Onshore Wind Glossary — 100 Key Terms

An A–Z overview of the most important terms and abbreviations in onshore wind energy — from turbine technology through permitting law to economics. With links to detail pages for deeper topics.

Abnahmemessung (acceptance noise measurement)

Officially required measurement of the sound power level after commissioning — within 6 months, per FGW TR 1 / IEC 61400-11. Verifies the values from the acoustic emission prognosis.

Anti-collision system (ABS)

Camera- or radar-based detection of approaching birds with automatic turbine shutdown. Standard mitigation measure in the central assessment zone under § 45b BNatSchG (Federal Nature Conservation Act). Cost EUR 100,000–250,000 per turbine.

Anzulegender Wert (applicable value / strike price)

The minimum price guaranteed by the EEG (EUR/MWh) from the auction process. The difference from the monthly market value yields the market premium. Ceiling value 2026: 7.35 ct/kWh.

Species protection report

Mandatory report in the BImSchG procedure with avifaunistic and bat surveys over at least one breeding season. → Detail

Asset management

Commercial management of a wind turbine: power marketing, insurance, maintenance coordination, authority contacts. Cost typically EUR 1–2/MWh.

Auction (BNetzA / Federal Network Agency)

EEG award mechanism for wind power subsidies. Four dates per year, pay-as-bid auction, ceiling value 7.35 ct/kWh (2026). → Detail

AVV marking (general administrative regulation marking)

General Administrative Regulation on the marking of aviation obstacles. Governs turbine lighting and demand-controlled night marking.

Avifaunistic survey

Bird component of the species protection report. Methodology standards per Südbeck et al. (DDA 2005), 6–10 site visits March–August. → Detail

BauGB § 35 (Federal Building Code § 35)

Planning-law privileged status (Privilegierung) of wind energy in the outlying area (Außenbereich) since 1996. → Detail

Bauleitplanung (municipal land-use planning)

Municipal land-use plan (Flächennutzungsplan) and local development plan (Bebauungsplan). Steers turbine sites via concentration zones or designated areas.

Bilanzkreis (balancing group)

Net balance of power fed in and drawn off by a marketer. The direct marketer bears the balancing-group risk (difference between wind forecast and actual wind).

BImSchG — Bundes-Immissionsschutzgesetz (Federal Immission Control Act)

Federal law governing plant permitting. Turbines > 50 m total height require a permit. → Detail

Blade pitch adjustment (pitch control)

Active adjustment of the rotor-blade angle of attack for power/speed control. Standard on modern turbines; also serves noise reduction in night mode.

BNatSchG — Bundesnaturschutzgesetz (Federal Nature Conservation Act)

Governs species protection (§ 44 prohibition of killing/disturbance), FFH compatibility assessment (§ 34), the intervention rule (§§ 13–17), and turbine exemptions (§ 45b).

BNK — Bedarfsgerechte Nachtkennzeichnung (demand-controlled night marking)

Anti-blinking system: the red turbine lighting only illuminates when an aircraft approaches. Mandatory since 2020. → Detail

Fire safety concept

Mandatory component of the BImSchG application, with a risk analysis of all fire sources plus a self-extinguishing system in the nacelle. → Detail

Bürgerwind (community wind)

Participation models for residents/municipalities — mandatory in MV, BB, NRW. Cooperative or GmbH & Co. KG, equity return 4–6 % p.a. → Detail

CAPEX — Capital Expenditures

Investment cost in EUR or EUR/kW. Onshore wind 2026 typically EUR 1,200–1,700/kW. → Detail

CEF measure

Continuous Ecological Functionality — an advance compensation measure in species protection that must be effective before the intervention.

Corine Land Cover

EU database for land-use classification (1 ha grid). Standard data source for surface roughness in wind modelling.

CRF — Capital Recovery Factor

Annuity factor for converting CAPEX into an annual annuity. At r=5 %, n=20: CRF ≈ 0.0802.

CT — thrust coefficient

Aerodynamic coefficient for the thrust of the rotor. Decisive for the wake turbulence behind the turbine. Full load typically 0.75–0.85.

DCF — Discounted Cash Flow

Economic-analysis method: future cash flows discounted to today's present value. Standard for evaluating wind investments.

DIBt guideline

Guideline for wind turbines issued by the German Institute for Building Technology (Deutsches Institut für Bautechnik). Structural standard for turbines.

DIN ISO 9613-2

International standard for outdoor sound propagation — the basis of every acoustic emission prognosis.

