Throughout the expansion of the wind power industry, continual technological advancement of wind turbine design and manufacture, coupled with improved installation and operating protocols, has driven growth. Without these technology advancements, wind power would not be on its current growth trajectory. Innovative wind farm siting and design, improved wind resource characterization, advanced techniques in wind farm construction and operation, and innovative equity and debt financing have all complemented wind power’s growing share of the power generation portfolio.
Wind turbine cost of energy competitiveness versus other power generation sources – characterized as levelized cost of energy, wind power system reliability, supply-chain stability, equity investment attractiveness, and minimized financial risk on par with other investments – collectively provides a reference to measure and judge wind power performance.
For the electric power consumer, cost of energy is where the rubber meets the road – the price the consumer pays per kilowatt-hour of electricity. As more productive turbines are brought online, producing more kilowatt-hours of electric power per nameplate megawatt rating, the cost per kilowatt-hour declines as more is generated per investment dollar (or CAPEX) and per dollar of operating cost (or OPEX), driving the total cost of energy lower and enhancing wind power viability.
Harnessing wind to perform work has been pursued for centuries. Early on, wind milled grain, pumped water and more. Today, electric power generation dominates wind power applications. Wind power generation has existed for a long time, almost from the introduction of electric power generation by Thomas Edison, George Westinghouse and others, from early proof-of-concept turbines to today’s industrial utility-class turbines developed and matured over the last several decades, continuing today to push the technology envelope.
As wind power generation continues to proliferate, technological advancements are bringing cost parity versus other power generation sources.
Contemporary wind turbine technology has advanced significantly over the past 20 to 30 years, with innovation accelerating in recent years.
Thirty years ago, the largest wind turbines were typically rated 100-200 kW, with some rated a bit higher and many rated lower. Twenty years ago, the largest wind turbines were rated 300-600 kW. Ten years ago, the largest turbines were rated 1.5-2.0 MW.
Today, the nominal rating for an onshore turbine is 2.0-4.0 MW, but many OEMs are pushing the envelope to 5 MW and beyond. Offshore turbines are rated 5 MW to 7 MW, with new turbines approaching or exceeding 10 MW. Over the years, as new size plateaus were reached, many believed turbine ratings had reached their limit, only to see the plateau shattered a short time later by new turbines pushing the size envelope yet again. Therefore, you can expect turbine ratings to continue increasing in the future.
Physical size has grown with the increase in power rating and efficiency. Thirty years ago, rotors were nominally 15-20 meters in diameter; 20 years ago, diameters grew to 40-50 meters; 10 years ago, diameters were 70-90 meters; and today, rotor diameters are 110-130 meters, with some exceeding 150 meters, but not for onshore and offshore applications. Aside from nameplate power rating, the driver of rotor size is energy capture (capacity factor). The higher the capacity factor, the lower the cost of energy. Milder wind sites require larger rotors to generate power output comparable to higher wind sites; higher wind sites combining larger rotors with advanced turbine operating algorithms to limit loads further energy cost.
Tower heights have also grown. Towers were 30-35 meters high 30 years ago, 50-65 meters high 20 years ago, and 80-100 meters high 10 years ago. Today, they approach 150 meters and higher. Taller towers access better wind resources, higher average wind speeds and reduced wind turbulence.
Control systems are more sophisticated. Thirty years ago, turbines had basic industrial control architecture, utilizing electro-mechanical components lacking onboard logic. A few had PLC-based pitch and yaw operation and SCADA communications. During the intervening years, programmable computer configurations were introduced, as computer technology and miniaturization continued advancing. Variable speed constant frequency systems utilized newly developed power electronics, improving energy capture, and proactive mechanical turbine hardware loads management software was introduced. Today, onboard load management systems manage complex internal turbine loads to optimize energy capture.
Turbine maintenance and safety matured over the decades. Thirty years ago, the sophistication in these areas was, at best, in its infancy. Much effort has been devoted to improvements, including collaboration with OSHA, yielding significant progress today and continuing into the future.
