They called on the Scottish Government to work with the UK and Welsh administrations, as well as regulators at Ofgem and the National Grid, to “enshrine and publicly promote” a policy of grid expansion.
It comes as their report said Scotland was “on a journey to net zero that requires an energy revolution”, with the move away from oil and gas meaning the country will “require a radically different energy mix”.
The committee insisted that an expanded National Grid was a “public good” as well as “a direct and inevitable consequence of decarbonising our energy supply to achieve net zero”.
Going forward, they said there should be a “principle of prudential investment in grid capacity in anticipation of future need” and to meet the Scottish Government’s target of achieving net zero emissions by 2045.
The report said “a clear statement of intent about, and plan of action for, speeding up grid connection is also needed from governments”.
The MSPs said: “It is unacceptable that developers are being asked to wait upwards of a decade for a connection.
“It is also completely at odds with ambitions to grow a world-leading renewables sector.”
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They went on to raise concerns that Scotland’s planning system could be a “major block on our net zero ambitions”, with the MSPs saying “momentum” will be needed to build the generating capacity and transmission infrastructure needed.
To tackle this, the committee called on Holyrood ministers to “streamline and simplify” the planning application process for renewable energy projects – although they also stressed the process must still provide for “robust interrogation of any major proposal” and give local people a say.
MSPs stressed: “As this report has made clear, an expanded National Grid is a public good, and a necessary one, in response to the climate crisis.”
As a result, they said there was “an urgent need for a national conversation, led by the Scottish Government, on what this change will mean” for Scotland and its different regions.
This work should be backed up by a long-term plan, produced together with network operators, Ofgem and the National Grid, which would give a “best estimate of the scale and type of new infrastructure that will be needed and where it is likely to go”.
This would mean that the “public can see upfront what changes are likely and the reasons for them”, the committee stated.
Convener Edward Mountain said those who had given evidence to the committee had agreed that “much more electricity will need to be on the grid for us to meet our climate change goals”.
He stated: “Urgent and bold changes are needed to both increase the grid’s overall capacity and to speed up the rate of grid connection.
“This is why we are calling for a national conversation to take place which explains clearly how we are going to take carbon out of the energy supply, the choices available on how to get there and what this could mean for people in their day-to-day lives.”
He added that the planning system needed to be “more agile”, reaching decisions on electricity and renewables projects “more quickly”, but also “without removing any of the fundamental rights of individuals and communities to have their say and to influence the process”.
Mr Mountain said: “Electricity infrastructure has a vital role to play as we face the climate emergency. But unless urgent action is taken by governments on both sides of the border, regulators and operators alike, it may well become an opportunity lost.”
Energy Secretary Neil Gray said: “I am grateful to the committee for its work.
“These recommendations are being considered as part of the Scottish Government’s approach to finalising its Energy Strategy and Just Transition Plan.
“Significant investment in our grid infrastructure is required to ensure clean, low cost renewable electricity can flow to where it is needed.
“Such infrastructure must be delivered with lasting benefits for our economy and for the people of Scotland.”
He added: “While policy and regulation relating to electricity networks is reserved to the UK Government, we must work together to enable a net zero power system which will drive down costs and increase benefits for customers, businesses, workers and communities.”