Direct marketing

Mandatory since EEG 2014 for all turbines > 100 kW. Power goes via a marketer to the power exchange or a PPA partner. → Detail

Doorway page

A Google penalty for pages that serve only as a lead funnel without standalone content. Programmatic SEO must avoid the doorway pattern.

DSCR — Debt Service Coverage Ratio

Ratio of cash flow to debt service. Bank standard for wind financing: P50 ≥ 1.25×, P90 ≥ 1.10×.

EEG — Erneuerbare-Energien-Gesetz (Renewable Energy Sources Act)

Federal law for remunerating renewable power generation. Currently EEG 2024. § 2: "overriding public interest" of wind energy. → Detail

Eingriffsregelung (intervention rule)

§§ 13–17 BNatSchG. An intervention in nature and landscape must be avoided, reduced, compensated for, or replaced. → LBP

Ice accretion detection

Sensor technology for detecting ice on the rotor blade with automatic shutdown. Mandatory near traffic routes within throwing range. Providers: Bofin, Eologix, Wölfel iSpin.

Ice throw report

Assesses the ice throwing range (Seifert formula: 1.5 × (D+H)) and the hazard to traffic routes. → Detail

ERA5

Copernicus reanalysis dataset for climate data, including wind speed. Standard for long-term extrapolation in wind assessments.

Erörterungstermin (public hearing)

Public hearing in the formal BImSchG procedure, where objections are discussed with the applicant and the authority.

FFH-Gebiet (FFH / Natura 2000 site)

Protected area under the EU Flora-Fauna-Habitat Directive. Part of the Natura 2000 network.

FFH compatibility assessment

§ 34 BNatSchG. Assesses the compatibility of a project with the conservation objectives of an FFH / bird-protection site. → Detail

FGW TR 1

Technical guideline of the Fördergesellschaft Windenergie (Wind Energy Promotion Association). Standard for measuring the sound power level of turbines.

Bat survey

Survey of collision-endangered bat species with nacelle monitoring April–October. Derivation of the shutdown algorithm. → Detail

Foundation

Shallow foundation (concrete, 600–1,500 m³) or piled foundation. Structurally dimensioned per the DIBt guideline.

Generator

Power generator in the nacelle. Doubly-fed asynchronous or synchronous generators with full converter (modern turbines).

Total height (Gesamthöhe)

Hub height + half the rotor diameter. Decisive for the BImSchG requirement (> 50 m), approach lighting (> 100 m), daytime marking (> 150 m).

Nacelle (Gondel)

The machine housing on the tower. Contains the generator, main bearing, gearbox (if any), transformer, controller.

Greenfield

A new-build site with no prior development — as opposed to repowering sites with existing turbines.

Hellmann exponent

Exponent in the height extrapolation of wind speed. Onshore α ≈ 0.16–0.28, water α ≈ 0.10.

Helgoländer Papier (Helgoland Paper)

"Distance recommendations for wind turbines to significant bird habitats" by the LAG VSW. Taboo and assessment zones for 24 bird species. Partly superseded by § 45b BNatSchG.

Eyrie control (Horst-Kontrolle)

Targeted search for birds-of-prey eyries in the planning area and surroundings. Part of the avifaunistic survey.

ICAO lighting

International obstacle marking for aviation — red night beacons + white daytime beacons. Today usually demand-controlled via BNK.

IEC 61400-1

International standard for the design requirements of wind turbines. Defines turbine classes I–IV (wind class) and A/B/C (turbulence class). → Turbulence tool

Immissionsort (IO) — assessment point

A point worthy of protection (residential building) at which noise/shadow is assessed.

Inertia (rotating mass)

Rotor inertia. Affects grid stability — wind turbines with a full converter have "synthetic" inertia via frequency control.

Infrasound

Sound < 20 Hz. Not covered by TA Lärm. Studies (UBA 2020) show no health effects below the perception threshold.

IRR — Internal Rate of Return

The discount rate at which NPV = 0. Standard return metric for wind projects. Onshore wind 2026: 7–10 % typical. → Tool

Jensen wake model

Linear wake-propagation model (Jensen 1983). Standard for layout optimization. Further developed into Larsen, FUGA, NO-Jensen.

Capacity factor

Ratio of annual yield to theoretical full-load annual yield. Onshore typically 25–40 %, offshore 40–55 %.

