Environmentalists generally hate giant factory farms. These massive livestock operations cause all kinds of environmental and health problems. Gigantic chicken, hog and dairy farms are notorious for catastrophic manure spills that kill millions of fish, pollute water with high levels of nitrates that cause spontaneous abortions, cause Salmonella, E. Coli, and cryptosporidium contamination, emit hydrogen sulfide that can cause brain damage in those exposed and even kill them, contribute to the dead zone in the Gulf of Mexico that degrades fishing and shrimping, and so on.
But there are large dairy operations that environmentalists could grow to love. The New York Times has an article about one of the largest dairy farms in the country. Fair Oaks Farms, which has 30,000 dairy cows, uses the methane from cow manure to generate the electricity that powers their entire operation, as well as fueling the tractor-trailers that take the milk to processors in three states. That saves two million gallons of diesel fuel alone per year.
Minnesota Public Radio has a story about the Crave Brothers cheese farm, which uses an anaerobic digester to process manure and waste whey to create methane that's burned to generate all the electricity for the farm's operations, as well as 300 additional households. The remaining waste is used as fertilizer and bedding for the cows.
In these operations potentially toxic manure is neutralized and turned into fuel and fertilizer in a sustainable and carbon-neutral fashion. Instead of taking methane and crude oil from deep within the earth that will be burned once, constantly increasing the amount of dioxide in the atmosphere and contributing to global warming, these farms use the natural carbon cycle to power their operations. Sunlight makes their crops grow, which takes carbon dioxide from the atmosphere; the cows eat the crops and produce manure; methane is extracted from the manure; the methane is burned and put back into the air as carbon dioxide; and the cycle is complete. The farms' operations can be carbon neutral.
There's a certain minimum size required for such an operation, from both an economic and efficiency standpoint. The larger the operation, the more steps in production you can colocate on the farm (growing feed, producing milk and meat, and more industrial process like cheese making or slaughtering), the more efficient the carbon cycle will be. This form of electrical cogeneration is a perfect way for factory farms to redeem themselves and become heroes of the environmental movement instead of the archvillains.
However, factory farms are guilty of other sins: they use antibiotics simply to increase weight gain, and they confine animals in inhumane, crowded and dirty conditions, rather than allowing them to wander aimlessly through idyllic grassy fields. There's no excuse for indiscriminate antibiotic use: the practice is quickly creating superbugs that are immune to our entire arsenal of antibiotics. Instead, farms should keep animal pens clean, which has been shown to be just as effective in increasing weight in poultry and is essential to proper dairy operations in any case.
The problem with aimless wandering is that manure will be dropped over large areas, making it less efficient to collect it for methane generation. The animals are part of a giant food- and electricity-generating machine, sort of like the people in The Matrix.
We should avoid unnecessary cruelty to animals, and maybe we can find a way to efficiently generate electricity from free-range cows. But if we can't, and the choice is between confined cows and a 10-foot rise in sea level in the next 40 years, the choice should be obvious. If environmentalists want to stop indiscriminate fracking, expanded use of coal and nuclear, they have to be open to all forms of carbon-neutral energy generation.
Even if it makes Bessie sad.