Wind Power: From Technology to Standards

To come to the brow of a hill and see on the horizon a line of giant wind turbines, their arms turning majestically, never fails to take one’s breath away. These are awesome structures, imposing in their size, their grandeur—and their simplicity.

World wind power capacity

Wind turbines are becoming ever more familiar as environmental concerns drive forward the agenda for renewable energy policies. In terms of world wind power capacity, 2009 figures quoted by the World Wind Energy Association (WWEA) show that China is currently the fourth-largest wind power producer after the United States, Germany, and Spain.

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In terms of world wind power capacity, 2009 figures show that China is currently the fourth-largest wind power producer after the United States, Germany, and Spain as quoted by the World Wind Energy Association (WWEA).

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World total installed capacity in MW

Situation in Europe

In Spain, at the end of 2008, there was an installed capacity of 16,740 megawatts (MW). That makes it the world’s biggest producer of wind power, after the United States and Germany. On windy days wind power generation is said to have surpassed all other electricity sources in Spain, including nuclear. On November 24, 2008, for example, wind energy produced 43 percent of the country’s power requirements.

Currently, just 1 percent of the existing world wind market is offshore with a generating capacity of 1.5 gigawatts (GW). Throughout the next decade, new sites capable of generating some 40 GW of electrical energy are expected to be developed in European waters. Half of those sites will likely be in the United Kingdom, according to the British Wind Engineering Association (BWEA). In the United Kingdom, where strong winds are frequent, it is easy to understand the benefits implicit in harnessing the energy of the wind and using it to generate electricity.

Not all countries have climatic conditions similar to that of the United Kingdom, across which 40 percent of Europe’s wind energy potential is said to blow. This puts the country in a strong position to benefit from the alternative energy source.

Going down under

On the other side of the world, New Zealand is another hot spot for wind power generation. The only downside is that the country is both isolated—its nearest neighbor, Australia, is 3 to 4 hours away by airplane—and relatively unpopulated. While the country can be self-supporting in terms of energy generation, its isolation makes it harder—and more costly—to export “spare” capacity.

However, domestic energy consumption is rising steadily in New Zealand. The growth in New Zealand’s total electricity consumption outstripped the increase in supply capacity by 30 percent in the eight years to March 2004.

With the total long-term potential from wind energy generation assessed to be in the order of 100,000 gigawatt hour (GWh) per year, this is an invaluable alternative to the hydro-electric power and gas-fired sources on which the country has based most of its power offering for the last 40 years.

There are currently four wind farms in New Zealand, with a total capacity of around 170 MW. More than 15 other sites are planned for expansion or development, each with a capacity of 19 MW to 300 MW.

NZ Windfarms Ltd. is a major operator. Its first project is a 48.5 MW wind farm on the Tararua Ranges near Palmerston North, in the South of North Island. The first stage of the NZ $80 million project was completed in 2006 with the installation of five New Zealand-made 30 meter-high Windflow 500 turbines (2.5 MW capacity) on the Te Rere Hau wind farm site. This has a mean annual wind speed of more than 10 meters per second. Sixty-five turbines are expected to be operational by the end of October 2009.

By the end of May 2009 there were 43 turbines operational, producing 20 MW. NZ Windfarms has recently lodged an application to install 56 turbines on an adjacent site. This site is expected to produce 95 GWh of energy per year.

Government incentives

Perhaps because of its isolation, New Zealand has a long history of being highly proactive in terms of sustainable energy production. However, many other governments are now putting incentives in place to encourage investment in methods of producing energy from the wind and other sustainable sources.

Sandy Butterfield, Chairman of the International Electrotechnical Commission (IEC) Technical Committee (TC) 88: Wind turbines, is also chief engineer for the U.S. government-funded Wind Program at the National Renewable Energies Laboratory (NREL). He expects the U.S. market to take off now in terms of production because of the current favorable political climate. Tax credits are an offer to companies that go down the sustainable route.

NREL has produced a model Wind Energy Deployment System that simulates energy capacity expansion potential in the United States up to 2030. The model demonstrates that using wind energy to produce 20 percent of projected electricity demand in this period would require 305 GW of technology, producing 1,200 terawatt hours (TWh) annually. At the end of 2007, 16.6 GW of wind capacity was installed and produced about 1 percent of national electricity demand. According to the study, “Assuming wind turbine size increases from today’s average of 1.6 MW to roughly 3 MW, this would result in more than 100,000 wind turbines.”

