Energy and land use

Energy and land use An instrument of US conservation policy? D a l e L K e y e s The past two years have witnessed a groundswell of interest in energy conservation issues and a number of studies on the relative merits of various conservation options Two studies in particular have detailed the expected benefits and to a lesser extent the costs of selected conservation strategies available to federal, state, and local governments in the USA? These strategies range from fuel price deregulation to various types of mandated conservation measures Partly because these studies did not investigate the entire set of available options and partly because none of the strategies is completely painless, attention has increasingly focused on avenues to energy conservation yet unexplored Among these is 'land use', its popularity due in no small part to its imprecise definition Land use means so many different things to so many people that few can deny its potential for affecting some aspect of the way energy is used This interest in reducing energy consumption by altering land use patterns is evidenced by a spate of articles appearing in the popular press and various non-technical journals} Compact, well planned communities The author is Research Associate are more energy efficient, it is argued, and governments should with the Urban Institute, 0 M St encourage - if not require - urban growth which is consonant with NW, Washington DC, USA sound planning principles But before we embrace land use controls Ford Foundation Energy Policy Project, as a primary device to throttle the flow of energy in urban areas, or A Time to Chose: America's Energy even as a useful supplement to other conservation strategies, we Future, Ballinger Publishing Co, Cam- should examine the magnitude of suspected energy savings associated bridge, Massachusetts, 1974; Federal with various land use patterns and the costs or difficulties involved in Energy Administration, Project Independence Report, Washington, DC, manipulating these patterns) Energy consumption in society is a function, among other things, of its spatial distribution The author describes studies of energy usage in metropolitan areas of the USA, simulation studies of alternative building types and the potential for energy conservation Rearranging the urban housing pattern into more compact high-rise patterns could lead to significant savings in domestic and transport energy consumption Some policy of encouraging more energy conserving urban structures might be beneficial but caution is needed in case the detrimental side-effects outweigh the benefits US Government Printing Office, November 1974 z See, for example, Anthony Downs, 'Squeezing Spread City', New York Times, March 17, 1974; pp 38-47; Herbert M Franklin, 'Will the New Consciousnessof Energy and Environment Create an Imploding Metropolis?' A m e r i c a n Institute of Architects Journal, August 1974, pp 28-36 3In recognition of this need the US government is sponsoring research on land use-energy linkages, some of which is being undertaken by the Urban Institute However, we need not wait for this work to bear fruit in order to take stock of what is currently known U r b a n spatial structure The overall relationship between patterns of land use and energy consumption (holding constant the influence of climate, population characteristics, intensity of industrialisation, end-use efflciencies and the like) derives from two intermediate relationships, one involving building types and the other travel behaviour It is more illuminating to speak of the spatial structure of urban areas rather than the pattern of land uses, for the energy used in any city is presumably a result of its three dimensional structure Theoretically, where densities are high, residential and commercial units are frequently smaller and often share common walls or are located in large structures, ENERGY POLICY September 1976 225 Energy and land use providing economies for space heating and cooling; where employment and commercial centres are located close to residential areas, travel will be reduced; and where development is located along transportation corridors and at sufficient density, people and goods can be transported by more energy efficient modes In order to measure the differences in energy use as a result of variations in urban spatial structure, a relatively detailed description of both energy consumption patterns and spatial structure is required for several urban areas which display significant structural differences Additional information on differences in energy use among different types of buildings can be used to make inferences about the heating/cooling effects of urban structure where direct data are unavailable Unfortunately, disaggregated data on energy use in urban areas is almost totally lacking, while description of the spatial structure found in various cities rests almost exclusively on population densities and density gradients Likewise, detailed empirical studies of energy consumption for individual buildings are not numerous Simulations of both hypothetical and real urban structures and building types must therefore be used to supplement and in some cases replace, empirical analyses of observed consumption and spatial structure or building characteristics ~To determine the magnitude of the effect on space heating, and cooling one needs only to characterise spatial structure in terms of population densities or, more precisely, the mix of building types But in order to specify the quantitative relationship between urban spatial structure and transportation energy use, one must be able to characterise development patterns along several dimensions - the relatige location of activity centres, the nature of the transport system, and the geography of the population density function In addition, the degree of local integration of different land uses and the travel consequences must be separated from the impact of region-wide land use integration That is, the impact of a high degree of metropolitan-wide segregation created by regional shopping c e n t r e s few in number but large in size - may be obviated by the presence of small commercial establishments in close proximity to many residential areas Regional Plan Association Inc and Resources for the Future, Regional Energy Consumption, Regional Plan Association, RPA Bulletin 