Social and environmental as well as engineering and cost factors must be evaluated. Computers can do that, and generate “site banks” as well
James A. Cleveland Richard B. Grover Joseph L. Petrillo Stone & Webster Engineering Corporation Boston, Mass. 02107 Elisabeth Ladd Energy Facilities Siting Council Commonwealth of Massachusetts Boston, Mass. 02108
I n the past few years, greater attention has been given to environmental considerations, especially during the early planning stages of a new facility. This attention has generally centered around requisite approvals from various federal, state, and local agencies to construct and operate a new facility. Potential owners of major industrial facilities are becoming increasingly reluctant to expend significant amounts of time and money for engineering and design, a t least until major approvals are granted. On the other hand, regulatory bodies require detailed definition of project plans prior to granting these approvals. Indeed, in some cases, regulatory agencies become involved in the actual siting methodology. The Nuclear Regulatory Commission, for example, places major emphasis on site selection methods. There have been instances, in recent years, in which utility and industrial owners have had to cope with significant delays in obtaining construction Feature articles in ES&T hace bj,-lines, represent the ciews o f t h e aurhors, and are ediled b j ’ the Washingron stafJ I f y o u are interested in contributing an article, contact the nianaging editor. 792
Environmental Science & Technology
approvals for new projects from federal and state regulatory agencies. In fact, the delays are becoming so lengthy, and the issues so complex, that owners have either deferred, or entirely cancelled major energy and industrial projects. Most of these issues are site-related, and the questions they invariably raise center around, “Why put the facility here?” Some examples of site selection issues and, in particular, the review of alternate sites which caused significant delays are the Seabrook Nuclear Power Plant in Seabrook, New Hampshire, the Point Conception LNG Terminal in California, and the Hampton Roads Energy Center in Portsmouth, Virginia.
Analysis of alternatives It has been estimated, for example, that over 70% of the delays in the nuclear power plant licensing process are directly attributable to siting issues. This situation is not expected to differ markedly for new fossil-fueled electric utility, or industrial projects, particularly in view of the recently enacted amendments to the Clean Air Act. One can appreciate the problems encountered during the adversary hearing process vis-a-vis siting issues, particularly for those projects which initiated the regulatory approval process only a few years ago. I f one considers the cumulative effect of increased federal and state environmental regulation over the past decade, it appears as though new laws are being enacted almost in an exponential fashion. Answering “what if” and “why didn’t you” questions becomes quite difficult in those instances, particularly if engineering judgments regarding siting issues, and consideration of associated environmental impacts were made several years earlier. This
is not to say that those decisions were not valid; however, providing the proper documentation for them may be difficult. The impetus behind a comprehensive and documented site selection study on the federal level is the N a tional Environmental Policy Act (NEPA). Simply stated, N E P A requires careful evaluations of alternatives to the proposed project (including no action), which are to be addressed as part of the Environmental Impact Statement (EIS). The EIS, prepared by the lead federal agency, and based on the applicant’s environmental assessment, is a N E P A requisite to the issuance of federal permits, since the issuance of federal permits for new utility or industrial facilities will constitute a “major federal action” pursuant to NEPA. Recently enacted Council on Environmental Quality regulations on EIS procedures, which call the analysis of alternatives “the heart of EIS,” clearly indicate the importance that an EIS will play in future decisions regarding siting alter na t ives. In addition to federal EIS requirements, many states have over the past few years instituted state siting laws, state environmental policy acts (fashioned after NEPA), or both. They generally follow federal requirements for a detailed evaluation of alternatives. To satisfy the aforementioned concerns, prospective owners of new energy and industrial facilities will likely have to delineate and document all decisions relative to siting new facilities within the framework of a formalized and structured site selection study. This study will become an integral part of the regulatory approval process, and therefore must be able to withstand the
0013-936X/79/0913-0792$01.00/1 @ 1979 American Chemical Society
rigors of public scrutiny during hearings before federal, state, and local regulatory bodies.