The study provides a quantifiable estimate of the costs, impacts, and benefits associated with producing 20 percent of the country’s projected electricity demand from wind technology. It demonstrates that the idea is technically feasible, not cost-prohibitive, and provides benefits in the forms of carbon emission reductions, natural gas price reductions, and water savings.

Butterfield says that to achieve this aim requires an annual growth rate of installed technology of some 16 GW per year. He adds, “These goals are realistic. There are no real supply-chain or technical limitations. However, we need to improve reliability and performance and lower costs to make the industry more viable.”

According to Butterfield, China is currently just behind the United States in terms of wind-generated power installation and is likely to overtake it soon. Denmark, Germany and the United Kingdom are all active in terms of offshore installation. “A huge expansion of the world market is going on,” says Butterfield. The TC 88 Strategic Policy Statement states: “It has been estimated that developing countries could supply 50 percent of the world’s electricity by 2030, with much of it supplied by wind turbines.”

Technical trends

"Wind farm" is a term frequently heard these days. Of course, with the problems inherent in connecting wind-generated power into national grids—particularly for isolated sites that may otherwise have poor power provision—it makes sense to harvest wind on a reasonable-sized scale. The more turbines, the better the economy of scale.

As the number of installed turbines rises, so does their capacity. Many turbines are now rated at 2 MW or above, while those designed for offshore installation may be rated at 3 to 5.5 MW. Smaller machines rated at 50 kilowatts (kW) or below, are also rising in popularity for individuals’ use.

IEC sets the standard in terms of wind-generated electricity

For its part, the IEC is making sure that equipment is certified, or is conforming, to a common set of standards. “The IEC standards are the only ones that can be applied globally,” Butterfield says. For other design aspects linked to mechanical specifications or civil engineering, for instance, many turbine designers look to Germanischer Lloyd for type certification, while project certification, in terms of installation and site suitability, has been supplied by the Norwegian firm, DNV Energy. These are the only other standards with any kind of international credibility.

The United States is looking at the standards developed by Mineral Management Services (MMS) for the offshore oil and gas marketplace as well as those from the ANSI-accredited (American National Standards Institution) company API in the same area. The country is struggling to come up with the right set of standards, comments Butterfield.

He adds, “This is a road-mapping exercise: international standards need to be road mapped to national standards.”

All parties want to arrive at the same point. As MMS states, “Many offshore oil and gas producing nations are considering what role developed standards should play in their overall regulatory regime. Governments understand that, if done correctly, a set of international standards that allows for regional differences can lower costs, make more resources economic to produce, and raise worldwide safety, and environmental performance. If done incorrectly, internationalized standards that are imposed on the industry from external sources can be inefficient, costly, and burdensome.” The statement is equally valid for wind turbines.

Further afield, “Canada is starting to look, and China, Japan, and Korea are all very keen to try to adopt IEC standards,” says Butterfield. He sees that there is currently a great opportunity for the IEC to act as a bridge between countries. “We need harmony between design and certification requirements,” he says.

[8/25/2009 update: Canada does have a wind turbine standard: CAN/CSA-C61400-1:08
--Editor]

Scope for the future

Butterfield sees the emerging area of wind turbines as a real opportunity for the IEC to demonstrate that it can respond rapidly to "new" environmentally-friendly technologies. “These new and different technologies have fairly specific needs,” he says. “For our part, we need to be able to allow technical committees to capitalize on recent changes to directives for sector specific conformity assessment requirements.”

There are some standard requirements for the installer and developer but there also needs to be a mechanism for documenting local conditions, believes Butterfield. “There needs to be a path for customizing to local requirements,” he says.

He adds, “TC 88 has developed a complex set of test and design standards. Even though standards need to be added, the process is quite mature and the mechanism for committees to work together is pretty well-developed.” Butterfield believes that the approach taken by TC 88 to produce relatively rapidly a system of design requirement and testing standards could be subsequently applied to other areas of new technology, for instance, in ocean technology by IEC TC 114: Marine energy [3].

“We’re opening the door to a raft of new technologies,” he says.

This article was originally published in the July edition of e-tech, the IEC (International Electrotechnical Commission) publication.