The Marais Poitevin Regional Nature Park towards a territorial energy mix

Chaire Paysage et énergie (ENSP), 2022

Regional nature parks are committed to the energy transition and adaptation to climate change. The Marais Poitevin Regional Nature Park is implementing an energy strategy with specific objectives and focuses. Firstly, it aims to make the Marais Poitevin an exemplary territory for energy management and the use of renewable energies, while preserving biodiversity and landscapes, in accordance with the Park’s Charter. The objective is also to reduce energy consumption and promote a diversity of renewable energies that respect the environment and the living environment. In addition, the Park carries out concrete and shared actions at the level of the 3 Departments, the 2 Regions, the 89 municipalities and 8 Public Establishments of Inter-municipal Cooperation, members of the Park, in connection with the State services, socio-professionals, associations, inhabitants… It is also a major player in relaying good practices, supporting experiments and offering decision-making tools to elected officials. The two priority areas of the energy strategy of the Marais Poitevin Regional Nature Park are energy management in various fields (housing, mobility, light pollution, etc.) and support for an energy mix (wind, solar, methanisation, wood energy, geothermal, etc.) that respects the landscape and biodiversity.

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The action of the Regional Natural Park

The Marais Poitevin is the largest wetland on the Atlantic coast. Situated at the interface of salt water from the ocean and fresh water from its watershed, it is composed of a mosaic of landscapes.

The upstream wet marsh is structured by a complex network of waterways (conches, ditches, gullies) lined with a dense network of pollarded ash trees and poplars. This marsh offers an intimate atmosphere that can be discovered from the inside. This area is protected as a classified site by decree of 9 May 2003 and has been labelled a Grand Site de France since 2010, with the label being renewed in 2018.

Closer to the coast, there are the large expanses of dried marshland. Sheltered by dykes and levees, the meadows and vast crops are structured by ditches and canals. Tamarisk hedges or reed strips enliven these open landscapes. Limestone « islands », often inhabited, form the high points of the dry marsh.

The Bay of Aiguillon and the coastline: the coastline is bordered by sandy beaches, dunes, forests, cliffs, mudflats and mown salt meadows (mizottes). The whole opens onto the ocean over 140 km of coastline. The Bay of Aiguillon is classified as a National Nature Reserve.

The edges of the Marais: the cultivated hillsides and plains form the fringes of the Marais and offer views over the canopy of the wet marshes.

This diversity of contrasting landscapes with varying scales and atmospheres requires appropriate energy responses to reconcile the implementation of the energy transition and the preservation of the landscape.

Acknowledged as a vulnerable area, a lever for action

The territory is subject to climatic hazards and in particular to rising water levels. Indeed, the marsh is an extremely fragile place located under the highest waters. It is an ancient marine gulf, protected by dikes. It is the urgency of climate change that has led the NRP to take a position.

Supporting an energy mix that respects the landscape and biodiversity

Methodology and monitoring committee

The NRP is a public structure that allows for exchange and mediation, but also the structuring of tools and networks of actors, to bring coherence to the territory. To implement the territorial energy strategy, the elected representatives of the Marais Poitevin NRP have created a « Climate and energy transition » vice-presidency. It is supported by a committee made up of elected officials, technicians, partners and experts who meet several times a year to discuss and propose strategic orientations.

On 1 April 2019, the NRP’s trade union committee approved the strategy’s objectives. To enable sharing and territorial energy enforceability, the NRP pays particular attention to :

« What is true in one territory is not true in others. We had to avoid copying other territories at all costs. We had to create our own energy mix » Pascal Duforestel, Delegate of the Nouvelle-Aquitaine region and Vice-President of the Energy and Climate Transition.

The choice was to avoid the confrontation between pro and anti renewable energies, by opening up a space for dialogue, culture and work to the territory’s elected representatives. In addition to the commissions, field visits were carried out in order to propose a range of inspiring interventions and to share initiatives.

Sobriety and energy management as a territorial project

Accompanying planning documents to promote coherent public policies

The Marais Poitevin NRP supports municipalities, communities of municipalities and individuals in their projects to reconcile the preservation of local urban, landscape and architectural qualities with energy management issues.