121, January 1974 Space heating and cooling efficiencies associated with high densities should theoretically apply to the industrial and commercial sectors as well as to the residential sector However, consumption data is typically available only for total energy use rather than just for space conditioning Since energy used for purposes other than heating and cooling is of greater importance in the commercial and especially in the industrial sectors, the discussion here is limited to residential energy use (Space heating and cooling represents approximately % of the total energy used in homes) 226 Energy studies Perhaps the most detailed study of metropolitan energy use in the USA has been conducted for the New York City region, where energy use for each of the region's 31 counties has been estimated by economic sector and by fuel type Urban spatial structure, however, is only represented by two variables - gross population density and the extent of the transit system As is shown in Table 1, the New York Metropolitan Area (which is composed of nine of the 31 counties in the region) has the highest area-wide and central city population densities and the most extensive transit service Of the five most populous metropolitan areas (and in fact of any area) in the USA One might therefore expect that the energy consumed in both the transportation and residentiaP sectors would be lower for New York than for any other area or for the country as a whole, once climate and other factors are accounted for Table shows that the Table Population and transit characteristics of the five largest US metropolitan areas (1970 and 1972 data respectively) SMSA a New York Los Angeles/ Long Beach Chicago Philadelphia Destroit SMSA population (x 106) SMSA population density (people p~r milex 10 ) Central city b Vehicle miles Vehicle miles of population of transit transit operated density operated per year per (people per year capita (Miles per sq (miles per person ) milex 103 ) x 106) c 11.6 5.4 26-3 420 36 7.0 7.0 4.8 4.2 1.7 1.9 1.4 2.2 6.2 15.1 15.2 10.9 64 146 65 34 21 14 a Standard Metropolitan Statistical Area as defined by the US Office of Management and the Budget b The central city within the SMSA as defined by the US Office of Management and the Budget c Approximate figures Source: The population data are taken from US Bureau of the Census, US Census Population, 1970, Vol 1, Part A, 1970 The transit data came from American Transit Association, 1972 Transit Operating Report, ATA, no date ENERGY POLICY September 1976 Energy and land use Table Annual residential and transportation energy consumption in the New York City area and in the USA (in million BTU per person) Net per capita energy usea Residential Greater b N Y C area United States 57.5 46.9 Transportation 34.2 81.9 a Net energy use is the total quantities of coal, oil, gas, steam and electricity in BTU equivalents delivered to each section (Electricity is converted at the direct heat equivalent of Btus per kWh.) b This is approximately equivalent to the NYC SMSA Source: Joel Darmstadter, Conserving Energy, Prospects and Opportunities in the New York Region Baltimore: The Johns Hopkins Press, 1975, Table 1-1 Joel Darmstadter, op cit Note b, Table These are money rather than total personal income figures a Reported income elasticities for expenditures on electricity in the USA range from about to 0.7 Thus, a 1% increase in income would lead to a to 0.7% increase in expenditures Although these elasticities are based on total personal income (which is slightly larger than money income) and apply strictly to electricity only, the relatively low values imply that the unexpectedly high consumption levels in New York cannot be totally explained by an income argument For a discussion of income-expenditure elasticities, see Robert Halvorsen, 'Residential demand for electric energy', Review of Economics and Statistics, Vol 57, pp 12-18, (1975) Since gross residential density is a poor surrogate for building types, we have attempted to statistically relate the RPA data on average per capita, per unit and per square foot energy consumption in each county to the percentage of onefamily units and the percentage of buildings with or more units found in each county In this way, we were able to show that an increase in the percentage of one-family units does contribute to increased consumption, although per capita income, the price of the various fuels, and other factors appear to be much more important in determining consumption levels The results of this regression analysis are roughly comparable to those of the energy simulations undertaken by Hittman Associates, to be discussed subsequently That is, the largest structures seem to be most efficient on a per unit basis but not on a per capita basis I ° A comprehensive discussion can be found in Melvyn D Cheslow and Mary Lou Olsson, Transportation and Metropolitan Development, The Urban Institute, Working Paper No - , 1975 average energy used for transportation by a New York resident is indeed less than that used by persons residing elsewhere in the country However, the per capita residential consumption is 15% greater in the New York area than the average for the country as a whole This rather puzzling observation may be at least partially due to the relatively higher per capita income level found in the New York area ($3911 versus $3118 in 1969 dollars for the greater New York City area and the USA, respectively 7) However, this 26% increase in income level could not sufficiently offset the 15% increase in consumption to explain the difference between the observed and expected results Climate may be a more important factor but its impact cannot be assessed without additional information In order to gain further insight into the observed relationships between urban spatial structure and energy use in the New York region, intra-regional variations can be probed Again, descriptions of spatial structure are limited, this time exclusively to population density The reported results are essentially a reaffirmation of the previous findings: residential consumption expressed on either a per capita or per square foot basis is approximately the same for each county in the region (Density ranges from 53 persons per square mile in Sullivan County to almost 70 000 in Manhattan.) Intra-regional density-transportation energy linkages are somewhat less ambiguous Per