WIND STORAGE BATTERY

It is hard to see how multi-million dollar batteries with capacities in the single digit megawatts could ever be economic enough to serve wind power in a utility-scale storage system. Nevertheless, Xcel Energy sees it and has invested a lot of money in the concept.

And Xcel Energy knows wind. Among U.S. investor-owned utilities, Xcel is the biggest owner of wind energy-generated electricity.

One thing is not hard to see: If Xcel has an economically viable technology for the utility-scale storage of wind-generated electricity, it will change the energy business.

Xcel obtained the battery technology from NGK, a Japanese company. The concept has worked in Japan on a small scale and the batteries have proven themselves in nonwind applications in the U.S.

Dick Kelly, CEO, Xcel: "But this is the first U.S. application of the battery as a direct wind-energy storage device…"

Since 2002, the state of Minnesota has been pushing Xcel Energy, its biggest utility, to acquire New Energy capacity. Although the state’s Renewable Electricity Standard (RES) calls for its utilities to obtain 25% of their power from New Energy sources by 2025, Xcel is required to obtain 30% by 2020.

It is clear the battery-storage concept is workable. The questions remaining: (1) Will it work at utility scale? (2) The wind is free but batteries are expensive, so is it economically viable?

click to enlarge

Xcel looks to harness wind energy for use even when there’s no wind; The project, which also includes the state and a tech firm, is installing a battery that is the first U.S. device that can store wind power.
Dee Depass, November 12, 2008 (Minneapolis Star-Tribune)

WHO
Xcel Energy Inc.; the state of Minnesota; S&C Electric Co.; Minwind Energy; NGK Insulators Ltd.; the Minnesota Renewable Development Fund; the Minnesota Renewable Development Fund; GridPoint; the National Renewable Energy Laboratory (NREL); the Great Plains Institute

WHAT
Xcel and partners will test a Sodium-Sulfur (NaS) battery designed to store wind energy.

click to enlarge

WHEN
- Tests of the battery technology are planned for Spring 2009. Installation is expected to be complete by April.
- 2002: the state of Minnesota mandated Xcel to obtain 825 megawatts of energy from biomass and wind.
- 2020: Minnesota requires Xcel to obtain 30% of its power from New Energy.
- 2025: Minnesota’s RES calls for the rest of its utilities to obtain 25% of their power from New Energy sources.

WHERE
- The test will take place at a wind installation in Luverne, Minn.
- The batteries were manufactured in Japan.
- Xcel Energy is based in Minnesota.
- GridPoint is based in Arlington, Va.

WHY
- Xcel bought the battery technology from Japan's NGK.
- The batteries are used in Japan to store wind energy. They are used in the U.S. for nonwind applications.
- The battery system consists of 20 50-kilowatt modules the size of two semitrailer trucks stacked on top each other weighing ~ 80 tons.
- The sodium-sulfur battery stores a full charge of 7.2 megawatt-hours of electricity (enough to power ~ 500 homes for ~ 7 hours).
- Cost of battery installation and testing: $5.4+ million.
- Xcel has invested $3.6 million in the project.
- The Minnesota Renewable Development Fund has invested $1 million.
- GridPoint has invested $750,000.
- The University of Minnesota will analyze the pilot project.
- Other participants: NREL, the Great Plains Institute.
- Xcel recently announced the development of 351 megawatts of new wind-energy production over the next 24 months and $900+ million in plans to up its wind capacity by 10% (includinbg a 201-megawatt project in southwest Minnesota's Nobles County and a 150-megawatt project in Dickey and McIntosh Counties in southeastern North Dakota).
- Xcel is also active in the development of the “smart grid.”

click to enlarge

QUOTES
Dick Kelly, CEO, Xcel: "Energy storage is key to expanding the use of renewable energy…This technology has the potential to reduce the impact caused by the variability and limited predictability of wind-energy generation."