57 terms shown
- 24/7 carbon-free energy24/7 CFEMatching consumption with carbon-free supply in every hour, rather than over a year. A much harder standard than annual matching, since it needs supply through the night and in still weather.
- Ancillary servicesThe services that keep the grid stable, such as frequency response and reserves held ready to run. Procured apart from energy, and increasingly a revenue line for batteries.
- AvailabilityThe share of time a plant, or a piece of it, is able to run. Contracts guarantee it; the gap between availability and output is the weather.
- BankingIndiaLeaving surplus generation with the grid to draw back later, under the state's rules: how long it can be kept, which hours it can be drawn in, and what share is deducted. Banking rules can change a project's value more than its tariff.
- Battery energy storage systemBESSBatteries with their inverters and controls. Charges when power is cheap or in surplus and discharges when it is dear or needed, which is why its value depends entirely on when it is run.
- Capacity marketUSA market that pays generators and storage to be available at times of system stress, separately from the energy they sell. Common in US regions and the UK; absent in most of India.
- Capacity utilisation factorCUFThe energy a plant produces over a period as a share of what its nameplate capacity would produce running flat out the whole time. Called capacity factor in most markets. Solar in a good site runs around 20 to 25%, wind higher.
- Captive powerIndiaGeneration owned by the consumers who use it, meeting the rules on ownership share and consumption. Captive supply is exempt from some charges that open-access supply pays, which is the point.
- Commercial and industrial consumersC&IBusiness electricity users, from offices and hospitals to factories and data centres. Their load patterns, tariffs and supply options differ, so renewable procurement starts with when and how much power each site uses.
- CongestionWhen a line or interface cannot carry all the power that wants to flow across it. Cheap supply on one side cannot reach demand on the other, so prices split between the two sides.
- Cross-subsidy surchargeCSSIndiaA charge on open-access consumers to make up the subsidy their utility tariff was carrying for other consumers. Set by the state regulator, and often the swing factor in whether open access pays.
- CurtailmentA generator producing less than it could because the grid operator has told it to, for a constraint on the wires or more supply than demand. Lost energy that the project's model should have priced in.
- Day-ahead marketDAMAn auction run the day before delivery. Buyers and sellers bid for each delivery block of the next day, and the exchange clears one price and schedule per block.
- Debt service coverage ratioDSCRCash available for debt payments in a period divided by the payments due. Lenders set a floor, often around 1.2 to 1.3, and size the loan so the project clears it in a poor year.
- Declared scheduleThe output a generator, or the drawal a buyer, commits to for each coming block. Settlement compares what actually happened against it.
- Deviation settlementDSMIndiaSettlement of the gap between scheduled and actual generation or drawal, block by block. Eligible wind and solar sellers have a revenue-neutral tolerance band: energy is still settled, but without an additional penalty. Rates and bands depend on the applicable rules.
- Digital twinA live model of a plant that runs alongside it, working out what the plant should be producing given the weather and its own state. The gap between the twin and the meter is where faults and underperformance show first.
- DispatchDeciding what each asset does in each block: how much to generate, when to charge and discharge, what to bid. Done well, dispatch is where a project's modelled return is actually earned.
- Duck curveThe shape of demand net of solar on a sunny day: low in the middle of the day while the sun is up, then climbing steeply into the evening as it sets. The steeper the evening ramp, the more storage and flexible supply the system needs.
- Edge connectorSoftware running at the plant that reads the equipment over the plant's own network and sends the data out, since the controllers themselves are never exposed to the internet.
- Energy management systemEMSThe software that runs a plant's dispatch: it takes the schedule, the prices and the plant's state and decides, block by block, what the equipment should do.
- ForecastingPredicting generation, load and prices for the blocks ahead. The schedule is built on it, so forecast error turns directly into deviation charges and missed revenue.
- Green day-ahead marketGDAMIndiaA day-ahead auction for renewable power only, cleared before the conventional day-ahead market. Buyers use it to meet renewable obligations; sellers get a separate price for green supply.
- Grid codeThe technical rules a connected plant must meet: frequency and voltage response, ramp rates, reactive power, what it does during a fault. Compliance is checked at connection and audited after.
- Hybrid projectA project combining two or more generation or storage technologies, often sharing a grid connection. Solar, wind and batteries can complement each other, making better use of the connection and changing when power is available.
- ImbalanceThe difference between scheduled and actual energy in a block. Every market charges for it in some form; the names and the formulas differ.
- Independent power producerIPPA business that generates electricity for sale to utilities, traders or other buyers, outside the traditional integrated utility model. It can sell under power purchase agreements, into markets, or through a mix of both.
- InterconnectionThe process of getting a plant connected to the grid: the studies, the upgrades the grid needs to take it, and the queue. In many markets the longest part of a project's life before it earns anything.
- Internal rate of returnIRRThe discount rate at which a project's cash flows sum to zero. The standard measure of a project's return: project IRR on all the capital, equity IRR on the owner's share after debt.
