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At least 163 records · Page 9Linked to original sources
USGS2004

Mineral, Energy, and Fertilizer Resources of the North Coast of Peru: Perspective from the Santa Rita B Archaeological Site

The Santa Rita B archaeological site is in the Chao Valley, approximately 65 km southeast of Trujillo, northern Peru. Location of Santa Rita B at the emergence of several drainages from the Andean cordillera is an important factor in the almost continuous occupation of the site over the past 3,000 years. Mineral resources are abundant throughout the Andes; however, the north coast of Peru was an important center for pre-Columbian mining, metallurgy, and craftsmanship. Success of the Chavin, Moche, Chimu, and other north coast cultures is directly related to the availability and exploitation of mineral and energy resources that include: gold (?silver), as electrum, mainly from placers, and copper from local oxide and carbonate occurrences and from sulfides related to copper porphyry occurrences in the cordillera. An alloy of these three metals is referred to as tumbaga, which is the primary material for Andean metalcraft. Anthracite was used for mirrors by north coast cultures and is available near Rio Chicama, Rio Santa, and east of Santa Rita B. These outcrops are a part of the Alto Chicama, Peru's largest coalfield, which extends from Rio Chicama, in the north, for 200 km southward to Rio Santa. Charcoal from the algorrobo tree and llama dung are considered to be the common pre-Columbian energy sources for cooking and metalwork; however, availability and the higher heat content of anthracite indicate that it was used in metallurgical applications. Bitumen is available from petroleum seeps near Talara, north of the study area, and may have been used as glue or as cement. Hematite, goethite, limonite, and manganese oxides from clay-altered volcanic rock may have provided color and material for ceramics. Guano from the Islas Gua?apes, Chinchas, and Ballestas was used as fertilizer for cotton and other crops.

Open-File Report↗
USGS2014

U.S. Geological Survey Science for the Wyoming Landscape Conservation Initiative: 2012 annual report

Southwest Wyoming contains abundant energy resources, wildlife, habitat, open spaces, and outdoor recreational opportunities. Although energy exploration and development have been taking place in the region since the late 1800s, the pace of development for fossil fuels and renewable energy increased significantly in the early 2000s. This and the associated urban and exurban development are leading to landscape-level environmental and socioeconomic changes that have the potential to diminish wildlife habitat and other natural resources, and the quality of human lives, in Southwest Wyoming. The potential for negative effects of these changes prompted Federal, State, and local agencies to undertake the Wyoming Landscape Conservation Initiative for Southwest Wyoming.

Wyoming↗
USGS2006

Chapter 7. The GIS project for the geologic assessment of undiscovered oil and gas in the Cotton Valley group and Travis Peak and Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces

A geographic information system (GIS) focusing on the Upper Jurassic-Lower Cretaceous Cotton Valley Group and the Lower Cretaceous Travis Peak and Hosston Formations in the northern Gulf Coast region was developed as a visual-analysis tool for the U.S. Geological Survey's 2002 assessment of undiscovered, technically recoverable oil and natural gas resources in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces. The Central Energy Resources Team of the U.S. Geological Survey has also developed an Internet Map Service to deliver the GIS data to the public. This mapping tool utilizes information from a database about the oil and natural gas endowment of the United States-including physical locations of geologic and geographic data-and converts the data into visual layers. Portrayal and analysis of geologic features on an interactive map provide an excellent tool for understanding domestic oil and gas resources for strategic planning, formulating economic and energy policies, evaluating lands under the purview of the Federal Government, and developing sound environmental policies. Assessment results can be viewed and analyzed or downloaded from the internet web site, http://energy.cr.usgs.gov/oilgas/noga/ .

