energy resources

• The biggest source of energy is non-renewable sources such as coal, oil, natural gas, and nuclear.
• Energy self-sufficiency is critical to the development and advancement of first world countries.
• Renewable sources of energy include solar, wind, hydroelectric, biomass, and geothermal.
• Large and medium-sized dams are very expensive to build.
• The future of hydropower depends to a large extent on the persuasiveness of states and potential public-private partnerships.
• The water used to generate hydropower is renewable and storable.
• Hydropower is extremely efficient.
• Operating and maintenance costs for hydropower are low.
• Energy is used in various sectors including agricultural, transportation, residential, commercial, and industrial.
• Energy is harnessed from various sources such as fossil fuels, solar, wind, and hydroelectric.
• Coal is formed by tectonic activity raising sea levels covering and killing vegetation, with plant debris accumulating and being buried under layers of mud and sand in sedimentation.
• Types of coal include Anthracite, Bituminous, Sub-bituminous, Lignite, and Peat.
• Petroleum, also known as oil and gas, is formed when a living organism dies, with about 0.1% of the organic matter transported to the bottom of the sea or large continental lakes, preserved in a poorly oxygenated environment.
• Source rock is formed when dead marine plankton and inorganic matter such as clay particles and very fine sand mix with anaerobic bacteria, transforming into dark foul smelling mud.
• Mud that contains 1 to 2% organic matter is transformed into a source rock.
• Source rock subsidence occurs when the weight of accumulating sediment pushes the source rock further under the Earth’s crust.
• Oil and gas form at a depth of 2,000 meters when the temperature reaches 100 C and kerogen starts to release hydrocarbon.
• The proportion of gas and oil generated depends on the type of source rock, with a source rock composed mostly of animal origin producing more oil than gas, and a source rock composed mainly of plant debris producing mostly gas.
• Migration is the slow, constant movement away of lighter hydrocarbons from the source rock.
• Reservoir rock is where hydrocarbon deposit is formed, with hydrocarbon molecules accumulating in large quantities in porous, permeable rock.
• Permeability is the connectivity of pore spaces that allow fluid to circulate within the rock.
• Cap rock is a layer of impermeable rock that prevents the oil or gas from rising laterally, forming a barrier and trapping the hydrocarbon.
• Structural traps are formed by changes in geological layers caused by the movement of tectonic plates, with reservoir rock sometimes deformed until it forms a completely sealed space.
• Stratigraphic traps are made up of sedimentary layers that may not have undergone tectonic deformation.
• A cap rock completely seals the reservoir rock.
• Hydrocarbon traps contain: oil, with significant quantities of dissolved gas; gas with light liquid hydrocarbons known as condensate; and both oil and gas, which accumulates in the upper part of the trap.
• If the reserves are developed, the gas dissolved in the crude oil may turn into LPG.
• Geothermal energy is harnessed by descending deeper into the Earth’s crust, where underground rock and water become hotter.
• The average rate at which temperature increases with depth is termed as the thermal gradient.
• The average value of the thermal gradient worldwide is 3C per 100 meters of depth but it varies between 1C and 10 C per 100 meters depending on the physical condition and geology of the region.
• Low temperature geothermal energy is used at temperatures between 20 C to 90 C for geothermal heating.
• Medium temperature geothermal energy is used at temperatures between 90 C to 160 C, where water is used on the surface as liquid form.
• High temperature geothermal energy is used at temperatures above 160 C, where water turns into steam when it reaches the Earth’s surface.
• Medium-temperature geothermal power plants involve power plants that harness groundwater via geothermal wells, built near aquifers located at depths of 2 000 to 4 000 meters.
• High-temperature geothermal power plants use water from water tables in volcanic regions at depths of 1 500 to 3 000 meters.
• The average geothermal flow on the surface is low, averaging 0.06 watts per square meter per year.
• The geothermal reservoirs are found in all the Earth’s sedimentary basins, but high temperature energy is most likely to be found near volcanoes.
• In volcanic areas, the geothermal heat flow can reach 1 watt per square meter.
• The replenishment capacity of geothermal reservoir depends on heat resources within the Earth’s crust and energy from outside the reservoir (solar heat) for very low temperature using heat pumps.
• Around 20 countries in the world produce geothermal power for an installed capacity of 10.93 GW, playing an essential role in countries like Philippines, where it accounts for 17% electricity produced, and Iceland where it represents 30%.