Capturing CO2 with Tomatoes
A California farmer is finding a unique way to capture emissions of carbon dioxide — piping the climate-altering gas from a power plant into his massive greenhouse, spurring more plant growth and tastier tomatoes.
This carbon capture and tomato storage project is the first of its kind in the United States although similar ones exist in Europe.
The new $13 million combined heat and power co-generation plant opens Aug. 22 at Houweling’s Tomatoes in Camarillo, Calif. The two GE-built engines will burn natural gas to keep the greenhouse warm, while generating some extra electricity that is sold back into the local grid. At the same time, the 8.8-megawatt plant feeds its waste carbon dioxide directly into Houweling’s giant 150-acre greenhouse.
“All the electricity (power) plants out there are putting CO2 into the atmosphere and heat which are two big consumptions,” said owner Casey Houweling. “If we use our energy wiser we would have impacts from two sides, reducing cost and becoming more efficient.”
Houweling says the co-generation plant is a big investment but he expects it will pay off in the long run. ”There will be a big benefit because we won’t be exposed to energy prices because we are selling the electricity,” Houweling said. “Long-term we believe this will stabilize our production costs.”The power industry has looked at many types of carbon storage projects over the years as a way to reducing atmospheric emissions of the heat-trapping gas. Some firms have tried injecting it underground to abandoned mines or salt deposits, others have tried bubbling CO2 through ponds of microscopic algae. But Houweling says that the extra CO2 is a perfect fit for his greenhouse. He already has to purchase the gas anyway from an industrial supplier to makes his plants grow.
“In a greenhouse, if we don’t add C02,” Houweling said, “the plants will pull down the level so much they will stop growing.”
Houweling says the addition of the co-generation plant makes his greenhouse facility almost 100 percent energy-efficient. He recycles 90 percent of his waste, captures rainwater for irrigation, and has deployed five acres of solar panels. The greenhouse-grown tomatoes also use less land than traditional row farming. That is a further energy savings, according to Scott Nolen, product line leader for General Electric.
“He can grow as much food on 150 acres as his neighbor in 5,500 acres,” Nolen said. Nolen said that until renewable sources of energy pick up the slack, there are still ways of making fossil fuel plants have less of an environmental impact. ”We’d all like to be in world where we don’t burn hydrocarbons,” Nolen said. “That’s not possible yet but in the meantime, we want to make sure every molecule of hydrocarbon we burn for fuel is as efficient as possible.”
Astronomers using data from NASA’s Hubble Space Telescope have caught two clusters full of massive stars that may be in the early stages of merging. The clusters are 170,000 light-years away in the Large Magellanic Cloud, a small satellite galaxy to our Milky Way.
What at first was thought to be only one cluster in the core of the massive star-forming region 30 Doradus (also known as the Tarantula Nebula) has been found to be a composite of two clusters that differ in age by about one million years.
The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters.
Lead scientist Elena Sabbi of the Space Telescope Science Institute in Baltimore, Md., and her team began looking at the area while searching for runaway stars, fast-moving stars that have been kicked out of their stellar nurseries where they first formed. “Stars are supposed to form in clusters, but there are many young stars outside 30 Doradus that could not have formed where they are; they may have been ejected at very high velocity from 30 Doradus itself,” Sabbi said.
She then noticed something unusual about the cluster when looking at the distribution of the low-mass stars detected by Hubble. It is not spherical, as was expected, but has features somewhat similar to the shape of two merging galaxies where their shapes are elongated by the tidal pull of gravity. Hubble’s circumstantial evidence for the impending merger comes from seeing an elongated structure in one of the clusters, and from measuring a different age between the two clusters.
According to some models, the giant gas clouds out of which star clusters form may fragment into smaller pieces. Once these small pieces precipitate stars, they might then interact and merge to become a bigger system. This interaction is what Sabbi and her team think they are observing in 30 Doradus.
Also, there are an unusually large number of high-velocity stars around 30 Doradus. Astronomers believe that these stars, often called “runaway stars” were expelled from the core of 30 Doradus as the result of dynamical interactions. These interactions are very common during a process called core collapse, in which more-massive stars sink to the center of a cluster by dynamical interactions with lower-mass stars. When many massive stars have reached the core, the core becomes unstable and these massive stars start ejecting each other from the cluster.
The big cluster R136 in the center of the 30 Doradus region is too young to have already experienced a core collapse. However, since in smaller systems the core collapse is much faster, the large number of runaway stars that has been found in the 30 Doradus region can be better explained if a small cluster has merged into R136.
Follow-up studies will look at the area in more detail and on a larger scale to see if any more clusters might be interacting with the ones observed. In particular, the infrared sensitivity of NASA’s planned James Webb Space Telescope (JWST) will allow astronomers to look deep into the regions of the Tarantula Nebula that are obscured in visible-light photographs. In these areas cooler and dimmer stars are hidden from view inside cocoons of dust. Webb will better reveal the underlying population of stars in the nebula.
