Dynamic power resource (more than a battery) to keep Maui grid solid
February 3, 2011 by Windpower Engineering
Filed under Community Wind Power, Wind Power Projects

Each island is energy independent of the others in Hawaii. For example, the island of Lanai has about a 6-MW demand. It is isolated from Maui, which uses 190 MW.

The battery in the DPR is a dry cell build around a particular alloy. Round trip efficiency is greater than 90%, going from ac to dc and back. It has almost no internal resistance so it can be charged and discharged quickly. There are no issues of hazardous materials or risks of acid spills so there are no containment structures. What’s more, cooling systems are unnecessary to prevent a thermal runaway. The cells will last about 10 years. The Kaheawa Wind Power II project is scheduled for completion in November 2011.
One knock against wind power is that it’s unreliable because of its variable nature. But it need not be that way say engineers at Xtreme Power Inc. The company manufacturers Dynamic Power Resources (DPRs), utility-scale energy-storage systems with power management. The company recently announced it has been selected to provide power for First Wind’s Kaheawa Wind Power II (KWP II) project on Maui. The 21 MW farm will use a 10 MW DPR (20 MWh) from Xtreme Power, its fifth in Hawaii. The DPR at the KWP II site will
rapidly respond to differences between the farm’s output and needs of the Maui grid, absorbing or delivering power as needed to reduce the variability inherent to renewable energy sources.
Utility typically carry online capacity to serve loads in excess 15 to 20% of actual loads. This typically has been done with generators.
Maui Electric Co. will be able to dispense with the excess capacity or so called spinning reserves. Should the grid for any reason, have a variance in voltage or frequency, the dynamic power resource will respond to mitigate those incidents. “The beauty of dynamic power resource or storage, its can respond almost instantly,” says Xtreme Chief Development Officer Darrell Hayslip. “We are installing 20 MWh of storage as response reserves. The utility will no longer spin a generator to meet temporary demand and it will be able to produce more energy when needed without burning fuel or emitting pollution. So when demand surges for less then a couple hours, it will come from the dynamic power resource.

It’s more than a big battery, says Hayslipp? It’s power storage with control electronics and power inverter and charger. Ten inverters with 2-MWh storage will be in a building.
This ramping and smoothing function is essential to managing large changes in wind-farm output. First Wind will also use the DPR to provide Maui Electric with responsive reserves to make better use of wind energy, as well as for supporting services such as frequency and voltage regulation
Xtreme Power, Inc.
www.xtremepower.com
Hawaii wind project includes battery storage
July 16, 2010 by Paul Dvorak
Filed under Power storage, Wind Power News, Wind Power Projects

Developer First Wind will include power storage and controls to better balance the power output from its wind project on Ohau.
A developer of power-storage equipment for utility-scale tasks will supply a 15 MVA, 10 MWh battery and power-management controls for the Kahuku Wind Project on Oahu. This marks the second Hawaiian project for which Xtreme Power, Kyle, Texas (xtremepowerinc.com) has supplied equipment. The groundbreaking follows the company’s first commercial pilot at the Kaheawa Wind Project on Maui. The latest wind project, 30 MW from 20 GE wind turbines, is supported by a 1.5-MW Xtreme Power energy storage and power-management system. Results from the Maui project demonstrated the ability of Xtreme Power’s equipment to control ramp rates (up and down) during changes in wind conditions, and to simultaneously store surplus wind power for redeployment during times of peak demand. Both projects are owned by First Wind in Honolulu.
“This marks the second project in which we’ve chosen Xtreme Power as a key partner to help us deliver reliable wind power for the residents of Hawaii,” says First Wind CEO Paul Gaynor. “Hawaii has a huge natural resource in wind and together with Xtreme Power, we are able to effectively deliver that power.”
Overall, Xtreme Power says the project on Maui has demonstrated an ability to:
- Reduce power variability by more than 95%
- Mitigate the issues associated with wind turbine trips and overloads, delivering consistent power to the grid, and
- Effectively store and deliver surplus power.

The 10-MWh storage is possible thanks to capabilities in Xtreme Power’s PowerCells, individual 12 V, 1 kWh, advanced dry-cell batteries that use an unconventional solid-state chemistry. The cell’s characteristics allow assembling thousands in massive parallel and series matrices, ideal for use in large-scale utility applications requiring hundreds of MW while maintaining a manageable footprint. Low internal resistance results in a capability to rapidly charge and discharge large amounts of power.
