China has to confront a lot of environmental problems brought forth by its own quick development, and when China confronts an issue they go all out! Renewable Energy World has a quick write up comparing and contrasting China and the USA in how they support green technologies.
The China Development Bank (CDB) is being relentless in its funding of clean-tech concerns. While American politicians battle it out over Solyndra’s collapse and potential loss to the government of $528 million, the Chinese are pumping billions into their clean-tech concerns, knowing full well that some of them will fail. The CDB put more than $30 billion in credit into its burgeoning solar companies in 2010, including Suntech Power, Trina, and Yingli. It recently announced financial commitments to ensure that its fledgling wind industry can join the ranks of GE, Vestas, and Siemens, allocating at least $15 billion in state-backed credit to China’s biggest windmill makers Sinovel Wind Group and Xinjiang Goldwind Science & Technology. And China has plans to invest some $45 billion in smart-grid companies and technologies alone over the next five years.
These investments haven’t gone unnoticed in the U.S., and have been front and center in recent complaints that have claimed that China’s solar industry, for example, has an unfair trade advantage.
Thermal solar power plants uses energy from the sun to heat up water and then run the resulting steam to power turbines. Simple enough, but now Siemens is looking to make that whole process more efficient by using salt.
Solar thermal power plants that produce hotter steam can capture more solar energy. That’s why Siemens is exploring an upgrade for solar thermal technology to push its temperature limit 160 °C higher than current designs. The idea is to expand the use of molten salts, which many plants already use to store extra heat. If the idea proves viable, it will boost the plants’ steam temperature up to 540 °C—the maximum temperature that steam turbines can take.
Siemens’s new solar thermal plant design, like all large solar thermal power plants now operating, captures solar heat via trough-shaped rows of parabolic mirrors that focus sunlight on steel collector tubes. The design’s Achilles’ heel is the synthetic oil that flows through the tubes and conveys captured heat to the plants’ centralized generators: the synthetic oil breaks down above 390 °C, capping the plants’ design temperature.
Startups such as BrightSource, eSolar, and SolarReserve propose to evade synthetic oil’s temperature cap by building so-called power tower plants, which use fields of mirrors to focus sunlight on a central tower. But Siemens hopes to upgrade the trough design, swapping in heat-stable molten salt to collect heat from the troughs. The resulting design should not only be more efficient than today’s existing trough-based plants, but also cheaper to build. “A logical next step is to just replace the oil with salt,” says Peter Mürau, Siemens’s molten salt technology program manager.
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