Geothermal City

Geothermal energy (|jē·ō′thərm·əl ′en·ər·jē)

(geophysics) Thermal energy contained in the earth; can be used directly to supply heat or can be converted to mechanical or electrical energy.



Geothermal Power


Thermal or electrical power produced from the thermal energy contained in the Earth (geothermal energy). Use of geothermal energy is based thermodynamically on the temperature difference between a mass of subsurface rock and water and a mass of water or air at the Earth's surface. This temperature difference allows production of thermal energy that can be either used directly or converted to mechanical or electrical energy.


Here's the CliffsNotes version of how geothermal energy works: You drill several wells to reach the hot rock of the Earth's crust (where, handily, the temperature never fluctuates with the seasons). These wells are then connected to a fractured rock region through which water can flow. This creates a heat-exchanger that can produce more hot water or steam than you can shake a stick at, which then power up electric generators at the surface. Unlike conventional fossil-fuel power plants that burn coal, natural gas, or oil, these generators don't need any fuel. Plus, they're not tethered to the same constraints as wind- and solar-based systems are, resulting in a potentially non-interruptible source of electric power.


Xianyang:The Reykjavik of the East?


Xianyang, not far from Xian and its famed terracotta warriors, is a regular coal burning bad air nightmare. But it’s now poised for a major change. Designated as “China’s official geothermal city,” in December Xianyang saw completion of the first phase of a massive geothermal heating project. The project is being undertaken by Shaanxi Green Energy, a private sector Chinese-Icelandic/Nordic joint venture. If all goes well, the company’s geothermal-powered heating system will be the biggest in the world, and Xianyang’s air will be a heck of a lot cleaner.

Xianyang is big, and it’s just the start. Driven by major concerns about energy security, pollution, and climate change, the Chinese government is working to achieve aggressive renewable energy targets: by 2020, China aims to get 16% of its total energy supply from renewables – up from 7% in 2005. Most of this is slated to come from small hydro, wind, and biomass. Geothermal doesn’t even make it onto your average graph visually representing China’s energy future. But it’s on the long-term horizon, and the sector is definitely heating up. With geothermal resources in almost every province, it’s just a matter of time before they’re tapped. And nothing telegraphs intention like Beijing’s plan to use geothermal pumps during the 2008 Beijing - Green - Olympics.


Currently the city is developing projects for its “thermal energy city”. These include:

>Tianyun thermal spring natatorium

>Qin Ban Hotel

>Xianyang Municipal Hospital

>East/West Water Treatment center


Geothermal Power Plants:


The Geysers, a geothermal power field located 72 miles (116 km) north of San Francisco, California, is the largest geothermal development in the world. It is currently outputting over 750 MW.[1] The Geysers consists of 21 separate power plants that utilize steam from more than 350 producing wells.[2] The Calpine Corporation operates and owns 19 of the 21 facilities. The other two facilities are operated by the Northern California Power Agency.