How the Denver Zoo Became the Greenest in the World

Photo Credit: Denver Zoo

Denver lays claim to the greenest zoo in the world. We were lucky to have George Pond, Vice President for Planning & Capital Projects at the Denver Zoo outline how they achieved this status at WREF 2012. As Pond reminded us, It’s a zoo story–but it’s not a “zoo thing.” It’s really a story about how large facilities can transform from drains on the system to neutral or net positive in their energy consumption.

As the most popular cultural attraction in Colorado with 1.9 million guests this year, 3,500 different animals and 80 acres in Denver’s city park, the Denver Zoo has traditionally consumed a great deal of resources. The path to becoming the greenest zoo in the world started with simple activities like recycling, saving trees and the Green Team, a group of true believers. When they decided to get serious about sustainability they began by auditing themselves to have facts and figures to establish a basis for understanding and action steps. This means they don’t guess–they have hard numbers to guide them.  At one time, the Denver Zoo was one of the Top 5 largest water consumers with 383 million gallons a year. This was one Top 5 list where they didn’t want to see themselves included. So, they decided to change things starting with low hanging fruit in water conservation, which is critical–especially in a state like Colorado.

When Pond and his team looked at the details of the zoo’s water consumption they were surprised to learn that suspect areas like irrigation and the aquarium only contributed to 3% of the water consumption. The biggest culprit for water use were the bird exhibits which contributed to 54% of the water usage each year. The team scored a big hit by changing the schedule for the flamingo pond by reducing in half the usage taking it from 40 million to 20 million gallons a year. Although it was a very successful project it didn’t come easily. As Pond points out, the biggest impediment to becoming more sustainable isn’t technology, it’s interpersonal. It took a great deal of trust building with the bird staff to reduce consumption while still serving the birds and guests well.

Photo Credit: Denver Zoo
Photo Credit: Denver Zoo
Photo Credit: Denver Zoo

Once they tackled water conservation they decided to find more ways to become sustainable and meet their mission to secure a better world for animals through human understanding. The team originally looked to the elephants for energy generation through  gasification of waste.  If you don’t know what gasification is it’s a high temp/low oxygen process to convert solid fuel into combustible gas.  However, they were quickly told that their elephants just didn’t generate enough waste. Tell that to the zoo keepers! The team then looked to other alternatives to take the waste stream at the zoo and convert it into energy. The challenge the team faced was how to take a diverse waste stream and package it into something that resembled fuel.

To make the zoo the greenest in the world, they had to do a lot of the work themselves, even creating their own Biomass Experimental Energy Development Lab. The zoo currently has patents pending on their fuel creation innovations. To wit, they created what is believed to be the first hybrid gasified tuk tuk. Yep, they’ve got a truck powered by poop. The zoo even had an event where the margarita’s were made in a blender powered by yes–waste.

The team has already reduced their contributions  by an astonishing 1.5 million pounds a year. The Denver Zoo is currently net positive on energy and aims to be a zero waste facility by 2025. Here are a few of the other benchmarks they hope to hit in coming years: save as much as $200k/year, generate up to 1M kWh/year, produce 600k BTU/hr. Renewable energy is so endemic to the way they work now that even though becoming LEED certified at zoo is not very easy they are now in process to become LEED platinum. They’re proud to be leading the way to creating standards for zoos around LEED certification.

The Denver Zoo is actually leading the way around sustainability in general in their industry. Although zoos around the country are implementing solar power, the Denver Zoo challenges others in their industry to take a systems approach around sustainability and renewable energy. Becoming a truly sustainable facility hasn’t always been easy but it has been gratifying for the Denver Zoo. Pond’s advice for others?

Start where you are. 

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