HELIOS ESS: Clapboard Island off the Coast of Maine

This private estate with a striking mansion and beautiful, natural scenery is located on Clapboard Island, off the coast of Maine. It gets its name from workers harvesting timber from the island into "clapboards" — long, thin wooden boards used for siding on buildings.

In addition to this private estate, Clapboard Island is home to a nature preserve, maintained by the Maine Coast Heritage Trust. The area features dense maritime spruce-fir and pine oak forests with mature understories and minimal signs of human disturbance. The local wildlife includes nesting ospreys and a pair of bald eagles. Visitors are encouraged to stay on designated beaches in the spring to avoid disturbing nesting eider ducks.

History

The estate, built in 1898 by railroad magnate Samuel F. Houston and architect Joseph M. Huston, sits on the western side of the island. The original home was erected in just 100 days by 100 local artisans, with the help of oxen that transported materials in winter over frozen Casco Bay.

The estate spans 37 acres at low tide and includes an 18-room mansion, guest house, barn, children’s playhouse, stone pier, five beaches, a helicopter pad, and hiking trails. The home features original pine floors (imported from Oregon), stone fireplaces, antique fixtures, solar and generator power systems, and over 3,200 feet of Casco Bay shoreline.

Ownership timeline:

• The Houston family began summering there in 1899 and continued for decades.
• In 1999, the former Ambassador to Portugal, Al Hoffman, purchased and renovated the island. For two decades, it served as their family compound, hosting past presidents and dignitaries.
• In 2024, the current owners purchased the property and it now serves as a private family estate.

Power System

The legacy system consisted of Outback Power inverters, Schneider Electric charge controllers, a small solar array on the barn, and 48 Trojan 2V Lead Acid batteries.

The old generators with a high amount of hours were barely functional, diesel-powered, and challenging to start and keep operational. The batteries required significant maintenance, and the system experienced substantial downtime.

With these functional and environmental concerns, the owners tasked Un-Grid with the following mandate:

• Remove all diesel and heating oil from the island and provide 100% clean energy power, with clean-burning propane available for backup and emergency operations.
• Remove and responsibly dispose of legacy lead-acid batteries and diesel/oil tanks.
• Provide power to the 37-acre estate, the mansion, and its five support buildings.

The new power system includes 320 kWh of HELIOS ESS Lithium batteries, which ensures uninterrupted operation for the vast estate. The solar + storage combination is large enough to support the main mansion, guest houses, barn, and other amenities. The estate owners enjoy reliable power with minimal maintenance, even during long stretches of inclement weather. Generators now serve only as backup, reducing fuel costs and barge delivery service charges.

Summary

The historic mansion is now updated with modern technology that remains hidden, but is essential to its longevity and comfort. After years of relying on aging Outback inverters, lead-acid batteries, and failing generators, the owners now have a completely modernized off-grid power system that makes the estate reliable, low-maintenance, and future-proof.

Visit the Discover Energy Systems website for more information on the HELIOS ESS.

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