Litigation risk

Recognised nature-conservation associations (BUND, NABU) can sue under the Environmental Appeals Act (Umweltrechtsbehelfsgesetz). The most common cause of delay in the BImSchG procedure.

Konzentrationszone (concentration zone)

An area designated in the municipal land-use plan in which turbines are permitted — with an exclusion effect outside it (before the WaLG reform).

LAI guidelines

"Guidance on determining and assessing the optical immissions of wind turbines" (LAI 2002). Defines the 30/30/8 rule for shadow flicker. → Detail

Larsen wake model

A further development of the Jensen model with better accuracy in the near field. Standard in WindPRO and WindFarmer.

LBP — Landschaftspflegerischer Begleitplan (landscape impact and management plan)

Intervention-compensation balance under § 15 BNatSchG. Mandatory component of the BImSchG application. → Detail

LCOE — Levelized Cost of Energy

Levelized cost of electricity in EUR/MWh over the lifetime. Central economic metric. → Detail · Tool

LIDAR — Light Detection And Ranging

Laser-based wind measurement. Alternative to the met mast, much faster to set up. IEC-certified for bankability since 2020.

L_WA — sound power level

The sound emitted by the turbine (in dB(A)). Source value for every acoustic emission prognosis. Modern onshore turbines: 104–109 dB(A).

Market premium (Marktprämie)

The difference between the applicable value and the monthly market value for wind. → Detail

MaStR — Marktstammdatenregister (Core Energy Market Data Register)

Federal Network Agency database of all German power-generation plants.

MEASNET

Certification network for wind measurements. The MEASNET audit standard for the bankability of wind assessments.

MERRA-2

NASA reanalysis dataset. Standard long-term reference for wind yield forecasts.

Mode (turbine operating mode)

Manufacturer-certified operating mode with a defined L_WA value. Standard: Mode 0 = full power; Mode 3 = noise-reduced (typically −3 to −6 dB).

Hub height (Nabenhöhe)

Height of the rotor hub above ground. Modern onshore turbines: 130–180 m, up to 200 m in forests.

Night mode

Noise-reduced operation 22:00–06:00. Speed/pitch reduction lowers L_WA by 2–6 dB. Yield loss 1–4 % p.a.

Natura 2000

European network of protected areas comprising FFH and bird-protection sites. Conservation objectives via § 34 BNatSchG.

Grid connection

Connection of the turbine to the public power grid. Medium voltage 20 kV or high voltage 110 kV. Connection cost EUR 500,000–1,500,000 per park.

NPV — Net Present Value

Present value of all discounted cash flows less the investment. Positive = economically viable.

Onshore vs. offshore

Onshore = on land, offshore = at sea. Repowering Hub covers onshore.

Ökopunkte (eco-points)

Tradable nature-conservation certificates. An alternative to one's own compensation areas — cost EUR 0.80–2.00 per point.

OPEX — Operating Expenditures

Ongoing operating costs. Onshore 2026 typically EUR 20–30/MWh. → Detail

Land lease (Pacht)

Usage fee for site land. Market-standard 6–10 % of power revenue + a fixed component. → Detail

Park layout

The spatial arrangement of several turbines. Optimization minimizes wake losses — see the turbulence indicator.

Payback period

The time until the cumulative cash flows have repaid the investment. Onshore wind 2026 typically 10–12 years.

P50, P75, P90

Probability quantiles of the yield forecast. P50 = mean, P90 = very conservative (bank standard).

PPA — Power Purchase Agreement

A long-term power supply contract between an operator and an industrial customer. → Detail

Privilegierung (privileged status)

Preferential planning-law treatment in the outlying area under § 35 BauGB. A prerequisite for turbine sites.

Source height (Quellenhöhe)

The noise / shadow-flicker source = hub height. Calculation standard in DIN ISO 9613-2.

Resting birds (Rastvögel)

Migrating birds that rest at the site during the spring and autumn migration. Survey at migration-corridor locations 8–12 site visits Sept–April.

Refurbishment

Major overhaul with component replacement — an alternative to repowering at good sites with an intact turbine.

Regional planning (Regionalplanung)

Spatial planning at state/regional level. Steers turbine sites via priority, designated, and concentration zones. → Detail

Repowering

Replacing old turbines with newer, more powerful ones. → Detail

Red kite taboo (Rotmilan-Tabu)

Under § 45b BNatSchG: 1,500 m close-range area (generally not permittable), 1,500–4,000 m assessment area.