The NRP issues opinions on planning and urban development documents so that they are compatible with the Park charter: limited urbanisation, urban forms adapted to the challenges of preserving wetlands, natural and agricultural areas, as well as the challenges of flooding and global warming. It also supports EPCIs in their PCAET: the NRP provides added value in terms of taking into account architectural, landscape and environmental quality in eco-housing, raising public awareness, training actors, experimentation, etc.

This support allows for the continuity of energy projects in territorial actions and consistency with other local issues, biodiversity and the living environment.

Carry out actions in favour of energy sobriety and carbon capture

The NRP promotes energy sobriety: soft mobility with an 800 km cycling network, including the Vélofrancette and the Vélodysée; promotion of eco-housing with support for a « bio-sourced materials » sector for renovation and construction, etc.

It conducts preservation and restoration programmes for environments with high carbon capture potential, such as peat bogs, reed beds and natural wet meadows. It is conducting a major planting programme « planting the pollarded trees of tomorrow » aimed at anticipating the evolution of the landscape weakened by chalarosis, which causes ash trees to die back. In addition to the heritage, economic and environmental dimensions of this scheme, it contributes to carbon capture. The plantations carried out in the Marais Poitevin by the Park are thus integrated into the « La Rochelle Carbon Cooperative » territory project. The Park participates in the governance of this cooperative tool, which brings together project owners and buyers of carbon credits, with the aim of achieving territorial carbon neutrality.

More generally, several actions are being carried out to raise awareness of energy and climate issues among local players:

The scale of the NRP for planning wind power in very contrasting landscapes

Faced with an increasing number of projects without a global vision, wind power was the first area of work for the NRP commission. The Park’s wind energy plan allows future infrastructure installations to be planned in a well-founded manner, taking into account the specificities of the territory. Approved by the deliberation of 1 April 2019, it translates into principles declined through maps and recommendations. The first map shows the current situation, i.e. the existence of a large number of wind farms in the Marais Poitevin, with more than a hundred wind turbines in operation or under construction, mainly installed along the road infrastructures bordering the Marais Poitevin.

Then a second cartography makes it possible to identify the landscape stakes, by qualifying the diversity of the landscape entities and the views. Finally, the mapping of the environmental and landscape vigilance zones was elaborated by taking into account the preservation of the most remarkable landscape and environmental spaces and the limitation of the sprawl and/or the encirclement of the NRP by the cumulative effect of the wind farms are determined by three levels of vigilance. Exclusion zones are proposed for protection areas and labels, such as the classified site of the Marais mouillé poitevin and the majority of the Grand Site de France which extends along the Sèvre. The objective is to avoid the effect of encirclement and to preserve areas of landscape breathing space. Areas of major vigilance have been identified in the valleys and plains of the south-east of Niort, the Vendée bocage to the west, the wetlands of the Marais Poitevin, etc. Finally, areas where studies are still to be carried out for bird watch are identified. This cartography is finely adapted to the scale of the SCOT and PLUi of the EPCI.

With this wind energy plan, the Park has adopted a strategy of densification of existing wind farms, provided that they do not present risks for the landscape and biodiversity (case by case studies).

For each project included in the strategy, a detailed analysis is carried out in order to specify the principles and recommendations for implementation, including for the densification of existing parks in order to avoid saturation phenomena. While densification must respect the landscape’s main lines, it must also integrate the movements of protected species and maintain ecological corridors.

Framing and supporting solar energy

A solar strategy that respects the landscape and biodiversity

Solar energy has an interesting development potential in the Marais Poitevin, which has a high level of sunshine. As with wind power, the challenge is also to reconcile the development of this form of renewable energy with the preservation of the built heritage and agricultural and natural areas.

With this in mind, on 9 April 2021 the NRP approved its solar strategy based on the following principles

In favourable sectors, and particularly on large roofs (farm buildings, commercial areas), the park encourages the transition to action with the support of advice facilitating the completion of projects, in conjunction with the Centre Régional Énergies Renouvelables (CRER) and citizens’ associations.

The Fontenay-le-Comte solar park

This 12.4 ha photovoltaic park is installed on a former military site that the Ministry of Defence sold to the town. Several criteria favoured its location on the plains of Bas Poitou, along the main roads:

The design (2009-2015), construction (2015-2016) and operation (since 2016) were carried out by Solairedirect, a subsidiary of Engie.

