in the South Island, while 62.9% was consumed in the North Island. South Island generation accounted for 40.9% of the nation's electricity in 2011, nearly all (97%) from hydroelectricity, while the North Island generated the remaining 59.1% from a mixture of mainly hydroelectric, natural gas, and geothermal generation, plus smaller amount of coal and wind generation. If all currently commissioned generation is available, both islands have enough generating capacity at peak times, without the connection between the two islands. However, the HVDC link provides benefits for customers in both the South Island and North Island: The link provides the South Island consumers with access to the North Island's thermal generation resources that can support the South Island demand during times of low water storage levels and low inflows to South Island hydroelectric lakes. The link provides North Island consumers with access to the South Island's large hydro generation resources that can support the North Island demand at times of peak load. The link plays an important role in the New Zealand electricity market, and allows North and South Island generators to compete with each other, therefore driving wholesale electricity prices down. The inter-island transmission system was designed as a high-voltage direct current (HVDC) system, despite the cost of the conversion from alternating current (AC) to direct current (DC) and back again, to suit the requirements of a long transmission line and a sea crossing. The link crosses Cook Strait, between the two islands, using submarine power cables laid along the sea floor. HVDC is more suitable than AC for transmission over long distances, and particularly where submarine cable transmission is required, because it is typically more economic, and has lower energy losses, despite the high costs of the AC/DC conversion process. Route The HVDC Inter Island link starts at two converter stations located adjacent to Benmore Hydroelectric Power Station in the Waitaki Valley. Electricity is taken from the main Benmore switchyard, which interconnects the Benmore generators and rest of the South Island transmission grid, at 220 kV via tie-lines across the Benmore tailrace. The AC power is converted at the stations to ±350 kV HVDC for transmission The HVDC transmission line crosses the Benmore power station tailrace and takes a route along the eastern side of the dam. The line continues north along the eastern shore of Lake Benmore, before turning north-east and then east to meet the Christchurch to