The site selection process Site selection studies for energy and industrial facilities are generally conducted in several phases. During each phase, the areal extent of study is reduced by identifying issues, developing criteria appropriate to the scale of analysis, and applying criteria in a structured format. A record of this process provides the documentation necessary for regulatory review of the selection of a site, or sites, from within the region of interest. The three-phase site selection process described in this article is similar, i n principle, to that discussed by others. A flow diagram for these three phases is shown in Figure 1 . During Phase 1, exclusionary criteria are applied to the region of interest, in order to eliminate large areas not meeting basic environmental, engineering, or regulatory requirements. Land area's with no exclusions become candidate areas for study in Phase 2. I n Phase 2 , candidate areas are evaluated, and potential sites are identified. Areal criteria are developed, and used to compare land within candidate areas, with regard to engineering suitability and environmental constraint. Potential sites are identified from those areas of maximum suitability and least constraint, which have sufficient area to accommodate the facility. I t is possible to identify 50300 potential sites which must be ranked, to designate approximately 10 candidate sites for consideration in Phase 3. During Phase 3, site-specific layouts are prepared. and conceptual engineering analyses and environmental assessments are conducted for the candidate sites. The results of engineering analyses can be quantified (site-related cost), while the environmental assessment is more qualitative in nature. Linear summation models (rating/weighting summation) can be used to develop an environmental score for each site. Siting issues Since the rating/weighting process involves opinion, and consequently some uncertaint), with respect to the relative importance of siting issues, sensitivity analyses are usually performed. By altering the weights of siting issues, sensitivity is calculated to determine the potential effect of the uncertainty on site ranking. Preferred sites a r e selected by comparing environmental scores, site
FIGURE 1
Site selection process
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scribed may be necessary. However, there is a significant problem with the site banking concept. That is, that during the intervening time between site identification and facility licensing, there are often changes that invalidate the original site identification and ranking, as shown in Figure 2.
FIGURE 2
What if?
Data changes
Public opinion changes
Regulatoq controls change
Economic conditions change
Demand changes
costs, and other issues (land acquisition, institutional, legal, and political issues), in a structured fashion. Two sites are evaluated with the most favorable site being carried forward for comparison with a third site. This iterative process is continued until all candidate sites have been evaluated and the most suitable site remains. Issues which are addressed in each phase of the site selection process include engineering, economic, social, and environmental concerns. Table 1 identifies typical siting issues from which criteria are developed.
Decisionmaking As a first step in each phase, siting issues are identified, and criteria are developed which apply to the type of facility under study. The level of detail of the analysis and the number of criteria addressed increase as the size of the study area decreases. Each study, while following a similar site selection process, is tailored to meet specific facilitv reauirements. Local. state. and federal regulations, proximity to’ raw materials, utility requirements, market considerations, waste disposal requirements, and other considerations are incorporated into the criteria, as needed. Group decisionmaking techniques, such as the Delphi and Nominal Group Processes, are often used to identify, document, and determine the relative importance of issues and criteria. Also, these techniques allow in794
Environmental Science 8 Technology
Engineering requirements change
corporation of diverse group opinions, including those of technical and scientific experts, clients, regulators, and public-interest groups. The product of this three-phase siting procedure is a site bank, with sites ranked by engineering and environmental suitability. The concept of site banking is that the entire siting process need not be repeated for each facility proposed. A siting study for a given type of facility usually leads to the identification of potential sites, which form a site bank. Successive facilities with similar siting requirements can use sites from this site bank; only Phase 3 of the siting process previously de-
TABLE 1
Siting issues Englneerlng/ economlc
Social/environrnental
Raw materials Terrestrial ecology Site development Aquatic ecology Product markets Foundations Land cost/ availability Waste disposal Seismic design Flood protection Emission control Transportation Labor Transmission
Water quality Socioeconomics Noise Air quality Hydrology Land use Demography Aesthetics Safety considerations Meteorology
Spatial analysis Two available methods for identifying sites in a documentable and defensible process are graphic overlay and computer techniques. These are similar in their approach, in that they both apply criteria in an areal or spatial analysis to identify potential sites. The graphic overlay technique is an effective way to document the process of selecting candidate areas within a large region of interest, and can also be effective in identifying sites during a typical Phase 2 analysis. The technique entails the mapping of individual criteria on separate sheets. For example, during a typical Phase 1 analysis, areas with incompatible land uses, such as national parks, wildlife refuges, or active military installations are excluded from further consideration by mapping their locations on clear overlays. Overlays for each of the criteria a r e registered, and visually composited. Areas on the map that do not have exclusions become candidate areas. The criteria and maps become a part of the documentation. During Phase 2, a similar procedure, which identifies levels of suitability for criteria, i s used to identify sites. Comparison criteria are used to identify areas of engineering suitability or areas of environmental constraint. Transparent overlays are again composited to identify the most promising locations at which to site the facility. The overlay technique is limited, in that approximately three levels of suitability can be portrayed on a single overlay, and only six to eight overlays can be composited at a given time. As the area to be evaluated, or the number of criteria, increases, the number of overlays which can be manipulated reaches a practical limit. Computer technique Computer techniques for storing and analyzing spatial data were first developed during the 1960’s. Many different systems have evolved. However, there are two basic types: those with gridded or cellular data structure and those using polygon data structure. Polygon data storage records the
