The cost of renewable energy has tumbled even further over the past year, to the point where almost every source of green energy can now compete on cost with oil, coal and gas-fired power plants, according to new data released today. Hydroelectric power is the cheapest source of renewable energy, at an average of $0.05 per kilowatt hour (kWh), but the average cost of developing new power plants based on onshore wind, solar photovoltaic (PV), biomass or geothermal energy is now usually below $0.10/kWh. Not far behind that is offshore wind, which costs close to $0.13/kWh. These figures are global averages and it is worth noting that the cost of individual projects can vary hugely – the cost of producing electricity from a biomass energy plant, for example, can range from as low as $0.05/kWh to a high of almost $0.25/kWh. However, all these fuel types are now able to compete with the cost of developing new power plants based on fossil fuels such as oil and gas, which typically range from $0.05/kWh to over $0.15/kWh.