City Moves Towards Zero Waste, Net Positive Energy

The City of St. Louis Park, MN is investing in numerous renewable energy sources, including a technology that will help it become both a zero waste community and net energy generator. Details of its efforts inside


What Happened?

St. Louis Park, just outside of Minneapolis, is planning future operations with energy generated from organic waste. In an effort to become a zero waste municipality, the city will start with green construction and investment in the latest clean technology.

The Goal

The green developments throughout St. Louis Park include the installation of an anaerobic digester that will convert garbage into biogas to power an engine and produce electricity. This electricity would then heat and cool building developments, while the byproduct of liquid fertilizer from the digester can be used to boost produce production in a nearby greenhouse.

Anaerobic digesters are more commonly used on dairy farms to transform manure and plant waste into energy sources. Currently, about 2,000 anaerobic digesters are producing biogas to generate electricity and power without releasing emissions.

The anaerobic digesters in St. Louis Park will function similar to those found on dairy farms, but use organic waste instead of manure. Because residential organic waste will be filled with varying components, unlike the more consistent and reliable manure, the digester will be modified to accommodate these fluctuations in ingredients.

The sealed anaerobic digesters will turn residential waste into biogas in about 21 days, able to convert 35,000 tons of organic waste into energy annually. This will translate into about 1.5 megawatts of energy, or enough to power most of the municipal buildings. The community also plans to integrate solar, wind and geothermal energy sources throughout developments to further increase sustainability and become a net producer of energy, rather than a consumer.

The point of adding the anaerobic digester is to reduce energy consumption and utilize all resources to create a zero waste community. Because there is no excess consumption, zero waste spaces are highly sustainable and therefore cost less for residents and cities to maintain.

Lisbon Gets It Done

Lisbon has a strategy to become the world’s first zero waste capital city that is more focused on making use of all available food. Collaborating with private companies and nonprofit organizations, Lisbon officials plan to end food squandering and promote sustainability through education and outreach projects.

The goal of the collaboration is to recover surplus resources throughout the city and ensure leftovers are sent to needy residents rather than be thrown away. Local restaurants, food providers and residents should collect untouched food items that are good and redistribute it to the needy through a collective effort.

Since launching in 2011, the program has spread to nearby cities of Loures, Cascais and Sintra. About 60 institutions receive food donations from the project, which helps feed 2,100 needy families. The project has gathered more than 250 volunteers to rescue nearly 900,000 meals without increasing costs to organizations or residents.

Demand for the project rose after it was discovered about 50,000 meals worth of food were wasted across Portugal each day. Conversely, around 360,000 Portuguese are starving every day. Through small efforts to reduce waste, many cities have been able to proactively lower hunger rates at no additional expense.

Cutting Back

Gov1 has reported on a variety of strategies to reduce overall energy consumption as well as focus on zero waste policies.