In 2003, the Scottish Executive confirmed a target that would see 18% of electricity generated in Scotland come from renewable sources by 2010. It also added that "Scotland should aspire to generate 40% of its electricity from renewable sources by 2020" (ENDS Report 339, pp 48-49 
).
The goal for 2020 was subject to some ambiguity, because Scotland currently exports a significant proportion of the electricity it generates to England. A target covering only electricity used in Scotland would be less ambitious.
The Forum for Renewable Energy Development in Scotland (FREDS), a stakeholder group chaired by Minister for Enterprise Nicol Stephen, has now concluded that the target should be expressed in terms of installed capacity, related to Scottish electricity demand rather than generation. The Executive says it intends to accept the recommendation.
FREDS expects total generating capacity in Scotland in 2020 to be similar to that in 2003, with new renewables largely replacing existing nuclear and coal plants. Some 6,300MW of renewable capacity would be needed to deliver 40% of generation, falling to 6,000MW when the target is expressed as a share of Scottish electricity demand. At present, 2,600MW of capacity is built or consented.
Neither measure is precise, but FREDS says that "using projected demand is the best way of determining the target". It notes that the target should not be regarded as a cap.
Although wind and marine renewables have grabbed the headlines in Scotland, FREDS also sees potential for 450MW of biomass-fuelled electricity.
The report concluded that the British electricity market is sufficiently flexible to handle any intermittency issues that might arise. The major concern is the need to strengthen the Scottish transmission system to allow exports from new renewables installations.
The National Grid, in its regular assessment of generation and transmission capacity, calculated less than one fifth of renewables capacity under development in Scotland is currently "allowable" because of transmission constraints. FREDS also points out there has been a "huge escalation" of "speculative" proposals with no guarantee of grid connection.
According to FREDS, existing plans for onshore wind development provide sufficient economic justification for grid strengthening and upgrades are under way. Scottish and Southern Electricity has been consulting for nearly 18 months on the most urgent transmission upgrade, to the line between Beauly and Denny. A final proposed route was published in July, and the company hopes to submit a planning application shortly.
The charging regime for using the transmission network may also present a barrier for renewables, especially large-scale installations in the Western Isles and offshore. At present, grid usage fees have a "locational" component known as zonal transmission charging that means remote generation pays higher prices for transmission (ENDS Report 362, pp 52-53 ).
The Government took on powers in the 2004 Energy Act to vary this charge in certain circumstances. It is now consulting on whether to reduce the charge for renewable energy projects in Shetland, Orkney and the Western Isles but not, as had been suggested, in Northern Scotland.2
The principle of locational charging has also come under pressure: Scottish Power has requested a judicial review of the system, while the Scottish National Party has suggested it could be challenged under EU Directives which require that electricity tariffs do not disadvantage renewables.
In a related consultation, the Department of Trade and Industry is seeking views on the regulation of the offshore transmission network which will be needed to serve the growing offshore wind industry. Energy regulator Ofgem is suggesting that the offshore regime should embrace the same principles of competition and cost-reflective charging as its onshore equivalent.