Is Wind Turbine Cheaper Than Solar?

Wind and solar energy are renewable energy sources that provide an alternative to fossil fuels like coal, oil, and natural gas. Unlike fossil fuels, wind and solar energy do not directly produce greenhouse gas emissions. With concerns about climate change and energy independence, there has been increasing interest in expanding renewable energy. This article compares the costs of wind and solar energy to help inform the growth of renewable power.

Table of Contents

Upfront Costs

When it comes to upfront installation costs for utility-scale wind and solar farms, wind turbines tend to have a higher initial cost. According to Comparative Cost Analysis Wind Turbine vs Solar Panel Installation, installing a 1 MW wind turbine costs around $1.3 million, while a 1 MW solar PV system costs around $1 million. The main factors driving wind’s higher upfront costs are:

Land acquisition – More acreage is needed for wind turbines due to spacing requirements.
Equipment – The turbines, towers, and other components are more expensive than solar panels and racks.
Foundation – Wind turbines require substantial concrete foundations.

Assembly – Cranes and crews are needed to assemble the tall towers and turbines.

However, wind farms can achieve economies of scale. While a single wind turbine is more expensive than a similarly-sized solar array, wind farms over 100 MW become cost competitive with utility-scale solar on a per MW basis. Still, the upfront installation costs for wind tend to run 10-25% higher than comparable solar farms.

Operating Costs

Wind power has higher ongoing operation and maintenance costs compared to solar power. Solar photovoltaic systems have very few moving parts, requiring little maintenance once installed. The main operating cost for solar is just cleaning the panels occasionally. In contrast, wind turbines have many moving parts including blades, gearboxes and generators that require regular maintenance and frequent replacement of parts. The American Wind Energy Association estimates typical operation and maintenance costs at $30-50 per MWh for wind power, while solar PV is just $10-25 per MWh.

According to the Department of Energy, operations and maintenance costs make up 20-25% of the levelized cost for wind power, but only 10% of costs for utility-scale solar. These costs include regular preventative maintenance, unplanned maintenance due to breakages or faults, spare parts inventory, land lease costs, and labor for turbine monitoring and maintenance staff.^[1]

Factors like extreme weather events, material fatigue, and unforeseen failures can drive maintenance costs higher over a wind farm’s lifetime. Replacing a gearbox or generator typically costs $250,000 or more. The unpredictability makes estimating total lifetime O&M costs difficult. In contrast, solar PV systems involves simpler maintenance tasks like checking electrical connections and cleaning panels, with fewer large-scale component failures.

References:

[1] https://www.energy.gov/eere/wind/advantages-and-challenges-wind-energy

Capacity Factors

Capacity factor refers to the actual output of a power plant compared to its maximum possible output. It is expressed as a percentage, with higher percentages indicating more reliable and consistent energy generation.

Wind farms generally have higher capacity factors than solar installations. According to the National Renewable Energy Lab (NREL), typical capacity factors for wind range from 30-50%, while solar PV capacity factors are generally 15-20%. The main reason for this difference is that solar only produces power when the sun is shining, while wind can generate electricity day and night as long as the wind is blowing.

Higher capacity factors make wind more valuable for grid operators, as it can provide a more predictable and steady supply of electricity. However, capacity factors can vary substantially based on location. Solar capacity factors tend to be higher in sunnier regions like the Southwest U.S., while wind capacity factors are optimized in windy areas.

Levelized Cost

Levelized cost of energy (LCOE) is a measure used to compare the overall competitiveness of different generating technologies over their lifetime. It represents the per-kilowatt hour cost (in real dollars) of building and operating a generating plant over an assumed financial life and duty cycle. Key inputs to calculating LCOE include capital costs, fuel costs, fixed and variable operations and maintenance (O&M) costs, financing costs, and an assumed utilization rate for each plant type.

According to a recent LCOE analysis by Lazard, the unsubsidized LCOE for onshore wind ranges from $26-50/MWh, compared to $29-41/MWh for utility-scale solar PV. This indicates that in some scenarios, solar can have a lower LCOE compared to wind. However, wind and solar LCOE can vary significantly based on resource quality, project size, location, financing and other factors. Incentives and subsidies also play a major role in determining actual system costs.

Currently, the federal solar investment tax credit (ITC) provides a 26% tax credit for systems installed through 2032, which helps reduce the LCOE for solar projects. The production tax credit (PTC) for wind is being phased out but still provides some financial support. When subsidies are factored in, Lazard reports an average LCOE of $37/MWh for wind compared to $33/MWh for solar.

Sources: Lazard LCOE analysis, Solar vs. Wind LCOE Comparison

Storage Needs

Both solar and wind energy have intermittent generation, meaning energy output varies based on weather conditions. This intermittency creates a need for energy storage to smooth out supply. However, there are some key differences in the storage needs for solar versus wind.

