The need that is satisfied might be even more important.

Starting with the problem both horses and autos solve: tranportation.  in your example you imply that the rise of the suto was primarily due to price reduction.  i would contend that a key enabler was government enabling the use of autos over horses.  during the early day of the auto, part of the issue with using auto transport over horse was teh roadways.  A horse could travel over many surfaces in many weather conditions (rain, snow, muddy, etc)  As the govenrment created auto friendly roadways, which were less horse friendly, autos became a better source of transportation than horses. which then led to the increase in demand, subsequent increase in competition for the transportation need, lowering the cost(price), and spiraling to where we are today. The auto did not tranform the energy source to be a more efficent means of tranportaion, it used a completely different source.

To relate this to the electrical energy market, the first task would be to relate the consumer needs(desires?): food storage(satisfied today by refrigerators), lighting(today satisfied by electrical lighting), temperture comfort (currently air conditioning and heating), and entertainment (television, internet, etc) to name a few.  Currently, many of these needs or desires are satisfied by electrical power.  The power is distributed primarily over government "freeways" of electricity (e.g. the public electrical grid).  These needs are currently satified by the "electrical fuel source"

To find the parallel to the early days of the automobile, we need to look at the consumer needs first.  As an example, lighting is primarily satified today by electrically powered incandescent/flourescent (some LED) devices.  The technology of which is substanitally over a century old.  To me, this is the "horse".  A true comparision to how the automobile changed transpotation, would be to find a source of lighting that is renewable, less wasteful, cheaper, or whetever other consumer criteria are needed, without focusing on the energy supply.  The power source to drive the revolutionary lighting system may come from electrical energy, may come from steam, may come from chemical luminesescne...only people far smarter than I will determine this. 

To relate the electrical energy back to the horse vs. auto would be like saying we needed to grow the grain for feeding the horse more efficently to get a better mode of transportation.  Short term, growing better grain (e.g. solar, wind, biomass, ... generated electrical power) may be a viable improvement.  the next century, will likely be driven by more substantial innovation of solving peoples needs and desires, rather than just growing better grain...