Alabama, Arkansas. Florida, Georgia, Louisiana, Mi↗
USGS2015

Global volcanic hazards and risk

An estimated 800 million people live within 100 km of an active volcano in 86 countries and additional overseas territories worldwide [see Chapter 4 and Appendix B]1. Volcanoes are compelling evidence that the Earth is a dynamic planet characterised by endless change and renewal. Humans have always found volcanic activity fascinating and have often chosen to live close to volcanoes, which commonly provide favourable environments for life. Volcanoes bring many benefits to society: eruptions fertilise soils; elevated topography provides good sites for infrastructure (e.g. telecommunications on elevated ground); water resources are commonly plentiful; volcano tourism can be lucrative; and volcanoes can acquire spiritual, aesthetic or religious significance. Some volcanoes are also associated with geothermal resources, making them a target for exploration and a potential energy resource. Much of the time volcanoes are not a threat because they erupt very infrequently or because communities have become resilient to frequently erupting volcanoes. However, there is an everpresent danger of a long-dormant volcano re-awakening or of volcanoes producing anomalously large or unexpected eruptions. Volcanic eruptions can cause loss of life and livelihoods in exposed communities, damage or disrupt critical infrastructure and add stress to already fragile environments. Their impacts can be both short-term, e.g. physical damage, and long-term, e.g. sustained or permanent displacement of populations. The risk from volcanic eruptions and their attendant hazards is often underestimated beyond areas within the immediate proximity of a volcano. For example, volcanic ash hazards can have effects hundreds of kilometres away from the vent and have an adverse impact on human and animal health, infrastructure, transport, agriculture and horticulture, the environment and economies. The products of volcanism and their impacts can extend beyond country borders, to be regional and even global in scale. Although known historical loss of life from volcanic eruptions (since 1600 AD about 280,000 fatalities are recorded, Auker et al. (2013)) is modest compared to other major natural hazards, volcanic eruptions can be catastrophic for exposed communities. In 1985 the town of Armero in Colombia was buried by lahars (volcanic mudflows) with more than 21,000 fatalities due to relatively small explosive eruptions at the summit of Nevado del Ruiz volcano that partially melted a glacier (Voight, 1990).

Book chapter↗
USGS2013

Assessment of undiscovered oil and gas resources of the Cretaceous-Tertiary Composite Total Petroleum System, Taranaki Basin Assessment Unit, New Zealand

The Cretaceous-Tertiary Composite Total Petroleum System coincident Taranaki Basin Assessment Unit was recently assessed for undiscovered technically recoverable oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey (USGS) World Energy Resources Project, World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 487 million barrels of oil, 9.8 trillion cubic feet of gas, and 408 million barrels of natural gas liquids.

Taranaki Basin↗
USGS2018

Northern Great Plains

In the Northern Great Plains, the timing and quantity of both precipitation and runoff have important consequences for water supplies, agricultural activities, and energy production. Overall, climate projections suggest that the number of heavy precipitation events (events with greater than 1 inch per day of rainfall) is projected to increase. Moving forward, the magnitude of year-to-year variability overshadows the small projected average decrease in streamflow. Changes in extreme events are likely to overwhelm average changes in both the eastern and western regions of the Northern Great Plains. Major flooding across the basin in 2011 was followed by severe drought in 2012, representing new and unprecedented variability that is likely to become more common in a warmer world. The Northern Great Plains region plays a critical role in national food security. Among other anticipated changes, projected warmer and generally wetter conditions with elevated atmospheric carbon dioxide concentrations are expected to increase the abundance and competitive ability of weeds and invasive species, increase livestock production and efficiency of production, and result in longer growing seasons at mid- and high latitudes. Net primary productivity, including crop yields and forage production, is also likely to increase, although an increasing number of extreme temperature events during critical pollination and grain fill periods is likely to reduce crop yields. Ecosystems across the Northern Great Plains provide recreational opportunities and other valuable goods and services that are ingrained in the region’s cultures. Higher temperatures, reduced snow cover, and more variable precipitation will make it increasingly challenging to manage the region’s valuable wetlands, rivers, and snow-dependent ecosystems. In the mountains of western Wyoming and western Montana, the fraction of total water in precipitation that falls as snow is expected to decline by 25% to 40% by 2100 under a higher scenario (RCP8.5), which would negatively affect the region’s winter recreation industry. At lower-elevation areas of the Northern Great Plains, climate-induced land-use changes in agriculture can have cascading effects on closely entwined natural ecosystems, such as wetlands, and the diverse species and recreational opportunities they support. Energy resources in the Northern Great Plains include abundant crude oil, natural gas, coal, wind, and stored water, and to a lesser extent, corn-based ethanol, solar energy, and uranium. The infrastructure associated with the extraction, distribution, and energy produced from these resources is vulnerable to the impacts of climate change. Railroads and pipelines are vulnerable to damage or disruption from increasing heavy precipitation events and associated flooding and erosion. Declining water availability in the summer would likely increase costs for oil production operations, which require freshwater resources. These cost increases will either lead to lower production or be passed on to consumers. Finally, higher maximum temperatures, longer and more severe heat waves, and higher overnight lows are expected to increase electricity demand for cooling in the summer, further stressing the power grid. Indigenous peoples in the region are observing changes to climate, many of which are impacting livelihoods as well as traditional subsistence and wild foods, wildlife, plants and water for ceremonies, medicines, and health and well-being. Because some tribes and Indigenous peoples are among those in the region with the highest rates of poverty and unemployment, and because many are still directly reliant on natural resources, they are among the most at risk to climate change (e.g., Gamble et al. 2016, Cozzetto et al. 2013, Espey et al. 2014, Wong et al. 2014, Kornfeld 2016, Paul and Caplins 2016, Maynard 2014, USGCRP 2017)

