The ageing electrical system is predicted to be under the most pressure next winter, a report published today by the Royal Academy of Engineering predicted.
The Government-commissioned study into the capacity of the system found that although it is able to cover projected levels of demand it will be stretched "close to its limits" and events like low wind, cold weather and unplanned plant outages could put the country's power supply at risk.
Dr John Roberts, chairman of the report's working group, said: "In the next decade, several coal and oil-fired power stations will be forced to close if they do not invest to comply with European regulation on pollution emissions.
"In addition to this, four nuclear plants are scheduled to close by 2019, further reducing the available capacity.
"Although the combined closures are not expected to bring the total available electricity capacity below the predicted peak demand, a reduced margin in the power available at any given time would reduce the flexibility of the system and increase the chances that otherwise manageable failures could jeopardise the country's power supply.
The Government needs to set the market conditions to encourage private investment to secure a modern and sustainable service, the report recommends.
It highlights a hiatus in investment, a result mainly of uncertainties over the reform of the electricity market and the current low profitability of gas plant.
"Modernising and decarbonising the system will come at a cost, with likely rises in the unit price of electricity and difficult decisions will need to be made," Dr Roberts said.
"This will only be achievable with the consent of the public and it is vital that government and industry work together to foster a constructive dialogue with the public about the challenges we face in achieving a low carbon, secure and affordable energy system for the future."