The designers ensured that the project was accepted by the municipality, the community of communes, etc. They carried out a simple flora and fauna study before checking that the project was compatible with the town planning document in force. Once these conditions were met, the project continued with the environmental diagnosis: protected species, historical monuments, etc.

A landscape consultancy highlighted the landscape sensitivities of the site. Solairedirect carried out a voluntary consultation process.

The NRP was involved in the planning of the surrounding area.

Assuming productive landscapes with methanisation

The SAS Déméter énergies land use project

The potential for methanisation is important in the territory with a tradition of dairy and butter farming. But this agricultural sector is difficult to maintain. Methanisation can allow the diversification of the activity. Two methanisation units are present near Niort, including SAS Déméter énergie located in the south-east of the NRP.

In operation since 2018, the Déméter énergies agricultural methanisation unit was initiated in 2014 by farmers in order to diversify their activities, secure their income, but also out of conviction about renewable energy. The resource is collected from twelve farmers, located less than 8 km from the site. Combined with a photovoltaic installation on the roof, the unit supplies the public buildings of Mauzé, the intercommunal swimming pool, etc.

The Institute for Training and Research in Environmental Education (Ifrée) was involved in the process to raise awareness of the project among the inhabitants. Participatory financing was also proposed. The overall cost of the project is nearly 6 million euros. From the outset of the project, the NRP has supported and accompanied the project leaders in their search for a qualitative landscape and architectural design. The advice helped to reduce the investments, while improving the appearance of the infrastructure.

The consultation process allowed us to realise that this project was much more than an agricultural project. We realised that it was a territorial project. The working groups helped us to adopt the most advanced environmental approach possible in our technical choices, but also by putting in place elements that we would never have thought of: participatory financing, a panel of noses to identify olfactory nuisances, etc. Vanessa Baudrier Paillat, Development Officer Sources: 451-vanessa-baudrier-paillat-responsible-for-operations-demeter-energy

The support project took place in several stages:

The choice of energy in an agricultural landscape

Several major principles of implantation were chosen. The unit favours a functional (photovoltaic hangar) and assumed implementation of the various buildings and technical elements (no digging to minimise the height of the tanks, etc.). The maximum height is 12 m in keeping with the agricultural and plain landscape context and near a small business zone. The buildings and technical elements have been harmonised with each other: raw concrete, metal or grey cladding finish. For the roofs, a dark RAL colour was chosen as close as possible to that of the photovoltaic panels. The tarpaulin for the digesters was of a neutral colour, without any logo.

In addition, the layout of the site has kept the need for berms and land movements to a minimum. Where necessary, planting has been used to mitigate them. Finally, a proposal for a local and varied plant palette and a choice of agricultural type fencing (chestnut posts, agricultural fencing, etc.) were favoured.

The Marais Poitevin, located in the heart of the Marais Poitevin region, is the only region in the world to have a sustainable energy supply.

The Marais Poitevin, located below sea level at the highest water levels, has been developed over the centuries. A complex system of dykes, hydraulic structures, etc. has made it possible to manage the water coming from the sea and the catchment area. Because of its characteristics, the Marsh is directly affected by climate change and rising sea levels. With the support of its Scientific and Prospective Council, the Park is carrying out new actions to encourage exchanges between elected representatives, inhabitants and experts, in order to facilitate collective intelligence and the co-construction of projects on this sensitive and complex subject.

These actions to raise awareness of adaptation to climate change involve

The Park also plans to expand its actions in favour of carbon capture:

While the NRP’s energy diagnosis shows a good evolution in the share of renewable energy production (from 12% in 2014 to 16% in 2018), the territory’s energy consumption has remained stable. The question of sobriety remains an important area of work to be carried out in order to achieve the objectives of the law on energy transition, while continuing the dynamic of renewable energy production adapted to the resources, uses and functionalities of the landscape, such as wood energy and geothermal energy.

These actions will be carried out in conjunction with the network of local actors, particularly the 8 EPCI members of the NRP, all of whom will be initiating their PCAET.

The work of animation will remain central to engage all the actors towards an energy and climate transition adapted to the local singularities.


Experience extracted from the guide « Energy transition: towards desirable landscapes » produced in 2021 - 2022 by the Landscape and Energy Chair of the Ecole Nationale Supérieure du Paysage de Versailles:

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