Can load-shedding technologies effectively provide immediate relief to the grid?


According to the EIA’s Annual World Energy Outlook 2008, total electricity usage in the world is supposed to approach 203 million GWh by 2030 across all sectors- residential, commercial and industrial. This number translates to a growth rate of 1.6 percent per year. Additionally, the last infrastructure report from the American Society for Civil Engineers downgraded the U.S. national power grid from a D+ to a D rating (on an A-F grading scale) and Europe also recognized the necessity to upgrade its transmission capabilities given infrequent, yet serious blackouts in the last few years. While most if not all agree that cleaner sources of energy are imperative, it is indisputable that that significant “gains” can be achieved through conservation and efficiency improvements. As the load demand reaches grid capacity in many areas, this is where some of the “low-hanging fruit” will be found.

Load-shedding is the process by which certain pre-established electrical loads are decreased or shut off as soon as peak energy demand is reached. Technical advancements have made this an easily implementable approach to managing energy demand. Recently, Axis Technologies Inc. announced the development of their next generation of energy-efficiency ballasts; a technology that is riding the wave of success from their original designs for daylight harvesting ballasts. The new prototype will provide load-shedding capabilities via wireless connection to the local power company’s Peak Demand Reduction Program, similar to the one initiated by the New York Power Authority in summer of 2008. Through breaker sequencing, Schneider Electric is addressing the same issue at a much larger scale delivering engineering power system control solutions to more industrial and commercial-type clients.

The true benefits of this type of technology can be seen when applied at a more macro-level. As previously mentioned an outdated grid combined with increased load establishes a propensity for blackouts. When the grid reaches capacity the natural tendency is for the AC transmission frequency to decrease. In a process called “under-frequency load-shedding”, pre-established constant values are given to the frequency settings, time delay settings and load-shedding amount, thus ridding the system of demand completely agnostic of the actual grid disruption. In an article in IET Generation, Transmission and Distribution entitled, “New Centralized Adaptive Load-Shedding Algorithms to Mitigate Power System Blackouts” researchers actually propose a unified system that reacts to disturbances by evaluating system responses and/or events (e.g. low voltage/stability and plant outages respectively). Load-shedding responds to the disturbance location and the amount shed is proportional to the magnitude of the disturbance. Through modeling, this methodology proved to both preserve stability and minimize the amount of load-shedding necessary to maintain stability.

On both sides of the micro and macro equation creative applications of load- shedding can provide answers to our preeminent concerns about the current grid infrastructure capacity. Part of the energy solution is making sure that the transmission capacity we currently have is being used in most efficient way possible and load-shedding is one technology which can both stave much needed infrastructure investment and realize immediate cost savings.

For information on adaptive load-shedding check out IET Generation, Transmission and Distribution, January 2009 Volume 3 Issue 1 http://www.ietdl.org/



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3 comments on “Can load-shedding technologies effectively provide immediate relief to the grid?

Javier, how does EnerNoc’s technology and their network address this? How does it compare to companies GridPoint and how will monitoring companies like Positive Energy be able to incorporate these technologies into their services?

-Ian

George

Great question, Javier, and the answer is an unequivocal YES! Load shedding is ‘low hanging fruit’ that is both easy and flexible to deploy. It also cost far less than building new generation facilities. The compelling value proposition is evident in Comverge’s and EnerNOC’s revenue growth rates – yet both are still unprofitable. Typically, a utility would pay the provider (e.g., EnerNOC) about $80K per MW committed, which is then shared with the customers in the form of monthly program payments and per-event payments. This space is going to become incredibly crowded, which is very good thing for everyone in the value chain.

FWIW, I agree with Jesse Burst in Grid Automation as to the current competitive landscape:

– Comverge will happily sell to utilities, but it also wants to aggregate its own “negawatts” and sell them back to the utility.

– EnerNOC is aiming primarily at the commercial and industrial space.

– Google wants to aggregate and create value from huge networks spanning entire regions.

– GridPoint is focusing primarily on platform software for utilities, not on gadgets for the home.

– IBM wants to custom build one-off software for large utilities.

– PowerMand hopes to sells software as a service to utilities, charging a tiny fee for each transaction.

– Site Controls Energy Systems (aka SureGrid) wants to tie into the existing building automation systems in commercial and industrial buildings.

– Tendril sells software for utilities, but also wants to sell devices via big box retailers such as Home Depot and Best Buy.

Jim

Great article. I work for a well-known DR company, but since we are touchy about how and what we communicate to the public I’ll leave my employer anonymous.

Basically, I feel that current DR programs, which in many cases are just more sophisticated versions of old utility interuptible tariff programs, are to smart grid what punch cards were to computers. We are barely scratching the surface of the potential that is out there. The biggest lesson has been that customers are willing to modify their behavoir for very modest financial incentives and that some industries are much better suited for demand response than others (e.g., rock crushers = good, just in time manufacturing = bad). We are at the beginning of a decades long period of massive innovation in the electric grid and DR is where this innovation is getting its start. We are going to see increasing automation, statistical modeling of DR as a firm dispatchable resource, interactive building controls, and home appliances knowing when its okay to suck a lot of juice and when to conserve. Its a fun place to be

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