A recent field trip along the Lower Severn Vale with a group of Landscape and Applied Ecology MSc students highlighted some of the opportunities and challenges associated with weaning ourselves off large-scale and centralised electricity generating systems.  The area of interest is part of the Severn estuary between Gloucester and the old suspension bridge carrying the M48 from Aust to Chepstow.

River Severn view from above Newnham

It encompasses, on the south side, much low-lying and flat land bordered by the Cotswold escarpment, and on the north side a more elevated landscape and restricted landscape hemmed in between the Forest of Dean and the river’s edge.  Down near the bridge the river widens out with shifting mud banks formed from the tidal currents, but above Sharpness it makes a series of great sweeping curves around Awre, Arlingham, and Rodley, funnelling in as it approaches Gloucester.  This area is famous for its massive tidal range and the Severn Bore, a wave that sweeps miles up the river every day with the tides, ranging in height from a few inches to three metres depending on the time of year.

For a long time the estuary has been a centre for nuclear power generation.  Two of the earliest Magnox generating stations were sited here at Berkeley (276MW capacity; operated from 1962 to 1989) and Oldbury (430MW; started generating in 1967 and was decommissioned in 2012) on the banks of the Severn, in a rural area of low population density.  Both are now closed and undergoing decommissioning work, although the legacy of these stations will last another 100 years before the reactor cores and their large containment buildings are safe enough to remove.

Decommissioned Magnox reactor at Oldbury. Sharpness wind turbine visible to left of main building
Decommissioned Magnox reactor at Oldbury. Sharpness wind turbine visible to left of main building

This may not be the end of nuclear power in the area as there are proposals for a new 2,700MW nuclear power station at Oldbury, some six times larger than the existing generating, which will undoubtedly have significant effects in terms of visual impact across a wide and largely flat estuarine landscape, on the aquatic ecology through the demand for cooling water from the river, and economically. A 2009 Environmental Impact Assessment (EIA) scoping report made reference to 3,300MW of installed capacity and 4 cooling towers up to 200 metres in height. Further down the Bristol Channel are two additional nuclear power stations at Hinkley Point.

More recently the area has seen rising interest in the application of renewable energy technologies, principally solar, wind, and tidal.  The tidal power of the Severn estuary has long held fascination for its potential to generate energy and schemes go back to the 19th century with at least ten alternative sites considered at one time or another.

A recent (2013) House of Commons Energy and Climate Change Committee report into one of the latest proposals (by Hafren Power Ltd) suggested the scheme could meet as much as 5% of the UK’s electricity needs.  The scheme would involve 1,026 Very-Low-Head (VLH) bi-directional turbines installed into an 18 km fixed tidal barrage between Brean in England and Lavernock Point in Wales and generating an estimated 16.5 TWh/year on both ebb and flood tides.  The report was not overly flattering, indicating that government financial support would be required for thirty years of operation and that environmental issues had not been resolved.  In particular there was concern over flood risk, intertidal habitats, and impacts to fish as well as a need for compensatory habitat ‘on an unprecedented scale’.  In addition local economic impacts and job losses were identified.

A barrage presents significant challenges, not only in terms of the technology to deal with a 15 metre tidal range but also with the effects of siltation from slowing down of currents (which would potentially reduce the lifetime and efficiency of energy generation), the loss of the Severn Bore, and potential ecological impacts on birds and aquatic systems (the whole estuary area is also recognised as being of international importance for migrating birds (designations include SAC, SPA, European Marine Site, RAMSAR, and SSSI). Other proposals call for various numbers and sizes of tidal ‘lagoons’ rather than a complete barrage across the river, although many of the potential problems indicated above also apply.

In many ways it seems that with large scale generating capacity, including both nuclear power and a tidal barrage it is an ‘either/or’ situation, i.e. we either have no power generation in the area, and use it to provide a range of ecosystem services, or we engage in large scale construction which will provide reliable and secure sources of power for 25–30 years.  But the cost of that power would include considerably reduced environmental quality (in its widest sense in terms of impacts on the landscape, and on social, cultural as well as ecological support services).  One alternative, which potentially offers a means to balance the benefits of new technology with limited negative impacts, has already appeared.  This refers to small or ‘community scale’ renewable energy generation utilising low-head hydropower, livestock waste in the form of anaerobic digestion (AD) plants, wind, and photovoltaic (PV) solar.  Driven by government subsidy in the form of generous feed-in tariffs (which are now decreasing), the whole Lower Severn Vale has seen a steep rise in the number of applications, in particular for wind turbines and PV arrays.  Community scale energy generation seems to offer a number of benefits from the new technology:

