Better forecasting of where the wind is blowing could allow British fossil fuel power stations to be switched off and counter critics' claims that wind power is too intermittent.

National Grid, which runs the UK's electricity grid infrastructure and spends billions each year on balancing energy supply with electricity demand, has made a significant upgrade to enable it to predict much more reliably where, when and how strongly the wind will blow.

Under an old system dubbed Windy Miller, after the windmill owner from children's TV series Camberwick Green, the grid company could predict with 85% reliability. The new system, in the works since 2008, will be accurate 87% of the time.

While it does not sound like much of a difference, consider that the UK's peak electricity generation is about 60GW. That means that a two percentage point improvement in forecasting could result in 1.5GW saved, which means three medium sized coal-fired power stations could be turned off. National Grid declined to be specific on the likely cost and carbon savings, but said they would be significant.

Alan Smart, energy operations manager at National Grid, said: "It's becoming more important to be able to predict output within a quite narrow spectrum of weather conditions. The new system will enable us to integrate this important renewable resource in the best way."

Adding wind energy to the electricity grid means managing its intermittency – the fact that the wind does not blow consistently. When energy from wind farms is not available, because the wind is either not strong enough or, at times, too strong for the turbines, then back-up electricity, usually in the form of fossil fuels, must make up the gap.

This can be costly in terms of both cash and carbon, because coal-fired power stations take time to power up and down. Gas-fired power generation can be turned on and off more quickly, but there is still a cost. Wind farms can only operate when the wind is between 4-26 metres per second, with optimal generation at 16 metres per second.

Wind makes up only a few percent of the UK's electricity generation at present, but within a decade should provide at least a fifth of generating capacity, if European Union targets on renewables are to be met. Most of this will come from large turbines offshore.

The improvements to National Grid's wind forecasting have come about largely by upgrading its software and back-end systems that process standard weather forecasts from Meteo Group. The method of weather forecasting remains the same, but by collating more precise data on previous wind patterns and improving the way it is processed within the system – using methods including neural networks – engineers have come up with a range of probabilities for how strongly the wind will blow in a given location at a given time. This can be fed into the company's systems to predict how much standby power will be needed from fossil fuels.

The new system will provide four daily forecasts at six-hour intervals, with forecasts for 34 key locations around the UK. National Grid is well-practised in forecasting electricity demand, as it needs to provide enough power to cover each peak – the most famous example is of millions of people turning their kettles on during half-time when England plays in the World Cup.

National Grid is planning several other ways to increase efficiency, as well as better wind forecasting. The company is developing a "smart grid", which will give better information on when consumers are using energy. Eventually home appliances will be able to be turned up or down according to demand.

New interconnectors with mainland Europe will also play an important role. National Grid recently switched on BritNed, a new connector with Holland that will carry 1GW. This will enable the UK to export electricity when it has a surplus, and import it when there is a lack. The company is planning up to 10GW of connecting pipes to Europe.

Nick Winser said: "This will make a huge difference to us. It will allow us to wring every drop from our renewable generation capacity, and make enormous savings in terms of carbon emissions."