capita transportation energy use decreases at an increasing rate up to about 0 0 persons per square mile, and then displays an increase as density increases still further These results could be partially due to the effects of congestion at very high population densities, but can also be attributed to the method of computation If employment or daytime county populations were used as the basis for computing per capita consumption, the reversal of the density-consumption relationship would be moderated if not eliminated The data on energy use in the New York City region thus provide suggestive evidence in support of the hypothesised transportation energy-spatial structure relationships and largely inconclusive evidence for the proposed residential energy-spatial structure relationship But the evidence is limited and subject to problems of data collection and analysis In addition, no information is provided on the effects or urban structure other than population density However, these preliminary attempts to probe the residential consumption data more thoroughly suggest that the use of data on building type rather than population density may provide more insights, and furthermore, that multi-family structures appear to be less thermally efficient than one-family units (See Reference 9) Although few researchers have investigated metropolitan energy consumption patterns directly, metropolitan transportation research is impressive, at least in volume if not in terms of consistent approaches and definitive findings? ° Travel behaviour in urban areas is typically characterised by the number of trips taken by individual residents, the travel mode used, and the length and speeds of those trips These characteristics are affected by a host of factors, many of which have little to with urban structure In fact, several studies have shown that household characteristics are much more important than structural features of urban areas H Unfortunately, not all studies have accounted for household characteristics when estimating the effects of spatial structure ENERGY POLICY September 1976 227 Energy and land use Although comparison of findings from the various transportation studies is inhibited by the lack of comensurate units of analysis, the following can be stated as general findings: l~Stowers and Kanwit, for example, observed that family size, income, and life cycle stage are more important than density of the neighbourhood or distance from the central business district in determining trip generation rates See J.P Stowers and E.C Kanwit, 'The use of behavioral surveys in forecasting transportation requirements', Highway Research Record, Highway Research Board, 1966, pp 44-51 ~2 See, for example, William Smith and Associates, Patterns of Car Ownership, Trip Generation, and Trip Sharing in UrbanizedAreas, prepared for the Bureau of Public Roads, US Department of Transportation; also Harold D Deutschman and Nathan L Jaschik, 'Income and related transportation and landuse planning implications', Highway Research Record, Highway Research Board, 1968, pp 52-65 ~3 See, for example, Wilbur Smith and Associates, op cit and Council on Municipal Performance, 'City performance', Municipal Performance Report, V o l l N o , , pp11-17 14See, for example, David M Branston, 'Urban traffic speeds- I: a comparison of proposed expressions relating journey speed to distance from town centre', Transportation Science, February 1974, pp 35-49 ~5 See Allan M Voorhees and Associate, Factors and Trends in Trip Lengths, NCHRP Report No 48, Highway Research Board, 1968; also Automobile Manufacturers Association, 1972 Automobile Facts and Figures, AMA, (no date) ~6 R.W Anderson, Residential Energy Consumption, Single Family Housing, Hittman Associates Inc, March 1973 and M Tokmanhekin and D.G Harvey, Residential Energy Consumption, Multifamily Housing Final Report, Hittman Associates Inc, June 1974 Residential t~ A.D Little Inc, and Commercial Energy Use Patterns, 197090, Project Independence, US Federal Energy Administration, November 1974 They used a relatively simple estimation method (known as the 'Degree-Day Method') developed by the American Society of Heating, Refrigeration, Air Conditioning and Ventilation 228 • As population density increases within urban areas, the number of non-pedestrian trips decreases This appears to be true for both generally high and generally low density urban areas 12 • As both population and employment density increases within urban areas, the percentage of trips taken by automobile decreases ]3 • As distance from the central business district increases in British cities (a surrogate for decreasing population density), the average speed of traffic at any point increases ~4 • Average metropolitan trip length has not been shown to vary consistently with average metropolitan population density, although some differences between central city and suburban lengths have been observed ~5 It is obvious that the existing empirical evidence does little more than whet the appetite Some findings (but not all) lend support to the hypothesised relationship between transportation energy use and urban spatial structure, but more is needed to substantiate it even in a qualitative sense Simulation studies o f alternative building types Several models have recently been developed to estimate the heating and cooling loads of various types of buildings They relate energy requirements to design and orientation factors, construction methods, construction and insulation materials and characteristics of the heating/cooling equipment One such study, on the energy requirements of protypical single and multi-family housing units found in the Baltimore, Maryland-Washington, DC area, concluded that sizable differences in energy requirements among these units are attributable to the type of structure within which the unit is housed.l~ The results appear in Table A general trend toward reduced energy loads with increased density of units is observed, due both to the inherent thermal efficiency gains and the smaller size of multi-family units On the basis of area the difference between single family detached units and units in highrise structures is about 20-30% Although these results apply, strictly speaking, only for the BaltimoreWashington region, the relative energy requirements among the various units should be applicable to most areas in the county since