Aarhus, the second largest city in Denmark, has made history today—it is the first city to power its water needs using raw sewage. Marselisborg Wastewater Treatment Plant is now able to generate more than 150% of the electricity required to run the plant. The excess power will be used to pump drinking water around the city.
Denmark’s breakthrough is attracting a lot of attention from around the world, with cities as far away as Chicago and San Francisco taking a keen interest in the development. But experts warn that just because Denmark did it, doesn’t mean it will be easy for other cities.
“Replicating Denmark’s experience and performance will not be easy,” said Molly Walton, Energy Analyst at International Energy Agency. Walton warns that the upfront costs alone can increase the price of water, making it a deal breaker for many cities.
And expensive it is. According to New Scientist, upgrading the facilities at Marselisborg cost nearly €3 million! That converts to $3,197,925 in U.S. dollars.
Here’s a breakdown of how it works. The plant uses biogas to generate energy. Biogas is gases that are created via the breakdown of organic matter in the absence of oxygen. In this case, the organic matter consists of wastewater and raw sewage. The gas that is created is then burned to generate heat and electricity.
“We don’t add any extra organic material like from restaurants or energy from wind turbines or solar panels,” said Lars Schøder, General Manager of Aarhus Water.
Although the technology isn’t new, no other city has done this before because of the high upfront costs. But experts at Aarhus Water believe the investment will pay for itself in as little as five years. They believe that the maintenance savings combined with the sale of surplus energy will be enough to make their investment worthwhile.