Generation Surplus During the Periods of Excess Renewable Energy Output – Over Generation
Due to overwhelming success of renewable generation (primarily wind and solar) installations in the past decade, electric utilities are now faced with highly variable energy outputs causing large fluctuations within their grid. Variation is largely dependent on the availability of wind or sun throughout the day. For example, during some periods of the day, the renewable energy output is creating a generation surplus or “overgeneration”. Generation surpluses are posing a significant challenge for conventional generation as well as causing system imbalances since conventional generation (thermal and hydraulic power plants) units cannot modulate their output beyond certain minimum levels. Although the existing utility systems are robust in balancing generation and customer usage, the grid operators are now fluctuating these conventional assets within their required minimum level operation. However, ramping up from these minimum levels to restore the system balance with fluctuating renewable energy output is a relatively new event for the grid. In some cases, the grid operators are taking renewable energy off-line to ensure the grid balance. The industry is expecting even more imbalance due to renewables as the new capacity from renewables increase in the coming years.
Based on various studies, the most significant grid load fluctuations are occurring when there is little or no Commercial segment HVAC demand. This is experienced in the spring typically from March through May. In fact, projects by utilities are now showing that there will be even larger decreases to conventional generation during overgeneration periods when more new renewables are placed online and operating at their peak capacity.
Solution: In order to compensate for overgeneration, Lincus is investigating the benefits of an Overgeneration Program as applied to water and wastewater processing customers. This is with the intent that rather than curtailing renewable generation during overgeneration periods, our customers will pump and process water and wastewater at much more economical rates. In order to fully investigate all practical and economical options, water pumping customers should first have hydraulic models of their systems, second, apply normal operating schedules and third, reconcile their water operations with the 12 month energy consumption history to quantify the overall benefit for fully utilizing the renewable power generation.