Rotor

3-blade rotor with a 100–180 m diameter. Modern large turbines 162–175 m.

Decommissioning (Rückbau)

Obligation under § 35 (5) BauGB: full turbine removal at end of life, secured by a surety bond. → Detail

Sabine formula

A simplified shadow-flicker geometry: maximum shadow length from turbine height and sun position. The basis of preliminary indications.

Shadow flicker (Schattenwurf)

The moving rotor shadow on residential buildings. LAI limits: 30 h/yr, 30 min/day, 8 h/yr actual. → Detail

Acoustic emission prognosis

Calculation of sound levels at residential development per DIN ISO 9613-2. Mandatory in the BImSchG procedure. → Detail

Sound protection report

Extended noise forecast + protection concept (night mode). → Detail

Low-wind turbines

Turbines with a low specific power rating (≤ 280 W/m²). For southern/inland sites. → Detail

Black stork protection

3 km taboo area + 10 km diversion corridor. The most common conflict species in Brandenburg.

Structural stability certificate

Structural verification per the DIBt guideline + Eurocodes. Reviewed by an independent checking engineer. → Detail

Site quality factor (Standortqualitätsfaktor)

Ratio of the yield achieved to that of the reference site. At a factor < 100 %, an EEG correction of the applicable value applies (low-wind bonus).

South bonus (Süd-Bonus)

EEG surcharge of 0.30 ct/kWh for sites in BW, BY, HE, RP, SL.

TA Lärm (Technical Instructions on Noise Abatement)

The Sixth General Administrative Regulation to the BImSchG. The benchmark for assessing noise. → Detail

Transformer station

Medium-voltage transformer for stepping up power before grid feed-in. In the tower base or as a separate station.

Turbulence intensity

The variability of wind speed. IEC 61400-1 class A 16%, B 14%, C 12%. → Tool

Type certificate

Turbine manufacturer's certificate of structural stability + aerodynamics. Issued by DEWI-OCC, TÜV, DNV.

ÜNB — Übertragungsnetzbetreiber (transmission system operator)

50Hertz (eastern DE), Amprion (west), TenneT (northern DE), TransnetBW (south). Pays the EEG market premium.

UVP — Umweltverträglichkeitsprüfung (environmental impact assessment, EIA)

Under the UVPG, for turbines from 20 units (mandatory), 3–19 units (screening). → Detail

UVS — Umweltverträglichkeitsstudie (environmental impact study)

The main document of the full EIA — all protected assets (humans, animals, plants, soil, water, climate, landscape, cultural heritage).

Availability

The share of time during which the turbine is technically available. Manufacturer guarantee 95–98 %. Standard 97 %.

Marketer (Vermarkter)

Direct marketers such as Statkraft, Axpo, EnBW, Next Kraftwerke. They take on the power + balancing-group risk for a fee of EUR 1.2–2.5/MWh.

Visualization

Photomontages from 6–12 representative viewpoints. Mandatory in the formal BImSchG procedure. → Detail

Full-load hours (VLh)

Notional hours at rated power per year. Onshore wind 1,500–4,000 VLh. → Detail · Tool

V_tip — blade tip speed

The speed of the rotor-blade tip. Modern onshore turbines 70–90 m/s.

WACC — Weighted Average Cost of Capital

Weighted cost of capital, equity + debt. The discount rate for DCF/LCOE. Wind 2026 typically 4–7 %.

Wake effect

The flow wake behind a turbine with reduced wind speed and increased turbulence.

WaLG — Wind-an-Land-Gesetz (Onshore Wind Act)

In force since 2022. Obliges the federal states to designate 2.2 % of their area by 2032. → Detail

Weibull distribution

Statistical distribution of wind speed at the site. Two parameters: A (scale), k (shape). Onshore typically k=2.0.

Honey buzzard taboo (Wespenbussard-Tabu)

1,000 m close-range area + 4,000 m assessment area under § 45b BNatSchG. Breeding density frequently underestimated.

Wind resource (Windhöffigkeit)

The mean wind speed at the site. Onshore economic threshold approx. 5.5 m/s at hub height. → Detail

Wind farm

Several turbines at one site with a common grid connection. Wake losses typically 5–10 %.

ZVI — Zone of Visual Influence

Visibility map: from which areas the turbines are visible. Part of the visualization reports.

Migration corridor (Zugkorridor)

A spatial concentration line of bird migration. At turbine sites in migration corridors, an additional resting-bird survey Sept–April.