Remote sensing could push next phase of wind energy growth

Source: Henry Gass, E&E reporter • Posted: Thursday, August 22, 2013

Wind power is one of the fastest-growing energy sectors in the world, but even this record-breaking growth has been limited by wind’s inherently fickle nature: What do you do when the wind changes direction, or dies completely? Wind can save you one minute and sink you the next, as any sailor will tell you.

New forecasting technology may now be on the horizon that could help wind developers both find the best locations for potential wind farms and then manage them as efficiently as possible.

Remote sensing devices, such as sonic detection and ranging (sodar) and light detection and ranging (lidar) systems, are likely to become some of the more prominent devices used in siting and managing wind farms, both on land and at sea.

Both variations of the well-known radar technology, the devices are ground-mounted and use Doppler effect analysis to measure the wind space above a wind power unit. They are poised to replace meteorological towers, or met towers, which won’t be cost-effective for much longer, according to a report released yesterday by Navigant Research, an energy sector research firm.

Feng Zhao, managing consultant with Navigant Research and author of the report, said the growing popularity of large, commercial-scale wind turbines will soon make met towers too expensive.

“The met tower is not economical at all for the new turbines,” Zhao said. “This offers the opportunity for new technology.”

Vertical challenges

The wind power market currently provides almost 3 percent of global electricity production, and the sector saw record growth in the United States last year, albeit via quietly popular local, residential-scale turbines (ClimateWire, Aug. 12).

Commercial wind power is gaining popularity, however, and while multi-megawatt wind farms do cost several million to install, their generating capacity makes them cheaper in the long run — if you have a reliable instrument to measure wind resources in the area, that is.

The main issue with met towers is the increase in cost; they’re still just as accurate as remote sensing devices.

Commercial-scale wind turbines almost exclusively exceed 100 meters in height. The cost of installing a met tower over 100 meters high jumps from a sub-100-meter cost of $40,000 to as much as $200,000, according to the report. Traditional, cheaper 60-meter-high met towers may not provide accurate readings.

Developers generally install several met towers in the course of a site assessment, and with remote sensors, a met tower or two will still be necessary to provide base-line wind data at 60-meter heights. Remote sensors, however, eliminate the need for expensive, 100-meter met towers. An average sodar unit costs around $70,000, and an average lidar unit $150,000.

“To provide the most accurate data in the cheapest way for towers more than 100 meters, lidar or sodar systems are cheaper,” he said.

The technology could also help accelerate the growth of offshore wind power, which is slowly gaining ground in Europe and North America (ClimateWire, Aug. 6).

With offshore wind farms typically 60 kilometers offshore or farther, installing met towers can get even more expensive, especially compared to remote devices, which can be mounted onto the turbines for little extra cost.

“The deeper the water, the more you have to pay for the foundations, so therefore the remote devices are much more popular,” Zhao said.

Optimizing wind power

With remote forecasting technology providing more accurate readings at greater range, wind power could see increased investment, as well as an indirect decrease in greenhouse gas emissions.

More accurate forecasts of wind resources mean greater investor confidence, which means more wind projects will get financed, Zhao said.

With grid operators also demanding more accurate power scheduling from renewables, individual wind plants often need to provide location-specific real-time weather and power generation data. Remote sensors can also help synchronize wind power generation with other energy sources, so as not to overload the grid during peak hours.

“The utility can easily understand how much wind power is going to be generated, so you can coordinate conventional energy sources with other renewable energy sources, including wind,” Zhao said.

Overall, the Navigant report forecasts that annual revenue from met towers and remote sensing devices for wind forecasting will surpass $300 million by 2020. Zhao predicts that, by then, remote sensing devices will gain the lion’s share of this revenue.

It may still take a few years for remote sensing devices to break out, however, simply because the technology isn’t familiar enough yet.

“The technology doesn’t have a long track record,” Zhao said. “It takes a few years to get utility developers and bankers to understand the coming technology.”