The Way Forward

400kV Overhead Network Pylon

Scottish Power Energy Networks (SPEN) Strategic Reinforcement Project
1  INTRODUCTION
Over the past 5-years or so the region has experienced a rapid escalation in the amount of electricity generated from renewable sources(I) to the extent that the existing high voltage transmission system can become overloaded at times. Furthermore, additional consented generation planned to be connected to the network over the coming years will lead to an unsustainable situation resulting in increased constraint payments. In view of the age of the existing transmission system, the operating voltage and the level of anticipated generation simply modifying the network to accommodate this additional
capacity is not possible which leaves an upgrade as the only option.

Moving to a high voltage super-grid network provides the region with the electrical transmission infrastructure it currently lacks and one that removes the current bottlenecks in transferring excess renewable energy from Dumfries & Galloway to England and Wales where demand exists. It also provides an alternative route to free up constraint on the Moyle Interconnector
between Auchencrosh and Northern Ireland.  However, the upgrade to a super-grid, while necessary, brings with it a number of undesirable features that are likely to significantly impact the lives of many people and businesses in the region as well as those who visit for holiday or recreation.

This paper discusses the needs case for this project and introduces alternatives that may help mitigate these negative impacts.  The aim is to work with SPEN to arrive at a solution that takes account of the need to preserve the special nature of the area. A cost estimate is included to support these alternative approaches.

2  THE NEEDS CASE
The existing 132kV high voltage transmission system has served Dumfries & Galloway well for many
years and provides the region with a reliable source of electricity to the point where, within the south
of Scotland, SPEN have sufficient confidence in their ability to maintain the system they have agreed
a target with Ofgem of 224MWh of ‘energy not supplied’(ii) each year up until 2021 [1].  Therefore,
just because a transmission system is old does not necessarily mean it needs to be replaced, as the
National Grid (2014) make clear:
“Transmission assets tend to have very long operational lifetimes, many in excess of 50 years. Although much of the equipment is obsolete, it is in good condition with many years of service left …” National Grid Electricity Ten Year Statement (2014, p.169).

Putting to one side the fact that the existing network is old and will eventually need to be replaced at some future time with more modern technology the single most important factor driving the upgrade is the growth in on-shore wind where in 2015 there is approximately 380MW of capacity [2] connected to a network that is rated at 105MW (iii). Fortunately there is a degree of mitigation that reduces the risk of overload and this arises from the intermittent and variable nature of wind power which tends to reduce the load factor (iv) in the summer months.  Notwithstanding this point, it is likely there will be times when network constraints restrict the amount of connected renewable generation resulting in turbines being shutdown thereby triggering constraint payments.

A recent announcement (v) by The Secretary of State for Energy and Climate Change, the Rt Hon Amber Rudd, MP., proposes to end the public subsidy for on-shore wind in favour of encouraging other renewable technologies.  Consequently, any wind farm not consented by the 18 June 2015 and having in place the necessary connection agreement as well as land rights will not be eligible for public subsidy.  This announcement will limit on-shore wind turbines within Dumfries &
Galloway to around 1000MW [3]; still enough to supply the annual needs of nine times the number of homes in the region [4] but still less than half of what might have been had the announcement not occurred when it did.

Even with this restricted level of renewable generation, however, the existing network will be significantly overloaded and SPEN estimate that constraint payments of up to £16bn could be triggered throughout the south of Scotland by 2030 without the proposed upgrade. In addition to accommodating the indigenous renewable generation this project proposal will also help unblock the 500MW Maybole Interconnector where there is currently a constraint due to the amount of renewable
generation feeding into the network around the Kilmarnock area.

In summary, therefore, SPENs proposal seeks to overcome current and future restrictions in transferring renewable energy to England and Wales thereby off-setting constraint payments that would otherwise be incurred. Additionally it enables the Maybole Interconnector to operate at full capacity and it overcomes the problems associated with obsolescence. It can, therefore, be considered a strategic reinforcement project.

3  THE IMPLICATIONS
The proposed super-grid comprising of sections of 275kV and 400kV overhead line (OHL) and supported on steel lattice pylons of up to 50m in height can dominate the landscape and although bestpractice guidelines exist for the siting of OHLs and pylons [6] this can only help mitigate the visual impact not remove it altogether.  Sub-stations too can dominate an area due to their physical size and interconnected infrastructure and are themselves subject to best-practice guidelines [7].

