Swedish Accelerator Will Be Carbon-Neutral

By Calla Cofield

In 2019 the European Spallation Source (ESS), a pulsed neutron beam research facility, will begin operations in Lund, Sweden. It will also be the world’s first carbon-neutral accelerator facility. ESS’s energy plan will raise its  initial costs, but should eventually save the facility millions of Euros a year. In the interest of fostering discussion about making science more energy efficient, ESS announced that they will host their first Green Energy for Sustainable Science conference in October of this year.

Talks at the 2011 APS April Meeting in Anaheim, California and at the 2011 Particle Accelerator Conference in New York City were both well attended, and met with questions from the audience about the specifics and the feasibility of the ESS energy plans.

“We get phone calls from people who say they want to come work for ESS specifically because we are doing this, they think it’s so cool,” said ESS Energy Manager Thomas Parker. “Most of the scientists I’ve met are very concerned about the environment…and are really enthusiastic about this project.”

The ESS will be an accelerator-based spallation source, so it will generate neutrons by first accelerating pulses of protons, and then colliding those protons with neutron-rich sources, such as mercury. The collision gives the neutrons enough energy to escape the nucleus and then interact with sample materials. By observing the interaction between neutrons and other materials, scientists can study the atomic and molecular structure of those materials. Research done with neutron sources includes in-depth chemical analysis of materials, identifying elements in archeological findings, developing new materials, purification of materials, the study of biological structures such as proteins or the development of new medicines, and fundamental neutron physics, to name a few.

In 2009, the OECD declared Lund the winning city in a bidding war to host the European Spallation Source, ESS. The city’s proximity to top science research institutes and relatively easy accessibility to other parts of Europe contributed most greatly to the win, but the “cream on top,” as ESS Communications Officer Marianne Ekdahl describes it, was the goal to make the facility carbon neutral, and to save money doing so.

“Saving money is what policy makers are most concerned about,” said Ekdahl. “But the scientists too…because the more money we save the more money we have to do science.”

Perhaps the most ambitious part of ESS’s carbon neutral plan will be to build enough new renewable energy sources, most likely wind turbines, to meet 100 percent of its electricity needs. The site of the future facility, where construction is set to begin in 2013, is a stretch of grassy farmland, spotted nearby with wind turbines. Parker says scientists have called it the facility “that makes neutrons out of wind.”

Even after incorporating the cost of building and maintaining a wind farm, ESS will save roughly eight million Euros a year from not relying on traditional electricity sources. The facility can expect an additional four million Euros in direct income from their plan to recycle their heat waste. Rather than dissipate the waste via cooling towers, as is common at most large facilities in the US, ESS will feed the heat into Lund’s district heating system. The energy savings from not using cooling towers, combined with efficiency gains in the accelerator design, will give ESS another 3 million Euros in energy savings a year, or a total savings of about 15 million Euros a year.

“So it is a useful revenue stream for us, but not something to boast about on Wall Street,” said Parker. But more than income, the renewable energy source will stabilize the cost of energy over the facility’s lifetime. If the price of non-renewable electricity goes up, the facility doesn’t have to worry that their operating budget will increase.

Parker and Ekdahl say the new plan has stirred up conversation in the physics community and gathered attention from other facilities. Parker even puts forth the prediction that, “this is how big science facilities will be designed in the future.”

But much of ESS’s energy plan is made possible by its location. Only a few cities in the United States utilize a district heating system like Lund, not to mention that in the United States, large science facilities tend to be located far away from large cities. Not all locations are ideal for renewable sources like wind or solar, and even ESS will have to take into account the inconsistency of some renewable sources, like wind farms. America also doesn’t have the kind of voucher system used in Europe, or quite as large an infrastructure for renewable energy sources. Kevin Jones, director of Oak Ridge’s Accelerator Research Division, says it is limitations like these, not a lack of desire, that has limited United States facilities in energy-saving approaches similar to Lund.  

“If any accelerator facility in the United States could find the right balance between its geographical location and its ability to draw on renewable, predictable sources of energy,” said Jones, “I think the management teams would jump at that opportunity.”  

Most of the ESS’s energy plans concern policy and management decisions, but improvements to the efficiency of these large machines and facilities is something accelerator physicists have been working on for decades. One of the techniques ESS used to reduce its annual energy bill was adopting superconductivity in some areas. Superconductivity trades the cost of heat lost through resistance in traditional magnets for the much lower cost of cooling the liquid helium needed to keep superconducting magnets at 2 Kelvin.

At ESS’s Green Energy for Sustainable Science conference, which Parker says is open to all areas of science, attendees will have a chance to discuss the changing demands on large science facilities to conserve more energy and be environmentally conscious. The conference will also discuss goals to lower energy consumption by big science facilities, new techniques to improve efficiency, and how laboratories can implement the technologies and approaches already available.