Huge volatility in renewable energy generation has underlined the scale of the challenge facing the Scottish Government in its net zero drive, which is set to become increasingly reliant on UK taxpayer funding.

While officials hailed an increase in renewables output as the SNP headed for defeat in the general election campaign, the figures concerned provided further evidence that efforts to reduce Scotland’s reliance on fossil fuel face major complications.

The latest Scottish Government energy statistics release showed the amount of electricity generated from renewable sources increased by 4% in the first quarter compared with the same period in 2023. The country felt the benefit of new developments such as SSE’s huge Seagreen windfarm off the Angus coast.

However, the impact of the vagaries of the weather was writ large in the update.

This showed that while renewable energy generating capacity has increased hugely in recent years total first quarter output was actually more than 5% lower than in the same period in both 2022 and 2020.

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One of the implications of the statistics is that Scotland needs a big increase in storage and transportation capacity to make sure it can use the renewable electricity that can be generated in times of low demand.

In the absence of such capacity we have been in the absurd situation of handing millions to renewables operators under the constraints payments system. This effectively rewards them for not  generating electricity.

The energy statistics report notes that storage projects accounted for almost half of the 46.8GW capacity in the planning and construction pipeline in Scotland at the end of March.

Pumped storage hydropower projects are seen as having the most potential. They work by using the flow of water between reservoirs and lochs to drive turbines. Developers such as SSE are working on a range of projects in the Highlands that will involve creating reservoirs and huge turbine halls in the hills.

However, the projects will take years to complete and will require huge support from taxpayers and/or householders in the UK.

SSE has made clear it will only commit to the Coire Glas project on the shores of Loch Lochy if the UK government guarantees a minimum price for its output. To sweeten the pill SSE has proposed using a cap and collar mechanism, under which it will make payments to the Government if prices exceed a set level.

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Developers in Scotland have been big winners under the subsidy regime that was put in place by the UK Government to boost investment in windfarms under the Contracts for Difference system, which guarantees them a minimum price for their output. This has inadvertently exacerbated the constraint payments problem by encouraging firms to develop windfarms before the required storage and networks capacity are in place. The costs have been added to the electricity bills of householders across the UK.

Scotland benefited disproportionately from the CFD system under the last Tory Government, which effectively banned onshore windfarm developments in England. More than 40 onshore wind developments in Scotland have won CFD support since 2015, compared with two in England.

But competition for CFD support is set to get much fiercer after the new Labour Government moved fast to end the ban of English developments - with alarming implications for Scotland.

The energy statistics report notes that onshore wind projects accounted for more than a quarter of the renewable energy capacity in the pipeline in Scotland at the end of March.

While the SNP based its election campaign on a claim that it would deliver a fair and managed transition to net zero, the Scottish Government has come under fire for showing apparent support for energy giants’ plans to develop a new gas-fired power station at Peterhead.

This could produce baseload electricity to help guarantee there is enough power to meet demand when renewables output flags.

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Friends of the Earth Scotland accused the Scottish Government of 28 breaches of the ministerial code in connection with its handling of a planning application for the power station from SSE and Norway’s Equinor.

The campaigning group claimed the plant would create huge amounts of pollution and lock households into higher electricity bills linked to fossil fuels for decades to come.  

The claims highlight the political opportunism of the SNP Government, which opposed North Sea oil and gas developments as it courted the green vote then cast itself as the defender of the industry after Labour proposed a windfall tax hike.

The Scottish Government faced further flak last week after announcing it would provide £2 million funding for plans to develop a huge carbon capture usage and storage (CCUS) cluster in Scotland. The cluster plan will involve capturing industrial emissions across Scotland and storing them in depleted oil and gas reservoirs under the North Sea.

In response, Friends of the Earth Scotland said: “There is a growing body of evidence that all it [carbon capture and storage] is doing is capturing public money and providing greenwash for continued fossil fuel expansion.”

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However, first minister John Swinney insisted the cluster project will be essential in securing the future of key industrial sites like Grangemouth and Mossmorran.

He declared: “We are determined to support projects like this to support the development of Scotland’s carbon capture and storage sector and the fair and just transition of [the] oil and gas sector.”

The SNP Government has been an increasingly vocal advocate for the Scottish cluster since 2021, when the Government led by Boris Johnson decided to prioritise the development of two schemes covering Northern England and Wales.

But the criticism of Johnson’s move only underlined how much the achievement of the Scottish Government’s carbon capture ambitions will depend on UK Government support.

With carbon capture in its infancy, the Government will have to provide huge subsidies to encourage firms to develop the required infrastructure.

In a report on the subject issued last week the National Audit Office noted that the Conservative Government had committed up to £20 billion to the early deployment of CCUS with the aim of having four clusters operational in the UK by 2030.

The watchdog noted that uncertainty remained around the funding available for future stages of the programme although the current budget is being used up quickly in support of projects such as the Scottish cluster.

“The government has so far spent £630 million on its CCUS programme, primarily through grants to support the early development of projects,” said the NAO.

To put the numbers highlighted by the NAO into perspective, the Scottish Government has budgeted to spend around £360m on energy efficiency and decarbonisation measures in the current tax year.