The electric grid is the vast network that transmits electric power from the place of generation to the end consumer. Most of our electricity is generated at large centers such as Thermal Power plants, Hydro-Electric plants and Nuclear Power plants. In the US, Hydro-carbons such as Coal, Oil and Natural Gas generate almost 70% of the total electricity. Nuclear plants account for about 19% and Hydro-electric plants contribute another 7%. See the full table over at Wikipedia. The majority of electricity consumption occurs in homes and buildings (commercial and industrial). Most people are completely unaware of the engineering involved in transmitting electricity from the source to the user. We take it for granted that everywhere we go we will have an outlet in the wall to plug in our devices. The figure below shows a high level overview of the electric grid’s current architecture.

Notice in the figure above that our current grid has a one-way flow of electricity from generators to consumers. There is no link in the reverse direction (from customer all the way back to the generation center). What would the link in the reverse direction accomplish? More importantly, what ‘substance’ should be flow on this reverse link? Clearly there is no point in transmitting electricity back to the source. But what would be worth transmitting in the reverse direction?

Just as the technology that enables the transmission and distribution of electricity on the grid is largely hidden to the public, there are many entities involved in ensuring the smooth operation of the grid. We are mostly familiar with our local utility company to whom we pay our monthly electricity bills. Some of the other players include the Service Providers and Operators that provide direct support to the consumer. Then there are the Energy Markets that determine the price of energy. 

These additional actors in the grid would benefit tremendously if they had access to real-time information about the status of the grid. How healthy are the transmission lines? Do any of the distribution centers need maintenance work? Which localities have greater load demands? To answer these sorts of questions, the grid needs to have some ‘smarts’. Information needs to travel from the consumer to the source of generation and to all other players involved.

In a previous post, I explained the factors motivating the work on the Smart Grid. One important factor that I missed was the need to Modernize the existing electric grid. An introductory video at the DOE’s website has a good visual example of how consumer technologies have evolved over the last 50 years but grid infrastructure that powers all these new technologies has remained stagnant. These screen-shots explain it all:

As you can see, audio players have evolved from huge vinyl disk players to the sleek iPod nanos; TV’s have gone from bulky CRTs to super thin LED; the latest generation of passenger Airplanes such as the Airbus A380 can carry 500 people and military aircraft have all sorts of technologies that are never even made public; And ofcourse the simple telephone has evoloved in to the Smart Phone. The one technology that has not changed in the last 50 years is the electric grid. Upgrading the components of the grid to modern devices can yield tremendous benefits in energy efficiency and cost savings.

A lot of work that falls under the Smart Grid umbrella involves upgrading the grid infrastructure to use the latest technologies in power generation and distribution.

To summarize, the Smart Grid is an upgraded, modern electric grid that uses the latest technologies in energy generation, transmission and distribution in combination with the latest communication technologies to relay information across the entire grid. This can be visually summarized as: 

Source for Images: NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 1.0, (NIST Special Publication 1108); January 2010