Users Guide to Off-Grid Energy Solutions
Petroleum products are refined from crude petroleum that is pumped from wells in many parts of the world. Crude petroleum is, in turn, refined in many refineries in the world. Refineries are of several types, but the most important process involves the "cracking" and distillation of the crude into a wide range of products that form the backbone of the world�s energy and petrochemical industries. The lighter petroleum fuels or "fractions" (benzene, kerosene, diesel) are the most widely used petroleum fuels for energy production in off-grid situations.
Figure 1: Diagram of Crude Oil Refining
Petroleum products, after biomass (wood, and agricultural and animal wastes/residues), provide more energy in rural, off-grid situations than all other forms of energy combined. Kerosene is one of the most important sources of lighting energy in the developing world. Kerosene is also an important energy source for refrigeration and freezing in clinics, hospitals and a host of commercial applications (refrigerators in hotels, restaurants, bars, etc.). Liquified petroleum gas/LPG is used to a limited extent for lighting and cooking in off-grid areas, but is also used for refrigeration and freezing in clinics, hospitals, schools and a range of commercial applications (refrigeration for butcheries, hotels, bars, etc.).
Gasoline (petrol or benzene [not the chemical benzine, but the petroleum fraction benzene]) is widely used for small (less than 3 kVA) generators, or gensets to produce electricity for commercial establishments, institutions and households. Diesel (or gasoil, the heaviest of these distillates or fractions) is the most widely used off-grid electricity generation and water pumping fuel source in the world. Diesel gensets are found all over the developing world, and serve as back-ups in most urban and grid-connected settings for essential services (such as hospital operating theatres, important telecommunications complexes, etc.).
Diesel fuel is the most widely available petroleum fuel in the world, and there are very few areas in the world, no matter how isolated, where diesel is unavailable, particularly given its paramount importance for transportation. This widespread availability makes diesel generation one of the easiest, and cheapest forms of off-grid electricity generation. Moreover, the fact that diesel gensets are sized to meet some of the smallest loads (less than 3 kVA) to some of the largest (over 1.5 MW), makes it a very attractive and widespread source of off-grid electricity and pumping.
butane: Either of two saturated hydrocarbons, or alkanes, with the chemical formula C4H10. Differences in structure between the two result in small but distinct differences in qualities. Both butanes occur in natural gas, petroleum, and refinery gases. They show little chemical reactivity at ordinary temperatures but burn readily when ignited in air or oxygen. They form part of gasoline and are sometimes added to propane to be marketed as bottled gas.
Gasoline: A mixture of the lighter liquid hydrocarbons, used chiefly as a fuel for internal-combustion engines. It is produced by the fractional distillation of petroleum; by condensation or adsorption from natural gas; by thermal or catalytic decomposition of petroleum or its fractions; by the hydrogenation of producer gas or coal; or by the polymerization of hydrocarbons of lower molecular weight.
kerosene: a light fraction petroleum product refined from the raw petroleum. Kerosene is one of the lighter "distillates" in a petroleum refinery, lighter than gasoil/diesel, and often in the same mix with jet fuel (e.g., Jet A1). It has been used for lighting, cooling and refrigeration for one hundred years. Kerosene is found throughout the world, and is one of the most common lighting fuels in the developing world. It is also often used for cooking, primarily in urban areas in the developing world.
LPG (liquified petroleum gas): A mixture of butane, propane and other light hydrocarbons derived from refining crude oil. At normal temperature it is a gas but it can be cooled or subjected to pressure to facilitate storage and transportation.
methane: A gas composed of carbon and hydrogen, the first member of the paraffin or alkane series of hydrocarbons. It is lighter than air, colourless, odourless, and flammable. Methane occurs in natural gas, as firedamp in coal mines, and as a product of decomposition of latter. It is a major component in the atmosphere of the outer planets. Methane is valuable as a fuel and in the production of hydrogen, hydrogen cyanide, ammonia, acetylene, and formaldehyde.
petrol: See gasoline.
propane: A colourless, odourless gas of the alkane series of hydrocarbons, formula C3H8. It occurs in crude oil, in natural gas, and as a by-product of petroleum refining. Propane burns in air at high temperatures and is valuable as a fuel. When it is used as a fuel, propane is not separated from the related compounds, butane, ethane, and propylene. It is used also as so-called bottled gas, as a motor fuel, as a low-temperature solvent, and as a source of propylene and ethylene.