As a transmission licence holder for the south of Scotland, SPEN (2015, p.2) recognise their duty under Schedule 9 of the Electricity Act 1989 which includes, “… to do what it reasonably can to mitigate any effects which the proposals would have on the natural beauty of the countryside…” which is interpreted by SPEN as balancing the technical requirements against the least disturbance to the environment and the people who live, work and enjoy the recreation within it [8]. Using these guiding principles SPEN claim that evidence from technical, economic and environmental factors lead, in most cases, to an OHL approach but they recognise there may be specific cases where undergrounding may be appropriate [9].

Unfortunately up until recent times the economic appraisal between OHL and undergrounding or other forms of mitigation have been performed using a simple capital cost estimate which has tended to favour OHLs as the preferred option. The Beauly-Denny line, for example, found a range of cost-escalation factors of between 7.1 – 15.6 for undergrounding compared to a 400kV OHL depending on the landscape character, presence of water courses, viaducts, road crossings and so on [10]. A more recent report [11], however, takes account of whole life-cycle costs for a 400kV transmission infra-structure and finds the average escalation factor to be in the region of 4.6 but recognises the actual value will be sensitive to a number of factors such as the length undergrounded and the load factor.

To most people living, working or enjoying recreation within Dumfries & Galloway this proposed project brings few obvious benefits given the already high levels of reliability and availability of electricity supply.  On the other hand, in its current form – based on OHLs and pylons – it is easy to foresee a number of dis-benefits such as a fall in residential visual amenity, (vi)
reduction in property values adjacent to the route [12], negative impact on tourism together with a fall in seasonal
employment from this sector, a general reduction in the perception of well-being [13], potential loss of historic and cultural heritage as well as the possibility of destructive environmental impacts to flora, fauna and wildlife.

The fundamental indicators of economic well-being for Dumfries & Galloway are already fragile with a continuing decline in private sector employment making it difficult to create future wealth from a diminishing business base [14]. Furthermore, Dumfries & Galloway has the 7th lowest  Gross Value Added (GVA) contribution of all 32 local authority areas in Scotland with a GVA/capita of 74.9% of the UK average in 2011 [15] and one which declined by almost 6% over the period 2000
– 2009 [16]. It is also classed as a predominantly rural-region in which the primary industry of agriculture, forestry and fishing supported by the tertiary sector in the form of tourism and hospitality provide a significant contribution to the wealth of the area [17].

The outstanding quality of rural Dumfries & Galloway’s natural and historic environment has helped underpin opportunities to develop rural recreation which together with tourism has aided the diversification of the traditional land based sector through the provision of accommodation, marketing of local products to visitors and access to recreational facilities with encouragement and support from local as well as the Scottish Government [18].  This emphasis on tourism and recreation in the broadest sense has been successfully exploited within Dumfries & Galloway to the extent it now supports 5977 full-time equivalent jobs from direct tourism related expenditure and a further 1358 jobs from indirect revenue streams. In 2009 the total contribution to the economy of the region from tourism was £270m or 11% of GVA [19] which emphasises the importance of this sector to the regional economy when compared to the lesser 8.5% contribution from Scotland’s tourism sector overall in 2013 [20].

Tourism is therefore seen as an increasingly important component of the Dumfries & Galloway’s rural economy, both in terms of jobs and wealth creation, where in 2015 income from this sector rose for the first-time beyond £300m; attracting more than 2,000,000 visitors with an average spend of £150 [21].  However, to enable this sector to continue growing through attracting increasing visitor numbers requires careful management of the natural beauty of the area and preservation of the visual amenity and historic and cultural environments.

While SPEN will aim to do all in their power to select a route that has a strong focus on local population and environmental sensitivity [22] by utilising the Holford [6] and Horlock [7] rules their present proposal will inevitably lead to one or more forms of economic loss which residents of the region will be expected to bear. The National Grid (2015, p.2) are forthright on this matter in relation to the potential fall in house prices, “… the effect on property value is not a material consideration
…” [23].  The overall impact on the region from this project in its current form, at both a personal and business level, is therefore expected to be negative and it is likely that even though most people will recognise the necessity for the project they will oppose it simply because of the potential impact it may have on them, their family and their livelihoods.

4  THE ALTERNATIVES
Two alternatives exist which may help make the proposal more palatable to many residents.  Both alternatives cost more on a capital cost basis than SPENs initial proposal but Ofgem and SPEN [1] recognise that transmission operators may have to consider the socio-economic impacts of their network reinforcements at an early stage and each network operator is given an allowance to reduce the visual impact in National Parks and Areas of Natural Outstanding Beauty – to be considered on a
case by case basis. Such funding, for which the customer inevitably pays, applies to this project through an allowance based on the consumer’s willingness to pay; a subject which is discussed in section 6.

