Assessing constraints on installations (planning, environmental, regulatory)
The development of ground and water source heat pump projects require regulatory consents. As built infrastructure, these projects will typically require planning permission, but other regulatory requirements may also apply depending on the sensitivity of the site and the scale of development. While these requirements will be project specific, having an overview of the potential constraints that may apply will help those who are developing early stage projects to assess and respond to the development risks posed by regulations.
As well as addressing any adverse environmental impacts, it is important to provide the regulatory authority with information about the positive environmental impacts to inform a balanced judgement on overall acceptability.
Overview
The regulatory framework is designed to protect people and the environment while supporting appropriate development. As low-carbon infrastructure, there is a presumption in favour of development at both the legislative and regulatory levels, provided the potential harm from a project does not outweigh the benefits.
The main way that new developments are controlled is through the planning system. England, Scotland, Wales and Northern Ireland each have their own devolved planning system, and each Local Authority has its own local development regulations (Local Development Frameworks in England, Local Development Plans in Scotland, Wales and Northern Ireland). Typically, the planning system will have a combination of development policies (e.g. housing) promoting where specific types of development should be located, requirements that these will need to meet, and management policies (e.g. green belt) which tend to relate to specific locations. Infrastructure for ground and water source heat pump projects tend not to be covered by development policies. In the absence of specific policy, wider legislative and policy support for sustainability and/or low carbon infrastructure will be relevant.
It is worth being aware that heating/cooling is a form of pollution. Obviously the heat exchange from a ground-loop collector is minuscule compared to that of a cooling tower on a coal-powered power station, but if you extract too much heat from the ground or water, you can cause the ground to freeze. An experienced designer can ensure you avoid these effects.
Type of Development
To assess the potential impact from development, you first need to understand what the development of the project entails. It may be useful to provide this information to the planning authority (either at the pre-application stage or accompanying a planning application) as not everyone will be familiar with ground and water heat pumps. In this toolkit you will find general information about various aspects and impacts of heat pump projects.
Environmental aspects
The technical knowledge and environmental benefits of heat pumps are well-proven to significantly contribute to the UK’s carbon reduction ambitions. If well-designed and competently installed according to appropriate environmental guidelines, electric heat pumps will pose very low risk to the surrounding environment. Vertical ground source heat pumps (GSHPs) present a greater environmental risk than horizontal pumps due to deeper ground penetration (see Figure 1). The carbon benefits and cost savings of heat pumps will vary depending on the pump’s heat source, size, efficiency, the type of fuel displaced, and the fuel’s cost.
Figure 1: Vertical heat pumps pose a greater environmental risk than horizontal systems (Source: Environment Agency, Environmental good practice guide for ground source heating and cooling V3)
For ground- and/or air-source heat pumps, the main environmental considerations include:
Impacts on land during the installation of a ground loop or borehole, including temperature changes and soil disruption
Noise from air-source heat pumps (normally located outside the building)
Leaks of the heat transfer fluid (for ground- and water-based systems) into surrounding soil and groundwater
Visual impacts from air-source heat pumps
Due to their direct exchange of water with the ground, ‘open-loop’ heating systems present a greater environmental and contamination risk than ‘closed-loop systems’, which are self-contained and filled with a specific thermal transfer fluid.
Impact on land
Horizontal GSHPs disturb a substantial amount of soil.
If this soil is contaminated, its disturbance poses a greater environmental risk due to the possibility of further dispersing the pollution. Following the installation of the heat exchange pipes, the trenches must be thoroughly refilled to ensure that any contamination is contained.
If there are artefacts in the ground, there may be impacts on cultural heritage; if there are habitats, these may be disturbed, with impacts on ecology – each of these potential impacts, and how to assess these, are discussed later in this section.
GSHPs reduce the temperature of the ground due to their heat exchange properties. In poorly designed and installed systems this can lead to the soil freezing. However, as the EU’s Heat Pumps – Technology and Environmental Impact report describes, the use of soil for ground source heating has negligible influence on vegetation above, with possible delayed flowering of plant life. During warmer summer months, soil temperature loss is usually recovered assuming that the system is correctly designed and installed.