  • Limited impact on the local environment
  • Communities can benefit financially
  • Dispersed generation feeding into the existing grid giving greater security of supply
  • Helping to meet UK and European targets for reducing carbon emissions and electricity generation from renewable sources of energy

The approach suggests the possibility of a better balance of benefits and costs arising from generating power, but twoa key issues remain:   isfirst of all, the land area required by renewable technologies (such as wind and solar) in order to replace large scale fossil fuel or nuclear power plants; and secondly, the impacts which occur as a result of energy development and how the pattern of costs and benefits is determined across local communities.  Our curiosity had been raised first of all byThese issues are inevitable given the land requirements needed by renewable technology to deliver the same output as a large fossil fuel plant,; and secondly, by reports in the media regarding the negative impacts the uneven distribution of both positive and negative effects of both wind and solarrenewable energy technology on local communitiesresidents living in the vicinity of such developments.  When ‘small scale’ energy developments start to multiply then a larger proportion of the population of a rural area is likely to be impacted.  This was ourbecame a starting point for, to looking at the Lower Severn area in terms of how the cumulative impacts of an increasing number of renewable energy generation projects might be assessed.  While the tidal barrage proposal is on the back burner, our the currentmain focus is on wind turbines and solar (photovoltaic or PV) farms, as these make up the majority of (renewable energy) planning applications.  During our a recent tour of the area we were able to identify a number of issues through discussions with developers, planning officers, and local residents, and these are summarised below.

PV solar generation

Individual projects can have limited impacts, especially if well sited and screening is required as part of the planning consent.  At Actrees farm for example, near Berkeley, a 7.6MW PV array is sited on poor agricultural land running alongside a railway embankment, which effectively screens most of the site from view points up on the Cotswold escarpment. Conditions on the permit requiring hedgerows to be allowed to grow up to 3 metres around the site will provide further screening from other directions.  Surprisingly a much larger development in the area, a 30MW PV array at Hillhouse Farm, received the fewest objections, partly because it lies adjacent to the busy A38, and benefits from screening by the road which is elevated above the general land area at this point.

solar2
PV solar array at Hurst Farm

Providing they are well screened, opposition to small PV development tends to be minimal and linked to concerns over the number of proposed sites within a limited area. Small developments (e.g. around 5MW) cover 25-30 acres and can be constructed very quickly (often in less than three months) and with careful siting are not intrusive. PV arrays are placed on a simple structure based on steel frames driven up to 1.8m into the ground. Only the transformers and switching gear require solid concrete foundations. The result is limited impact; in some cases grazing by sheep can occur once the panels are installed, and other ecological services are not affected. After 25 years the panels can be removed and the land returned to its original state. Problems tend to come with larger projects which have a more significant visual impact. A proposed 50MW array, for example, covering 270 acres on the tip of the Awre peninsular received a high number of objections and potentially had a significant impact on the landscape. A map of the proposed location can be found within this news article.

It is worth noting that 9 solar farms of this size would be required to equal the installed capacity of a small generating station such as Oldbury, but this would not generate as much power due to the limited number of hours with sufficient light to generate power.  However, it would be cheaper to build and operate than a nuclear facility, and have far less environmental impact.

Wind

Wind turbines tend to elicit more controversy, perhaps due to their prominence in the landscape and movement of the blades.  Flicker, glare, and ecological impacts can be a cause for concern but there is support as well as opposition for wind turbines.  One example is the single large turbine at Sharpness sitting above the commercial dock area where it is visible across a wide area on both sides of the river.  The turbine has a total height of 122 metres (to the tip of the blades) with an installed capacity of 1.2 – 2.5MW it is able to supply 736 – 1,226 average homes per year, During our visit it was reported that the full generating potential is not realised due to restrictions to limit negative impacts on local receptors such as housing and bats. In this case glare and flicker from the blades can cause problems for local residents when the sun is at a certain height in the sky, and also a pocket of warm air forms behind the blades in which insects gather, providing a feeding ground for bats.

