A vertical axis wind turbine known as the PacWind Delta II is available for small commercial operations. It produces 10 kilowatts of electricity in a small footprint and is completely silent. The turbines can be placed very close together and stacked up to five high. Eighteen months ago, Energy Matters reported that five large vertical axis turbines, each producing 5,000kilowatts, were towed to the North Sea and installed there. The Delta II is suitable for use in cities and provides electricity for the locality where it is installed, reducing the cost of building network infrastructure. It operates in wind speeds as low as ten kilometres per hour.