Powering our communities with offshore wind energy
Offshore wind power is energy that is generated by wind turbines located on bodies of water, usually in oceans and seas. It is becoming more important as we navigate the energy transition. Why? Because offshore wind farms produce significant amounts of clean, green, renewable energy.
Traditionally, the US hasn’t been that invested in offshore wind. But that has changed in recent years. After all, if we hope to achieve our net zero sustainability goals, offshore wind will need to play a big role. Let’s learn more about offshore wind.
Where are offshore wind farms and how are they designed?
We have the opportunity to generate a significant amount of clean energy with offshore wind turbines. But just how do we get that power to the shore so we can use it?
Offshore wind farms currently being proposed in the US are located approximately 15 to 30 miles from shore. The Bureau of Energy Management (BOEM) has a defined process to evaluate and determine the offshore wind lease areas.
Location of windfarms
There are two main types of wind turbines. Fixed bottom foundations can be used at water depths up to approximately 200 feet. Floating turbines are being planned for deeper waters where fixed foundations are not feasible.
Types of turbines
The number of turbines in each offshore wind farm can vary significantly. Some windfarms are large with more than 100 turbines. Besides the number of wind farms, the capacity of individual turbines can also vary. The trend however, is for windfarms to continue grow in the future.
Size of windfarms
Offshore wind turbines require thousands of kilograms of precious materials. These include copper, nickel, manganese, chromium, zinc, and more. If we hope to increase our offshore wind power production, we must mine for these minerals and metals.
Mined materials needed
How are the offshore wind farms connected to the shore?
So, the cables finally reach the shore. But what happens next? How do we get the energy into the grid?
Cables are typically installed using a hydroplow—a machine opens a trench with water jets and installs the cable at the same time. The cables are placed about six feet deep. This protects the cables from other marine activities like fishing.
The offshore cable route needs to be selected based on the most efficient routing, seabed conditions, marine traffic, and other offshore infrastructure. Environmental and marine life constraints also need to be considered.
An offshore wind turbine sends the electricity it produces to the shore by using a cable system. There are two basic types of transmission cables: High Voltage Alternating Current (HVAC) and High Voltage Direct Current (HVDC). HVDC is the preferred option for offshore transmission distances greater than 60-70 miles or when the power being transmitted is greater than 1000 MW.
High voltage cables
The offshore wind power needs to be collected and converted at an offshore substation. The purpose is to convert the energy into a form that can be efficiently transmitted to shore.
Protecting these cables is paramount as damage to the cables can result in power outages. It can take up to three months to repair damaged cables—that’s a lot of power lost.
Where does the offshore wind power go?
Ok, so we got the power to the substation. Now what? Who gets to use this energy?
Next, the cables need to be connected into the grid. That means transmitting the power, either underground or overhead, to the designated inland substation. Both options can have an environmental impact, so a strong permitting process and public outreach are critical components.
Connecting to the grid
Regulations dictate avoiding sensitive shoreline resources and habitats as much as possible. One way to avoid impacts to sensitive shoreline resources is to go under the shore using horizontal directional drilling (HDD). HDD allows us to completely bypass the shoreline and bring the cables up further inland.
Horizontal Directional Drilling (HDD)
Once the cables reach the shoreline, the next challenge is connecting them to the grid. The substation infrastructure will likely not be located right on the shore, so additional transmission cable lengths will likely be needed.
Who gets to use this energy once its in the grid?
Offshore wind power can provide our communities with bountiful, clean, and renewable energy. While there are challenges with transmitting this energy to the shore and nearby power grid, we have a team of experts that can navigate the process.
From installing the turbines, to routing and protecting the cables, to connecting the cables to power our communities, we bring together the right team of experts to successfully deliver these kinds of offshore wind projects.
Offshore wind power can be used to power city infrastructure like street lamps, traffic lights, road signs, recreation facilities, and more.
For communities with charging infrastructure, we can use the energy to charge up electric vehicles. This way avoids charging them with grid power that may still be produced from fossil fuels.
We can also use the electricity to power mass transit and transit facilities. This helps transport our people more sustainably.
Once the power has been directed into the electrical grid, the power can be used by nearby communities in many ways:
1. Homes: The electricity can be used to heat, cool, and power homes in a less carbon-intensive manner.
2. Commercial Users: Large electricity users will have access to the same power that homeowners will use.
Residents and consumers
Want to learn more? Check out our offshore wind team here.