the climate in this region imposes both heating and cooling demands The Arthur D Little Organization has explicitly incorporated regional climatic variations in a similar study of residential energy consumption 17 They estimated a heating and cooling load differential between prototypical single family detached and high rise units of about 65% for a given area, averaged across all regions However, the error involved in both of these sets of estimates is largely unknown (although the Hittman analysis was more rigorous) and the values should be accepted as very rough approximations of ENERGY POLICY September 1976 Energy and land use Table Average annual energy requirements for heating and cooling prototypical housing units in the Baltimore-Washington area a In-structure energy consumption (Therms) Structure type Per unit Per square ft of floor area Per occupant Single-family detached Townhouse Low-rise High-rise 1000-1100 896 575 493 0.590-0.648 0.689 0.512 0.506 250 275 224 192 246 a The value for the single-family units are not entirely comparable with those for the multifamily units as type of construction and building materials were not completely standardised A range of values is indicated for the single-family unit with masonry walls as the prototype tested differed somewhat in insulation characteristics from the multifamily units Source: R.W Anderson, op cit and M Tokmahekin and D.G Harvey, op cit Reference 16 energy savings due to building type In order to judge better the validity of these studies, careful analyses of actual residential consumption patterns as a function of household and building characteristics (including type) is urgently needed Studies o f alternative urban structures 18 Jerry B Schneide and Joseph R Beck, Reducing the Travel Requirements of the American City: An Investigation of Alternative Urban Spatial Structures, Research Report No 73-1, Departments of Urban Planning and Civil Engineering, University of Washington, August 1973 19The authors found, for example, that by rearranging the location of most people and jobs in the area, a 66% reduction in total travel (total person-minutes for work trips) and a 87% reduction in the maximum link load or level of use on the most highly used highway could be achieved Another arrangement involving a rearrangement of 'only' a quarter of the total population and jobs would produce a 43% and a 63% reduction in these factors, respectively The results indicate that travel requirements can be minimised by locating most people and jobs at the least central node and by matching the number of people and jobs at each node However the optimal arrangements for Seattle would require extensive relocation of the existing population and employment base 20 Jerry L Edwards and Joseph L Between Schofer, Relationships Transportation Energy Consumption and Urban Structure: Results of Simulation Studies, Department of Civil Engineering, Northwestern University, January 1975 We now turn our attention to studies of alternative arrangements of urban areas These studies estimate either total travel from which transportation energy can be calculated or energy used for travel directly In the first study, undoubtably the most theoretical of those to be reviewed, Schneider and Beck have developed a procedure for searching through a very large number of possible spatial arrangements of jobs, residences, and transportation networks ~8 Using simple assumptions about travel behaviour (based primarily on the gravity model), those spatial arrangements are then selected which minimise total travel time or maximise other objectives In order to lend an air of realism to the undertaking, the urban area in and around Seattle, Washington, was characterised by a very simple network of transportation nodes (employment and residential centres) and links (highways) and the impact of redistributing population and employment among the nodes was estimated ~9 Methological restrictions severely limit the general application of their findings For example, only work trips made by automobile were considered, while the translation of total travel time and link loading factors into energy savings requires more specific information about vehicle speeds and flow rates But perhaps the most restricting characteristic of the analysis is the simplistic representation of urban structure Still, the results shed some light on the range of travel savings which may be achievable, ignoring for the moment real world constraints to urban development processes Another study compares the expected transportation energy savings from a more limited number of urban structural alternatives 2° However, each alternative is characterised in much more detail than in the Schneider and Beck study and those spatial structures which are used for test purposes are intended to be better approximations of feasible urban development patterns ENERGY POLICY September 1976 229 Energy and land use 21 More specifically, the elasticities of consumption with respect to the second m o m e n t s of both population and employment about a central point are considerably less than one zz Eric Hirst and John C Moyers, 'Efficiency of energy use in the United States', Science, Vol 179, 1973, pp 9 - 3 230 Examples of energy-intensive as well as energy-efficient spatial structures were created from three basic urban shapes (concentric ring, linear, and polynucleated) and several combinations thereof A spatial distribution pattern of basic employment was specified together with a transportation network including up to three nodes, each with unique service characteristics Total population, total employment, labour force participation rates and certain travel behaviour characteristics of the residents were drawn from an existing city - Souix Falls, South Dakota - and the spatial distribution of residential and commercial activities specified by the Lowry land use model In this way 37 different combinations of spatial structures and transportation network structures were constructed Total travel levels by mode were calculated using simple gravity and route assignment models Finally, energy consumption was computed from information on the length and speed of all types of trips The results of the 37 simulations indicate that the energy consumption levels for the most and least energy-intensive hypothetical urban areas differ by a factor of about ten However, one