Sunday, July 12, 2009

Smart grids and the concept of Distributed Generation

Here is something I wrote for the NERD (Notes on Engineering Research and Development) magazine. This magazine aims to motivate Indian students to write about their field of interest and research. It has got contributions form all the IITs plus a few from Indians outside India.

Distributed Energy generation typically refers to a multitude of small generators instead of having one huge generator that takes care of the entire load.

A smart grid is defined as one which integrates advanced sensing technologies, control methods and integrated communications into the current electricity grid.

So whats so different about these modern grids as compared to older grids? - The major difference is the fact that it is designed to deal with both ways power, rather than the traditional design where the grid just gives out power.

Comparing only the power delivering part, at the transmission level today’s grid is efficient, smart, intelligent. Its at the distribution level that there is a difference. At the distribution level and at the customer level, there are opportunities for automation, intelligent appliances, advanced data collection networks. This in part is because there was no need previously as there was little demand matching done. The Smart Grid makes it possible to integrate large scale intermittent generation through demand response.

The typical components of a smart grid are :-

1) SCADA (Supervisory Control and Data Acquisition), PMUs (Power Management Units), FACTs (Flexible AC transmission systems), Advanced Conductors - At the generation, transmission, substation levels. These things help in maintaining the power quality, reliability and efficiency .

2) Substation Automation. - Helps in resource utilization and demand matching.

3) Distribution Automation, MicroGrid. - Enables synchronization of distributed generators.

4) Advanced metering, Demand response, and distributed resources - at the customer end.
- Helps in demand matching at the consumer level. Ensures correct pricing as there is power both in and out of a building.(As the building also has a generator, when it is producing more than it needs, it sells power to the grid and when in deficit, it buys from the grid.)

So what does it achieve?

1) Reduce peak demand by actively managing consumer demand: The ratio of available appliances and equipment that can respond to both consumer and grid operator priorities continues to grow. Because these grids can manage power both out and in the grid, it will reduce the need for power, especially during high-use periods. like hot summer afternoons when the cost of producing and delivering power is extremely high.

2) Balance consumer reliability and power quality needs: Although some uses of electricity require near perfect reliability and quality, others are almost insensitive to these needs.
For eg- A device working on a resistor heating up or a motor rotating, does not really care a lot about the quality. But a device using electronics, needs to care more about the quality of power in. It cant afford to have a lot of frequency changes or voltage sags or swells.

Similarly, there can be some critical loads that need a very reliable power - Like a server or some central controller type thing cant afford to go off.

A smart grid will be able to distinguish the difference and adjust power reliability and quality accordingly at an appropriate cost.

3) Mine energy efficiency opportunities proactively: A smart grid will furnish consumers and utilities with accurate, timely, and detailed information about energy use. Armed with this information, one can identify ways to reduce energy consumption with no impact on our safety, comfort, and security.
This would mean that just be managing our demand and supply better, we can reduce the total amount of energy required. This will help us gain some understanding and insight into how our energy use affects our environment, and economy.

4) Improve overall operational efficiency: A smart grid is automated, and smart sensors and controls are integral to its design and operation. This will help the grid operators to easily identify, diagnose, and correct problems, and will even have the capabilities to anticipate problems before they happen.

5) Seamlessly integrate all clean energy technologies: Clean energy is so central to the idea of sustainable development that it cant be left behind, especially by a modern technology.Roof-top/side-wall solar systems, wind farms, small community hydro-plants and storage devices will become a fundamental part of the grid. These clean energy technologies will generate not only energy and power, but perhaps more importantly save on the fuel consumption.

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