Bureau of Land Management Solar Energy Program Western Solar Plan
PDFROD  ||  Subscribe  |  News  |  Calendar  |  Glossary  |  Related Links

Establish Technical and Economic Suitability Criteria

The BLM will consider technological advances in solar energy generation systems, the location of energy load centers, existing and planned transmission lines, energy demand, and changes in economic suitability as part of the process to identify new or expanded SEZs.

In addition to considering the demand for solar energy across a State or region, BLM's process for identifying new or expanded SEZs will take into account technological advances in solar energy generation systems and/or transmission infrastructure, energy load centers and associated flow, existing and planned transmission lines, and any known constraints to development. These additional factors will influence the decision regarding which general region will be chosen for new or expanded SEZs.

A number of factors determine the technical and economic suitability of an area for utility-scale solar energy development, including the quality of the solar resource, terrain, and proximity to existing load and infrastructure. These factors may vary by State and/or region and will continue to evolve over time. As part of its SEZ identification process, the BLM will work with outside experts, industry, transmission planning organizations, State and local agencies, and other stakeholders to establish and apply appropriate technical and economic suitability criteria.

Size Threshold

An SEZ should generally encompass an area large enough to accommodate multiple utility-scale solar energy projects, provide flexibility for siting, and provide opportunities for shared infrastructure. SEZs on public lands should also be large enough to generate ample quantities of solar-generated power to justify the effort and expense required to determine whether the area is well suited for solar energy development. Smaller areas of BLM-administered lands located adjacent to private, State, or other Federal lands that are suitable for solar energy development may, however, be appropriate for consideration as SEZs if they can be used in conjunction with adjacent areas.

Solar Insolation

Solar insolation levels in areas identified for new or expanded SEZs will typically be high, thus allowing for optimum power production. Higher insolation values provide significant benefits for solar generation facilities. Under BLM's Solar Energy Program, areas with direct normal solar insolation levels less that 6.5 kWh/m2/day would not be available for individual applications without an approved land use plan amendment (i.e., they would be excluded). However, in view of expected technological advances, shifting market conditions, and evolving State and Federal policies, the BLM may consider the identification of new SEZs in areas with insolation levels lower than 6.5 kWh/m2/day. Providing this type of flexibility for SEZs is consistent with the policy objective identified in the Record of Decision (ROD) of working with industry and other stakeholders to identify additional SEZs in which there is a combination of industry interest and reduced conflicts.

Different types of insolation are most relevant to the different large-scale solar generating technologies. For concentrating solar technologies, direct normal insolation is most pertinent, while for photovoltaic (PV) systems, global tilt insolation is the appropriate measure of the solar resource. As part of the process to identify new or expanded SEZs, the BLM may consider both direct normal insolation and global tilt insolation depending on the technologies being contemplated for a given SEZ.

Slope Threshold

Most solar generating technologies must be sited on relatively flat ground to ensure that the solar collectors can utilize the solar resource effectively. Depending on the technology, the required slope can range from less than 2% to more than 5%, although lower slopes are generally better for siting solar energy generation. Under BLM’s Solar Energy Program, areas with slopes greater than 5% would not be available for individual applications (i.e., they would be excluded). However, as part of the process to identify new or expanded SEZs, flexibility in applying the slope criterion may be appropriate, particularly for PV or dish engine technologies that are more adaptable to land with steeper slopes. In considering new or expanded SEZs, areas with higher slopes should be otherwise well suited for development. It is unlikely that lands with slopes of greater than 10% would be technically viable for utility-scale solar production.

Load Areas To Be Served

When considering the appropriate locations for new or expanded SEZs, the BLM will consider the load areas likely to be served by new solar generation. The BLM will rely on outside expert consultation regarding electricity demands, markets, and renewable energy policies (e.g., DOE, State energy offices).

The BLM will also consider relevant Federal and State policy goals and trends, such as possible retirement of generating facilities and/or State Renewable Portfolio Standard (RPS) policy (or policies). For example, the RPS in a given State may have been met, and new solar energy development would be expected to serve demand in another State. The location for new SEZs would therefore have to consider existing or proposed transmission lines and capacity available to move new generation to load out of state. Consideration would also have to be made for the importing State's RPS policy (or policies).

Infrastructure Access

As part of the identification of new or expanded SEZs, the BLM will consider proximity to existing infrastructure, such as transmission lines, utility corridors, roads, and a suitable workforce. Where SEZs can be located close to existing infrastructure, environmental disturbance may be minimized through the use of the existing facilities (in some cases, however, transmission lines may be sited in environmentally sensitive areas that are not suitable for locating SEZs). The use of existing infrastructure may also reduce construction and mitigation costs, making locations close to existing and useable infrastructure attractive to developers.

Transmission Systems

New or expanded SEZs should be located in areas sufficiently close to load centers or in areas where transmission can be reasonably expected to be available in time to serve the quantity of generation planned. The BLM will consult with State and regional transmission planning and coordination authorities, State energy offices, and transmission system operators to evaluate available capacity on existing and proposed lines and to discuss other potential transmission-related barriers.

In considering potential locations for new or expanded SEZs, the BLM should catalog all existing and proposed transmission lines serving an area in relation to the power generation potential from a proposed SEZ. Consideration should also be given to foreseeable changes in load, such as retirement of generating facilities. Where new transmission lines are needed, they should be planned to utilize existing rights-of way (ROWs) or designated utility corridors to the extent practicable.

In considering potential locations for new or expanded SEZs, the BLM should catalog all existing and proposed transmission lines serving an area in relation to the power generation potential from a proposed SEZ. Consideration should also be given to foreseeable changes in load, such as retirement of generating facilities. Where new transmission lines are needed, they should be planned to utilize existing rights-of way (ROWs) or designated utility corridors to the extent practicable.

Roads

The ability to utilize existing paved roads for access to SEZs can also reduce impacts associated with development; therefore, SEZs should be located adjacent to major paved roads where possible. For potential SEZs where existing paved roads are located some distance away, existing dirt roads should be upgraded for site access to the greatest extent possible in order to minimize land disturbance. Finally, the proximity of the SEZ to a potential workforce should be considered to promote sustained workforce success in the SEZ region.

Updated: 7/24/2013