must take care to sort out the effects of urban structure alone (shape, population distribution and employment distribution) from those of the purely transportation-related factors (available modes and service characteristics) This is made difficult both from the interactive nature of urban structure and transportation and from the way the results are presented in the report Still, some disaggregation can be made, if only in an approximate manner If those test cities which differ only in shape are compared, then the linear cities appear to consume least and the concentric ring cities most, perhaps by as much as a factor of two However, 'shape' is in many ways a surrogate for population and employment distribution The authors report that energy consumption is negatively correlated with employment and population concentration; that is, those structures with compact spatial distributions are more efficient However, relatively large increases in concentration have to take place to achieve significant savings 2~ Looking at variations in the transportation system alone, an 8085% decrease in energy consumption is predicted for a concentric ring city which realises an increase in transit usage from to 70% But this figure must be considered highly approximate, as the urban structural variables were not held completely constant in these comparisons In addition, other estimates of modal shift impacts have been less optimistic Hirst and Moyers, for example, report a potential decrease in energy use of about 25% for an increase in transit patronage from the current level of 3% to a future level of 51%.22 We can again conclude that dramatic changes in urban structure will produce sizable savings in the amount of energy used to transport people However, since the range of structures was determined a priori, we cannot be sure that each of the test structures is feasible, given the past and probable future processes which lead to urban development This is true despite the use of a partially validated land use model to distribute secondary employment and population in a realistic manner once the location of the primary employment had been specified Moreover, it is difficult to glean from these results implications for development added over the next few decades to existing urban areas of various structural types - the issue which is of most interest from a policy perspective ENERGY POLICY September 1976 Energy and land use 23 Margaret Fulton Fels and Michael J Munson, 'Energy Thrift in Urban Transportation: Options for the Future', in Robert H Williams, ed., The Energy Conservation Papers, Ballinger Publishing Company, Cambridge, Mass 1975 2"Two other options examined by Fels and Munson are based primarily on changes in urban structure and are worthy of further examination One option assumes that people will retain their desire for low density living but will locate in order to shorten their journey to work Employers wilt likewise respond by clustering in a few large employment centres throughout the metropolitan area Low density residential villages would thus develop around these centres, greatly reducing the journey to work for the average resident On the other hand, non-work trips are likely to be unaffected, or, if commercial activities are also clustered in a few large centres, will probably be longer Significant net savings are nevertheless achieved; approximately 20% and 35% savings are estimated, relative to the most energy consuming option for 1985 and 2000, respectively The savings from this development trend which appear in the report incorporate several technological and energy price changes as well The savings noted here were calculated from the reported data with the effects of other changes factored out Another option emphasises high density residential living but assumes a noncontiguous pattern of employment Nonwork travel is thus greatly reduced while average work trips are lengthened But the former effects outweigh the latter producing approximately 25% and 30% savings in consumption, with respect to the highest energy patterns, by 1985 and 2000, respectively zs James S Roberts, Energy, Land Use, and Growth Policy: Implications for Metropolitan Washington, Metropolitan Washington June 1975 Council of Governments, The final two studies confront the relevant issues more directly Both examine the energy impact of future growth options for specific metropolitan areas and both assess the relative effectiveness of alternative but related conservation options The first is a study of urban transportation energy consumption in the Trenton, New Jersey, Metropolitan Area between 1975 and the end of this century33 Among the many conservation options considered, some relate directly to urban spatial structure (eg, increasing home-work proximity) while trends in development patterns underlie or condition the use of other strategies Realism in the projected effects is improved by using the population, employment, transport network, and transportation behaviour characteristic of Trenton as the basis for the estimates Future changes in these characteristics must still be assumed, but the sensitivity of the results to these assumptions can be measured Fels and Munson calculate that a four fold and ten fold difference in per capita energy consumed for transportation in Trenton is possible, in the extreme, by the years 1985 and 2000, respectively This is the difference between the 'everybody wants a luxury car' option (where long and more frequent trips are taken by richer people living further apart and driving less efficient autos) and the 'energy consciousness' option (where fewer and shorter trips are taken by people living closer to each other and to work and travelling by more efficient modes and in more efficient autos) Between these extremes are options which feature innovative forms of mass transit, fuel price increases, technologically modified autos, and various combinations of these 24 The final study investigates the energy implications of alternative growth scenarios for the Washington, DC area 2s The scenarios selected for examination are broadly representative of different urban structures They include (a) S p r a w l - low density, non-contiguous residential growth at the fringe with new employment primarily at the metropolitan centre, (b) W e d g e s a n d c o r r i d o r s - all new development located in a radial