The secret second life of Dorothea Dix sunflowers

It turns out, sunflowers are more than just a pretty face. Sustainable energy is stored in the seeds of the summer blooms that are bringing thousands of visitors to Dorothea Dix Park in Raleigh.

After the flowers wilt in the fall, Raleigh Water workers will harvest the plants to create biodiesel.

“We'll extract the seeds from the flowers and we'll take it back to our Neuse River Resource Recovery Facility and process them into biofuel that can be used to operate our farming equipment at our facility,” said Ed Buchan with Raleigh Water. “We have over 1100 acres of land out there that we’ve been farming since 1976,” he said.

The environmental efforts are the result of a grant from the state of North Carolina years ago to pilot test the process. Raleigh Water was able to acquire equipment that can process the sunflower seeds and extract the oils.

“In the past, we had some sunflowers in the front of the wastewater property there near the Greenway, but we had problems with people coming on to the application field, so we had to think of a different way to show off these cool flowers,” said Buchan.

Buchan says Raleigh Water applies wastewater to the farmland to grow sunflowers and corn, among other crops, that can take up nutrients from the biosolids and be harvested to provide a fuel source. After having problems with flower-hunting trespassers at the facility, Raleigh Water teamed up with Raleigh Parks, Recreation and Cultural Resources to create a public sunflower field at Dorothea Dix Park.

198,000 seeds were planted in May to create this Summer’s batch of flowers. Buchan says they will likely harvest them in October.

Assistant Professor Joe Sagues specializes in biocarbon utilization at NC State and says biofuels can offset climate change by reducing the amount of carbon pollution released into the atmosphere. “Biofuels are attempting to replace fossil fuels, which are dependent on finite geographically constrained resources,” he said. “With the use of renewable domestic biomass feedstocks, we can grow our own fuel here in domestic soil and do it in a renewable fashion.”

Biofuels are primarily used for transportation, such as the ethanol in gasoline, but can also be used for heating or to generate electricity. Domestic biofuel production and consumption has generally increased each year since the 1980s.