Report↗
USGS2024

Three-dimensional temperature maps of the Williston Basin, USA: Implications for deep hot sedimentary and enhanced geothermal resources

As part of U.S. Geological Survey's (USGS) efforts to identify and assess geothermal energy resources of the US, a three-dimensional (3D) geologic and thermal model has been constructed for the Williston Basin, USA. The geologic model consists of all sedimentary units above the Proterozoic and Archean crystalline rock (called basement herein), with a total sedimentary thickness of up to 5 km near the basin center. Twenty-nine geologic units were mapped from interpreted formation tops from 16,465 wells. A 3D temperature model was constructed to a depth of 7 km by constructing a 3D heat flow model for the sedimentary units, followed by estimating underlying temperature using a one-dimensional (1D) analytic solution for heat flow within the underlying crystalline basement. Using the sedimentary basin model, heat flow was simulated in 3D and was calibrated using three temperature datasets: 1) 24 high-confidence static temperature logs (equilibrium thermal profiles), 2) more than15,000 drill stem test (DST) measurements from >7,000 wells, and 3) more than 45,000 bottomhole temperature (BHT) measurements from >14,000 wells. The DST and BHT datasets provide broad spatial coverage, but are lower confidence, primarily because measurements were made prior to attaining thermal equilibrium. DST and BHT measurements were binned regionally to develop representative thermal profiles that generally agree with these lower quality data (hereafter called pseudowell temperature profiles). Layer properties (primarily thermal conductivity and compaction curves) were set to best estimate values, then the heat flow model was calibrated to fit pseudowell and static temperature logs primarily by adjusting basal heat flow to approximate the overall temperature profile. Minor adjustments to thermal conductivity allowed adjusting changes in slope at lithologic contacts. Resulting maps include 3D temperature and basal (bottom of sedimentary units) heat flow estimates, which are used as input for the temperature model of the basement. The crystalline basement temperature model uses an analytic 1D solution to the heat flow equation that requires estimates of heat flow and temperature at the upper boundary (i.e., the sediment/basement contact), radiogenic heat production within the crystalline basement, and reference thermal conductivity (i.e., uncorrected for temperature). Two regions of high heat flow are identified: 1) in western North Dakota along the North American Central Plains Conductivity Anomaly and 2) in eastern Montana near the Poplar dome. Within the sedimentary column in the center of the basin of the basin, an area of approximately 100,000 km2 is predicted to have moderate- to high-temperature geothermal resources (>90 °C) under the thickest sequences of sediments. Where thick insulation and high heat flow coincide, electric-grade resources can be less than 4 km deep. Assuming a maximum feasible drilling depth of 7 km, temperatures are predicted to be as high as 175 °C. The geologic model may be used to identify strata at sufficient temperatures that may have natural permeability or that may have conditions that favor development of enhanced/engineered geothermal systems resources.

Montana, North Dakota, South Dakota↗
USGS2017

Assessing U.S. coal resources and reserves

The U.S. Coal Resources and Reserves Assessment Project, as part of the U.S. Geological Survey (USGS) Energy Resources Program, conducts systematic, geology-based, regional assessments of significant coal beds in major coal basins in the United States. These assessments detail the quantity, quality, location, and economic potential of the Nation’s remaining coal resources and reserves and provide objective scientific information that assists in the formulation of energy strategies, environmental policies, land-use management practices, and economic projections.

