Additional information on specific country data and on the methodology used for calculations is reported in Appendix 4.A. Table 4.6 provides the final results on a country-by-country basis. The values used in our model lie in that range, with the exception of those for the United Kingdom, above USD 7/MWh at 10% penetration level and double at 30% penetration (Redpoint, 2008). This probably reflects the challenge of balancing wind in small isolated electricity market. No studies have reported balancing costs for solar technology: thus, this study works with balancing costs that are similar to those calculated for wind power. This is not unreasonable: ramping rates tend to be smoother with solar energy, while forecast accuracy is lower (Barth, 2011).