The present proposal calls for a new 275kV OHL from Auchencrosh to Newton Stewart and a 400kV OHL from Newton Stewart to Harker with 132kV spurs at Glenlee to Kendoon and Tongland; thus effectively creating a west-east conduit or arterial collector network to transfer excess energy from the region to where the demand exists and provide a 500MW 2-way connection with Northern Ireland.

The 400kv OHL has been sized to accommodate about 700MW of consented renewables as well as the Moyle Interconnector [24] so there will be times when, because of the disposition of renewable generation in the region and when energy is flowing to Northern Ireland, the network between Harker and Newton Stewart will be lightly loaded and other times when generating capacity flows in the opposite direction the load on the network will increase.

If the generating capacity remains limited to that consented on the 18 June 2015 then this opens up the first alternative which provides SPEN with some flexibility and many residents the opportunity for improving the visual impact and reducing economic loss.  This is predicated on the fact that Glenluce and Kendoon will see the largest increase in renewable generation over the next five years or so, to over 400MW and 200MW respectively with other areas to the east of the region remaining more or less as they are today.

The first part of this proposal is the establishment of a sub-sea HVDC link of around 1000MW capacity between Auchencrosh and some convenient point on the Lancashire coast such as Heysham. The choice of Auchencrosh, although further north and west of alternative landing points in the area, avoids environmentally sensitive regions and the need for additional infrastructure is overcome as Zone 1 is planned to receive a new 275kV network between Newton Stewart and Auchencrosh. Additionally, Auchencrosh already has a sub-sea cable which forms the Moyle Interconnector so the addition of a second HVDC converter station in this region should minimise any additional environmental impact over alternative sites.

The advantage of this proposal is that electricity flow to Northern Ireland can be taken from generation in the west of the region while flow from Northern Ireland and any excess generation in the region can go directly south through the sub-sea link to centres of demand thereby reducing transmission losses. This leaves the proposed west-east transmission network less heavily loaded to the point where it may be possible to downgrade from a 400kV super-grid to a 132kV network between Newton Stewart and Harker having between 350-500MW capacity. At 132kV, pylons are lighter, smaller and cheaper as is the rest of the infrastructure, leading to less visual impact. Furthermore, at this voltage there is greater flexibility to accommodate undergrounding as the cost escalation factor approaches unity [25] compared to the equivalent cost of a 400kV OHL network.

The second alternative retains the proposed west-east super-grid as a collector and transmission network for all the renewable generation in the region as well as providing a 2-way connection to the Moyle Interconnector. The difference, however, is that sections of the network may be undergrounded to avoid sensitive areas.

The following section estimates the additional cost of these alternatives and arrives at an annual figure per consumer that allows SPEN to recover these extra costs as well as earn a reasonable return on their investment.

5 COST ESTIMATE OF ALTERNATIVES
As the alternatives impact only the proposed 400kV network any variation in cost is estimated from this base cost – to evaluate which use has been made of the more recent introduction of life-cycle transmission cost structure estimating [11] which takes account of fixed and variable costs over the asset life depreciated over 40 years [26]. This base cost is estimated to be in the region of £330m (vii).

The cost for a suitable sub-sea HVDC interconnector is arrived at by evaluating several similar UK project proposals in various stages of execution (viii) to arrive at an estimate for a 211km, 1000MW link of £620m which suggests that earlier calculations [11] for a sub-sea alternative to landbased 400kV OHLs have fallen significantly since 2012 due to a number of factors such as: a) experience gained in the use of this technology, b) technology costs have fallen due to competition entering the market and c) volume effects.

The undergrounding of the alternative 132kv network is estimated at £2.0m/km based on underground cable costs of £1.3m/km for a 4-circuit 576MW capacity [25] together with £0.7m/km to accommodate switchgear and transformers costs etc., resulting in a figure of £262m for this option.  Consequently, the additional cost of this alternative is estimated to be in the region of £552m (= £620m + £262m – £330m). If only half the 132km route is undergrounded the additional cost falls to
around £500m.

The second alternative is based on retaining the 400kV network but undergrounding all – if this were technically possible, which is unlikely – or only part of it and here a figure of 50% is assumed, i.e. a maximum of 65km, typically in several sections. The additional cost in this case is in the order of £508m.