configuration along rapid rail transit routes and concentrated near stations, (c) B e l t w a y o r i e n t e d - all new development located along a cirumferential highway, and (d) D e n s e c e n t r e higher density, more concentrated development focused on the metropolitan centre The energy implications for future travel were examined using a simple transportation model calibrated to explain current travel behaviour in the area The results show that the sprawl pattern would be about twice as energy-intensive (considering automobile consumption only) as the dense centre and transit oriented patterns by 1992 Again one cannot say that a 50% savings is realistically obtainable, only that this is the difference between these two extremes of spatial structure, given the assumptions about travel behaviour upon which the simulation is based Before proceeding it is important to place the simulation studies just discussed in perspective Most of the alternative urban structures simulated are grossly unrealistic given current US development patterns Even where conscious efforts have been made to provide residential opportunities in close proximity to employment centres, a very poor matching of employees and households has resulted In order for many of the simulated structures to be realised a considerable change in attitudes and preferences must occur ENERGY POLICY September 1976 231 Energy and land use Planning is certainly not a sufficient condition to alter development patterns Relative effectiveness of a land use policy 2s This assumes that the same number of people would be accommodated in units of the same aggregate floor space This may not be totally realistic as some reduction in floor space typically accompanies a move from a single family detached unit to a multi-family unit (Floor space is usually traded for location) Some additional savings may be expected simply from a reduction in the size of the average unit found in high density developments Relative comparisons among alternatives assume that the absolute value for each is known In the case of energy conservation strategies, the available evidence will only allow us to reduce the degree of speculation about the effectiveness of each With this caveat in mind an attempt will now be made to estimate the savings that could reasonably be expected to obtain from the control of new development patterns and to place these in the context of savings potentially achievable from alternative conservation strategies Looking first at energy consumed for residential space heating and cooling, we have three pieces of evidence from which to derive an estimate of probable savings The two simulations predict that a 2030% (Hittman Associates) or 65% savings (Arthur D Little) could be achieved if all new development resulted in the construction of high-rise buildings rather than single family detached units 26 A more modest estimate is justified since even in very high density growth patterns, a mix of housing types will be found In addition, the absence of empirical verification of the simulation results, as judged by the New York City findings, further argues for a reduced estimate Thus, a value of 20% for the potential savings accruing to new high density development will be used for discussion purposes Probable transportation energy savings from efficient development patterns can likewise be estimated from the simulation studies, modified by the empirical evidence Table shows the energy differences between the most energy consuming development patterns, and other more efficient patterns tested in the two studies which simulated the effects of new growth to existing urban areas The most efficient scenarios are not presented as their realisation seems most unlikely even under extreme conditions This is probably true for the dense centre pattern in the Washington study as well The Table Simulated transportation energy use differences for various patterns of incremental, growth Total additional energy consumption (from the base year a) and percent reduction in this increment from the base case (in BTU per year x 1012 ) Growth pattern Luxury car (base case) Home-neighbour proximity (modifiedb) Home-work proximity (modifiedb) 1985 (Total) (%) 1992 (%) 2000 (Total) (%) 8.5 - 16.8 6.6 22 10.5 37 6-4 26 12.0 29 70.6 59.5 35.1 Sprawl (base case) Wedges and corridors Dense centre a Early ' s for the first three patterns, for the last three patterns b These options have been modified from the original study by assuming no technological modification of the auto, no introduction of innovative transit modes, no use restrictions on the auto, and no 232 (Total 16 50 increase in fuel prices Source: The first three patterns are taken from the Trenton, NJ study (Fels and Munson, op cit Reference 23) and the last three from the Washington, DC study (Roberts, op cit Reference 25) ENERGY POLICY September 1976 Energy and land use Table Probable reduction in total US energy consumption per year from efficient development patterns (%) Percent of annual consumption a (1968) Savings (%) Estimated reduction in total consumption (%) Savings (%) Urban residential space heating Urban residential air conditioning Urban automobile and bus travel 7.4 20 1.5 0.5 20 0.1 8.5 20 1.7 (approx) Total 2~ The adoption of a comprehensive plan however, does not insure that local development will actually take place in accordance with the plan Local zoning ordinances need only reflect the plan's general intent and, in any case, are susceptible to significant change through the issuance of variances a Stanford Research Institute, Patterns Vol of Energy Consumption in the United States, prepared for the Office of Science Energy Intensiveness of Passenger and Freight Transportation Modes, 1950-70, 1, Part A, 1970; and Eric Hirst, and Technology, Executive Office of the President, 1972; US Bureau of the Census, US Census of Population, 1970, ORNL-NSF-EP-44, Oak Ridge National Laboratory, April, 1975 other development options represent less extreme deviations from what may be expected in the absence of more stringent land use control In fact, the wedges and corridors scenario is based on the region-wide land use plan accepted by all local governments in the Washington area 27 The reductions in incremental energy consumption over the base cases which are associated with these growth patterns are thus much more realistic To some degree