Energy yield calculations for domestic scale wind turbines

Dreaming of becoming a domestic wind turbine owner?

– Three important factors!

small wind 21. Location of turbine suitable for energy production?
The same turbine can produce up to four times more energy at a ideal site than at a not so suitable one. This is partly due to where you live but also the nature of the surroundings. Nearby vegetation and buildings and obstacles 50-1000 m away have a significant impact on the energy in the wind and how this energy reaches the turbine.

2. Where is the most suitable location for a turbine on my site?
Moving the turbine as little as 50 m may increase the energy production considerably and an optimization of the turbine siting is therefore extremely important.

3. Problems with noise?
The municipality has to approve the erection of a turbine.  An impartial noise calculation is therefore one of the most important documents in the approval process which needs to show compliance with the legislation. The noise calculation may result in a different location of the turbine than originally planned.

We can help you in the process of making a decision, getting answers on the critical questions. In the following we will take you through a more technical and detailed description of what we can offer, the costs and the process.

Product Description

The expected energy production of a domestic wind turbine is calculated by EMD using a calculation model from our own developed software windPRO. EMD collates the wind model calculations and interpretation of the results in a short report which will be e-mailed as a PDF document to the client.

The calculation results contain an expected energy production for the specific wind turbine, calculation results for chosen reference turbines and a detailed overview of the specific domestic wind turbine divided into twelve wind directions. Based on this information the impact of the different obstacles in different wind direction is analyzed. If the customer has ordered additional calculations, these will be presented in separate reports.

It is important to note that the results may contain uncertainties as the calculations are based on a calibrated ideal wind model and the calculations are based on small turbines with a low hub height in turbulent wind conditions.

Various turbine types are influenced differently by such conditions and there can also be considerable influence from local obstacles such as buildings, windbreaks and trees.

Conditions – data from the client

small wind 3The price and the extent of the calculations are based on the fact that EMD takes on the consultancy task without a prior site visit. Therefore it is crucial that we receive all the necessary information as per below by e-mail:

  • Site and proposed location of the turbine (co-ordinates based on markings on an aerial photo) and boundary of client’s property.
  • Data on the turbine – hub height, rotor diameter and power curve (and noise data if available).
  • Indicated on the map: type of obstacle, exact size and height of buildings, trees and vegetation (forest) within a distance of 800 m of the turbine.
  • Photos taken from the proposed turbine location in eight compass directions (N, NE, E, SE, S, SW, W, NW).
  • Noise / shadow flicker calculations are additional calculations: Requires the locations of neighbours (noise or shadow recipients) and status of their property (country house, specific noise sensitive areas).

Visualization is an additional calculation: Required photo with GPS-position and direction (if there is no Google Streetview of the actual location).

Conditions – data from EMD

EMD uses their own information in the calculation as follows:

  • Wind data: Latest wind statistics for Denmark
  • Roughness model for Denmark.
  • Height data for Denmark (DK DHM 2.5 lines).
  • Surface scanning of Denmark (DK DHM 1.6 m grid surface).
  • Topographical maps and aerial photos.
  • Generic power curve – if no further information available from the customer.
  • Production calculations of a certain number of existing neighbouring turbines (reference turbines).

Noise calculation is an additional calculation: Correct location of noise recipients based on orthophotos and on information from client.

Procedure – energy yield calculation

The process when performing an energy yield calculation of a domestic wind turbine with a given hub height.

  • The client requests EMD to produce an energy yield calculation of a domestic wind turbine inclusive all the above-mentioned information.
  • EMD sets up a calculation model in windPRO and perform an optimization analysis of the specific turbine location taking into consideration the local wind resources.
  • The client receives the result by e-mail of the optimization analysis and based on this the client can make a final decision on the location.
  • EMD performs a calculation on the expected annual energy yield based on the agreed location and a suitable number of reference turbines in the area.

EMD performs a final analysis of the calculation input, turbine power curve and the calculation results. Finally EMD will produce a report on the expected annual energy yield of the turbine which will be e-mailed to the client.

Price and delivery

small wind 1Time of delivery and prices are as follows:

  • Energy calculation: Price DKK 4,000 inclusive 25% Danish VAT.
  • Additional calculations: Prices as per below.
  • Terms of Payment: Upon ordering, the client will receive an invoice by e-mail. Upon receipt of payment, we will initiate the work.
  • Time of Delivery: Within two to three weeks.

Term of Delivery: As per EMD’s standard conditions on consultancy services.

Additional parameters and calculations

The following additional calculations are possible in case there are many and/or significant obstacles or the approval process from the municipality is dependent on noise and shadow flicker calculations. The additional prices (to an energy yield calculation) are as follows:

  • Sensitivity analysis on the effect of alterations of height of the local obstacles (such as hedgerows and vegetation): Price DKK 2,000 inclusive 25% Danish VAT.
  • EMD can perform calculations on the noise impact on the surroundings (neighbours): Price DKK 2,000 inclusive 25% Danish VAT for projects with up to five neighbours. Please contact us for an exact price if the project includes more than five neighbours.
  • EMD can perform calculations of the shadow flicker impact on the surroundings (own property, neighbours): Price DKK 2,000 inclusive 25% Danish VAT.
  • Energy calculations with up to two different turbine types or hub heights: Price DKK 1,000 inclusive 25% Danish VAT.

Visualization of the turbine by means of Google Streetview (if possible) or using geo-referenced photo (GPS-position and compass direction will be included in the photo): Price DKK 2,000 inclusive 25% Danish VAT.

Contact

Please contact EMD for further information and ordering of consultancy services.

To read this information in Danish, please click here