News

Three Insights on the Cost of Wind Power

Earlier this year, the International Energy Agency (IEA) and the National Renewable Energy Laboratory (NREL) released a comprehensive study focused on the cost of energy from wind. The report is a useful resource for anyone interested in the path that wind power has taken, and the road ahead over the next several decades. The following lays out some insights from our perspective—considerations for airborne wind and the power industry as a whole.

1. The cost of installing wind power has increased over the last eight years. There are two primary drivers of this increase: first, turbines continue to grow in size, with larger blades and taller towers that allow for greater electricity production. Growing in size means using more materials, which is more expensive. That cost is offset by the fact that a larger turbine selling more power can make more money. But a second factor has pushed turbine prices even higher: the price of commodity inputs like steel and fiberglass has risen this decade. Higher priced materials make turbines more expensive, and compound the cost increase for large turbines.

2. The cost of producing wind energy is expected to decrease 20-30% by 2030. Of course, what really matters in energy production isn’t how much a technology costs to install, but how much it costs over its life relative to how much energy it generates, known as Levelized Cost of Energy (LCOE). A wind farm built in an average location in the US today has an LCOE around $0.07 per kilowatt hour (kWh) if you exclude tax incentives. A 30% reduction would mean the average US wind farm will produce a kWh of power for a little less than 5 cents. That’s on the low end of the range for wholesale power rates in the US today. So while it’s exciting to see projections of lower costs, conventional wind power won’t be a clear winner against other sources of electricity generation without new innovation.

3. Cost reducing innovations are either “bigger + taller” or tertiary to turbine technology. The report outlines some direct turbine improvements, such as improved blade control systems that make turbines more efficient. But nearly every expected innovation falls into two other camps. The first is longer blades and taller towers, which as explained above have the tradeoff of increased material use and upfront cost. The second is improvements in the turbine supply chain such as better manufacturing processes and more accurate weather forecasting. This suggests that most of the innovation in conventional wind turbine technology has already been achieved.

From our perspective at Makani, this all adds up to a big opportunity. Our technology drives cost reductions directly, by eliminating most of the mass of conventional turbines and generating more energy. We’re working to make clean, renewable wind power competitive with fossil fuels—not in 2030—but in the next few years.

  • AWT

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.x

    Airborne Wind Turbine

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.x

    Airborne Wind Turbines

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.x

    Autonomous Controller

    An on-board computer that controls the flight path of the wing by changing the position of the control flaps.x

    Avionics

    The electronic backbone of the AWT. Avionics include the sensors, actuators, controllers and communication systems that keep the wing flying on its desired path.x

    Capacity factor

    The average power output divided by the name plate power output of a power plant. Capacity factor demonstrates the frequency with which a power plant is running at its name plate capacity.x

    COE

    Cost of Energy or the total cost to generate energy that is fed into the grid.

    Firming Power

    The outside power generation needed to stabilize the flow of electricity to the grid when an inconsistent resource, like wind or solar, creates less electricity than needed.x

    Ground Station

    The base station for the AWT, includes a winch for retrieval of the wing and storage of the tether.x

    Car vs. AWT

    A typical compact car weighs about 1.2 tons and produces about 30 kW during the 10 seconds it takes to slow from 25 m/s (50 mph) to a stop. Each cubic meter (~1.2 cubic yards) of air weighs only .0012 tons and a good wind day might be traveling at 25 mph (11 m/s), so Wing 7 would have to to interact with 350 cubic meters of air (about 23 dump trucks worth) every second to extract an equal amount of power. In reality it is not as efficient to design an AWT to completely halt the air it interacts with, so we design our AWTs to exert a smaller force on an even larger body of air.x

    Material efficiency

    Material efficiency refers to how much power is output in relation to the raw material needed for construction of the generator.x

    Rated power

    The amount of power a plant delivers when operating at full capacity.x

    Rated capacity

    The amount of power a plant delivers when operating at full capacity.x

    Rotors

    The rotors capture the accelerated wind as it rushes across the wing and convert it into electrical power with small, direct drive generators. The hybrid rotors can act as propellers as well as turbines, allowing the wing to stay aloft if the wind dies.x

    Turbines

    The rotors capture the accelerated wind as it rushes across the wing and convert it into electrical power with small, direct drive generators. The hybrid rotors can act as propellers as well as turbines, allowing the wing to stay aloft if the wind dies.x

    Tether

    The tether is made of high strength fibers surrounding a conductive core. The tether carries the traction force of the wing and transmits the electrical power to the ground station.x

    Tethered

    The tether is made of high strength fibers surrounding a conductive core. The tether carries the traction force of the wing and transmits the electrical power to the ground station.x

    Usable land

    Factors that influence whether land is usable include site geography, ecology, and wind patterns, for example. x