In spite of predictions that the worldwide shortage of silicon is easing, companies are still aggressively working to lock down more of it.

Chinesesolarfirm Yingli Green Energy Holding Co. said Tuesday it signed three contracts for the key solar-power ingredient, pushing company shares up 28 cents, or 1.15 percent, to $24.70 per share.

Meanwhile, Silicon Valley-based, solar manufacturer SunPower (NSDQ: SPWR) said it will officially open the largest ingot-pulling factory in Korea on Wednesday. Ingots are chunks of silicon that are sliced to make wafers.

The announcements come after Solarfun Power Holdings said Monday it signed a silicon contract with Hoku Scientific (see Chinese Solar May Trade Margins for Market Share).

While companies are securing their silicon supplies, some analysts say prices for the precious stuff are likely to remain high, especially for new entrants (see Chinese Solar May Trade Margins for Market Share, Could China Steal the Solar Throne?, Silicon Shortage Has Big Impact, Silicon Starvation, Panelists Debate When the Silicon Shortage Will End).

Setbacks, such as an apparent delay in AE Polysilicon's planned Pennsylvania plant, probably aren't helping (see Silicon Setback).

Yingli (NYSE: YGE) was sparse on details about its deal to secure enough silicon to produce more than 40 megawatts of modules, not even disclosing the name of the supplier.

But the company said it expects the silicon to be delivered by the first quarter of next year.

In related news, Yingli also said it ordered $56 million worth of silicon ingot furnaces from Merrimack, N.H.-based GT Solar, a subsidiary of GT Solar International.

The furnaces, which each can grow multicrystalline ingots weighing up to 450 kilograms, are expected to bring Yingli’s installed furnace capacity to about 600 megawatts in 2009 from about 200 megawatts today.

And SunPower said Wednesday it, along with joint-venture partner Woongjin Holdings, will open a 151,536-square-feet silicon ingot-pulling factory in Korea.

The factory will make ingots exclusively for solar cells in export markets. Korea's DC Chemical will provide the bulk of the silicon to make the ingots.

SunPower also will get some extra perks from the venture, including a contract to buy $250 million worth of ingots over five years.

SunPower also said Tuesday it would build and operate a 1-megawatt solar system at a Hewlett-Packard (NYSE: HPQ) printer-manufacturing plant in San Diego.

In exchange, HP will purchase the solar-generated electricity.

But investors weren't impressed by the news, dropping SunPower shares $2.40, or 2.22 percent, to $105.60 per share.