Wind turbines present a lucrative opportunity for farmers/ land owners, particularly for land that is difficult to cultivate. In many areas where the land has become infertile due to salinity or loss of top soil, wind farm can provide farmers with an alternate green income. However before embarking on that project, the farmers must assess the feasibility. In this guide a few major factors that dictate the profitability of turning your farm into a wind farm are listed. It should be noted that the foot print of a wind turbine is extremely small, meaning that agriculture can be carried out in the farm while simultaneously keeping wind turbines on site. Other than assessing the site, the current energy policy and the choice of the type of turbine/s also impact hugely on the viability. They are all explained in the following sections:
1. Site Survey
1.1 Wind Resource
Wind Resource is the prime factor that will determine the feasibility of any site. Normally it is determined by setting up a Metmast, recording and analysing the wind speed and wind direction for a period of an year. In many countries data from the closest weather stations can be obtained. However it is always best practice to measure the data on site as local factors such as terrain and plantation can severely alter wind speeds. For a farm investing in Wind resource measurement may be expensive and time consuming proposition, particularly if it is not required for planning permission. In such cases data from the closest weather station can be extrapolated. Similarly the production of nearby wind-farms (within 30 mile radius) can be assessed. If the wind farms in close proximity have a high capacity factor (25% and over), than it can be said albeit with caution that the site is feasible.
1.2 Site Suitability
Farms in remote areas accessible through tracks, or sites present on top of a hill have to factor in the added costs. The shorter and easier the transport route is, the lesser the costs. Often for installing turbines above 15 kW capacity, in addition to earth moving machines and transportation of turbine itself, a crane may also be required. The new telescopic masts to a certain degree have alleviated the need for cranes but the presence of this mechanism depends upon the make of the turbine. The composition of earth and terrain on site will determine the cost of ground works. If the farm owner wishes to export the electricity to the grid, then the proximity to an energy highway (HV line) would be beneficial. There would be less cable to lay down and less excavation for cable track would be needed. It should also be considered that the site should have no obstacles, (building, trees, mound or pylons) in the direction of prevalent wind as they can either shade the wind or cause turbulence.
1.3 Planning Permit Requirements
In many areas around the world, maps have been issued by local municipal (council) offices for areas where turbines can be installed without cutting through the red tape of planning permission. The areas given the green signal exclude all areas in the vicinity of airport runaway, telecommunication poles and Radars. In addition places of historic interest or places near recreation spots (national parks, golf courses) are also prevented. Similarly a site of ecological interest may also be prevented from installing turbines. Often councils are satisfied if bird migration through the site is minimal. An avian radar installed on the site can provide this data. Farm owners therefore must investigate if their land does not fall in the restricted area or there are height restrictions for Turbine installations
2. Types of Turbines
There are several types of turbines particularly in the small wind power category. For an overall more reliable systems it is always advisable to go for larger wind turbine than several smaller ones. Therefore it is better to install a single 10 kW turbine than two 5 kW ones, not only from the cost perspective but also from a system reliability point of view. The technology developed for large scale wind turbines, cascades down to smaller versions with time. The benefits of large turbines over their smaller counterparts have been explained in this article.
As can be noticed from the table, the price per kilowatt drops with the increasing size of the turbine. Thus their is a greater return on investment with the choice of larger turbine. However as in many cases, the size limitation can not be only because of finance. Often planning regulations prohibit turbines above a certain height.
Turbine sizes up to 15 KW are popular among farmers living off grid. A single wind turbine of 10 KW -15 KW can provide enough energy (up to 50,000 kWh) to meet the farms requirements, but as usual things can vary case to case.
Another important factor in determining the choice of turbine is the power curve. For example, if the turbine Cut-in speed is 4.5 m/s than it could prove unfeasible for a site that observes a high number of hours (an year) below that wind speed.
If turbines need to be installed on a farm just to achieve grid independence, than policies do not matter as such. However, if the farmer is looking into selling electricity to the grid than renewable energy policy would be crucial to the feasibility of the turbine. Many governments around the world in a push towards reducing carbon emissions have introduced a FIT or Feed in Tariff scheme. These schemes make it binding for the government (or energy companies) to pay the electricity generator a certain amount for every unit produced regardless of its end user. Similarly in many countries additional amount is paid for exporting the energy to the grid.
Often Energy/Utility companies acts as the middle man between the farmer and the FIT allowance body. Power Purchase Agreement is drawn between purchaser and the generator. The farmer should be careful in protecting their long-term interest and the PPA should be drafted with due consideration. As farmers are generally not well versed with the technical aspects or the legal framework of selling energy, it is best to outsource the drafting of the PPA. There are agencies that provide these services for a small fee.
On the other hand, there are utility companies that might approach a farmer and ask for the lease of their land for wind farms. In such cases, only consent and the lease price is settled with the farmer/ landowner and there is little or no say in other aspects of the project. If a fair price is being paid, such projects can be the very beneficial as the farmer/land owner does not have to worry about the day to day up keep of the wind-farm.
In today’s world, farmers have great alternatives for generating green incomes through solar panels, wind turbine or by producing bio-diesel. In fact many of the small to medium scale size turbine companies today were initiatives taken by farmers. Barren lands that cannot be used for irrigation anymore provide and opportunity however the right equipment selection for the right site is needed. Green banks in many countries are specifically set up to provide capital investment.