As both alternatives require a similar additional capital investment of around £500m this figure is used below to arrive at the additional cost to household electricity bills [28].

Ofgem, under price control mechanism, TIIO-T1, limit transmission operators to recovering costs and earning a reasonable return on capital subject to delivering value for consumers, behaving efficiently and achieving targets [27].  For each operator this return will be slightly different depending on their level of gearing and in the case of SPEN their weighted average cost of capital (WACC) for 2013-2021 under TIIO-T1 is 4.91% pre-tax. In addition transmission assets are depreciated over 40 years [26] which implies an amortisation rate of 2.5%.

The implication of this is that an additional £500m of expenditure represents an additional cost to the consumer of 7.41% (= 4.91% + 2.5%) per year of the additional capital cost which is £37.05m per annum.

As Scottish Power Energy Networks revenue from transmission and distribution was £1135m in 2014 [26] the additional annual premium to be recovered from SPENs electricity consumers represents 3.26% (= £37.05m/£1135m * 100%) of revenues. Further to this the average annual household electricity bill in the UK in 2014 was £592 [29] and as transmission costs represent 4% of a consumers electricity bill transmission costs for the average household represents £23.68 per annum.
The additional annual premium to consumers that enables SPEN to recover their costs and make a return on the additional £500m therefore equates to £0.77 per household (= 3.26% * £23.68). However, because distribution charges account for around 16% of consumers electricity bills [27] the additional household premium will increase to around £3.85per annum (= 5 * £0.77).  In summary, therefore, and based on the above estimates a sub-sea cable option together with reducing the supergrid to 132kV and undergrounding, or alternatively maintaining the super-grid and undergrounding up  to 50% of the route will cost the typical household in the order of £3.85 per annum in addition to what they currently pay for their electricity.

Having established the order of cost the question then becomes, “Is the customer willing to pay this additional premium to protect the visual amenity and their environment in general?” The following section examines this proposition.

6 CONSUMERS WILLINGNESS TO PAY
Social cost benefit analysis seeks to assess the net value of a policy or project to society as a whole while recognising that the valuation of non-market impacts such as loss of visual amenity or environmental assets may introduce concerns for health, well-being, family and community stability cannot simply be inferred from market prices [30]. One way to overcome this problem is to attach a value to non-market goods by looking at the impact these things have on utility – in the broadest sense
the satisfaction an individual may derive from the consumption of a particular good.  Because it is difficult to observe utility directly it is usually inferred from hypothetical choices people make based on their willingness to pay (WTP) (ix) or willingness to accept (WTA) (x)

National Grid [31] in acknowledging the difficulty in determining consumers WTP to mitigate the visual impact of electricity infrastructure impact in National Parks and Areas of Outstanding Beauty (xi) commissioned research to evaluate the social cost benefit placed on visual amenity for the UK as a whole. The results from this large-scale qualitative and quantitative research programme are interesting in so far as:-

1 Respondents appear to have more appetite to pay to mitigate the visual impact of future infrastructure rather than existing infrastructure.
2 The most valued mitigation interventions are those associated with large projects of distances up to 50 miles in all types of area, including rural areas.
3 The highest benefit is believed to be obtained by undergrounding.
4 Around 70% of those living in urban or town and fringe areas visit a non-designated (not an NSA area) at least three times each year.
5 The most widely mentioned usage of the countryside in NSAs or other rural areas were cycling, running and walking with two thirds visiting the other rural areas for such pursuits.
6 Transmission infrastructure is considered ‘ugly and an eyesore’ by 55% of respondents.

Beyond these general findings, which apply equally to Scotland as to the rest of the UK, respondents were willing to pay up to £13.40 per household for 8 years to underground cables up to 10 miles in length in both NSAs and other rural areas. This increases to £16.27 for NSA areas up to 20 miles in length and at 50 miles this increases further to £20.33 for NSAs and £14.81 for other rural areas. Overall, therefore, the study finds that 59% of respondents believe there is a need to lessen the
visual impact of transmission infrastructure – with the bias firmly in favour of new infrastructure – and that the countryside would be improved by doing so (at 64%).

In recognition of the concept of the consumer WTP Ofgem [32] have increased the cap for transmission operators to explore mitigating impacts of existing infrastructure in designated areas from £100m to £500m. Meanwhile SPEN [1] acknowledge that this allowance for mitigating measures would potentially apply to their proposed new OHL project in Dumfries & Galloway.

