According to the IEA/NEA 2010 Projected Cost study, load factors in OECD countries vary between 22% (Italy) and 41% (United States) for wind and between 10% (Netherlands) and 25% (France) for solar photovoltaic (PV). Assuming an entirely realistic average load factor for wind-power turbines of 25%, this means that the share of wind on windy days is four-fold its average figure. This means, for instance, that the Danish system can only be balanced by being closely integrated with the Nordpool electricity market with its ideal balancing conditions due to the almost exclusive reliance on hydropower by Norway.