Screening is typically performed by an outside party or an independent renewable energy expert or team. It is a review of the possible technology options that identifies dead-ends and further narrows the list to probable technologies for the project. A screening provides a preliminary assessment of how much energy could be produced by various renewable energy technologies and conducts a high-level analysis of expected costs and savings, utility considerations, and potential incentives.
Federal agencies can analyze specific sites or conduct an agency-wide screening across properties to decide which areas have the greatest renewable energy potential. When conducted in conjunction with a new construction project or major renovation, an agency should get results from a screening prior to the planning charrette in the programming phase, as the information is vital to early design decisions and energy performance goals. Screening results are also very useful in creating early budget requests that adequately capture the capital costs needed for integrated renewable energy projects.
In a construction project, the designated project energy lead should take responsibility for the screening. This may involve hiring an outside renewable energy firm or assembling a team that has familiarity with each type of renewable energy resource under consideration. The team also needs expertise in resource assessment for each technology, economic evaluation of projects, and policies governing use and size, such as interconnection, net metering, incentives, and project funding mechanisms. Although a screening will add additional costs at the start of a project, it can save time and money in identifying cost-effective options and potential barriers for renewable energy integration. The agency should stipulate specific expertise with each technology identified for consideration during preliminary screening.
Background Project Information
Any information known about the project at this early stage should be provided to the screening team as it may affect the potential for various technologies.
Project location is one important factor. If more than one location is under consideration, the screening may be able to provide a comparison of energy potential. Project type and use are also important as the energy screening for an off-grid visitor's center will look very different than one for a 200,000 square-foot office park. The agency should consider project goals or early limitations on siting or use, as well as specific energy requirements, such as a need for on-site back-up generation.
This background information will be used to generate ballpark estimates of energy use and needs, which will help the team understand the type and scale of technologies to be included in the screening.
Assessing Renewable Energy Resources
The first phase of the screening process is to review the potential renewable energy resources available to the site of the construction project and determine which technologies have viable resources to warrant further evaluation. The resource maps used in the preliminary screening will not be enough for this phase of assessment. Experienced providers will be able to access a variety of data to determine estimated renewable energy production at the site. The screening team will use specific resource assessment tools, such as PVWatts, RETScreen, or data from wind resource models, to get better details on specific production estimates from proposed renewable energy projects. Further information on resource assessment for each technology is available in the renewable energy technology resource pages.
For technologies with enough resource to be a viable option, the team may look at detailed resource data on a daily or even hourly basis to develop specific energy production estimates and to assess their fit with the potential energy needs in the building.
Economics of Renewable Energy Systems
Once developed, the production estimates can be used to conduct an economic evaluation of each technology. A number of issues factor into the economic viability of a renewable energy system, but the primary factors to be looked at in screening are:
- Renewable Energy Costs
- Existing Energy Costs
- Policies for Electricity Systems
It is important to note that the screening only provides a preliminary look at these issues. The actual design and needs of the building are still pending at this stage, and the screening team is only working with generic technology equipment assumptions. Still, this information can be used to understand options and inform early budgets and life-cycle cost analysis.
Renewable Energy Costs
The cost of renewable energy technologies is central to the economic equation for any renewable energy system. Equipment costs alone vary by type of technology, size of system, location, and design. Any renewable energy screening should include early cost estimates, even if they are based on system cost averages or a generic designs. The screening should estimate both costs and production estimates for the same type of system.
Renewable energy technology costs need to include not only the initial cost for equipment and installation, but also operations and maintenance costs and cost of replacing components over the useful system life. For example, an inverter may need to be replaced once or twice during the useful life of a photovoltaic system.
Because early cost estimates are critical to both early planning and budgeting, this guide outlines how to compile life-cycle cost estimates for renewable energy systems. Details are available on the estimating renewable energy costs page.
Existing Energy Costs
To fully understand the economics of any renewable energy system, Federal agencies need cost information for the energy that the renewable energy system will offset. The screening should provide reasonable estimates of the current energy costs. Whereas the price of most renewable energy systems are fixed once they are installed, existing energy costs will vary based on fuel costs and other factors, and they will almost certainly increase over the project life. For ease in using this information in life-cycle cost analysis, the agency should ask the screening team to use projected increases in line with those designated under life-cycle costs analysis regulations.
If the project will be connected to utility services for gas and/or electricity, the first step is to check utility websites for initial rate information to inform cost estimates. Because these rates are often complex, the screening team should include an expert able to decipher the details of local utility tariffs and other information to provide offset energy cost estimates at the utility-level for the expected customer class over the life of the project. In some cases, optional tariffs, such as time-of-use rates, net metering, and other economic incentive rates, need to be assessed to determine the best options for potential renewable energy projects.
If the project is located away from utility services, then the economics are different. Cost estimates can be informed by comparable traditional off-site energy sources such as diesel generators or propane tanks. In these cases, economics should include not only the cost of the equipment, but other factors such as on-site noise and pollution as well as the risks and costs associated with stocking and replenishing on-site fuel sources.
Financial incentives offered by Federal and state governments, local utilities, municipalities, and private organizations have a great effect on renewable energy project economics and should be considered even at this early screening stage. Potential incentives could include rebates, loans, tax incentives, grants, bond programs, green building incentives, leasing/lease purchase programs, and performance-based incentives. The Database for State Incentives for Renewables and Efficiency (DSIRE) lists available incentives by state and location.
Economic evaluation of technologies needs to account for the nature of the incentives. Incentives come in a wide variety of types and have a variety of limitations on accessing them. Incentives can be:
- Automatic if the project meets certain criteria
- Restricted to certain size/types of systems
- First-come, first-served for a limited pool of funds
- Competitive in rounds of funding
- Restricted to certain users or owner types (such as rural projects).
In addition, Federal agencies or other public entities cannot directly access tax-related incentives, such as tax credits. Using a different ownership structure for renewable energy project funding could allow an agency to benefit from these tax incentives. A screening should address these options if it has a significant impact on the viability of particular technologies.
Policies for Electricity Systems
A number of key energy policies affect the use of renewable electricity systems at the facility site. The availability and terms of these policies, which vary by state and even utility service territory, can make a major difference in whether certain renewable energy technologies are economic or even viable. These policies include interconnection standards, net metering, time-of-use rates and feed-in tariffs. Detailed information on these policies is available in the key policies for renewable electricity use page.