boundaries of data, which provides more spatial accuracy, while ceullar data facilitate data manipulation for analysis purposes. Some hybrid systems use polygons for data storage, but can convert to a cellular structure for analysis. Computer systems have been applied to siting problems with varying degrees of success. Early applications often consumed considerable effort in development of capabilities, thus providing poor cost-effectiveness. Others suffered, not because of a fault of the system, but rather because of inadequate data, or the method used in structuring the analyses. Computer analyses can offer significantly more flexibility and precision than can overlays, in the manner in which criteria are modeled. Modeling refers to the manipulation of data, in response to the siting criteria. However, a sophisticated computer system can provide no better results than the criteria and data used as inputs. I n most siting studies, Phase 1 can be more easily performed by use of overlay, rather than computer techniques. Subsequently, a candidate area becomes the unit for computerized analysis. A reference grid is established for the candidate area. Figure 3 shows the base map of the candidate area with a reference grid superimposed. Data for the area, which are pertinent to siting (such as topography, soils, geology, land use, surface water, and utilities) are collected and stored in computer files. A variety of computer manipulations can be performed on data, to meet the analytic requirements for siting issues. Engineering, environmental, and social models are constructed to combine and transform data to estimate site suitability, with respect to relevant issues. The results of the individual models can be displayed independently on computer maps, and also can be combined to produce a summary of suitability. The sensitivity of the summary can be determined by recombination of the components, reflecting an expected range of variability of importance weights (Le., weighted according to importance) among models. From the analyses of the candidate area, sites can be identified and rated according to the issues modeled. The best sites then receive further study in Phase 3 to confirm and refine the site ranking; this ranking leads to the selection of a preferred site or sites. The primary advantage of using the computer in a siting study is the ease of analysis and reanalysis, as dictated by regulatory or other changes. In addi-
tion, numerous considerations can be included in the decision process.
Siting example T o demonstrate the analysis required for site selection and site banking, several issues are addressed. It should be noted that criteria are developed in a similar fashion to that described in the methodology overview. Issues are first identified, and criteria are then developed in a documented decisionmaking procedure. For the purposes of this example, eight issues are modeled, as follows: Transmission Transportation Topography Water availability Hydrology Land use Ecology Visual T o illustrate how issues are modeled, transmission and ecology are discussed. First, transmission corridors are investigated to determine their suitability to provide for the needs of the proposed facility. A transmission corridor is found within the sample study area of approximately 300 mi2 (14 X 11 mi). Proximity zones are generated by the computer, around the transmission corridor (Figure 3). Better site suitability, based on transmission proximity, is shown by darker shades. The number of zones and the width of each are set by the criteria, and not fixed by the computer programs. In the model presented here, the effect of transmission is strictly a factor of distance. It may be more realistic to consider, also, the effect of the topography or other potential barriers on accessibility. It is within the capabilities of the computer system to incorporate these considerations. The ecology model Development of the ecology model requires more complex structuring of computer manipulations. For this example, the model focuses on terrestrial ecology. Two subissues are addressed: endangered species critical habitat, and wildlife habitat value. Endangered species critical habitat, as designated by the Fish and Wildlife Service, constitutes a legal prohibition. Wildlife habitat value is an attempt to identify the areas important to local wildlife patterns. Avoidance of these areas should minimize ecological impacts. Determination of wildlife habitat value is based on water, vegetative type, human activities, open/forest edges, and diversity. Spatial configuration of
features is assessed, and multiple factors are cornposited by superimposition, addition of value, and logical combination to produce the map shown in Figure 3. In order to select sites, the results of all models are summarized into a single representation of suitability. The models are weighted according to the relative importance of the issues, and then summarized in a weighted index. The relative importance of issues can easily be adjusted to reflect different points of view, or to test the sensitivity of the results to the weightings. The range of grays in Figure 3 represent levels of suitability, with darker areas being more suitable. Sites are identified from the summary of models. The size of the proposed facility determines the number of cells that constitute a site. In this example, the cell size is 10 acres; the minimum site size is 200 acres. Consequently, clusters of 20 or more cells of high suitability are identified as sites and shown in Figure 3. Sites can be ranked by level of suitability. The most favorable sites receive detailed site specific evaluation in a Phase 3 assessment, as discussed previously. The remaining sites are held in a site bank for future use. Periodic update of input data can be made, and models recalculated, to keep the site bank current.
