Scotland faces being plunged into darkness for days, possibly resulting in deaths and widespread civil disobedience, due to the country’s over-reliance on green energy, a new report has warned.

A massive gap in the electricity system caused by the closure of coal-fired power stations and growth of unpredictable renewable generation has created the real prospect of complete power failure. 

According the Institution of Engineers in Scotland (IESIS), there is a rising threat of an unstable electricity supply which, left unaddressed, could result in “deaths, severe societal and industrial disruption, civil disturbance and loss of production”.

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The organisation is also warning that the loss of traditional power generating stations such as Longannet, which closed in 2016, means restoring electricity in a “black start” situation – following a complete loss of power – would take several days. 

Its new report into the energy system points to serious power cuts in other countries, which have resulted in civil disturbance, and warns: “A lengthy delay would have severe negative consequences – the supply of food, water, heat, money, petrol would be compromised; there would be limited communications. The situation would be nightmarish.”

IESIS is now calling on the Scottish and UK governments to transform their approach to how the electricity system is governed, with the creation of a new national energy authority with specific responsibility for safeguarding its long-term sustainability and avoiding blackouts. 

The startling warning comes against a background of increasing reliance on “intermittent” energy sources such as wind and solar power. 

Earlier this month ScottishPower became the first major UK energy firm to switch entirely from fossil fuels to green energy after selling its remaining gas and hydro stations to Drax for £702 million.

The closure of Hunterston B nuclear power station in Ayrshire, scheduled for 2023, is causing concern there will be an even wider gap in the nation’s electricity supply.  All UK coal-fired power stations are expected to close by 2025, while reliance on electricity to meet the needs of electric vehicles and domestic heat rises.

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The engineering body has also raised concerns that an electricity system designed specifically for gas and coal-fired generation is being asked to take on a new form of supply without having undergone full engineering assessment. 

It also highlights a piecemeal approach to siting new energy generating plants driven by private companies and efforts to meet CO2 emissions targets rather than the overall security of the electricity system. 

Iain MacLeod, of the IESIS, said: “The electricity system was designed with generation coming mainly from coal and nuclear energy. However, as we change generation sources to include intermittent renewables, we must review how the system works with these new inputs. The risks involved when introducing new sources of generation need to be controlled. Intermittent renewable energy sources do not supply the same level of functionality as power stations to meet demand at all times and avoid operational faults. Intermittency issues ... relevant to wind and solar energy have not been adequately explored.”

IESIS has published its call to action in a report, Engineering for Energy: A Proposal for Governance of the Energy System, which it plans to take to the Scottish and UK governments.

It argues that Longannet was closed “well before assessments of the impact of its closure had been completed” and adds that transmission is now being upgraded “before detailed decisions about the siting of generation facilities have been made”.

The EISIS report warns the closure of thermal infrastructure such as coal and gas-fired generators will affect the restoration of supply after a system failure, when wind generators have a limited role and nuclear generators cannot be quickly restarted.

It also stresses that the cost of integration of intermittent renewables to the current electricity system will lead to increasing energy costs for consumers.  

It adds: “The extra generation and storage needed to safeguard security of supply, the facilities required to ensure it is stable, extra transmission facilities, and energy losses over power lines from remote locations will all contribute to rising costs.” 

A spokesman or SP Energy Networks, which owns and maintains the transmission network in central and southern Scotland, said: “The resilience of the system, and the ability to deliver an efficient and timely Black Start restoration, minimising the social and economic aspects of such an event, continue to be areas of particular focus.” 

Scottish Conservative energy spokesman Alexander Burnett said: “No-one disputes the need for Scotland, and everywhere else, to move towards cleaner generation of energy.But this has to be done in a sustainable way which ensures there are no blackouts and enough power to meet the needs of the country”. 

A Scottish Government spokesman said: “While electricity policy is reserved to the UK Government, we are working closely with National Grid and the Scottish network companies to ensure that Scotland has a secure and stable supply of electricity.  Renewable generation now plays substantial role in meeting electricity demand across Scotland and reducing the carbon intensity of the electricity that we generate. 

“Our energy strategy highlights the need to plan and deliver a secure, flexible and resilient electricity system.”