Returning now to what WTP might mean for SPEN and their proposal for Dumfries & Galloway, assuming that the majority of the proposed network runs through what might be regarded as ‘other rural areas’ this suggests that based on their number of consumers [26] the available mitigation allowance would be almost £50m per year for each of eight years (= £14.81 * 3,354,000) which is roughly equivalent to undergrounding 5km each year over 8 years or around 1/3 of the total
400kV OHL.

Alternatively, given the growing importance of sub-sea interconnectors to the security of supply within the UK as well as to the provision of cheaper electricity from overseas markets (Norway particularly with 92% hydro-electric power) there is an argument for SPEN considering their customer base to be represented by the number of UK households [33] which would increase their visual amenity mitigation allowance to £397m (= £14.81 * 26,700,000) each year which would be more than sufficient to install an HVDC link between Auchencrosh and Heysham while downgrading the proposed super-grid to 132kV and undergrounding much of this route.

7 SUMMARY AND CONCLUSIONS
The majority of people impacted by SPENs proposals, whether residents of the region or visitors, are likely to be negatively impacted and for that reason they will either oppose these plans or consider the area less suitable for tourism and recreation and go elsewhere. The end effect will be a number of disbenefits resulting in a loss of economic value from the area.

Alternatives exist that cost more on a straight capital cost comparison but as a transmission network infrastructure may be in place for up to 100 years or more – blighting the region for generations to come – there needs to be greater flexibility for examining alternatives using life-cycle costs and discounted cash flow methods.

Of the two alternatives and their variants presented in this report to mitigate the impact of this necessary project, both of which result in additional capital expenditure of around £500m, one is strategic in so far as it builds on plans for an interconnected European sub-sea electricity. The other is simply a form of mitigation making use of undergrounding for part of the route and elsewhere large towers and OHLs will remain visible for several km either side of the transmission network that will
lessen the visual amenity although hopefully avoid areas of habitation.

The cost of these mitigation measures are fractional to the average consumer; adding around two thirds of 1% to annual electricity bills. Furthermore, consumer WTP has been demonstrated to be firmly in favour of mitigating the loss in visual amenity from new infrastructure for which consumers are willing to pay, up to a certain level.

SPEN have an allowance that can be used towards implementing such measures and while consumer WTP may constrain undergrounding to a total of 40km of 400kV OHL it is possible that with a degree of flexibility and innovation on SPENs part their allowance could be increased to satisfy the strategic needs of installing a sub-sea interconnector.

8 RECOMMENDATIONS
There is a need at a strategic level to communicate concerns to all layers of government to help SPEN recognise the need for a flexible approach in order to:-

a)  Appreciate that any opposition is directed against SPENs current proposal not the need for the project itself.
b)  Understand we want to work with SPEN to identify a more acceptable solution.
c)  Generate a solution that preserves the special nature of the area; retaining the visual amenity as well as the cultural and historical heritage.
d)   Protect Dumfries & Galloway’s reputation as a place of choice for tourism and recreation as well as inward migration.
e)   Look on the sub-sea link alternative as part of a strategic European electricity grid network infrastructure to maximise the efficient use of renewable energy.
f)  Recognise consumers WTP to mitigate new transmission infrastructure and that this willingness extends to all rural areas not just NSAs.
g)  Encourage the use of whole life-cycle costs when comparing alternative capital proposals.

There is also merit in working with SPEN at a technical level to evaluate the alternatives further, free of capital cost constraints. Such co-operation might include activities such as:-

a)  Understanding how Amber Rudd’s announcements on the 18 and 22 June affect SPENs assumptions.
b)  Exploring SPENs projections for other renewable generation over the next 10-20 years to determine network expansion capability.
c)  Appreciating where future load centres may arise in the region, if at all.
d)  Conducting load-flow analysis to understand how well the design capacity of proposed circuits cope with normal and abnormal conditions.
e)  Appreciating how other network modifications outwith Dumfries & Galloway may impact their plans for this project as well as the alternatives proposed here.
f)  Evaluating SPENs flexibility in applying mitigation allowances and how WTP influences their level of engagement in such activity.
g)  Refining cost estimates in this report against figures held by SPEN.

