Due to unavailability of larger sites, small projects with five or fewer turbines represent 75% of the German market. Their costs per kWh should be compared with premium prices in the "small band" under England's NFFO. The tendering process of NFFO would result in higher prices if larger additions to capacity would be demanded. Thus if England wanted to reach the same capacity or the use of a similar proportion of potential sites as in Germany, prices would be more similar in both countries. Concentrated use of the sites available also leads to high costs for environmental offsets in Germany.
Before applying for building permits and grid connection, German developers must choose the type of turbine. This also reduces the ability to bargain for lower prices. My project in Friedrichskoog near the coast was recently completed with rather outdated Vestas V39-500 turbines after waiting for grid connection for years, at costs above the most recent list prices. Higher towers for inland sites with corresponding foundations also add to costs per square meter.
Finally, I think that purchase prices in England are tied to overall inflation, while in Germany they are tied to prices of electricity, which many think are bound to fall under increased competition. In conclusion, much of the German "wind economic miracle" seems to depend on rather low equity returns, accepted by investors looking for an environmentally sustainable use of their savings.