- Intraday marketTrading between the day-ahead auction and real time, continuous or in sessions, for positions that need changing before the real-time window opens.
- Investment and production tax creditsITC, PTCUSFederal credits that pay back part of a project's capital cost (ITC) or pay per unit generated for its first years (PTC). Which one a project elects can move its return by points.
- Landed costThe all-in cost of power delivered to the buyer's meter: the energy, plus wheeling, losses, surcharges and taxes. The only price on which two offers can be compared fairly.
- Levelised cost of energyLCoEThe present value of a project's lifetime costs divided by the present value of its lifetime energy, per megawatt-hour. It estimates the constant energy price needed to recover those costs at the chosen discount rate.
- Locational marginal priceLMPUSThe price at one point on the grid: the cost of supplying the next unit of power there, including congestion and losses. Prices differ from node to node when the wires between them are full.
- Market clearing priceMCPThe price at which bids and offers balance in an auction. Every cleared buyer pays it and every cleared seller receives it, whatever they bid.
- Megawatts and megawatt-hoursMW, MWhMegawatts measure power: the rate of generation, consumption or battery charging. Megawatt-hours measure energy over time. A steady 4 MW for 15 minutes delivers 1 MWh. A battery's MW rating and MWh capacity describe different limits.
- Merchant powerPower sold into the markets at whatever price they clear, instead of under a long-term contract. Higher expected revenue, and the risk that comes with it.
- Modbus and OPC UAThe industrial protocols most plant equipment speaks. Modbus is old, simple and everywhere; OPC UA is newer, structured and secure. Reading either is the first step to seeing a plant live.
- Monte Carlo simulationRunning a model many times with its inputs drawn at random from their ranges, to see the spread of outcomes rather than one estimate. Where P50 and P90 come from when the inputs are uncertain.
- Net present valueNPVA project's future cash flows discounted to today and summed, less the investment. Positive means it earns more than the discount rate; the IRR is the rate at which it reaches zero.
- Open accessIndiaThe right of a consumer above a size threshold to buy power from a supplier other than the local utility, using the utility's wires for a charge. The route most corporate renewable supply in India takes.
- P50 and P90The output a project is expected to exceed half the time (P50) and nine years in ten (P90). The developer plans on P50; the lender sizes debt on P90, so the gap between them decides how much the project can borrow.
- Payback periodHow long until a project's cumulative cash flows repay the investment. Simple to read, blind to what happens after, so it sits beside IRR rather than replacing it.
- Performance ratioPRA solar plant's actual output as a share of what the sunlight on its panels would give at their rated efficiency. It normalises output for measured sunlight, while temperature and other losses still affect the result.
- Power purchase agreementPPAA long-term contract to buy power at agreed terms, typically ten to twenty-five years. Physical when the power is delivered over the grid, virtual when only the price difference is settled and the power is sold elsewhere.
- Real-time marketRTMA market that clears shortly before delivery, usually within the hour, so parties can adjust their day-ahead position as forecasts and plant conditions change.
- Renewable energy certificateRECAn instrument representing the attributes of one megawatt-hour of renewable electricity, which may be traded separately from the energy. Certificate systems include RECs, guarantees of origin and I-REC(E); eligibility and claim rules depend on the market.
- Renewable purchase obligationRPOIndiaA requirement on utilities and large consumers to take a set share of their power from renewables, rising year on year. Met with supply, or with certificates.
- Round-trip efficiencyThe energy a battery gives back as a share of what went in. Around 85 to 90% for lithium-ion; the rest is lost as heat, and has to be paid for.
- SCADASupervisory control and data acquisition: the system that reads a plant's equipment and sends it commands in real time. Every inverter, breaker and meter reports into it.
- Sensitivity analysisMoving one input at a time and watching the result. Shows which assumptions the answer actually depends on, so the diligence goes there.
- Settlement blockThe unit of time a market or grid settles on. Fifteen minutes in India and much of Europe, five minutes to an hour elsewhere. Schedules, prices and deviation charges are all set per block.
- State of chargeSoCThe battery's estimated charge level, expressed as a percentage of a stated reference capacity. Its operating limits determine how much energy is available for dispatch; the percentage basis should be stated when comparing systems.
- TariffThe price a consumer pays per unit of electricity, usually in parts: an energy charge per unit, a demand charge on peak load, and fixed charges. The grid tariff is what a renewable supply has to beat.
- Term-ahead marketContracts for delivery days to months ahead, traded on an exchange. Sits between the spot markets and long-term power purchase agreements.
- Time-of-day tariffToDA tariff that changes with the hour: higher at the evening peak, lower in the middle of the day or at night. Shifts what a battery is worth, since it decides when stored power is dearest.
- WheelingMoving power over the grid from a generator to a buyer who is not the utility. The wheeling charge is the fee for the wires, and wheeling losses are the energy lost on the way.
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