need at least a couple of tons of batteries. (Even a fork lift useful for half a day at a time in a reasonably busy warehouse carries around 800 lb of Lead batteries?)
The Lithium batteries currently used in most "electric" vehicles provide higher storage density, but THERE ARE NO available batteries that can operate beyond about 1,000 recharge cycles (most much fewer) and replacing the batteries in a typical electric car will cost (now) on the order of one-third (or more) of the original (subsidised) cost of the vehicle.
IF (should print that as a bigger IF) an auto battery set can meet the "design goal" of 1,000 cycles, recharging daily means the vehicle is dead in 3 years or less, without a complete replacement of the batteries. Accidentally running the batteries dead ONCE can reduce their capacity by as much as 50%, but the mfrs claim they've protected against that(???).
The basic materials used, even at current usage levels, are considered "critical supplies" with Lithium being available only from a very few places with "unstable governments," and without development of alternate materials or alternate sources for the ones now used, any widespread use of Li batteries for massive energy storage likely will drive prices to astronomical levels. (My checkbook indicates 3200 mah Li rechargeable AA batteries for my camera are already 3.2 times the price they were 4 years ago, but I haven't bought any for a while so I haven't researched current price spreads.)
So far as is now known, THERE AIN'T NO GOOD ANSWERS - YET, and although some "possibly helpful" new things do appear from time to time, leaping in the air in unbounded enthusiasm just means you'll eventually come down hard.
(Small happy hops are permitted, if reasonably restrained - but checking to see who's watching is recommended to avoid later embarrassment.)