Fact Sheet↗
USGS2007

Fly Ash: From Cradle to Grave

The Energy Resources Program of the U.S. Geological Survey promotes and supports coal research to improve the understanding of the coal endowment of the United States. This results in geologically based, non-biased energy information products for policy and decision makers, land and resource managers, other federal and state agencies, the domestic energy industry, foreign governments, nongovernmental groups, academia, and other scientists. A more integrated approach to our coal quality work involves what we call a 'cradle to grave' approach. These types of studies focus not on just one aspect of the coal but rather on how or where different quality parameters form and (or) occur and what happens to them through the mining, production, transport, utilization and waste disposal process. An extensive suite of coal quality analyses, mineralogical, petrology, and leaching investigations are determined on samples taken from the different phases of the coal utilization process. This report consists of a tutorial that was given on June 10, 2007 at the 32nd International Technical Conference on Coal Utilization & Fuel Systems, The Power of Coal, Clearwater Coal Conference in Clearwater, Florida, USA. This tutorial covers how these studies are conducted and the importance of providing improved, comprehensive, science-based data sets for policy and decision makers.

Open-File Report↗
USGS1979

U.S. Geological Survey activities in New York, 1979

This report describes the work of the U.S. Geological Survey and summarizes projects conducted in New York during 1979. Many of these projects are continuing into the 1980's. The major programs provide basic scientific information concerning water, land, and mineral resources. The Survey also supervises the exploration for mineral fuels on leased outer continental shelf lands. The programs are: (1) Water resources investigations--These encompass (a) statewide networks of measurement stations that provide continuous records of streamflow, groundwater levels, water quality, and sediment discharge, and (b) projects to study local or regional water problems as well as critical water problems of national scope or interest. (2) Geologic and mineral resource surveys and mapping--These studies focus on geologic, mineral, and energy-resources investigations both on land and offshore. (3) Conservation of lands and mineral resources--These studies include the classification and evaluation of mineral resources on the outer continental shelf. (4) Topographic surveys and mapping--These studies include quadrangle, small-scale, and special mapping. (5) Land information and analysis--These studies focus on the interpretation and application of earth-science and related information to multi-disciplinary land-resource and environmental-impact problems. (USGS)

Open-File Report↗
USGS2025

A probabilistic assessment methodology for the evaluation of geologic energy storage capacity—Natural gas storage in depleted hydrocarbon reservoirs

The need for energy storage, particularly underground, where capacity and duration may far exceed battery storage technologies, is especially relevant given the increasing demands for reliable power alongside the development of intermittent renewable electricity sources. Geologic energy storage facilities already exist, and expanded use would enable storing gases such as methane and hydrogen. In 2018, a National Academies of Sciences, Engineering, and Medicine report, “Future Directions for the U.S. Geological Survey's Energy Resources Program,” recommended that the U.S. Geological Survey (USGS) prioritize assessing underground energy storage in geologic formations in the United States. The U.S. Geological Survey has since developed a methodology for assessing natural gas storage capacities in depleted hydrocarbon reservoirs on a national scale. The methodology introduced in this report prescribes three approaches for calculating gas storage capacity. This methodology relies on the availability of input data, including cumulative hydrocarbon production records, reservoir petrophysical properties, and reservoir pressure data. Assessment inputs can be obtained from public, State-level databases and propriety national-scale databases, although the use of analogs could be warranted for estimating input parameters. Probabilistic assessment results are aggregated to play, petroleum province, regional, and national scales. The steps defined in this report are demonstrated on the Michigan Basin Province, which includes the Mississippian Sandstone Gas Play and the Clinton Structural Play. This methodology could be used to systematically and consistently assess hydrocarbon plays and provinces for natural gas storage capacity across the United States.

Michigan↗
USGS1979

The Yampa River basin, Colorado and Wyoming : a preview to expanded coal-resource development and its impacts on regional water resources

Expanded coal production and conversion in the Yampa River basin , Colorado and Wyoming, may have substantial impacts on water resources, environmental amenities, and socioeconomic conditions. Preliminary results of a 3-year basin assessment by the U.S. Geological Survey are given for evaluation of surface- and ground-water resources using available data, modeling analysis of waste-load capacity of a Yampa River reach affected by municipal wastewater-treatment plant effluents, and semiquantitative descriptions of ambient air- and water-quality conditions. Aspects discussed are possible constraints on proposed development due to basin compacts and laws regulating water resources, possible changes in environmental-control regulations, and policies on energy-resource leasing and land use that will influence regional economic development. (Woodard-USGS)

Water-Resources Investigations Report↗
USGS2026

Spatio-temporal modeling for assessing geoenergy resources: A workflow applied to gas in place variation in coal beds