Opposition poster to wind turbine planned for Tidenham
Opposition poster to wind turbine planned for Tidenham

Cumulative effects

One of the difficulties for local authorities is assessing the cumulative effects of numerous small schemes which over time can alter the character of an area.  There is no real guidance or methodology for assessing cumulative impacts and the planning process does not permit planning Officers to take into account other applications for a similar type of development when making their recommendations.  This has created concern among Parish and District councils in the area.  Where changes to government policy stimulate interest in particular types of renewable energy development it can lead to a flurry of planning applications, which can then become a burden on local authorities with limited resources.  The main reason for the Parish Council objections to Actrees Farm PV array, for example, were concerns about cumulative impacts from a further nine planning applications for similar developments in the area.  Under planning regulations only existing developments or those already granted planning permission can be taken into account when considering cumulative effects – so in terms of getting permission it is very much a first come, first served situation.

PV solar farm on Awre Peninsula
PV solar farm on Awre Peninsula

There are also at least five other large single turbines planned within the ten-mile stretch of estuarine coast between Chepstow and Lydney, creating a similar situation to the south side of the river regarding the assessment of cumulative impacts by planning bodies.  .  Although each turbine forms a single application for planning purposes some local residents have argued that the outcome is the creation of a ‘wind farm by stealth’; one current proposal for an 87 metre turbine on a grassy knoll by the A48 in Tidenham, for example, has generated opposition from both the Parish Council and some local residents.  Even where community benefits are part of the development package the negative impacts of such large scale development are likely to be unevenly spread, and it can be difficult to avoid generating opposition from those who feel they will be more severely affected.

Inequalities arising from sharing the benefits from the positive impacts, and the imposition of negative impacts, lie at the heart of many of the arguments over the spread of renewable energy generation.   While photovoltaic panels might appear to be more benign in terms of negative impacts (providing they are well screened), the land take is larger (approximately 5 acres per MW of generating capacity).  Wind turbines, on the other hand, need to be sited in the open, often on raised ground, and of minimum size in order to capture sufficient energy.  This and the necessity for moving parts make them more visible, and potentially more likely to attract a negative response, particularly in cases where the majority of the financial benefits accrue to individual landowners, while the negative impacts are imposed on a larger community of interest.

Community benefit

One approach to overcoming local opposition created through perceived inequalities in the distribution of positive and negative impacts has been through offering financial grants to local communities in which generating capacity is sited, as inducements for support.  Amounts offered can vary widely but do form a potential income stream for small rural communities, which can be attractive in a time of austerity and government cut-backs.  Guidance on community benefits is provided by the Scottish Government on “Good Practice Principles for Community Benefits from Onshore Renewable Energy Developments”.  The guidance suggests that for projects between 50Kw and 5MW a suitable community benefits package would include ‘a minimum of £5,000 per MW per year, index linked for the operational lifetime of the project’, in addition to ‘consideration by developers of the scope for community investment’.  The guidance document also identifies a number of ways for local communities to benefit from local energy development including:

  • Benefits derived from undertakings directly related to the development such as improved infrastructure
  • Wider socio-economic community benefits in terms of job creation
  • Benefits derived from community ownership in the development, referred to as “community investment”
  • Voluntary monetary payments to the community that are not related to anticipated impacts of the planning application usually provided via an annual cash sum, often referred to as a community benefit fund
  • Other voluntary benefits which the developer provides to the community, (i.e. in-kind works, direct funding of projects, one-off funding, local energy discount scheme or any other site-specific benefits)

Creation and management of this form of ‘community benefit’) is not straightforward.  It is an area where Planning Officers must not get involved and thus lies completely outside of the formal Planning process.  It raises issues of who, or what, is the relevant ‘community’ that should benefit, how those benefits should be distributed, and who should make the decisions.  There is little guidance on the decision making arrangements for utilising the income from renewable energy projects, it very much depends on the local arrangements made with the owner, and it is not always locally elected bodies that are involved, in some cases independent funds with trustees are established.  Allocation of the funds themselves can therefore result in controversy.   In terms of governance key questions to be explored include the extent to which there are genuine benefits for the community, and whether those most affected by the negative impacts are adequately compensated.

Planning process

The planning process is not perfect and planning officers from both sides of the river, in Stroud and the Forest of Dean emphasised the importance of treating each application in exactly the same way.  Due process must be followed otherwise either developer or opposition group has room to argue they were unfairly treated.   The process was described by one planning officer as one of “patient negotiation” which always involves “a balancing act between competing interests” with limited resources for analysing the situation and monitoring compliance.

Sharpness wind turbine
Sharpness wind turbine

Planning Officers do have ways of influencing proposed developments and can, for example, impose conditions on development to ameliorate impacts.  However, it is elected councillors sitting on planning committees that make the final decision, and although they are guided by advice from Planning Officers they do not have to slavishly follow that advice.  Elected Councillors are not experts and may have limited understanding of the issues; and, like anyone else they can be influenced by persuasive arguments.  The aim of the planning process is to balance competing interests but the process is not perfect and without doubt it is difficult for local residents to oppose developers, who often have deeper pockets.  Appeals and judicial review are very expensive as those opposing the proposed wind turbine in Tidenham are aware.