Computers make things easier There have been instances in recent years in which utility and industrial owners have had to cope with significant delays in obtaining construction approvals for new projects from federal and state regulatory agencies, because of siting issues. As stated previously, recently enacted Council on Environmental Quality regulations on EIS procedures, which call the analysis of alternatives “the heart of the EIS,” clearly indicate the importance that future siting decisions will play in the timely issuance of these approvals. The two techniques discussed here, graphic overlay and computer, are both capable of making the spatial discrimination necessary, and of providing requisite documentation for site selection. Overlays are similar to traditional maps, and therefore are more easily understood by those unfamiliar with spatial analysis. However, overlays are physically cumbersome, and are difficult to replicate or update. Also, both the range of values on each map and the complexity of the analysis are limited by the practical constraints of the technique. Computer storage allows more Volume 13, Number 7, July 1979
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FIGURE 4
How a computer selects sites It looks over a candidate area
..
. . . displays ecological constraints . .
. . . outlines the transmission Droximitv . .
complex data that are easily updated. The analysis is more flexible, and provides the capability of a greater variety and complexity of data manipulation. A repeat of the analysis, with minor modification to the criteria, is both quick and easy. In addition to discrimination between land areas to identify sites, the computerized process provides a rating of the identified sites. Such a ranking is not always possible with overlays, and is usually achieved by the addition of a subsequent step. The use of the computer can provide a significant advantage to siting decisions. As digitized data becomes more readily available, and as the sophistication of the computer techniques continues to increase, the use of computerized analysis in site decisions will become increasingly prevalent.
Additional reading Hobbs, B. F., Voelker. A. H., Analytical Power Plant Siting Methodologies: A Theoretical Discussion and Survey of Current Practice, Oak Ridge, December 1976. Petrillo, J. L., Power Plant Siting-An
Overview of Economic, Environment, Social and Legal Issues, Engineering Foundation Conference, July 13, 1977. Ladd, E., Solar Power Plant Siting, AIP Annual Conference, September 27-30, 1978.
Graf-Webster, E., et al.. Methodologies for Power Plant Siting, Mitre Corporation, February 1975. Voelker, A. H., Power Plant Siting: An Application of the Nominal Group Process Technique, Oak Ridge Kational Laboratory, 1977.
James A. Clebeland (I) is an Encironmental Engineer in the Enrironniental Engineering Dicision of Stone & Webster Engineering Corporation ( S &W ) . He has recentlj, directed an extensice three-state site selection study f o r a major electric utility. Cleceland has engineering degrees f r o m Vanderbilt Unicersity and the Unirersitj, of Maine. Richard B. Grover (r) is an Encironrnental Planner in the Encironmental Engineering Dicision of S & W . While at S & W he has applied computer techniques to the problem of energylindustrial facility siting. Grocer is a graduate of the Harcard Graduate School of Design where he assisted in the decelopment of IMGKID, a package of computer programs f o r the purpose of storing, analyzing, and displaj’ing land-resource information.
. . . and shows the final sites
Joseph L. Petrillo (I) is an Assistant Chief Engineer in the Environmental Engineering Division of S & W . H e has ocerall responsibilitj’f o r site selection acticities. He presented a paper on the subject at the Engineering Foundation Conference on Nonconcentional Power Plant Siting in July 1977, and has discussed the subject at carious meetings and forums, including the American Bar Association National Institute meeting in September 1978 on Industrial Regulation and Energy Choices. Petrillo holds engineering degrees f r o m Tufts Unicersity. Elisabeth Ladd (r) has recently been appointed Director of the Energj, Facilities Siting Council f o r the Commonwealth of Massachusetts. Prior to this appointment Ladd was the Supercisor of Socioeconomics and Land Planning at Stone & Webster. While at S & W s h e acted as a site selection specialist, responsible f o r the application of siting techniques f o r a major three-state site selection study. S h e attended the Harcard Grauate School of Design and authored “Solar Power Plant Siting,” presented at the American Institute of Planners’ 61st Annual Conference.
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