The Port of Detroit is seeking to implement low carbon technology and fuel sources to reduce its environmental impacts, writes Michele Witthaus
Responsible for the generation of US$900 million in annual economic activity, the Port of Detroit spans the Detroit and Rouge Rivers and is comprised of 24 private businesses and governmental bodies.
Given its status as an essential transport and manufacturing hub, the port generates significant carbon emissions. Cruise traffic contributes to the emissions challenge, with several cruise lines incorporating the Port of Detroit in the US leg of their Great Lakes cruises.
Emissions goals
The Detroit/Wayne County Port Authority is a government agency that oversees the advancement and growth of maritime related industries in southeastern Michigan. In April 2024, the Authority initiated a year-long carbon study to understand the impact maritime activity in Detroit had on local air quality.
The study’s goals are to reduce greenhouse gas emissions from port activity to net zero by the year 2040; and to reduce other harmful emissions from port activity, including dust, odours, sound, vibrations and light emissions that negatively impact health and the environment.
The first phase of the study included the development of a baseline carbon footprint for the Port of Detroit. The Port appointed Tunley Environmental for its technical expertise, to quantify and recommend strategies to reduce carbon emissions for the Port, and Southwest Detroit Environmental Vision (SDEV) to lead the community engagement. As part of its role, Tunley developed an interactive map that shows carbon emissions for each port terminal and other entities that comprise the Port of Detroit.
At the launch of the project, Mark Schrupp, executive director of the port authority, said: “The maritime industry is responsible for 3% of global emissions, and it’s growing. We must work to convert from fossil fuels to zero-emission power sources in our ships, port equipment and trucks by 2040 in order to avoid catastrophic effects of climate change.” He added: “The steps we’re announcing…will have an immediate impact on air quality and will improve the lives of residents in our community.”
The port’s industrial history has left an enduring legacy of air pollution, a situation which the study aims to address with targeted solutions. “The overall aim of the project is to reduce greenhouse gas emissions and air pollutants, and to improve both the environment and human health,” says Emily Alexander, Associate Carbon Scientist, Tunley Environmental. “Detroit was named the most challenging city to live in with asthma in 2022. High levels of pollution produced from heavy industry led to poor air quality, which in turn has a negative impact on the health of those living and working near industrial sites.”
Crucially, the Port Authority has no enforcement powers over those who operate along the waterway, meaning that the study required persuading private businesses to voluntarily hand over operational data. “The Port Authority partnered with local community organisations to develop a plan that included community members’ voices to help guide the plan to decarbonise,” Ms Alexander says.
Carbon challenge
In recent years, Detroit has become a popular port of call for river cruise ships thanks to attractions such as the Henry Ford Museum and the Detroit Art Institute. In 2022, a total of 52 cruise vessels docked at the port, bringing around 15,000 passengers.
“The results of the Baseline Carbon Assessment of the Port of Detroit show that the 2022 cruise season fuel use generated 1,182 metric tons of carbon dioxide (tCO2),” says Ms Alexander.
“An additional 16 tCO2 resulted from dock operations to ensure safe and smooth cruising, including dock-side staff commuting, waste disposal, and transportation for passengers to various Detroit sight-seeing locations. This nearly 1,200 tCO2 of emissions makes up 4% of the overall transportation baseline emissions for the Port of Detroit.”
The carbon emissions were calculated using the fuel consumption of the ships as they move through the Detroit River and while docked. The calculations utilised emission factors from the International Maritime Organization (IMO) and the US Environmental Protection Agency (EPA) to calculate emissions based on data provided by the port authority.
As part of the decarbonisation project, the port authority is considering sustainable alternatives for the cruise operations, which often run their diesel engines for up to eight hours at a time while docked. Shore power is one of the most popular solutions considered by ports seeking cruise ship decarbonisation but is not currently under consideration for the port.
Ms Alexander explains: “While this makes sense for large port operations with hundreds of stops per year, or the largest, most power-intensive ships, it is less clear if the benefits outweigh the cost in Detroit. It would take grant assistance or high utilisation of the installed system to fund installation. DTE, the sole energy provider of Detroit, has aging infrastructure and 65% of their energy mix is made up of fossil fuels, therefore, notable upgrades to the energy system will need to be made to decarbonise the grid.”
As a result, she says, after an initial feasibility study, shore power was deemed not financially viable in the short term, although the port authority plans to revisit electrification of cruise ship operations in the future, in the hope that costs will come down and electricity production in the Detroit area will include a higher percentage of renewables. “Further studies on shore power are needed to understand the feasibility and financial undertaking required to implement by all involved parties, including the port authority, utility provider, and cruise ship companies.”
In the meantime, the port authority is encouraging the cruise industry to move towards lower carbon fuels. The immediate recommendation to decarbonise the cruise ships traveling through the Port of Detroit is to encourage the use of biodiesel rather than traditional diesel.
“Biodiesel is often derived from soybean oil and can be used as a drop-in replacement in diesel engines,” says Ms Alexander. “Biodiesel burns more cleanly, and a 100% biodiesel blend has a 74% reduction in carbon emissions over its lifecycle, resulting in significant reduction of carbon emissions, as well as some reductions seen in particulate matter, a harmful pollutant to human health. As the cruise industry operates during the warmer months, higher blends of biodiesel could be used without worry about potential impacts of cold weather.”
Future cruise sustainability
In addition to addressing the fuel source of cruise vessels in the Port of Detroit, decarbonisation will depend on also finding ways to reduce secondary cruise emissions.
Waste management practices are in the spotlight in this regard. “It is the responsibility of the port authority to receive and manage waste generated on board the cruise ships, but they have little control over how the cruise lines decide to dispose of items,” says Ms Alexander.
“The port authority hopes to encourage recycling and composting on all cruise ships, as well as putting into place on-site recycling and composting receptacle to receive and properly dispose of cruise ship waste.”
Another emission source is transportation used by passengers during their time exploring Detroit. “Often, charter buses are organised for tours to historic sites around the city. These buses are primarily diesel powered.
The Port of Detroit is seeking service providers who have hybrid or electric options to reduce emissions associated with cruise ship operations.” The Port has committed to ensuring that transportation and activities offered to passengers are low carbon and sustainable.
The decarbonisation project is expected to improve coordination and future planning within the port, as well as fostering engagement with residents and strategic economic development for maritime trade. The cruise industry’s role is an important one in this process, says Ms Alexander.
“As it continues to grow, the Port Authority wants to ensure it does so in a way that prioritises the health of the environment, and the people of Detroit,” she concludes.