The ability to estimate spatio-temporal changes in hydrocarbon reservoir properties and energy resources within pore volumes is essential for optimizing production, reservoir management, geologic energy storage, and safety in underground mining operations. In coal seams, predicting remaining methane gas-in-place (GIP) is critical for quantifying producible gas and improving mine safety and productivity through effective ventilation planning. Although such changes are commonly evaluated using physics-based numerical simulation models, these approaches often require extensive data, calibration effort, and time. This study presents a spatio-temporal geostatistical modeling approach that bridges the gap between purely spatial models and full numerical simulations. The method is applied to a case study of coal seam degasification in the Mary Lee coal group, Black Warrior Basin, Alabama, USA, to estimate GIP evolution over time within a selected mining district. The analysis uses published data from prior natural gas production history-matching of degasification using vertical wells. Empirical spatial and temporal statistics were calculated for reservoir pressure and water saturation, and spatio-temporal variogram models were fitted to experimental variograms. These models provided the structural basis for spatio-temporal kriging, integrated with spatial estimates of time-invariant parameters (porosity, density, and thickness) to estimate GIP. This approach enabled estimation of GIP changes over time, including periods without data. Boxplots of GIP estimates indicated systematic depletion and decreasing spatial variability, reflecting the impacts of degasification. Comparison with cumulative gas production from empirical well records showed approximately 85% agreement based on a relative similarity metric. Spatio-temporal GIP estimates were also used to estimate methane emissions to longwall ventilation systems and compared with reported emissions from the U.S. EPA Greenhouse Gas Reporting Program, showing similar distributions (≈80%) given data limitations. Overall, this integrated modeling approach provides time-dependent GIP estimates with broader implications for resource assessment applications.

Alabama↗
USGS1976

Hydrologic studies of the U.S. Geological Survey related to coal development in Colorado

The coal resources of Colorado are extremely valuable. Viewed in the perspective of the existing energy crisis, coal is the sole energy resource for which the United States is completely self-sufficient. The productive life of known oil and gas fields is measured in decades, whereas the productive life of coal resources, based on present rates of production, is measured in centuries. Twenty-eight percent of the State of Colorado is underlain by coal (fig. 1). The U.S. Bureau of Mines estimates that total coal resources that can be strip mined are approximately 18 billion tons (16.3 billion t). Development of coal resources and associated activities will impact water resources.

Colorado↗
USGS1983

U.S. Geological Survey program of offshore resource and geoenvironmental studies, Atlantic-Gulf of Mexico region, from September 1, 1976, to December 31, 1978

Mineral and energy resources of the continental margins of the United States arc important to the Nation's commodity independence and to its balance of payments. These resources are being studied along the continental margins of the Atlantic Ocean and the Gulf of Mexico in keeping with the mission of the U.S. Geological Survey to survey the geologic structures, mineral resources, and products of the national domain.'(Organic Act of 1879). An essential corollary to these resource studies is the study of potential geologic hazards that may be associated with offshore resource exploration and exploitation. In cooperation with the U.S. Bureau of Land Management, the Geological Survey, through its Atlantic-Gulf of Mexico Marine Geology Program, carries out extensive research to evaluate hazards from sediment mobility, shallow gas, and slumping and to acquire information on the distribution and concentration of trace metals and biogenic and petroleum-derived hydrocarbons in sea-floor sediments. All these studies arc providing needed background information, including information on pollutant dispersal, on the nearshore, estuarine, and lacustrine areas that may be near pipeline and nuclear powerplant sites. Users of these data include the Congress, many Federal agencies, the coastal States, private industry, academia, and the concerned public. The results of the regional structural, stratigraphic, and resource studies carried out under the Atlantic-Gulf of Mexico Marine Geology Program have been used by the Geological Survey and the Bureau of Land Management to select areas for future leasing and to aid in the evaluation of tracts nominated for leasing. Resource studies have concentrated mostly on the Atlantic Outer Continental Shelf frontier areas. Geologic detailing of five major basins along the U.S. Atlantic margin, where sediments are as much as 14 km thick, have been revealed by 25,000 km of 24-and 48-channel common-depth-point seismic data, 187,000 km of acromagnetic data, and 39,000 km of gravity data, plus 10,000 samples and logs obtained from U.S. Geological Survey and industry drilling (for example, coreholes of the Atlantic Slope Program, Joint Oceanographic Institutions Deep Earth Sampling, Continental Offshore Stratigraphic Tests, and the Atlantic Margin Coring Program). A sedimentary section of Jurassic and Cretaceous age grades from terrigenous clastic rocks nearshore to carbonate rocks offshore; this section is part of an extensive buried bank-platform complex that could contain large reserves of natural gas and oil. The volume of sediment deposited offshore far exceeds the volume deposited onshore where extensive accumulations of oil, gas, and minerals have been found. Commercial exploratory drilling offshore thus far has been limited to the Baltimore Canyon Trough area off New Jersey, where at least two holes have found gas; leasing has taken place in the Southeast Georgia Embayment, where drilling was scheduled to begin in 1979, and is imminent in the Georges Bank area off New England. In addition, hydrogeologic and hydrochemical data obtained from the drilling studies have delineated freshwater-bearing submarine extensions of land aquifers that are important coastal ground-water resources. Hazards in the Georges Bank area include sand mobility associated with strong currents and storm-driven waves; high concentrations of suspended sediment in the water column that, when mixed with spilled oil, may sink to the bottom; and slumping along the upper slope. In the Baltimore Canyon, high sediment mobility accompanies major winter storms, and slumped material may cover as much as 20 percent of the upper slope. Potentially unstable slope areas are being studied in great detail to provide data on timing, triggering mechanisms, and rates of sediment movement. In the Southeast Georgia Embayment and Blake Plateau Basin, strong Gulf Stream flow poses a major problem to all offshore operations. In the Gulf o

