ENVR 201: Energy Systems, Accounting, and Transition

Vocabulary flashcards covering energy systems, energy accounting concepts, conversion efficiencies, storage technologies, and energy carrier definitions from ENVR 201.

Power

The rate at which energy is generated, transferred, or consumed over time, measured in units such as Watts ($\text{W}$), kilowatts ($\text{kW}$), horsepower, and $\text{TWh/year}$.

Energy

The quantitative capacity to perform work or the total amount transferred over a duration, measured in units such as Joules ($\text{J}$), Calories ($\text{Cal} = \text{kcal}$), kilowatt-hours ($\text{kWh}$), $\text{BTU}$, and ergs.

Primary Energy

Energy found in natural resource forms before being subjected to any human-engineered conversion, transformation, or purification process.

Final Energy

The energy delivered and made available to consumers for use after losses incurred during primary transformation, refining, and grid transmission.

Useful Energy

The portion of final energy that successfully performs the desired function after end-use conversion losses (e.g., shaft power from a motor or heat delivered to a room).

Energy Services

The valuable human benefits and material outcomes provided by energy consumption, quantified in non-energy physical units such as illumination, kilometres travelled, warm rooms, and tonnes of steel.

Energy Efficiency

A unitless conversion ratio of useful energy output to total energy input, strictly defined within the range $0 \le e \le 1$.

Energy Efficacy

A performance measure expressing the amount of a valuable service obtained per unit of energy consumed (or energy consumed per unit of value), with examples including $\text{lumens/W}$ and $\text{L/100\,km}$.

Energy Carrier

A substance or medium (such as electricity, hydrogen, ammonia, or refined chemical fuels) that stores energy in a transportable form from generation to end use.

Green Hydrogen

Hydrogen produced through the electrolysis of water powered entirely by renewably-sourced electricity.

Blue Hydrogen

Hydrogen produced from fossil natural gas and steam via steam methane reforming.

Haber–Bosch Process

A chemical synthesis process combining nitrogen and hydrogen to produce ammonia ($\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$; $\Delta H^\circ = -91.8\,\text{kJ/mol}$), primarily used for synthetic fertilizer production and chemical feedstocks.

Lithium Iron Phosphate (LFP)

A lithium-ion battery cathode chemistry that uses no cobalt and no nickel, commonly utilized in grid-scale energy storage and electric vehicles.

Sodium-ion Battery

An emerging commercial rechargeable battery chemistry entering mass production in 2024–2026 that completely eliminates the need for lithium.

Redox Flow Battery

A rechargeable stationary battery that stores chemical energy in external liquid anolyte and catholyte tanks, which are pumped through an electrochemical cell separated by an ion-selective membrane.

Heat Pump

An electrified heating and cooling device that transfers thermal energy between spaces rather than creating heat via combustion, providing $3$ to $4\text{ units}$ of heat per unit of electricity consumed.

High-Voltage Direct Current (HVDC)

An electric power transmission system that utilizes direct current to efficiently transport bulk electrical energy over long distances and undersea connections with low resistive line losses.

Building-Integrated Photovoltaics (BIPV)

Photovoltaic materials incorporated directly into building envelopes and facades—such as solar glass tiles or curtain walls—simultaneously functioning as the outer building material and as an electricity generator.