Technology

A key factor limiting the number and location of small scale renewable energy developments is the technological limits associated with linking to the grid.  The economics of energy generation are based on being able to feed into the grid.  The level of feed-in-tariffs provided by the government for each kilowatt hour of power are a major determinant of which projects get built, but just as important are the location of generating stations in relation to the grid, and the capacity of the grid to absorb that power.  The grid infrastructure was made for exporting and distributing power from large centralised generating stations and not importing it from a multitude of small sources.   The ability for the grid to receive power is quite limited and the low availability of connections allows very few opportunities, effectively dictating where renewable generation can be sited. When one takes into consideration that the cost of any grid infrastructure upgrade is usually very high (regularly £1 million plus) many projects quickly become economically non-viable.

An additional technical restraint is line degradation.  The available connecting capacity drops with increasing distance from a sub-station and therefore sites need to be close to substations, which are usually in urban areas.  When one also takes into consideration the fact that PV projects are only allowed on low quality agricultural land or brownfield sites, that brownfield sites in urban areas often have high land values, and that to get the economies of scale needed to make the cost of grid connection and planning costs viable the sites usually need to be a reasonable size (a minimum of 5MW, which equates to around 25 – 30 acres for a PV array).   As one developer noted, “5MW is the ‘sweet spot’ for the smaller ground mounted PVs to make projects viable”.  The same developer also clarified the considerable financial risks associated with developing PV projects.  These can be in the region of £1 million per MW of installed capacity when the costs of sourcing land, acquisition, planning, design and build are taken into consideration, requiring up to a £100,000 outlay before planning is approved.  Add into this a wide range of other potential barriers including local opposition, gaining access to the grid, flood risk, landscape grading, mitigating impacts, and it can quickly be seen that small scale renewable development is not a risk-free investment activity for developers, or landowners.

A balancing act….

Small scale electricity generation from renewable sources comes with a wide array of problems. It is not a panacea and on its own is not going to solve our thirst for electricity, which will continue to need a mixed supply, at least until we work out how to overcome the storage problem.  For the foreseeable future this will include large scale generation providing base power (possibly nuclear and fossil fuels) as both wind and solar are intermittent, lacking certainty regarding the amount and timing of power generated.  Tidal power offers more regular, guaranteed power that can be more easily predicted but comes with considerable technological challenge and financial costs; and in the case of estuarine barrages the ecological costs might be too high.

We could certainly increase the level of power from renewable sources, though with the technical constraints of the grid we perhaps should be looking at larger scale renewable  generation adjacent to existing sources of supply, rather than scattering small production units across rural areas.  An alternative might be a vastly increased effort focused on making every building generate some of its own power, reducing the overall demand for electricity from other sources, although this will come with additional economic costs.  Managing small scale renewable energy development in rural areas requires a delicate balancing act to ensure that wider communities share in the positive benefits of local energy production and are not left with merely the negative impacts.  The planning system, based on the need to balance competing interests, has limited capacity to control developments, yet improvements are required in order to adequately account for the cumulative effects of multiple small-scale generation projects.  One alternative is to require some level of community ownership of generating capacity, but although a Rural Communities Energy Fund (RCEF) exists to support community based projects, other considerations such as the size of the feed-in-tariff, technological constraints, and the human and social capital required are far more important determinants of success in the development of small scale renewable energy projects.

Questions were raised on our tour of the Severn Vale as to whether small scale generation may even be entirely the wrong approach. Serious concerns over the limited ability of the grid to absorb more renewable input, and prohibitive costs of changing a system that is built for distribution of power suggest we should be looking towards other solutions.  We should perhaps be questioning more deeply the rush to cover the countryside with small scale generating stations when we have the technology to become more energy efficient (thus reducing consumption), and to construct and retrofit a wide range of buildings, each with its own generating capacity, across wide swathes of urban land where demand is concentrated.  If we are serious about creating sustainable energy supplies with minimal environmental impacts we should be investing resources as close as possible to the end user, not in small scale projects that concentrate the benefits of energy generation into the hands of a few individuals, while imposing all of the negative aspects on wider rural communities.

 

Base of Sharpness turnbine - illustrating its scale
Base of Sharpness turnbine – illustrating its scale