Modernizing energy plants

The hero of Miguel de Cervantes’ early 17th century novel Don Quixote famously fought windmills he imagined to be giants. In retrospect, he might have been a man ahead of his times.

Back then, however, windmills ground corn. Today they generate electricity. Harnessing the power of the wind is nothing new, and nor is hydropower: Even the Romans and the ancient Egyptians were familiar with the power of flowing water.

Injecting fresh energy into old plants

Nevertheless, today’s general public is used to thinking of the renewable energy sector as one still in its infancy. In fact, the first generation of wind and solar power facilities has already seen better days. Some of them are now over 20 years old, and in urgent need of a facelift.

“In general it makes sense to completely renew older power plants rather than to service them or repair them,” Daniel Kluge from the German Renewable Energy Federation (BEE), says. The main reason, he says, is the rapid rate of development in the field. “Within a period of 20 years there has been a huge improvement in efficiency and quality in the renewable energy sector,” he stresses.

According to Alexander Sehwohl from the German Wind Energy Association (BWE), upgrading facilities is known in the wind energy sector as “repowering.”

“This refers to the replacement of older power plants with new, more efficient ones,” he says. The upgrade inevitably pays off: Last year, 116 wind turbines in Germany were replaced by 80 new ones that generate much more energy than the old facilities.

“The old turbines had an installed capacity of a total 56 megawatts, the new ones can generate over 183 million megawatts,“ Sehwohl says.

That does not necessarily mean that older turbines are now obsolete, however – wind turbines generally have an average lifespan of 20 years, depending on the type and make.

A bright future for solar energy

Solar energy plants boast similar longevity.

“Solar cells are extremely long-lasting,” says Christian Hallerberg from the German Solar Industry Association. “Many of the solar power plants that began operating in the 1980s are still running.”

Solar cells require less maintenance than wind turbines – once installed, the modules suffer little wear and tear because they do not need to withstand any mechanical impact.

Even though their efficiency decreases in the course of time, their precise lifespan is hard to calculate. Some manufacturers estimate it to be 35 years, while others maintain that they retain 80 percent of their initial efficiency after 20 years.

The solar technology sector too has developed at a rapid pace – with increasing innovations often going hand-in-hand with falling costs.

“The system costs of photovoltaic generators have been halved since the technology was first introduced,” says Hallerberg. “Installing solar cells on the roof is getting cheaper all the time.”

Not only is the technology developing – solar cells are also visually less obstructive than ever and can now be bought in a semi-transparent format.

An unwinnable fight no more

Similarly, boosting the performance of aging hydropower plants requires relatively little investment. On the Caribbean island of St. Vincent, for example, a number of hydropower plants are currently being renovated with help from the German Agency for International Cooperation (GIZ).

“The pipework and machinery are being overhauled,” says Sven Homscheid, a technical consultant with the GIZ. In the foreseeable future, 30 percent of St. Vincent’s electricity needs will be met by hydropower. For the time being, the island is still heavily reliant on oil.

With hydropower plants dotted all over the world, the scope for further development of the technology is vast and strides are being made in the field.

Engineer Hartmuth Drews, for example, believes that historic water wheel systems that used to power mills can now be used to generate electricity.

He has come up with a “Water Wheel” that is a cost-effective and reliable solution to generate renewable energy almost anywhere water flows. As it says on his website: “(The) system makes it possible to produce large numbers of Water-Wheels based on a ‘wrist watch system’ making it adjustable in diameter and width…..Water-Wheels can be scaled to almost any size and can be manufactured anywhere in the world.”

“The technology was specifically developed to modernize existing hydropower plants,” says Drews. Germany alone is home to an estimated 25,000 appropriate sites – i.e: former mills. The engineer has also attracted interest from Nigeria, Bangladesh, Ethiopia and Brazil.

Drews promises that his Water Wheels can generate enough electricity to supply 15 households. Hundreds of years ago, Don Quixote’s tilting at windmills might have been a futile battle – but these days, it makes perfect sense.

Nele Jensch (jp)
Editor: Sonia Phalnikar