Wind farm site configuration improved over the years as site challenges were resolved – ranging from erosion management, to site environmental impact minimization, to wildlife considerations, to lightning management, to grid compatibility and more – innovating to yield improved site solutions.
Site construction, turbine erection practices and procedures have all become more sophisticated, as requisite crane size and site management requirements have grown larger and more complex. The application of lean management techniques on construction sites has greatly improved efficiencies and thereby reduced costs during the construction phase of projects, yielding a more competitive cost profile for wind versus other power generation alternatives.
Look for turbine ratings and component sizes to continue evolving, enabling milder wind sites while improving capacity factors, with longer blades, higher towers, larger drivetrains, more efficient equipment packaging and designs producing more power out of less mass.
Controller sophistication and capabilities advancements will continue to improve data capture and analysis, enhance capacity factor and machine reliability, reduce downtime, economize operation, and improve forecasting accuracy.
Hybrid configurations incorporating multiple power generation sources (such as wind-solar, wind-gas, etc.) will be considered more rigorously, as power generation market integration economics drive situational lowest cost of generation decisions.
Enhanced development and deployment of energy storage and management systems to facilitate wind-generated power dispatchability, including technology development to more efficiently utilize transmission and distribution systems, will increase grid capacity utilization and reliability.
Turbine buyers and finance entities seek to minimize risk and ensure financial returns. They seriously analyze technology risk, turbine OEM balance sheet size and financial health to guide turbine selection, which has driven turbine OEM consolidation, evolving the industry profile to tier-one OEMs versus the others. Configurations deviating from the current industry norm are shied away from, and any turbine OEM lacking a large balance sheet is deemed too risky. Non-tier-one OEMs have an uphill battle to secure market share. Unless or until a disruptor successfully intervenes, designs will continue to align with conventional configurations. In other words, don’t expect to see any broad implementation of such dream ideas as multiple turbines on a single tower, multiple-length blades, vertical axis turbines, etc.
Wind power is approaching an ideal position, with the cutting of the production tax credit/investment tax credit umbilical (arguably a form of commercial/industrial training wheels) resulting in wind power passing an important milestone and becoming market-based, with no government financial assistance, which is in bold contrast to all other competing power generation technologies. No more tax credits or tax equity gambits, and no more controversial public assistance to rally wind opponents – just clear-cut capitalism to drive the best economic power generation solution to market. Ideally, all other forms of power generation will follow suit.
The ideal common denominator is total cost per unit of power consumed, encompassing total lifecycle and value chain costs (technology performance, transmission and distribution, dispatchability/energy storage, applicable taxes, overall cost of the carbon footprint of the manufacture and supply of power generation hardware, site costs, cost for scrubbing air to remove combustion byproducts, storing spent fuel, mitigating local thermal emissions, etc.).
What is the future of wind power? As in any forecast, reality will likely deviate from forecast the further into the future you peer. (We try to project power generation solutions decades into the future, but remember that half a century ago, we went from no space travel to a man on the moon in less than a decade, demonstrating that yes, things can be changed significantly in a very short period of time if we commit to accomplish the change, with failure not an option.) Considering unsolved challenges (energy storage, transmission optimization, etc.), as-yet-unknown technological developments and innovations, and disruptive technologies yet to be identified, a broad spectrum of possible future scenarios emerges.
Viable, objective, commonsense quantitative decision-making criteria should be established – facts- and physics-based, unswayed by political ideology; spin factor influences or echo-chamber noise; or any other factor that might sway power generation evolution from a naturally driven pathway governed by technological advancement and real economics.
Among all forms of power generation, wind is one of only a handful of power generation sources without a significant environmental impact from power generation operations – no thermal, air, water, residual fuel or other waste stream issues.
Robert C. Rugh, former president and CEO at DeWind, wind vice president at Mitsubishi, manufacturing vice president at GE Wind Energy and predecessor companies, and product line manager at Westinghouse Electric, currently provides consulting services to the power industry. He can be reached at email@example.com.