It is difficult to put actual costs to the relative benefits and disadvantages of different technologies. Energy normally has a market-place price in terms of e per GJ (gigal-joule) or pence per KWh (kilowatt hour). What is missing are the external costs, which are in effect paid by society. The EU, under its ExternE study, has attempted to evaluate these for various electricity generation technologies (see Table 10.3). It has taken into account a wide range of factors, including health risks and environmental damage, and expressed them in euro cents per KWh. These are of course the extra costs in addition to the normal market price of electricity, which as an EU average, is about 4 euro cents per KWh.