they may still be over-statements due to possible exaggerations inherent in the base cases (ie, neither base case appears to be a simple extrapolation from present trends), but they provide a basis for arriving at reasonable approximations Again, the lack of strong empirical evidence to substantiate the simulated savings lends credence to this approach Since some but not all aspects of the home-neighbour and homework proximity patterns could likely be accomplished by vigorous growth management efforts and since the wedges and corridor growth concept was practical enough at least to appear in the Washington area comprehensive plan, a value of 20% will be used for probable savings by 1985 resulting from energy efficient changes to existing urban structures As a first order approximation of the magnitude of savings which could be achieved at the national level by 1985, the estimated urban structure efficiencies can be converted into a fractional reduction in annual US consumption levels and applied to the projected annual consumption level in 1985 Table illustrates the calculation of the fractional reduction in annual US consumption using 1968 as the base year This saving should be applied only to the total new consumption represented by future growth Using the US Federal Energy Administration's (FEA) conservative projection for 1985, energy consumption of 103 quadrillion British Thermal Units (BTU) per year, the difference between projected 1985 and actual 1972 consumption is 31 quadrillion BTU per year 28 Assuming that the distribution of fuel consumption among economic sectors and the distribution of people between rural and urban areas remains approximately constant, the total one year savings in 1985 would be approximately 0.9 quadrillion BTU Other conservation actions have ENERGY POLICY September 1976 233 Energy and land use been assessed by FEA and the savings from those that are most closely related to land use consideration are as follows 29(in 1012 BTU): Mandatory fuel efficiency standards for autos (20 mpg) 1.9 Special gasoline taxes Mandatory thermal efficiency standards for new buildings 1.2 1.0 Seen in this context, the likely savings from more efficient land development patterns are significant but not dramatic The relative effectiveness of still other related policies can be anticipated from the results of a study already discussed From data reported by Fels and Munson, it appears that increases in fuel prices combined with reductions in auto weight and modification of the internal combustion engine will produce savings about three times greater than those from land use measures alone) ° Of course, many of these conservation measures are highly interrelated and should not be considered alternatives in a strict sense Thermal efficiency standards are likely to affect the most inefficient building types (single family detached dwellings) to the greatest extent, reducing the energy differential between high and low density development patterns Likewise, imposition of automotive fuel efficiency standards will serve to reduce the differential between compact and dispersed development And fuel price increases in general will create an impetus toward more energy efficient urban structure The effectiveness of a land use policy is therefore really a function of which other policies will also be employed 'Costs' of a land use policy Federal Energy Administration, Project Independence Report, Federal Energy Administration, November 1974, p 26 29 Federal Energy Administration, op cit Reference 28 30 Fels and Munson, op cit Reference 23 31 See William K Reilly, The Use of Land: A Citizen's Policy Guide to Urban Growth, Thomas Y Crowell Co, New York, 1973 and Fred Bosselman, David Callies, and John Banta, The Taking Issue, Government Printing Office, 1973, Washington, DC 32 The recent defeat of a national land use bill in Congress is evidence of public sentiment against governmental encroachment on private property rights, even though the bill had land use planning, rather than regulation, objectives For a more detailed discussion of suggested changes in land use policy and the implications for private property rights, see Peter G Grown, The American Law Institute Model Land Development Code, The Taking Issue, and Private Property Rights, The Urban Institute, URI 13300, 1975 2e 234 In judging the suitability of any policy, relative efficacy is but one of two considerations Cost, acceptance, or general feasibility is the other We are far from being able to say with any authority what the monetary effects are of applying land use controls to create a given spatial structure Certainly, limiting the supply of land for certain uses will affect land prices which, in turn, will be reflected in the cost of urban goods and services But little more than that assertion can be made The 'costs' of a land use policy can more reasonably be discussed in terms of legal and political acceptability The right to private ownership and use of land in the United States has a rather substantial history, though public bodies (especially local governments) have made significant inroads in regulating land use during this century Recently, arguments for a much greater public involvement have been proffered by groups anxious to prevent 'land abuse' and environmental degradation 31 These groups espouse public regulation of land use far in excess of what has traditionally been allowed by the courts No longer would development controls be fettered by community health, safety, and morals criteria alone The new powers would be based on an expanded and rather amorphous definition of 'community welfare' Energy conservation would undoubtably be considered a justifiable community objective thus legitimising alterations in urban spatial structures to achieve this end, often without compensation for those whose property would be reduced in value or even confiscated But such an expansion of public powers is far from being universally accepted by the courts and has hardly met with unanimous public acceptance 32 So the question ENERGY POLICY September 1976 Energy and land use 33The simple calculations of probable energy savings described in the previous section are designed to reflect reasonable expectations That is, the efficient development patterns selected for analysis were those that appeared to deviate moderately from present patterns A mix of housing types