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Advanced super capacitor-based storage

Storage, Supercapacitors

Utility Applications for Dispatchable Energy Storage

A large solar facility with snow on the ground and mountains in the background

The following list briefly describes the applications for dispatchable energy storage. Supercapacitor Energy Storage is uniquely qualified to meet these needs due to its longevity and ability to be cycled daily with no degradation in capacity or life. Where chemical batteries fall short, supercapacitors fill the requirements as a long-term solution. Supercapacitors are non-toxic, non-flammable and non-hazardous.

  • Frequency regulation helps balance momentary differences between electricity demand and supply within the transmission grid, often to help maintain interconnection frequencies close to 60 Hertz.
    Supercapacitors have two major advantages here over chemical batteries. They provide high C-rate capability for rapid response and long cycle life for durability. Since supercapacitors do not contain an electrolyte, there is no creation of dendrites which reduce battery life.
  • Spinning reserve is the unused dispatchable generating capacity of online assets that provides grid frequency management, which may be available to use during a significant frequency disturbance, such as during an unexpected loss of generation capacity. This reserve ensures system operation and availability. Dispatchable generators are those that can be turned on or off to meet immediate needs of the system.
    Utilizing gas-fired power plants for spinning reserve is a significant source of greenhouse gas emissions from utilities. Furthermore, most of the time, fuel is burned with no electricity production resulting in a very low capacity factor and high cost per kWh for the plant. Supercapacitors, with their rapid response capability can provide a significant portion of this industry requirement without emissions. By managing both the supply of balancing reserves and absorption of excess base load generation the supercapacitor solution can supplant spinning reserve needs in the 5-minute to 6-hour time frame thus eliminating up to 90% of greenhouse gases and do so at a significantly lower installed cost per kW and operation cost per kWh.
  • Voltage or reactive power support ensures the quality of power delivered by maintaining the local voltage within specified limits by serving as a source or sink of reactive power (the portion of electricity that establishes and sustains the electric and magnetic fields of alternating-current equipment).
    Supercapacitors can be installed just about anywhere along the distribution network. From the substation down to individual homes, the addition of energy storage would eliminate most voltage and reactive power issues, particularly those caused by Distributed Energy Resources (rooftop solar).
    While chemical batteries can provide this support their short cycle life and degradation of performance from daily cycling make them a poor solution. Supercapacitors long life, temperature insensitivity, and rapid response are ideally suited for grid support issue resolution.
  • Load following supplies (discharges) or absorbs (charges) power to compensate for load variations—this application is a power balancing application, also known as a form of ramp rate control.

The same capabilities that make Supercapacitors superior for voltage support and spinning reserve apply for load following. Supercapacitors are a high-speed, low cost alternative to generation dispatch and can be implemented near the problem for vastly superior, surgically accurate problem resolution.

  • Arbitrage occurs when batteries charge during periods when electrical energy is less expensive and discharge when prices for electricity are high, also referred to as electrical energy time-shift. Utility Time of Use rates reflect the value of electricity through different periods of the day. By charging higher rates for electricity during peak demand hours, utilities are discouraging the consumption of kWh, their primary source of revenue. Furthermore, large deviations between off- peak and on-peak rates encourages customer to self-manage their energy with onsite solar and energy storage. When a utility proactively installs energy storage to move electricity between time periods, they retain the sale of kWh, eliminate the need to overbuild the network and diminish the advantage of customer owned DERs. Properly deployed, long cycle life Supercapacitor energy storage allows utilities to retain control of the grid and their business.
  • System peak shaving reduces or defers the need to build new central generation capacity or purchase capacity in the wholesale electricity market, often during times of peak demand.

A prime use of energy storage is to absorb excess daytime solar and wind generation and supply that energy when demand is highest. Supercapacitor energy storage can be sized and located for specific needs within the distribution system. Unlike chemical batteries, their long cycle life and rapid response characteristics are ideally suited for this need. Because they can be located near large loads, they help defer millions of dollars of transmission and distribution upgrade work.

  • Load management provides a demand side customer-related service, such as power quality, power reliability (grid-connected or microgrid operation), retail electrical energy time-shift, demand charge management, or renewable power consumption maximization (charging the battery storage system during periods when renewable energy is greatest so as to consume the maximum renewable energy from the battery system, i.e. charging with solar during the day or charging with wind during high wind periods).
    The complete solution would optimize local DER generation and loads. By utilizing Supercapacitor energy storage as an integral part of daily supply and demand management, the utility can help customers optimize their energy use and minimize their impact on grid operations.
  • Backup power, following a catastrophic failure of a grid, provides an active reserve of power and energy that can be used to energize transmission and distribution lines, provides start-up power for generators, or provides a reference frequency. Modern battery Power Control Systems (Inverters) coupled with Supercapacitor energy storage are capable of providing black-start, microgrid structure, and network reliability. These systems will improve grid resiliency and maintain service for customers who either cannot afford their own DER with UPS or are located such that solar is not a viable option.
  • Transmission and distribution deferral keeps the loading of the transmission or distribution system equipment below a specified maximum. This application allows for delays in transmission upgrades,avoids the need to upgrade a transmission system completely, or avoids congestion-related costs and charges.
    A significant part of the cost of transmission and distribution network cost is the need to overbuild for those few high demand hours of the day and for momentary demand spikes on the network. By strategically installing Supercapacitor energy storage, costly system upgrades can be deferred and more efficient use of existing facilities achieved. This is closely aligned with power arbitrage capabilities of Supercapacitor energy storage.
  • Co-located generator firming provides constant output power over a certain period of time of a combined generator and energy storage system. Often the generator in this case is a non-dispatchable renewable generator (for example, wind or solar).
  • Renewable energy resource adoption is a critical factor in utilities achieving federal, state and local air quality requirements. Co-location of Supercapacitor energy storage, even with fossil fuel generation, provides optimization of the fossil generation resource during partially loaded runtime and eliminates variable generation from renewables.
  • Storing excess wind and solar generation reduces the rate of change of the power output from a non-dispatchable generator in order to comply with local grid requirements related to grid stability or prevent over production or over-production penalties. Non-dispatchable generators cannot be turned on or off in order to meet immediate needs and are often intermittent resources (generators with output controlled by the natural variability of the energy source, for example wind and solar).
    The adoption of more renewable energy resources requires energy storage such that these resources can be operated as though they are dispatchable generation.
    Supercapacitor energy storage allows for daily cycling, stabilizes variable generation sources, and allows greater penetration and use of renewables in the resource mix.
Related
Storage
Capacitors were first invented in 1669 and have been made a fundamental part of electric applications since American scientist, Michael Faraday, determined the nature of capacitance and electricity.
Batteries, Chemical, Supercapacitors
Lithium-based batteries have limited lifetime cycles due to parasitic reactions that occur every time the battery is discharged and recharged. If kept in a 100% charged state, this parasitic reaction increases, further decaying the battery life. Super capacitors achieve 100X the cycle life of a lithium battery because there is no such reaction in the capacitor discharge/charge process. Since the parasitic reaction does not exist, super capacitors can be kept at 100% charge indefinitely with no degradation of life.