Supporting Electricity Grids As Wind Power Reaches New Highs

As winter storms lash northern Europe, Denmark has announced record highs for wind's contribution to its national electricity production. Global wind power capacity is set to grow by a further 50 to 100 percent by 2020, so it's well worth considering how to make the most of these wind resources and the challenges that must be faced.

First, a little background: Last year, Denmark produced 39.1 percent of its electricity from wind, with its most productive month exceeding 60 percent. One some blustery days, the country sourced more than 90 percent of its electricity from wind.

Elsewhere in Europe, the United Kingdom and Germany also set record highs for wind energy.

EUROPE - AND BEYOND

And it's not just a European phenomenon. In Texas, regulators say turbines in the state set a new wind power record, 10,296 megawatts, on March 26, 2014. This accounted for nearly 30 percent of the 35,768 megawatts of electricity coursing through the grid at the time.

As I'm now based in Beijing, I am also witnessing first-hand China's rapid push toward wind. By the end of 2013, China had an installed capacity of more than 90 gigawatts.

The focus is now shifting from building capacity to exploiting this new renewable energy production as efficiently as possible, so that the country can reap the full economic benefits.

So, what's the key to making the most of wind energy?

DENMARK'S EXAMPLE

It turns out, there's a lot we can learn from Denmark's example, where even in July, its least productive month for wind power, its contribution to the total electricity supply was still greater than 20 percent.

From a technical point of view, the intermittent nature of wind presents challenges for operators of wind farms and transmission and distribution grids. One turbine will experience rapid fluctuations in output, in response to gusts and eddies in the wind, and when multiple wind turbines are installed this can lead to power quality issues.

Grid operators demand stability. Poor power quality can lead to instability and outages. The gap between the two can lead to curtailment, when transmission operators set a limit on the amount of electricity they will accept.

So what is Denmark's secret? The country has been at the forefront of wind power since the 1970s and has already overcome many challenges that other countries are only now facing.

NO SINGLE SOLUTION

The answer is that there is no single solution to enabling high penetration of wind power. Instead, Denmark's wind farm builders and operators and its transmission grid operator have together implemented a number of solutions to overcome intermittency and reinforce the grid to accept the power.

One of the main foundations of Denmark's success is its ability to import and export electricity to its neighbors. The country has invested in interconnectors with a total capacity of almost 6.5 gigawatts.

If the wind is blowing in Denmark, it can export excess electricity. But if there's a lull, it can import electricity generated by wind or other sources from other countries. The latest interconnector is Skagerrak 4, which ABB has just commissioned to improve existing connections between Denmark and Norway.

On the generation side, Denmark's wind farms have also invested to ensure their output meets grid code requirements by mitigating the impact of transient voltages and power dips.

ABB, in particular, has a variety of solutions to help ensure grid code compliance in terms of reactive power, voltage control and fault ride-through, as well as dynamic reactive power compensation. These solutions are implemented at various points in the wind energy chain, starting within the turbine, at the point of connection to the grid or running in the wind farm control system.

Texas Transmission

Other areas of the world are also finding ways to maximize energy from wind.

For instance, in Texas, where wind capacity expanded rapidly from 2006 to 2009 and transmission congestion arose as a challenge, the state responded with programs that have included the construction of more than 3,500 miles of transmission lines.

Since then, the number of curtailments - as well as instances of wind-related negative electricity pricing - in Texas have been steadily dropping, according to the U.S. Energy Information Administration. And ABB has played an active role in the Lone Star State, too, supplying equipment including Static Var Compensators to reinforce the grid and improve the reliability and quality of power.

Increasing wind energy fed into power grids also requires further development of our industry standards, as well as some profound changes in how energy markets work and remunerate energy and ancillary services. ABB's involvement with leading industry associations like the European Wind Energy Association is extremely important to ensure we bring one strong voice to regulators and governments.

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