favouring, but not restricted to, multifamily structures and urban spatial arrangements moderately increasing home-work and homeshopping proximities were selected But the studies on which these calculations are based appear to be sufficiently nebulous and the findings sufficiently uncertain as to make the 'reasonable expectation' conclusion questionable Certainly, local governments would have to be much more vigorous in implementing land use plans Indeed, new and somewhat more restrictive plans would likely be needed, at least judging from the growth scenarios used in the Washington, DC, simulation study In any event, the realisation of more efficient urban structures which would produce significant energy saving within the next 10 years will produce vocal opposition from some parties at best, vehement objections and legal challenges at worst The road to publicly imposed energy efficient development patterns is far from smooth 34 Intended and actual results of infrastructure investments frequently vary, however For example, major rapid transit systems built in recent years have been shown to increase centrifugal suburbanisation rather than creating more compact urban areas becomes, could significant energy savings from efficient urban structures be realised through the application of currently accepted land use control measures? 33 Perhaps a more productive line of inquiry concerns the justification of governmental involvement in principle It can be argued that smoothly functioning private land markets composed of numerous informed and willing participants will adequately reflect the scarcity value of energy and create more efficient urban structures in the absence of additional land use regulations Perhaps the best public role is one of market monitor Certainly, failures in private land markets should be corrected and many would argue that energy prices should be deregulated in favour of market-determined prices Although local governments rarely influence the price of fuel directly, special commuter or parking taxes can push gasoline prices toward market levels The same is true for the price of space heating and cooling fuels There is much that local governments can to improve the operation of private markets Builders can be required to disclose the thermal efficiency of their buildings and information can be provided to urban residents on the likely transportation costs associated with selected residential locations within specific metropolitan areas Practices of mortgage and rehabilitation loan lenders can be corrected, if necessary, to insure that central city investments are not unduely discouraged Local governments are also directly involved in the land development business themselves To some extent, then, urban spatial structure can be shaped by inducement (strategic placement of infrastructure and public facilities) rather than by restriction? This approach is likely to engender considerably less opposition than the enforcement of stringent land use regulation alone Conclusion From an examination of the available evidence we have seen that the channeling of new urban development in a 'reasonable' fashion over the next 10 years in order to produce more energy efficient urban structures can save significant although not dramatic quanties of energy Furthermore, these savings are comparable to, and highly interrelated with, the expected savings from non-land use conservation strategies On the cost side of the ledger, a strategy based purely on land use control would appear to present political and legal problems since the degree of control would have to be significantly greater than is presently experienced in order to achieve the estimated savings On the other hand, sharp increases in the price of fuels may work to encourage more efficient development patterns in the absence of increased land use regulation Likewise, technological improvements in end-use efficiencies and increased thermal efficiency standards may reduce the need for additional regulation by reducing the energy differential between efficient and inefficient development patterns Significantly, technological improvements and heightened standards may to some degree offset the land use consequences of price rises Local governments are encouraged to explore a range of options before setting sail toward greater manipulation of development patterns Those public activities which serve to strengthen the private ENERGY POLICY September 1976 235 Energy and land use market response to decreased fuel availability will most likely be the least 'costly' to undertake However, where markets are not free, due to federal regulation, or where savings beyond those obtainable from private markets are socially desirable (perhaps from a national defence standpoint), additional intervention in the form of land use regulation may be justified In addition, local governments should not ignore the positive land development influence associated with public investment decisions Lest even these cautious encouragements lead some to call for sweeping new public authority for urban planning to conserve energy, one additional admonition is in order Single purpose planning can usually achieve single purpose objectives But the development and management of urban areas involves difficult trade-offs among multiple objectives The most thermally efficient city just may prove to be the deadliest from an air pollution perspective Some of the work now underway at the Urban Institute is designed to sort out the net results of alternative development decisions The choices are surely not simple and the effects not always apparent, but ignoring the broader ramifications of decisions designed to achieve single purpose ends will just as surely produce suboptimal solutions at best 236 ENERGY POLICY September 1976 ... ENERGY POLICY September 1976 233 Energy and land use been assessed by FEA and the savings from those that are most closely related to land use consideration are as follows 29(in 1012 BTU): Mandatory... more rigorous) and the values should be accepted as very rough approximations of ENERGY POLICY September 1976 Energy and land use Table Average annual energy requirements for heating and cooling... Operating Report, ATA, no date ENERGY POLICY September 1976 Energy and land use Table Annual residential and transportation energy consumption in the New York City area and in the USA (in million