Algaculture - A  term used to describe the farming of algae using aquaculture. Certain algae species contain large quantities of lipids (fatty oils) that may potentially be used as a viable and easily sustainable feedstock for the production of biodiesel. Many species of algae replicate quickly and form dense colonies which theoretically can yield more energy per acre than any other feasible crop feedstock. The algae can also be used to clean wastewater and feed livestock, maximizing the environmental benefit. Algae farming has been studied intensively in the last 30 years, but production cost, species sustainability, and large-scale production remain as barriers to its current use in commercial manufacture. 

Bagass (or Bagasse) – The biomass that remains after the crushing of a sugarcane stalk for juice extraction. Generally, bagass can account for approximately 30% of the remaining biomass of the sugarcane plant after processing. It is currently not directly used to produce biofuels, namely ethanol. Generally bagass is used in tne cogeneration of heat for brewing and electricity.

Many ethanol refineries are designed to use agricultural waste as heat and electricity sources and  are said to practice CHP (combined heat and power). Bagass can be used with the sugarcane as a fuel feedstock in the production of ethanol.

Biodiesel – Biodiesel is a clean burning, renewable diesel fuel that can be refined from algae, vegetable oils (including soy beans, sunflowers, peanuts, rapeseed, palm oil, jatropha etc.), fish oils, animal tallow, and used restaurant oils and grease. Pure biodiesel contains no petroleum, but can be blended freely with petroleum-based diesel. Blends of up to 20% biodiesel with 80% petroleum diesel (B20) can generally be used in unmodified compression ignition (diesel) engines. Biodiesel can also be used in its pure form (referred to as B100), but often minor engine modifications are necessary to avoid maintenance or performance problems. Biodiesel is simple to use, nontoxic, and essentially free of sulfur and aromatics. Biodiesel produced for sale as a legal road fuel in the United States is required to meet the ASTM D6751 fuel specification.

For biodiesel the use of algal feedstocks is an area of intense study because the theoretical energy yields are much  greater than for other feedstocks . There are additional environmental advantages to algae, including CO2 consumption and the potential for the usage of wastewater in its cultivation.

Biodiesel is general manufactured in free-standing facilities.

Biofuels – Biofuels are solid, liquid, or gas fuel consisting of or refined from biomass. Biofuels differ from fuels produced using natural resources, e.g., petroleum, coal, and nuclear fuels, in that they are renewable. Corn, soybeans, flaxseed, rapeseed, sugarcane, palm oil, and jatropha are currently grown to produce ethanol and biodiesel. In addition, algae, hemp,  miscanthus, and switchgrass (amongst other options) are currently being researched for their viability as sources of lipids or sugars for use in fuel refining. Biomass by-products or wastes  from the  industrial, agricultural, forestry and consumer origination  can be used as well,  including manure, wood chips, straw, sawdust, rice husks, and sewage. Biodiesel, butanol, and ethanol are the best-known biofuels.

Biomass— Generally refers to plant matter cultivated or processed for use as biofuel. Biomass can be living organisms, dead organisms, and/or the byproducts of plant or animal metabolism. It excludes such things as coal or petroleum in part because, although coal and petroleum do consist of organic products, their final form was the result of geologic processes.  Biomass is a renewable fuel and is a form of stored solar energy.

Butanol (Biobutanol) – Traditionally butanol has been produced from petroleum, but the viability of butanol production from biomass is proven. Like ethanol, it is refined via fermentation, although the process differs slightly. Butanol is fermented using the bacterium Clostridium acetobutylicum.  Butanol is generally believed to be highly compatible with current gasoline engine technology and  is less corrosive than ethanol and can use the current gasoline distribution infrastructure for transport and delivery.  Experimental modifications of the process show potentially high EROEI (energy returned on energy invested).  Butanol can be mixed with boyh gasoline and diesel. Butanol  viscosity is higher than ethanols, and the product may  gel in colder  weather. Dupont has released a fact sheet on biobutanol indicating that  currently existing ethanol plants can be cost effectively retrofitted to refine butanol and that such a retrofit will prepare the facility for future production of biofuels using future feedstocks, e.g., lignocellulosics.

Carbon-neutrality – Generally carbon neutrality refers to the balance maintained when a fossil fuel is burned, releasing CO2 into the atmosphere, and the use of a renewable fuel to produce a comparable amount of energy so that the net balance of CO2 emissions are balanced with CO2 used to produce the renewable energy source.

Biofuels are generally thought to be "carbon-neutral” because  feedstock production using plants captures equivalent amounts of  CO2 from earlier generations of feedstocks used to produce biofuels and subsequently burned as fuel.

Absolute carbon-neutrality cannot be achieved if fossil fuels are used in any part of the production or distribution of the biofuel. We at Promethean recognize that fossil fuels will play a role in human energy usage for many years to come. That said, carbon-neutrality is an achievable ideal, and its pursuit has the greatest potential of reducing the amount of CO2 in the environment with a net positive impact on Global Warming.

Carbon sequestration – Carbon sequestration is the process of removing CO2 from the atmosphere. Current technology research and development seeks to capture and store the CO2 and store it in sinks, while releasing oxygen (O2) into the atmosphere. The process of carbon capture and storage is often referred to as CCS.

EROEI or Net Energy Gain – Energy Returned on Energy Invested or Net  Energy Gain refers to a method of cost accounting applied to energy production that considers the total resources as energy inputs required to produce and distribute fuels to consumers. A useful example might be the calculation of the energy inputs used to grow corn that includes the costs of any petroleum-based fertilizers, any fuel consumed by  farm equipment to harvest or transport the corn for processing at an ethanol production plant, the heat used to brew and distill the ethanol and the energy necessary to transport the ethanol to market are all factored into the accounting.

 Surprisingly many fuels – including petroleum from older fields or foreign origination – exhibit 1:1 or negative EROEI. The work and energy exerted in the process of making gasoline is extraordinary.  Producing gasoline at a 1:1 ratio means that an equal amount of energy is used to produce and distribute the energy ultimately used; in essence to provide the energy in a gallon of gas to a consumer took the equivalent energy of a gallon of gas.