Andrew Larkin: Ice-free Connecticut River tells a thermal tale
COURTESY OF ANDREW LARKIN A view of ice Jan. 7 on the Connecticut River above the Vermont Yankee nuclear power plant in Vernon, Vt.
NORTHAMPTON — There was recently a photograph in the Gazette showing people ice-fishing on the Oxbow section of the Connecticut River. At the same time, there is no ice at all on the river itself, and I wondered why this might be.
On Jan. 7 I drove north along the river. At the Northfield public boat ramp I found a little ice forming at the edge of the river, but there was mostly open water. At the Hinsdale public boat ramp the entire river was covered with ice and one could see across the river to the Vermont Yankee nuclear power plant. At Brattleboro, the river was frozen as well. At the Vernon canoe takeout, just downstream from the nuclear power plant and about half a mile from the Hinsdale site, the entire river was open.
This plume of heat extends all the way down to Northampton.
There is so much heat discharged from the nuclear power plant that the river in Northampton is still too warm to freeze; the winter is cold enough for the Oxbow to freeze, and one would expect the water from the north to be colder, not hotter.
This is not because the water is flowing, since the Connecticut River is also flowing at Brattleboro and is cold enough to freeze. This is an effect independent of global warming. It is a product of the nuclear power plant at Vernon.
When the plant is running, it is 33 percent efficient, as compared to other non-nuclear power generation sources that approach 70 percent efficiency. In other words, nuclear sources of energy produce twice as much heat per unit of energy delivered as conventional energy sources. Since Vermont Yankee produces about 650 megawatts of energy, it yields about 1300 megawatts of heat, which must be dispersed, either through the cooling towers or into the river, using water to transfer the heat into the environment.
Much of today’s dialogue on the environment focuses on greenhouse gases, which serve to trap heat. But greenhouses also have heaters inside that contribute to warming. In this way, nuclear power plants warm the greenhouse. Also, there is a widely held view that nuclear power plants do not contribute to global warming. However, nuclear power plants are tremendous users of energy. Mining and trucking related to this industry consume resources, often in the form of fossil-based fuel. Consider also the use of resources for the production of the non-nuclear parts of the reactor, such as the vessel itself and the cooling towers.
The claim is also made that nuclear power plants do not contribute to greenhouse gases.
Much of the popular thinking about global warming focuses on the greenhouse effects of the gas carbon dioxide, yet there are other greenhouse gases, notably methane and water vapor. For example, in deserts the days can be hot, but nights are much cooler because the absence of water vapor, which allows heat to radiate. That is why cloudy nights are warmer than clear nights.
With the cold upon us this winter, there is line between freeze and thaw and so this is an ideal time of year to make observations about the thermal output from Vernon.
When I first started rowing on the river in Northampton in the 1980s I had to stop around Christmas because the river froze, and I resumed in March. Now I can row throughout the year. Part of the effect is related to global warming, but local effects are in play, too.
Take a look around. At the Oxbow boat ramp you will see open water extending into the Oxbow part of the river while the main part of the Oxbow is frozen. Water coming down the river from the north, where it should be colder, is warm enough to keep the water open.
Examine the river banks. The sun will warm some spots locally, but in the shade, such as at the Elwell Island Park dock, there has been snow on the dock. These observation suggest the land is cold enough to produce ice; however, the water is too warm to freeze.
Open water is known to absorb heat, whereas ice reflects heat. The open water from Vernon itself is thus contributing to global warming.
Most of the year, the thermal effects of the Vernon plant are invisible. But now they are clear. A large thermal plume from Vermont Yankee is warming our environment and melting ice. This should be seen as a small part of the big picture on global warming.
Andrew Larkin lives in Northampton.