Circular↗
USGS1981

Water-resources investigations of the U.S. Geological Survey in Wyoming, fiscal year 1980

This report contains lists and location maps of streamflow and reservoir stations, ground-water stations, water-quality stations, sediment stations, and peak-flow partial-record stations that are currently being operated in Wyoming. Water-resources appraisal projects are also described, including many that are related to development of energy resources. The general locations of the projects are shown on maps. The U.S. Geological Survey is striving to coordinate its water-resources investigations with those of other agencies. This report is one phase of that coordination effort and serves as an annual progress report to cooperators and the public. (USGS)

Open-File Report↗
USGS2018

A simple method for partitioning total solar radiation into diffuse/direct components in the United States

Solar radiation is a major sustainable and clean energy resource, and use of solar radiation is expected to increase. The utilization efficiency of solar energy varies with the relative proportions of the direct and diffuse components that compose total solar radiation and with the slope and aspect of the irradiated surface. The purpose of this paper is to develop a simple method for estimating diffuse and direct solar radiation at sites with observation of only total solar radiation. An existing model for estimating diffuse radiation, i.e., a linear relationship between the diffuse fraction (the ratio of diffuse radiation to total solar radiation) and the clearness index (the ratio of total solar radiation to extraterrestrial radiation), is applied to 7 sites across the continental United States with observations of diffuse and total radiation. The linear model shows good monthly performance. The model parameters (slope and interception) show a strong seasonal pattern that exhibits small variation across the 7 sites; therefore, the average values of the two monthly parameters may be used for estimating diffuse radiation for other locations with observations of total radiation.

International Journal of Green Energy↗
USGS1971

Banquet speech "Man's conquest of energy, its ecological and human consequences"

The world's energy resources suitable for power production are of two classes: (1) various channels of the continuous energy flux from extraterrestrial sources, and from the earth's interior, and (2) chemical, thermal, and nuclear energy stored in the outer part of the lithosphere and in the oceans. The continuous energy influxes are from: solar radiation, 178,000 × 1012 watts; geothermal energy, 32 × 1012 watts; and tidal energy, 3 × 1012 watts. Of the solar energy influx, the only fraction suitable at present for large-scale power production is the approximately 40,000 × 1012 watts expended in evaporation of water and in atmospheric and oceanic circulation. Of this, the world's potential water power is about 2.9 × 1012 watts. A very small fraction of the solar influx, 40 × 1012 watts, is stored chemically by photosynthesis. A minute fraction of this, stored during the geologic past, is the source of the energy of the fossil fuels, coal and petroleum. Tidal power is capable of large-scale development in a small number of coastal localities with a total potential power of about 64,000 megawatts. Of the sources of stored energy, geothermal energy is the least important. Installed capacity by 1970 is about 1,125 electrical megawatts, and the ultimate potential is estimated at about 60,000 megawatts, with a lifetime of probably less than a century. The largest sources of stored energy, other than nuclear, are the fossil fuels. The initial minable world reserves of coal and lignite are estimated to have been about 7.

IEEE Transactions on Nuclear Science↗