According to the report, the US generates over a billion tons of cow manure annually, most of which is left in storage areas to decompose naturally. That decomposition process produces air pollution and greenhouse gases (we reported earlier that an Argentinian study had concluded as much as 30% of that country’s greenhouse gas emissions could be coming from their cattle).

Anaerobic Digestion

Through the process of anaerobic digestion the manure can be converted into methane-rich biogas, and a nearly odorless sludge which can be used as a fertilizer. The biogas can be used as-is for heating homes or cooking; it can also be converted to natural gas by a scrubbing process that removes the carbon dioxide and hydrogen sulfide and then used where CNG would be used today (e.g. in powering vehicles).

Cow Power
The UT report suggests that using this biogas to generate electricity could help reduce the amount of power generated from coal fired power stations, and in doing so help reduce the carbon emissions. The results of the study suggest that using this biogas could result in a reduction of between 44 and 173 tons (40 to 157 tonnes) of carbon dioxide emissions.

The real question I was left with after reading the report though was whether electricity generation is the best use of this biogas. Are any of the other possible uses better at reducing carbon emissions?

[Via Earth2Tech]

The folks over at Green Upgrader found this video, and another one, that both make fun of the idea that coal energy is clean energy. The US has huge reserves of coal and generates over half its electricity by burning it. According to the folks at Coal is Dirty, that alone produces 10% of the global CO2 emissions. And that’s before you even look at the other emissions from burning coal (everything from sulphur dioxide to health-damaging mercury).

So, if coal is dirty, then what are the alternatives?

Solar
For many places in the US, solar panels on the roofs would make a great alternative source of energy. Some places around the world are already taking advantage of solar energy on many houses. CleanTechnica reported last week that 90% of homes in Israel have solar water heaters, and that Spain is following them. A week earlier they had reported that Hawaii had passed a law requiring a new homes in the state to be equipped with solar water heating.

I’m not a huge fan of laws that are so specific since they rapidly end up being out of date as technology advances, but I do see some value in having building codes that mandate some form of energy generation in each new building. While many cities/states are encouraging home owners to retrofit solar or wind power, it would be far more effective to have the systems integrated into new homes from the outset.

Wind Power
An interesting complement to solar power, residential wind power is certainly viable now. Unlike large commercial installations covering hilltops and plains huge windmills, a residential turbine like the Seahawk shown in the photo, will fit into most suburban areas.

For commercial locations, larger models are available generating up to 10KW from each turbine, and since they are vertically oriented, they can be mounted much closer to each other than the more conventional windmill type generators we’ve all see on the TV.

Tidal Energy
This one is not for most individuals, but for coastal communities a tidal energy generation system, which remains mostly below the waterline, might make a more aesthetically pleasing solution than large offshore wind farms like the one proposed in Massachusetts.

The Green Upgrader reports that one town, just 10 miles from the Cape Wind project, is planning just such an underwater tidal energy system. Residents of Edgartown, on Martha’s Vineyard, are planning to install 50 underwater turbines which they hope will power as many as 1500 homes.

Geothermal Energy
Another power source that is not really for individuals, but is being used in a number of places around the world to feed clean electricity into the grid. Here in California, just a little north of the San Francisco bay area in an area known as The Geysers, is the largest geothermal power plant in the world, currently producing over 750MW of power.

All told though, geothermal only produces about 1% of the world’s power today. There are also some disadvantages to it making it perhaps less clean than other renewable sources.

Biomass/Biogas
Among the other ideas out there is power generation from biomass, where plant material is used to generate power either directly (e.g. by burning it), or by using it as food for naturally occurring bacteria that then generate biogas (basically methane) which can be used as an energy source.

Another very similar idea is using the methane produced in landfills to generate heat and/or power. The SC Johnson manufacturing plant in Waxdale, Wisconsin makes use of methane gas from a neighbouring landfill and natural gas as fuel for its twin cogeneration turbines.

Hydro-electric Power
An older form of clean energy, widely used around the world is hydro-electric. While the power itself is clean, the impact on the environment both upstream and downstream of the dam and powerplant can be serious. Here in the US, the Colorado river projects are perhaps the most controversial. As well as generating power from two dams (the Hoover Dam and the Glen Canyon Dam), the Colorado River is also used as a source of water for Wyoming, Nevada, Colorado, Utah, Arizona, New Mexico, and California. Perhaps even more controversial is the Chinese Three Gorges Dam project. On the plus side, it will generate a lot of clean hydro-electric power, hopefully reducing China’s dependency on coal fired power stations, and reduce the potential for natural disasters downstream from the dam. But, as CNN reports, some feel the impact of the dam upstream might make for an environmental disaster, turning the man made reservoir behind the dam into a “stinking effluent lake filled with raw sewage and industrial chemicals backing up for 600 km (372) miles.”