A new term is entering the demand response lexicon – “generation response,” or GR for short. GR is similar to DR in that its main objective is to achieve the necessary balance of supply and demand of electricity on the grid. But, unlike DR, which focuses on what happens when demand outpaces generation, GR addresses the generation side, seeking to control both generation variability and times when generation outpaces demand. A surplus of power is just as serious a problem as a shortage of power, because grid operators, in order to maintain a supply/demand balance, must either store or disconnect the oversupply when it exists.
So far, utilities and grid operators have not had to address this situation very often, but as more and more renewables, such as wind power, are integrated into the grid, the operators must frequently deal with surplus of energy when the wind is blowing briskly for any length of time. This is especially true in cases where wind generation accounts for more than 20% to 25% of the available power, such as in the Pacific Northwest and in Canada’s Maritime Provinces. In these and other parts of North America, wind power is rapidly becoming a serious variable that can lead to excess energy supply.
How are grid operators addressing this issue? Without the use of storage technology, such as batteries, which are currently expensive and have never been scaled to the level needed, Bonneville Power Administration, has, for example, been compelled to break its “must take” contracts with its wind power producers in order to limit the amount of power it receives. In 2011, Bonneville was forced to pay a penalty of around $15 million to the producers of the wind energy that it turned down. It’s not surprising, then, that many wind farms are forced to shut down in order to avoid or reduce power oversupply. According to a Greentech Media article, approximately 25 terawatt-hours (TWh) of wind energy was curtailed or idled in the United States in 2010 (the amount of electricity used each year by 2.25 million U.S. homes!), a figure projected to exceed 40 TWh in 2011. Fortunately, there are other and better solutions.
One solution is to time-shift the energy use of certain appliances or equipment in homes and commercial businesses to take advantage of available power. This idea – akin to virtual storage – is currently being tested by three utilities in Canada’s Maritime Provinces in a collaborative research project, PowerShift Atlantic. In this project, the utilities are able to directly control thousands of residential water heaters and commercial equipment like HVAC systems and large commercial freezers by either pre-heating or pre-cooling the equipment, for the sole purpose of increasing energy usage at times of excess power. The goal of the project is to find acceptable ways to deliver the excess power in homes and businesses at times when it isn’t needed with minimal or no disruption to the customer. This type of load management, or GR, is made possible by hardware with embedded software technologies provided by Sequentric Energy Systems and advanced predictive analytics and control software by Integral Analytics.
This innovative GR approach, which is considerably more affordable than battery storage technology, could be the answer to the dilemma of excess power on the grid.
Tags: Demand Side Management, Digital Utility Strategies, Distributed Renewables, Renewable Energy, Smart Grid Practice
| No Comments »