Noise Production
While heat pumps do produce some noise, often this is only a nuisance for poorly installed systems, and is therefore an important consideration in the planning process. Without a fan unit, most ground and water source heat pumps produce a low noise level similar to that of domestic refrigerators - up to 40 decibels. Air-source heat pumps are louder, producing a maximum noise of 60 dB. The effect of noise from heat pumps will also depend on where the pump itself is situated and the sound transmission of adjacent structures. The most relevant consideration is how noisy the background noise environment is – in a city, the noise may not even be noticeable, whereas in a quiet rural location the same equipment with the same noise levels may be loud enough to cause nuisance.
Good maintenance will prevent noise increase through worn equipment or faulty mount.
Impact on Water
Water Source Heat Pumps (WSHPs), and even GSHPS, have the potential to alter the temperature of water bodies, causing potential harm to the ecological life of rivers, wetlands, and underground aquifers. Deeper heat pump systems in particular can affect the flow and quality of aquifers during their drilling, installation and decommissioning.
Vertical ground loops present particular concerns when penetrating land and water due to the risk of thermal transfer liquid leaking from the heat exchange pipes and polluting the life in surrounding water bodies.
Due to these potential hazards, the relevant nodal agency (e.g. EA in England, SEPA in Scotland) will need to approve the abstraction of water from the ground, with open loop systems being at higher risk of environmental contamination.
Regulatory issues - water environment
Regulatory control is applied over activities that may affect the water environment. The Environment Agency (EA) is the regulator in England; SEPA (Scottish Environment Protection Agency) is the regulator in Scotland; Natural Resources Wales (NRW) is the regulator in Wales; and the Northern Ireland Environment Agency is the regulator in Northern Ireland. For detailed site-specific guidance, you should refer to the regulator for the respective country, but the basic principles described here will apply.
There are different levels of control applied to proposed activities, depending on the type and amount of water abstraction or impoundment that is desired. The first step is to understand which of the below is required for your plans:
Following of General Binding Rules;
Registration of the activity;
Licencing for the activity.
Different licencing requirements apply to operations:
Boreholes drilled to a depth of less than 200m require a simple licence;
Boreholes to or below a depth of 200m. require a complex licence level of authorisation.
Visual impact
Since their heat exchange pipes are hidden underground, ground and water source heat pumps have relatively low visual impact. Air-source heat pumps, however, can have a visual impact if the air handling units are visible at the building exterior (see Figure 2).
Figure 2: Unless hidden, air-source heat pumps can have visual impact on the site or building.
(Source: Homebuilding & Renovating, 2020)
Carbon impact
Domestic heating and hot water production currently account for 20% of the UK’s total carbon emissions. The use of efficient heat pump technology has the potential to reduce this figure to 12%, if widely adopted across UK houses.
The carbon impact of heat pumps depends upon; a) the efficiency of the system (COP), and b) the type of fuel it is replacing, which would have been used otherwise. According to DEFRA, heating from a ground-source heat pump offers a clear carbon emission saving against all other conventional heating methods.
| Domestic heating fuel type | kg Carbon per kWh energy consumed |
|---|---|
| Domestic electric heating | 0.283 |
| Oil | 0.268 |
| Mains gas | 0.184 |
| Air source heat pump | 0.094 |
| Ground source heat pump | 0.071 |
If the electricity powering the heat pump is renewably sourced then there will be a further carbon saving in operation. If gas is not available and other fuels such as coal, oil or LPG are being displaced as a source of heating then there will be a greater carbon saving in use.
