• Home
• Introduction
• Assessing Renewable Energy Options
  • Preliminary Screening
  • Screening
  • Agency-Wide Screening
  • Feasibility Study
  • Policies for Renewable Electricity Use
• Planning, Programming, & Budgeting
• Project Funding
• Building Design
• Project Construction
• Commissioning
• Operations & Maintenance
• Major Renovations
• Training
• Outreach
• Resources
• Acknowledgements
• Contacts

Renewable Energy Feasibility Study

After a Federal agency has identified probable technologies through the screening process, a detailed review of the feasibility and economic viability of each renewable energy technology, also called a renewable energy feasibility study, can determine which combination of renewable energy technologies most effectively meet the energy requirements and goals.

When integrating renewable energy into a new construction project or major renovation, this level of renewable energy assessment will typically be commissioned by the design team and should be completed during to the schematic design phase. While a screening looks at the viability of each type of renewable energy, a feasibility study gets into details used to choose technologies and options within a technology type, such as the scale of wind turbine or the type of solar thermal systems to best reach project goals.

The feasibility study takes a deeper look into the remaining technologies to:

• Quantify how much energy each technology could produce or offset, and the value of that energy
• Review details of utility interconnection, tariffs, and revenue
• Analyze access to financial incentives as well as project funding models
• Review National Environmental Policy Act (NEPA) and permitting requirements and operational costs
• Assess economic feasibility with a detailed and credible life-cycle cost analysis according to Federal procedures.

Renewable energy feasibility studies provide technology and financing recommendations an agency or site should pursue. Ultimately, the feasibility study needs to provide enough information for the agency and the design team to make informed decisions about the types of technologies to include in the final project design.

The feasibility study should be performed by an outside party or an independent renewable energy expert. This can be the architecture and engineering (A&E) firm, but it is unlikely that the A&E firm would have the appropriate level of expertise to conduct this type of study. More likely, the A&E firm would hire this out to an objective consultant or team with detailed knowledge of the renewable energy systems under consideration, including technical and design issues, resource assessment, relevant policies and incentives, utility tariffs and interconnections issues, NEPA evaluations, and project funding mechanisms. The entity conducting the study should not be a manufacturer, installer, or organization affiliated with any product or technology under consideration in the project. The project energy lead should be involved in assuring that the feasibility team has the appropriate expertise. In some cases, the agency may arrange to contract these services directly, but the feasibility team must coordinate closely with the A&E firm since feasibility results directly affect design choices.

All renewable energy technologies depend on adequate access to renewable resources to perform optimally. More details are available at this stage on the overall project siting and orientation, so the effect on renewable energy can be assessed in more detail. At the feasibility study stage, it is important to consider not only the types of technologies, but also the specific opportunities for system location and orientation. At this stage, the agency should look at what specifics are needed for optimal production from the renewable energy systems planned for the site.

A Deeper Look at Screening Issues

The screening, which may be performed by the same group or a different independent renewable energy expert or team, reviews possible technology options and narrowed the list of technologies to probable technologies for the project. The screening also looks at the available resources, potential constraints and risks, expected cost savings, and utility incentives available. The screening is used to inform design requirements, but the feasibility study needs to get to a level of detail to inform the final selection of technologies to meet actual requirements in the most cost-effective manner.

The feasibility study will likely revisit a number of issues looked at during screening, such as resource assessment, technology costs and offset energy savings, interconnection and other policy issues, and available incentives. The feasibility study needs to provide much more precise information based on project and facility specifics and actual technology options. Rather than using estimated offset energy costs, for example, the feasibility study needs to model the full details of the facility's expected energy tariffs and offset energy savings based on net-metering or other revenue streams. These details can be critical to choosing the correct types and sizes of technologies.

Options within Technology

After the renewable energy technologies to be included in a project have been determined, it is time to start considering the types, manufacturers, and sizes of systems needed to accomplish the design criteria. Using photovoltaics as an example, fewer modules made of a higher-efficiency cells (such as single crystalline) would be needed for approximately the same power output as more modules made of a lower-efficiency cell (such as thin film). If a project location is space-constrained, a higher-efficiency and potentially higher-cost module may make the most sense. However, if a project has an abundance of space, a lower-efficiency and less costly module may be most practical.

NEPA, Permitting, and Zoning Issues

In addition to costs and savings from potential renewable energy technologies, the feasibility study should assess the issues and concerns associated with each technology as it relates to compliance with NEPA and all local, state, and Federal zoning and permitting issues.

Many technologies will not have any issues at all, but certain technologies can trigger a number of reviews. For example, wind turbines of a certain height must be cleared by the Federal Aviation Administration to ensure they do not interfere with airport flight patterns. This is not an issue in most cases, but it can prevent the economic use of wind power in certain circumstances.

If a technology is likely to add to the NEPA compliance of the building, that needs to be identified at this stage. This may require including certain renewable energy technologies in public meetings about the building or require working with state, local, or other Federal agencies on review. This also may be a factor in the selection of technologies for the project.