One of the world’s largest geothermal power stations was officially opened this May on New Zealand’s North Island. A joint venture between Mighty River Power and Tauhara North No. 2 Trust, the new 140-MW Nga Awa Purua Geothermal Power Station increases geothermal’s share of power in New Zealand to around 14%—a proportion that has more than doubled since 2005.
It’s no surprise that China leads the world in recent power capacity additions. What may surprise you is the precise mix of options this vast country is relying upon to meet its ever-growing demand for electricity. As a result, this ancient civilization is fast becoming the test bed and factory for the newest generation and transmission technologies.
At the opening ELECTRIC POWER 2010 plenary session, both the keynote speaker’s address and discussion among the Power Industry Executive Roundtable participants pointed to the renewed appeal of natural gas and proposed cap-and-trade legislation as being potential game-changers for the U.S. power industry.
One indication that the world’s offshore wind sector is poised to soar is the escalating competition between turbine makers. This April, General Electric (GE)—the world’s second-largest manufacturer of wind turbines—announced it would introduce a 4-MW gearless wind turbine (a design requiring no gearbox between turbine and generator) in 2012. The move directly challenges market leader Siemens Energy, of Germany, and its head-to-head competitor, Denmark’s Vestas Wind Systems.
After more than a decade of debate, in April, U.S. Interior Secretary Ken Salazar approved Cape Wind, a proposed 130-turbine offshore wind farm for Nantucket Sound in Massachusetts. It would be the first wind facility in U.S. waters. Despite remaining hurdles, the approval marks a shift in political winds for the nation’s fledgling industry, and it could spur further development of projects proposed for relatively shallow waters along the East Coast and in the Great Lakes.
Soldiers could one day carry 600-W power plants on their backs, or set up arrays of up to 20 kW in streams deeper than 4 feet, if a prototype being developed by California-based Bourne Energy comes to fruition.
Growing water demand and reduced runoff due to drought has depleted waters feeding many hydroelectric power plants around the world—sometimes causing severe power shortages, such as in Brazil and New Zealand. The 2,080-MW Hoover Dam (Figure 4), a facility that generates power for more than a million people in Arizona, Nevada, and Southern California, is not immune to this phenomenon. According to a recent study by the Scripps Institution of Oceanography, the Colorado River system, which includes Lake Powell and Lake Mead (both manmade reservoirs), is suffering a net deficit of nearly one million acre-feet of water per year.
Mexico has already developed substantial large hydro and geothermal resources. However, without policy changes and government-sponsored financial incentives, unconventional renewable sources are taking the equivalent of baby steps.
Shrinking water supplies will unquestionably constrain the development of future power plants. A hybrid system consisting of concentrated solar thermal power and desalination to produce water for a plant, integrated with a combined cycle or conventional steam plant, may be the simple solution.
In mid-February, the Geological Society of London raised the hopes of those promoting geothermal energy when results of exploratory drilling in Weardale, County Durham, revealed record levels of permeability in granite. Although the results are promising for the development of geothermal energy, they may have less welcome implications for the safe disposal of radioactive waste in deep repositories.