Solar generation peaks during the middle of the day and drops off in the evening after sunset. This creates a need for 4-8 hours of energy storage to shift excess daytime solar generation to the evening hours. In comparison, wind can blow at any time of day or night. Wind intermittency is more unpredictable, requiring about 24 hours of energy storage to smooth wind’s variable output (CNBC).

Batteries are often paired with solar while pumped hydro storage is more common for wind. Batteries have shorter discharge times (4-8 hours) suitable for solar shifting, while pumped hydro provides longer duration storage (24+ hours) needed to smooth wind. However, batteries are modular and feasible in more locations than pumped hydro.

Overall, integrating wind power requires about 3 times more storage capacity than solar. The longer discharge durations increase wind’s storage costs compared to solar. However, wind’s lower capacity factors also reduce the absolute amount of storage capacity required relative to solar’s higher output.

Transmission Costs

Transmission infrastructure costs are a significant component of the levelized cost for both wind and solar farms. Long distance transmission lines are often needed to connect renewable energy projects to the grid, especially for large utility-scale installations built far from population centers. According to a 2019 study from the Lawrence Berkeley National Laboratory, the average levelized transmission capital cost for renewables ranges from $1 to $10/MWh (https://emp.lbl.gov/news/new-national-lab-study-quantifies-cost).

In general, transmission costs tend to be higher for wind farms compared to solar photovoltaic (PV) systems. This is because good wind resources are often located in remote areas that require longer transmission lines to connect to the grid. An analysis by Thunder Said Energy found that transmission accounts for around 9% of the levelized cost of energy for onshore wind farms, versus only 2-4% for solar PV projects (https://thundersaidenergy.com/downloads/wind-and-solar-costs-of-grid-inter-connection/). The transmission costs are lower for solar farms that can be sited closer to population centers with existing grid infrastructure.

However, transmission costs can vary considerably based on project location and grid saturation. In areas with congested grids or long distances from renewable resources to load centers, transmission costs will be higher regardless of technology type. Careful siting and grid planning is essential to minimize transmission expenses.

Location Factors

Location has a significant impact on the costs and performance of both wind and solar power. According to a study from Nature, geographical constraints play a major role in determining the reliability of renewable energy. For wind power, location affects the wind resource availability and capacity factor. Sites with consistently high wind speeds will produce more power. Coastal and mountainous areas tend to have better wind resources. The density of air also impacts energy production – humid climates with dense air generate more energy. Solar power is also heavily influenced by location. Areas that receive more annual sunlight produce more electricity. Deserts and the Southwest USA tend to have the highest solar irradiance levels.

In terms of costs, location affects permitting, transmission, and labor expenses. Remote sites usually require more infrastructure investment in roads and transmission lines. Areas with high labor costs will have higher project expenses as well. Ultimately, regions with plentiful wind and solar resources can produce renewable power at lower levelized costs due to high capacity factors. But these prime locations are limited, so costs rise as suboptimal sites are utilized to increase renewable penetration. Careful siting is crucial to minimize costs for both wind and solar projects.

Other Factors

There are some other relevant factors to consider when comparing wind and solar power beyond just upfront and operating costs.

The lifespan of solar panels is typically around 25-30 years (Source), while wind turbines may last 20-25 years before needing major repairs or replacement (Source). This can impact the long-term costs and viability of each technology.

There are also decommissioning costs to account for at the end of the system’s useful life. Solar panels can often be recycled, while old wind turbine parts may be more difficult to dispose of properly (Source).

In terms of environmental impact, wind turbines can negatively affect birds and bats through collisions or habitat disruption. However, they have a relatively small overall footprint compared to solar farms which can take up significant land area (Source). Visual and noise pollution are other considerations for both technologies.

The intermittency of wind and solar resources also influences how they are integrated into the grid. Wind power tends to be more variable while solar production is more predictable day-to-day. This affects their capacity factors and storage needs (Source).

Conclusion

In summary, there are pros and cons to both wind and solar in terms of upfront costs and long-term operating costs. Solar often has lower upfront costs for residential installations, while wind can have lower operating costs long-term for utility-scale projects. However, capacity factors and transmission costs also play a role.

Overall, recent forecasts show that utility-scale wind and solar have reached LCOEs of $30-60/MWh in optimal locations, with wind generally having a slight edge over solar. For residential installations, solar dominates with an LCOE of around $150/MWh compared to small wind turbines at over $200/MWh (according to EnergySage).

Thus, for utility-scale renewable generation, wind likely holds a small advantage in terms of overall lower LCOE currently. But for residential power generation, solar is generally the cheaper and more practical option over small wind turbines.