If Scotland is to become the UK's renewable energy epicentre, it will need some serious rewiring, discovers Bernadette Redfern.
When the government set its ambitious target of deriving 10% of electricity from renewable sources by 2010 (NCE 20 November 2003), it had high hopes for Scotland.
The combination of wide expanses of hillside raked by powerful winds, a coastline scoured by fast-running tides and Atlantic waves, and a sparse population makes the highlands and islands of Scotland a natural focus for development of new renewable energy capacity: Of the additional 10,000MW of green energy the UK has to produce by 2010, it is hoped that 6,000MW will come from north of the border.
There is a problem, however.
Although nature offers the raw resources for considerably more than 6,000MW of power, getting it from source to the points of consumption - the UK's major towns and cities - is impossible with the current transmission infrastructure.
National Grid Transco (NGT), which operates the UK electricity distribution system, plays down the situation: 'Certain important pinch points will need upgrading, in particular circuits across the AngloScottish border and into the north of England, ' says a spokesman.
Transmission lines have in the past been constructed to deliver electricity from large centralised power stations to widely dispersed consumers.
Not only do renewables demand a system that can cope with widely dispersed points of generation, but to date much of the flow of energy has been from south to north.
To assess the feasibility of getting power from renewablesrich Scotland to the energyhungry south, the Department of Trade & Industry (DTI) asked NGT, Scottish & Southern Energy (SSE) and Scottish Power (SP) to develop options.
The result of this inter-company effort was a Renewable Energy Transmission Study (RETS), which proposes a three-stage upgrade of Scotland's transmission network.
During each stage, the transmission network will be upgraded and extended to provide an additional 2,000MW of carrying capacity. The entire rewiring will cost £1.5bn.
Critically, the power upgrade must win public acceptance.
Although most people support renewable energy in principle, nimbyism inevitably rears its head when companies are planning to install new pylons and wind turbines close to properties. Electricity companies report increasing difficulty in negotiating 'way leave' for the routing of lines and erection of pylons on private land.
Uncertainty over public reaction makes it difficult for anyone to estimate exactly how long the upgrade projects will take, though the aim is to start construction next year for completion of the upgrade by 2008/9.
SSE has already encountered intense opposition to the proposed route of a new 400kV overhead power line linking the highlands with central Scotland, to be built in the first phase of the Scottish transmission upgrade. It will replace an existing 132kV, 200km line running from Beauly, north of Inverness, to Denny near Falkirk. Consultation on the route of the line ended in April and nearly 700 responses were analysed. A new route proposal was born out of the consultation.
However, there are still five problem areas where a final solution has yet to be found, all of which must be resolved before the plan can be submitted to the Scottish Parliament for approval.
Scottish Power is consulting on three major projects to upgrade its distribution and transmission system and these fall into stages one and two of the RETS upgrade. The first is the only new build scheme proposed under the upgrade, involving construction of a 60km long, 240kV transmission line from Kilmarnock in South Ayrshire to Kendoon in Galloway. The other two projects are upgrades of exiting transmission lines. SP wants to increase the operating voltage of 103km of line between Eccles and Newcastle and to upgrade the operating voltage of pylons along the M74 corridor between Strathaven and Carlisle. Each of these projects will also require numerous substation modifications and extensions. The total budget for new build work is set at £400M.
RETS estimates that National Grid Transco will have to spend up to £690M to make changes to the grid.
Queuing for approval
There are 59 renewable energy projects awaiting planning permission in Scotland, says the Scottish Executive. Onshore wind accounts for 49 of these and seven of the projects are hydropower schemes. Three are biomass incinerators.
Consents have recently been granted to 30 schemes, one of which is the 130MW Hadyard Hill onshore windfarm in South Ayrshire. Scottish & Southern Energy (SSE) last week began preliminary works on the £90M project, which upon completion in summer 2005 will be the UK's largest onshore wind energy installation.
'The scheme is open to tender. We expect to have appointed a contractor within the next four to six weeks, ' reports an SSE spokesman.
The number of turbines will be decided by the winning contractor, who will select the turbine design and power output. But SSE is expecting the farm to have around 60 turbines, each rated at 2MW-2.3MW.
Scottish Power's 142.6MW Black Law windfarm has also received consent and, on completion in 2005, will overtake Hadyard Hill as the UK's largest.
Of the seven hydropower schemes awaiting planning permission, Glendoe, at the western end of the Monadhliath mountains near Inverness, is by far the largest. It will sit close to the south east corner of Loch Ness and produce 100MW of energy (NCE 15 May 2003). A new reservoir contained by a 1km long, 35m high impounding dam will drop water 600m onto turbines in the power station, which SSE says will probably be built underground. The company is confident that the £85M scheme will get the go ahead shortly. 'The Highland Council has just approved the development and it is now up to the Scottish Executive, ' says an SSE spokesman.