Monhegan Island

At a Glance
• System Configuration: 4 × C65 Stand Alone Capstone Microturbines (260 kW total modular array) running on liquid diesel, paired with a solar PV array and Capstone CLC controls
• Thermal Output: 1,720,000 BTU/hr (1.72 MMBtu/hr) of recovered hot water piped to the nearby Monhegan Museum of Art and History for space heating and dehumidification
• Financial Impact: ~$20,000 / year in fuel savings; $1M project primarily funded by a USDA High Energy Cost Grant
• Fuel Source: Liquid Diesel (meeting EPA stringent ultra-low emissions standards)


The Challenge
Located twelve miles off the coast of Maine with no subsea connection to the mainland grid, Monhegan Island must generate 100% of its own power. Serving 60 year-round residents alongside a surge of seasonal visitors, the Monhegan Plantation Power District (MPPD) faced high fuel shipping expenses, seasonal demand spikes, and strict environmental requirements for island power generation. The island needed an ultra-low emissions off-grid baseload solution that met stringent EPA standards, reduced overall fuel consumption, provided heat recovery, and could be maintained locally despite remote offshore logistics.


The Solution
The Monhegan Plantation Power District turned to Veristar Energy to engineer and deliver an advanced 260 kW microturbine CHP microgrid system, replacing legacy, inefficient diesel generators and moving them to standby status.
• Ultra-Low Emissions Diesel CHP: Deployed four Capstone C65 microturbines operating on liquid diesel, supplying clean, quiet, and steady baseload electricity that meets strict EPA emissions mandates.
• Integrated Hybrid Microgrid: Integrated the microturbine plant with an on-island solar PV array and Capstone CLC automated controls, dispatching solar generation to displace fuel burn during peak summer daylight hours.
• Museum Waste-Heat Recovery: Captures 1.72 MMBtu/hr of exhaust waste heat and pipes hot water to the neighboring Monhegan Museum of Art and History to provide continuous space heating and critical climate dehumidification.
• Local Maintenance Training: Leveraged the oil-free, single-moving-part architecture of microturbines to train local island personnel to perform routine service and maintenance, overcoming offshore logistics constraints.


The Results
• $20,000 Annual Fuel Savings: Significantly reduces annual fuel consumption and barging costs through high-efficiency microturbine operation, solar pairing, and heat recovery.
• 90%+ Grant-Funded Infrastructure: Upgraded critical municipal island infrastructure utilizing a $1 million USDA High Energy Cost Grant to minimize the financial burden on local ratepayers.
• Quiet & Clean Power: Drastically reduces nitrogen oxide, particulate emissions, and sound levels compared to traditional diesel generators, preserving the tranquil island environment.
• Autonomous Energy Resilience: Delivers reliable 24/7 off-grid power and heating to an island community completely isolated from mainland electricity networks.