The suggestion is part of the switch away from fossil fuels and nuclear power to relying on renewable energies, following the Fukushima nuclear crisis.
In wooded regions of the state, potential for wind development amounts to as much as 6.2-9.3GW, the NRW environment ministry said at the end of March. This would double or treble capacity in the state, which stood at 3.01GW at the end of last year, after an addition of 160MW in 2011.
Prior to a state wind energy regulation passed last July, turbine installation in wooded regions had not been allowed. Now, with that ban lifted, the state government has published a guide to wind energy in forested areas to encourage wind turbine installation. The forests consist of pine trees, which have no great ecological value.
Motivating landowners is important. Some 64% of around 878,000 hectares of forested area in the state is privately owned, and the average wooded holding is just five hectares. "Here, it depends directly on the will of the wood or forest owners whether they make the area available for installing wind turbines," said Axel Kammerling, chief commissioner of woods at the NRW forests and wood authority in Muenster.
The forestry authority has initially looked at around 348,000 hectares of forest that lie outside protected areas, where wind-energy development could best be concentrated. Assuming just 5% of this area, or 17,400 hectares, can be used and that one 3MW turbine is assigned per 8.5 hectares, around 2,050 turbines with more than 6GW of new capacity could be installed.
The guidelines recommend use of turbines with a hub height exceeding 120 metres as they use layers of air high enough above the treetops not to be greatly influenced by the trees or landscape below. "Wind speeds are higher, turbulence is reduced and the wind blows more constantly at greater heights above ground," the document points out.
Steffen Kircher, a lawyer at the Stuttgart-based legal practice Menold Bezler Rechtsanwalte, which has specialist experience in wind-energy use in woods and forests, says species protection also needs special attention because of the prevalence of wildlife. Kircher adds that developers must be aware of the additional permit usually required for 'change of land-use' from forestry to wind turbine installation, while access for machinery and turbine components can also be a problem, potentially requiring tree felling forest tracks that would incur additional costs.
There are some wind farms in forested areas in other parts of the country, but it is not widespread yet. Last September, nature protection organisation Deutscher Naturschutzring (DNR) said the states of Brandenburg and Hessen will not fulfil their targets for wind energy without using forested or protected areas. In the states of Rheinland Pfalz, Baden-Wurttemberg and Bavaria, the only regions with adequate wind speeds are hill tops and ridges, most of which are wooded, DNR said.