August 25, 2010 - tidal energy; sewage anaerobic digestion

What is the first federal facility anywhere to use tidal power as an energy source? A Coast Guard station in Eastport, Maine is claiming the title with its project to install Ocean Renewable Power Company's tidal energy turbine and generator. ORPC installed a 60 kW tidal turbine and generator in March 2010. Last week, ORPC announced that the unit had commenced powering the Coast Guard's 41' utility boat with electricity of a quality compatible with being grid-tied. Yesterday, in Eastport, there was a celebration of the project's successes and promises.

Lewiston and Auburn, two of Maine's largest sister cities on either side of the Androscoggin River, share sewer treatment services through the Lewiston-Auburn Water Pollution Control Authority. Currently, the plant treats 12.7 million gallons of sewage per day. This process results in two major products: clean water, and the solids that (in technical ways, if not semantically) make up the difference between sewage and water. The authority mixes about half of the solids with wood to make a marketable compost, but has to pay to dispose the remaining solids. Now, the authority is considering installing an anaerobic digestion plant. This plant would have two major effects. First, it would significantly reduce the mass of solids requiring disposal -- up to a 40% reduction. Where that mass would go produces the second major effect of the plant: through anaerobic digestion, combustible gas (primarily methane) is produced from the solids. This gas can be burned in a gas turbine, which can be tied to a generator. For Lewiston-Auburn, gas production is estimated at 170,000 cubic feet of methane per day; the authority estimates that it can produce 2/3 of its own electricity requirements from this fuel stream. The cost? $16.6 million. On September 8, the board of the authority will vote on the project.

The public debate over wind energy's merits continues with this letter to the Lewiston Sun Journal critical of developing wind near small towns and mountains in Maine. Claims made include "they will not produce enough energy to make a dent in our needs, but it will make some investors very rich" and "the energy will be sold out of state".

Copper theft is an issue in Maine. Copper is valuable for its scrap value. Thieves strike utility infrastructure as well as homes. Here's a news report of a thief busted for stealing the copper piping from a house listed for sale.