9 REFERENCES
[1] Scottish Power Energy Networks (2012) RIIO-T1 Business Plan Update, January 2012, Executive Summary.
[2] RenewableUK (2015)
[3] Turbine Watch (2015)
[4] Dumfries & Galloway Council (2012) Housing information briefing note No.1, Estimates of household dwellings.
[5] National Grid (2014) Electricity Ten Year Statement, 2014.
[6] Holford Rules with National Grid Company (NGC) 1992 and Scottish Hydro Electric Transmission Ltd (SHELTL) 2003 Notes.
[7] Horlock Rules: NGL Substations and the Environment: Guidelines on Siting and Design, 2006.
[8] Scottish Power Energy Networks (2015) The Dumfries & Galloway Strategic Reinforcement Project: Routeing and Consultation Document, May 2015.
[9] Scottish Power Energy Networks (2015) Major Electrical Infrastructure Projects: Approach to Routeing and Environmental Impact Assessment.
[10] Scottish Hydro Electric and Scottish Power (2007) Proposed Beauly to Denny 400kV Overhead Transmission Line: The use of underground cables as an alternative to overhead line. Report APL/STG-41, Final Report October 2007.
[11] Parsons Brinckerhoff (2012) Electricity Transmission Costing Study.
[12] Sims, S. and Dent, P. (2005) High voltage overhead power lines and property values: a residential study in the UK. Urban Studies. Vol.42(4), pp.665-694.
[13] ONS (2015) Measuring National Well-being: Life in the UK, 2015.
[14] Dumfries & Galloway Council (2008) Regional Economic Strategy, 2008.
[15] Dumfries & Galloway Council (2013) Economic Briefing Report, April 2013.
[16] Eurostat (2010) Key size class indicators, non-financial business economy.
[17] Eurostat (2014) Regional Yearbook, 2014.
[18] Scottish Executive (2005) Scottish Rural Development Programme.
[19] Dumfries & Galloway Council (2011) Regional Tourism Strategy, 2011-2016.
[20] Tourism Scotland, 2020.
[21] ITV News (2015) Tourists bring record profits to Dumfries & Galloway, 8 July 2015.
[22] Scottish Power Energy Networks (2015) Dumfries & Galloway Strategic Reinforcement Project: background to needs case, 2015.
[23] National Grid (2015) Factsheet: Our transmission infrastructure and its effect on local people, communities and the local economy.  Reference CRFS11/01/15.
[24] Private communication with Richard Wylie and Diyar Kadar of SPEN on 14 July 2015.
[25] RWE npower renewables (2010) RWE npower renewables awards £15m construction contract to Welsh company for Gwent y Mor Offshore Wind Farm.
[26] Scottish Power UK PLC (2014) Annual Report and Accounts for Year Ending 31 December 2014.
[27] Ofgem (2013) Factsheet 117, Price Controls Explained.
[28] Stour Valley Underground (2012) How much would it add to electricity bills to put transmission lines underground?
[29] DECC (2015) Annual Domestic Energy Bills, 2015, Table 2.2.3 Average Domestic Standard Electricity Bills in 2014 for UK Regions.
[30] HM Treasury (2003) The Green Book, Appraisal and Evaluation in Central Government.
[31] Accent (2012) Consumers’ Willingness to Pay Research, Final Report, July 2012.
[32] Ofgem (2012) RIIO-T1: Final Proposals for National Grid Electricity Transmission and National Grid Gas., 17 December 2012.
[33] ONS (2014) Families and Households, 2014.

Footnotes
I The Scottish Government have set a target of achieving 100% of electrical energy from renewable sources by 2020.
ii This metric excludes random one-off events and represents the annual electrical energy consumed by approximately 50 homes.
iii This is the summer rating at elevated ambient temperature. The winter rating is higher, typically 132MW.
iv Load factor is typically calculated from the equation (energy supplied in a year/rating of the turbine multiplied by the hours in a year). For Southern Scotland the average load factor varies from 21% in the summer months to 37% in the winter months
v Announced by DECC on the 18 June 2015 and repeated in Parliament on the 22 June 2015
vi Residential visual amenity refers to the visual amenity experienced by residential properties including their gardens. For more information see Gillespies (2014) Wind Turbines & Pylons: Guidance on the application of separation distances from residential properties, Final Report, July 2014.
vii Evaluated from 132km at £2.5m/km
viii These include Kent-Zeebrugge, the Western Link, Blyth – Norway and Peterhead – Norway. Regressing the costs, capacity and length of these sub-sea links suggest a value for Auchencrosh to Heysham in the region of £620m as being a reasonable estimate.
ix WTP is the maximum amount of money an individual is willing to give up in order to receive a good.
x WTA is the minimum amount of money an individual would need to be compensated to forego or give up a good.
xi Equivalent to National Scenic Areas (NSA) in Scotland

 

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