Durham County
Translated an 80% renewable energy mandate into a four-phase, fundable action plan for one of North Carolina's most progressive county governments
Summary
Optony and a team of sub-consultant specialists collaborated with Durham County, North Carolina to develop a comprehensive Renewable Energy Plan (REP) capable of guiding the County from its current energy baseline to 80% renewable energy by 2030 and 100% by 2050. The engagement spanned building electrification, onsite solar assessment, community solar, transportation decarbonization, and fleet electrification — evaluated through a consistent lens of financial feasibility, equity, and local economic development. The resulting plan serves as the County's primary strategic and operational guide for meeting goals adopted by the Durham County Board of Commissioners.
The Challenge
To respond to the Durham County Board of Commissioners' resolution calling for a transition from fossil fuel-powered operations to 80% clean, renewable energy by 2030 and 100% by 2050 — while ensuring the resulting plan was not aspirational in name only, but a financially grounded, equity-conscious, and operationally actionable document capable of guiding investment decisions, staff priorities, and utility partnerships through mid-century.
Our Approach
Optony's approach established a strong preference for locally sited renewable generation and direct fuel switching, treating the purchase of Renewable Energy Credits (RECs) as a last resort rather than a primary compliance mechanism. The team structured the engagement to produce a plan that was actionable and relevant at every level of County operations — from individual building retrofits to fleet procurement to utility engagement.
Each phase of the REP was designed around five core strategic priorities: reducing building electricity consumption through energy efficiency and on-site generation; replacing fossil and nuclear electricity supply with renewable alternatives; advancing building electrification through heat pump water heaters, solar-source heat pumps, and renewable fuels; transitioning the County fleet to electric and renewable diesel options across vehicle classes; and ensuring that all strategy selection and implementation decisions were evaluated through an explicit equity framework.
Strategies across all phases were ranked using Net Present Value and the percentage of energy content that could be transitioned away from fossil fuels, ensuring that investment sequencing reflected both financial return and mission impact. All recommended actions were designed to align with existing County planning documents, including the Local Government Operations Climate Action Plan and the County's broader Strategic Plan.
47% reduction in greenhouse gas emissions by 2030
The REP's phased approach provides a concrete roadmap to cutting Durham County's greenhouse gas emissions nearly in half within the decade.
53% renewable energy use by 2030, 72% by 2050
The plan charts a trajectory from the County's current fossil-fuel-dependent baseline to majority renewable energy use by 2030, with continued acceleration toward the 100% long-term target.
Four-phase plan covering buildings, solar, fleet, and equity
The REP integrates onsite solar, building electrification, transportation decarbonization, and community solar into a single, sequenced implementation framework with a budgeted timeline through 2050.
Solutions Delivered
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Renewable Energy Plan Development
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Onsite Energy Technology Assessment
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Building Electrification Strategy
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Fleet Electrification and Transportation Decarbonization
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Renewable Energy Certificate (REC) Strategy & Procurement Guidance
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Solar Feasibility Assessment
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Load Forecasting and Energy Baseline Analysis
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Gap Analysis and Scenario Modeling
The Solution
The final Renewable Energy Plan was structured across four sequential phases.
Phase 1 established a verified 2019 energy baseline and long-range forecast across electricity, natural gas, gasoline, and diesel — providing the quantitative foundation for all subsequent gap analysis and investment prioritization.
Phase 2 produced a comprehensive, annotated inventory of high-impact strategies evaluated across feasibility, financial performance, health benefits, and equity, surfacing both near-term opportunities and structural barriers for County leadership.
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Phase 3 developed two buildout scenarios — Phased and Accelerated — with rooftop solar investments aligned to planned roof and HVAC replacement cycles to minimize incremental capital outlay. Duke Energy's projected renewable supply was incorporated into both scenarios, with explicit adjustment guidance if utility projections fell short.
Phase 4 then delivered a full implementation timeline and budget through 2050, with built-in trigger points for reassessing emerging technologies including biogas, biofuels, and battery storage.
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To support ongoing decision-making beyond plan delivery, Optony deployed the Climate & Energy Scenario Analysis (CESA) Tool, enabling County staff to independently model strategy trade-offs, visualize pathways to their energy goals, and adapt the plan as market conditions evolve.
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A four-phase Renewable Energy Plan providing a concrete roadmap to 80% renewable energy by 2030 and 100% by 2050.
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Projected 47% reduction in greenhouse gas emissions by 2030, rising to 72% by 2050 under the phased implementation scenario.
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Deployed the CESA Tool to give County staff an ongoing, independent capacity to model scenario trade-offs, evaluate emerging technologies, and adapt the plan as market conditions and utility projections evolve.
Results & Impact
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