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
Filed Under: Community wind, Projects
