What does the future hold for wind energy?
Researchers around the world use increasingly sophisticated models in an attempt to predict the future of energy—considering technology deployment, grid integration, costs, and more. Using powerful computers, the models can analyze dozens of scenarios, testing the impact of cost trends, performance, finance, policy, and a host of other factors.
But there is another way to see the future, short of using a crystal ball – ask the experts.
As part of a working group for the International Energy Agency (IEA) Wind Technology Collaboration Programme, researchers at Berkeley Lab (along with the National Renewable Energy Lab, U-Mass Amherst, and Insight Decisions) surveyed 163 wind energy experts from around the world about the future of wind power, focusing on potential future costs. The findings are described in a study published in the journal Nature Energy.
These experts come from the wind industry, think tanks, labs, government agencies, and non-profit groups. They were asked about three applications of wind power: the onshore turbines that are sprouting all around the world, fixed-bottom offshore turbines that have mostly been deployed in the waters of Northern Europe, and floating offshore turbines that have only been tested in pilot deployments thus far.
Overall, the experts see big cost reduction potential in all three categories of technology, with the expected cost of energy dropping between 24 and 30 percent by 2030 in the “median” case (the survey also asked for “low” and “high” cost cases, neither of which are described here). Of course, each wind technology starts from a different point on the cost curve, as shown in the figure below.
Not surprisingly, experts believe that onshore wind energy will remain lower-cost than offshore, at least for typical projects. But they see more-significant absolute reductions in offshore wind costs over time, and so a narrowing occurs between onshore and offshore applications. A similar trend is apparent for fixed-bottom and floating offshore wind: while floating turbines are expected to remain more costly in typical projects, the gap narrows over time. In general, experts are less certain about offshore wind trends, showing a wider range of responses (as shown by the shaded areas in the figure).
WHAT CAUSES THE COST DECLINES?
There are five key components that drive the cost of energy: capital cost (CapEx), operating costs (OpEx), cost of financing (WACC), performance (capacity factor), and the life span of the project.
Technical advancements can reduce wind power costs over time, such as larger rotors and taller towers, improved and lighter materials, greater component reliability and turbine life, more capable software controls, and understanding of wind flow.
Market factors can also contribute, such as “learning by doing,” policy stability, transmission to access high-quality sites, the lower cost financing that comes with industry maturation, and efficiencies in the supply chain.
On the other hand, prices might increase if there is weak demand for new wind power additions, a depletion of higher-quality wind resource sites, or a lack of investment in new transmission to access the best sites.
Perhaps the most visible trend is size. Wind turbines have been getting steadily bigger over time, and experts think that trend will continue, especially offshore. Fixed-bottom offshore turbines, not limited by the need to move equipment by trucks, are expected by the experts to grow to average 11 megawatts by 2030, up from 3.5 megawatts for projects installed in 2014, with rotor diameters and hub heights in 2030 averaging a staggering 190 meters and 125 meters, respectively. Each one of those turbines could power 4000 typical US homes.
Here are the survey results for each kind of application: onshore, fixed-bottom offshore, and floating offshore.
Onshore wind is economic in some locations already, with recent contracts in the United States—benefitting from federal tax incentives—signed for roughly $20 per MWh. A big trend driving this cost reduction is the use of turbines with lower “specific power.” Specific power is the ratio between the capacity of the generator and the area swept by the blades, measured in watts per square meter (W/m2). Longer blades sweep a larger area of the wind, thus capturing more energy. If longer blades are attached to a smaller generator, the result is a higher capacity factor.
While initially intended for regions with lower wind speeds, these low specific power turbines are increasingly being installed in higher wind resource areas, resulting in more output per dollar invested, and hence lower costs of electricity.
The experts in the survey expect this trend to continue, with taller towers, longer blades, greater durability, lower capital costs, and longer turbine life all contributing to cost declines of about a quarter by 2030 and more than a third by 2050, both in the median case.
Fixed-bottom offshore wind is commercial, with costs falling for recent contracts, but still pricey in comparison to onshore options.
For offshore wind, many experts believe that increased and steady deployment is the most important driver for the technical advancements, standardization, and supply-chain efficiencies in manufacturing, installation, and operations required to achieve lower energy costs. Larger machine ratings are identified as a key driver to reducing CapEx, as are reduced financing costs.
Experts see greater cost reduction potential for fixed-bottom offshore turbines than for the more mature onshore turbines. By 2030, the median estimate is for a 30 percent reduction, and over 40 percent by 2050.
Floating offshore wind, with turbine platforms anchored in place, is still being tested with no large-scale commercial deployments yet. By floating the turbines, developers can get access to deeper water areas, potentially farther offshore and with better wind resources. Places like Japan or the US West Coast, where the seabed drops off quickly into the Pacific, could be attractive to floating technologies.
Experts think that energy costs for floating turbine technology could fall rapidly, especially from 2020 to 2030. Higher capacity factors, lower financing costs, and increased turbine life spans are noted as especially important.
SOME EXPERTS ARE MORE EXPERT THAN OTHERS
There is great uncertainty in the future cost of wind energy, as revealed by the survey findings. To help understand some of this uncertainty, the survey designated some respondents as “leading experts,” due to greater experience, specialization, and reputation in the field.
Interestingly, the leading-experts group tended to be more optimistic about future cost reductions for all three types of wind deployment, as indicated in the figure below. All experts saw cost reductions for all three applications in the median case, but leading experts saw greater and faster savings.
There were also variances according to the sector that the experts worked in. Equipment manufacturers, for example, were generally less bullish about cost reductions in the near term. By 2050, though, most predictions coalesced across types of experts.
While the survey stops short of speculation, it could be that those experts closest to the ground (or water) have greater insight to future cost trends. Or, conversely, it suggests that they have the most faith in a positive outcome.
By Ryan Wiser, Joachim Seel, and Bentham Paulos, LBNL
The survey was conducted under the auspices of the IEA Wind Technology Collaboration Programme (www.ieawind.org). Berkeley Lab’s contributions to this report were funded by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy.
A webinar summarizing the findings of the survey will be held on Tuesday September 27, from 8:00am to 9:00am Pacific Time (11-12 Eastern Time, 5-6 pm Central European Time). To receive log-in instructions for the webinar, register here: https://cc.readytalk.com/r/6j3tvwsn8lto&eom.