BEIJING (TheStreet) -- Chinese wind-power stocks, once given up for dead in the investor doldrums, have roared back to life in recent weeks on expectations of government support for the renewable energy sector and overseas demand.

Investors are betting on future Chinese government policy directives and subsidies that boost profits for manufacturers of wind power turbines, gearboxes, blades, towers and transmission equipment.

They're also betting that multinational wind energy companies such as VestasSiemens, General Electric and Senvion will step up orders for the Chinese-made equipment and parts that are used to build offshore and onshore wind energy farms worldwide.

Contractors building big wind farms, particularly those off the European coast, often buy lower-rung products such as steel towers from China. And tower fabricators such as China's Titan Wind (002531:Shenzhen) are making good money on that demand.

Shenzhen-listed Titan, which is only nine years old and listed in 2010, has seen its stock value climb 55% since the beginning of the year. The company has gotten major contracts from Vestas and GE. And it's currently planning to build a factory in India to complement existing plants in China and Denmark.

Another stock investor favorite is China's largest wind turbine manufacturer Xinjiang Goldwind Science & Technology (002202:Shenzhen), whose stock value has jumped 22% since January 1.

During the same period, wind sector suppliers Ningxia Yinxing Energy (000862:Shenzhen) and Sinoma Science & Technology (002080:Shenzhen) have seen their stock prices rise 18% and 13%, respectively. Shares in an energy conglomerate with a wind division, Shanghai Electric Group (2727:Hong Kong), have risen 3.5% so far this year.

On the other hand, investors don't like Sinovel Wind Group (601558:Shanghai), which has been accused of intellectual property theft in the United States and China. The stock has lost 8.5% of its value since Jan. 1.

Wind energy stocks generally did well in China before 2011, the year authorities admitted to an overcapacity of wind farms in remote parts of the country. Some farms built by speculators with government help were even beyond the range of power transmission lines.

Investors fled the sector, and wind stocks slumped through most of 2013. But after posting profits last year, shares in companies such as Titan and Sinoma started rising again.

Wind stocks have also won favor because the government is showing a growing degree of interest in combatting eastern China's chronic air pollution, which has been partially blamed on coal-fired power plants. In February, the National Energy Administration said boosting wind energy factored into a government goal to increase the percentage of non-fossil fuels in the nation's energy mix to 15% by 2020.

The government's short-term goal calls for increasing China's installed wind power capacity to 18 gigawatts by the end of this year, up from 16 gigawatts in 2013, mainly by building offshore wind farms along the east coast.

At the time of publication, the author held no positions in any of the stocks mentioned.

This article represents the opinion of a contributor and not necessarily that of TheStreet or its editorial staff.