According to the US Geo Survey, a typical wind turbine will produce more than 843,000 kilowatt hours (kWh) monthly at a 42% capacity. The potential of wind power to create electricity for cities or communities is very promising. A modern wind turbine can produce about 8 Megawatts of electricity. This is enough power to run six homes for an entire year. Staggering prospects indeed! Now, think about the contribution of wind farms to the power grid. Today, wind power is the largest renewable energy source and the most cost-effective large-scale renewable electricity in the US.
Before we can look at how much power one wind turbine can produce, let’s look at how wind turbines work.
How Do Wind Turbines Work?
Naturally, kinetic energy is produced when the wind blows. The same principle applies when generating electricity via wind turbines. As these turbines rotate, it generates massive kinetic energy from the air in motion, which is converted to electrical power. The function of these turbines is to tap into the potential of wind speeds and move the rotor, which is connected to a generating set that will convert the wind power to electricity. Before wind turbines can generate electricity, the wind speed has to be at least 9 miles per hour.
These wind turbines are usually made up of the following parts;
- Huge blades (these are attached to the hub of the turbine, jointly making up the rotor)
- The tower (to keep the rotor blades and generator as far from the ground as possible in the case of vertical axis turbines. Horizontal axis turbines keep the generator on ground level)
- The nacelle (it provides housing for the electrical parts, generator, and gearbox)
- The foundation (to secure the turbine to the ground and give it stability)
How Much Electricity Does a Wind Turbine Produce?
Just like solar power, in which the number and type of solar panels and the hours of sunlight determine the amount of electricity produced, the ability of a wind turbine to meet your electricity demand depends on the following:
- Wind speed
- Size of the wind turbine
- Location (onshore or offshore wind farms)
- How many wind turbines are being used
In essence, the taller the turbine, the longer the wind turbine blades and the more effective it becomes in generating renewable energy from wind resources.
The improvements in technology in recent years have greatly benefited the wind industry because it has resulted in manufacturers making taller wind turbines. This means the better harnessing of wind energy and the generation of more electricity.
The location of the wind turbine also determines how much electricity a wind turbine can produce – we have onshore wind turbines and offshore wind turbines. An average onshore wind turbine can generate 2-3 megawatts of electricity yearly, while an average offshore wind turbine can produce almost 4 megawatts of electricity yearly. More than enough to heat many residential pools. This is enough energy to power several homes for a year. Even a wind turbine producing 1 megawatt can meet the annual electricity demand of 300 homes.
Most onshore wind turbines produce between a range of 1-5 megawatts of electricity yearly. As we said earlier, the size matters, so if the output is a single megawatt or thereabouts, it’s most likely small wind turbines. The wind farm is at its most productive capacity when the wind’s speed hits a minimum of 30 miles per hour.
However, wind turbines depend on strong wind to produce enough electricity because a drop in wind conditions will significantly reduce the electricity generation output. Numerically, if wind speeds go from 30 mph to 15 mph, the electricity generated will reduce by 1/8 of what it was producing when the wind was stronger.
Onshore Vs. Offshore Wind Energy: Which Does it Better
Let’s delve into their meaning to appreciate their capacity, efficiency, and differences fully.
Onshore wind energy simply means wind power being generated from commercial wind turbines on a land-based wind farm. Its wind farms are ideally located in fields or areas with small populations where there are fewer obstacles to disrupt the free flow of air most wind turbines need to generate electric energy.
The UK is a significant utilizer of wind projects for generating electrical energy. Onshore wind power production went commercial in the country in 1991. Today, the UK has more than 1,500 active land-based wind farms. The energy produced from these wind farms is more than 12 gigawatts yearly – significantly contributing to the country’s national power grid.
Land-based wind energy production is far more beneficial to the environment than traditional energy sources such as fossil fuels. Like other renewable energy sources, wind turbines produce clean energy, which means less carbon footprint in the atmosphere. At the same time, an onshore wind power plant’s land can still be used for agricultural purposes.
On the flip side, offshore wind energy production entails the generation of electric power from winds blowing across the sea. Though the US has significant offshore wind energy operations, it’s nowhere near what the country can achieve in the coming years. The UK, for instance, has about 35 sea-based wind sites with more than 2,200 offshore turbines installed across them.
Offshore projects incur higher maintenance costs than onshore operations and cost more to install or construct.
Regarding efficiency in energy production, the offshore wind industry comes out on top because the wind from the sea is stronger, more consistent, and has few or no obstacles in its path. Due to the obvious geographic advantage the sea has over land when it comes to wind power, a sea-based wind project will require fewer wind turbines to generate the same amount of electricity as a land-based project.
The Cost of Wind Turbines
The short answer is wind turbines cost a lot. Most commercial wind turbines cost between $2.6 and $4 million with a capacity factor ranging between 2-3 megawatts. A wind turbine can cost as much as $1.3 million per megawatt of electricity – a whopping figure. Offshore turbines cost even more because their capacity can be as large as 12 megawatts.
A wind turbine can cost as much as $1.3 million – a whopping figure. However, this cost is more of an investment than an expense because wind energy is very rewarding in the long run. Besides, the power generated from these turbines, if privately owned, can be sold to utility companies. One way to reduce the cost of running a wind power plant is by using a smaller number of larger turbines.
Maintenance & Repairs
As wind energy technology continues to make progress, the costs of repairing or servicing wind turbines will eventually reduce. The average cost of a kilowatt hour of electricity ranges between 1 and 2 cents, which equals $42k-$48k yearly.
These costs entail:
- The rent for the land (for an onshore project)
- Administrative tasks
- Spare parts
These costs are recurring expenses, but the money wind turbines make from local utility firms will be far more than its maintenance or repair cost.