Maine Eyed for Project that Converts Electricity to Storable Gas

by Tux Turkel (Press Herald) Wind and other renewables produce excess power that could be used in the state’s natural gas pipeline system. -- ... The transmission lines connecting Maine’s far-flung renewable generators to the regional electric grid sometimes are too weak to carry all their power. When that happens, grid operators order generators to reduce output or even stop running, to prevent overloading and jeopardizing reliable service. The practice is called curtailment.

At one substation in northern Maine, there’s a bottleneck that forced grid operators to curtail 75,000 megawatt hours of renewable power last year, according to a recent legislative presentation. That’s enough electricity to run 10,000 homes.

Upgrading the transmission system is very expensive. It could be better if there was some way to soak up the wasted energy potential, not just for a few hours in huge batteries, but for days or even months.

To do this, power-to-gas technology uses surplus renewable electricity to create hydrogen and natural gas, or methane.

For instance: During the winter, wind farms in eastern Maine may produce more power than they can feed into the grid. The pilot plant could use surplus electricity and equipment called an electrolyzer to extract hydrogen and oxygen from water, capture the hydrogen and mix it with natural gas in the pipeline system.

A further step could turn the hydrogen into natural gas through a process using carbon dioxide. In Colorado, the federal National Renewable Energy Laboratory has partnered with California gas utility SoCalGas to build the nation’s first biomethanation reactor.

In Germany, methane gas derived from wind power and created through the methanation process is now being fed into gas pipeline networks.

Besides surplus wind and solar energy, Maine has other significant resources that could be used to generate renewable natural gas, according to Brad Bradshaw, president of the Velerity management and consulting firm, as well as the Portland-based Hydrogen Energy Center. In a presentation to the study group, Bradshaw outlined the potential from landfills, which emit methane as waste decomposes, as well as dairy farms and municipal wastewater treatment plants.

Summit is partnering with some central Maine dairy farms on a project to turn cow manure into renewable natural gas and inject it into its distribution system. The facility is due to be online in 2021.

At the Brunswick Landing business park, an anaerobic digester system uses municipal and other organic waste to create methane gas and generate electricity. A second digester is in the planning stages, according to the Midcoast Regional Redevelopment Authority, which operates the business park. A manager with the digester’s owner, New York-based Genesis Industrial Group, couldn’t be reached by phone or email to ask about the company’s latest plans.

For one thing, some environmental groups are opposed to any incentives that prop up the natural gas industry. In southern California, where renewable natural gas has become an issue for debate, groups such as the Sierra Club label it “greenwashing,” more of a public relations campaign than an earth-friendly solution. Some critics point out that the pipeline system is mostly filled with natural gas and contains only a minor proportion of renewable gas. READ MORE