With many European nations embarking on smart metering programmes, Duncan Sinclair of Redpoint Energy examines the ways in which advanced meters can be used to combat the highly variable output of intermittent energy sources such as wind.
In January 2011 the European Wind Energy Association (EWEA) announced that Europe is set to beat its target of drawing 20 per cent of its energy from renewable sources by 2020, and that wind energy is now powering five per cent of total energy generation across the region.
The renewable energy strategies being implemented are a key part of each nation’s decarbonisation agenda, which seek to reduce CO2 emissions. Many have ambitious short-term targets for incorporating renewable sources into the energy mix, and to meet these targets, a sea-change is required in the way countries approach energy production and consumption – including the way in which it is sourced, controlled and regulated, and the way in which it is funded.
Most importantly, it is essential to recognise the defining characteristic of a renewable source – i.e. the intermittent nature of its output, and the fact a renewable is subject to fluctuations in weather conditions. The rotors of wind turbines only turn when the wind blows, in the same way that solar panels only generate power when the sun shines.
A power paradox
Wind power technology is a hugely advanced market in Europe, with more than 75,000 MW of installed capacity. In fact, it is the most widely tapped renewable energy source in Great Britain to date. However, its popularity perfectly illustrates the problem with renewable and the difficulty in balancing supply and demand. There are many conflicting views on how far output can be relied upon at times of peak demand: numbers range from zero to 30 per cent of installed capacity in any given country. Aside from the uncertainty – a problem in itself – even 30 per cent compares rather unfavourably to the 90 per cent that can be expected on average across the conventional generation fleet (namely fossil fuels and nuclear).
This unpredictable and highly variable output creates a whole new paradigm for energy management, and a whole new series of challenges for the energy industry and governments to overcome.
Indeed, the problem only gets more challenging with the more wind we harness. In smaller countries for example, there is a particular challenge as output from renewable plant is highly correlated. In other words, the same weather conditions are likely to have a similar impact at each wind generation plant in a particular region, and possibly across the whole country.
Simply put, if one wind turbine isn’t running, the chances are that many others aren’t either. There is a far greater possibility that there will be little or no output at all from the entire wind fleet than there is with conventional generation, where outages at individual plants tend to be independent of each other.
And so we are left with a paradox: renewables can displace thermal generation, saving fossil fuels and reducing carbon emissions, but we will still need almost as much conventional capacity as we have today to meet demand when the output from renewables is low. We would also need more thermal generation to provide balancing services, since the variations in wind output are difficult to forecast.