Past and current clients include:
- United States Department of Agriculture
- Burlington Electric Department
- Green Mountain Power Corporation
- Renewable Energy Development Fund
- Mashantucket Pequot Tribal Nation
- Municipality of Anchorage
- PacifiCorp
- Citizens Energy Services
- Long Island Power Authority
- Vermont Transco
- Vermont Electric Cooperative
- Efficiency Vermont
- Vermont Department of Public Service
- New Hampshire Electric Co-Op
- Public Service of New Hampshire
- Norwich Public Utilities
- Tri-State Generation and Transmission Association Inc.
- Unitil
- National Grid
- Energy Trust of Oregon