Potential Impacts – Cultural Heritage
Depending on the sensitivity of a site, cultural heritage is more or less likely to be a potential impact. The following table lists some designations and the status, along with a guide on sensitivity. This may change and for issues of high sensitivity, it is likely to be necessary to get the professional opinion of a qualified cultural heritage assessor.
| Criteria for Establishing Relative Sensitivity/Importance of Heritage Assets | ||
|---|---|---|
| Sensitivity | Asset Importance | Criteria |
| High | International or National | World Heritage Sites Iconic Sites and Monuments Scheduled Monuments Category A Listed Buildings Inventory of Gardens and Designed Landscapes Inventory Battlefields Fine, little-altered examples of some particular period, style or type |
| Medium | Regional | Category B Listed Buildings Conservation Areas Major examples of some period, style or type, which may have been altered Remains of national importance that have been partially damaged |
| Low | Local | Category C Listed Buildings Lesser examples of any period, style or type, as originally constructed or altered, and simple, traditional sites, which group well with other significant remains, or are part of a planned group such as an estate or industrial complex Cropmarks of indeterminate origin Remains of regional importance that have been partially damaged or remains of national importance that have been largely damaged |
| Negligible | Negligible | Relatively numerous types of remains, of some local importance Findspots of artefacts that have no definite archaeological remains known in their context Remains of local importance that have been largely damaged Isolated findspots Undesignated structures |
These resources are useful for checking the known cultural heritage sensitivity of your site:
- Historic Environment Map Viewer in NI
Direct Impacts
Potential direct effects on known cultural heritage features can occur within the footprint of the proposed development or in areas affected by related works, where avoidance of such features is not possible. There is also the potential for direct effects on as-yet-undiscovered archaeological remains, which may occur where sub-surface remains are present but have not yet been identified because they have no visible, above-ground elements.
Direct effects on known or as-yet-unidentified cultural heritage features may result from:
Ground-breaking and landscaping works related to the construction of the proposed development;
Movement of machines over or near to sensitive areas, resulting in the disturbance of elements of a feature, including through the rutting and/or compaction of archaeological deposits;
Clearance of stone and vegetation from upstanding ruins;
Demolition of upstanding buildings of potential historic interest;
Changes to peat hydrology and consequently preservation levels.
Potential direct effects on the archaeological resource are typically permanent and irreversible.
The significance of a potential effect resulting from a direct change caused by a proposed development is assessed by taking into account the sensitivity of the cultural heritage feature and the magnitude and nature of the effect.
Indirect Impacts
Potential indirect effects are the potential effects on the settings of cultural heritage features. While the potential effects are primarily visual in nature, there are instances where the setting of a cultural heritage feature may be affected even when important views to or from that feature are not affected (for example, where the development affects the curtilage of a listed building but is not visible in important views from or to that building).
Potential setting effects include:
Effects on the inter-relationship between features;
Effects on the relationship of a feature to the wider landscape;
Effects on other significant views to or from features.
In addition to effects from a development, effects on setting may result from:
Changes in views associated with the construction or decommissioning phase of a development;
Changes in views resulting from the operation of the proposed development.
The significance of indirect impacts is assessed by considering the asset’s relative sensitivity and cultural value, in conjunction with the magnitude of visual impact predicted on it.
| Approach to Valuing Ecological Receptors | |
|---|---|
| Level of Value | Examples |
| International | An internationally designated site (e.g. Special Protection Area (SPA), Special Area of Conservation (SAC) or RAMSAR site), or site meeting criteria for international designations. |
| Species present in internationally important numbers (>1% of biogeographic populations). | |
| National | A nationally designated site (Site of Special Scientific Interest, SSSI, or a National Nature Reserve, NNR), or sites meeting the criteria for national designation. |
| Species present in nationally important numbers (>1% UK population). | |
| Regional (Natural Heritage Zone or Local Authority Area) | Species present in regionally important numbers (>1% Natural Heritage Zone population). |
| Sites falling slightly below criteria for selection as a SSSI. | |
| Local | Wildlife Trust Reserves, Local Nature Reserves. |
| Areas of bird habitat or species considered to appreciably enrich the ecological resource within the local context, e.g. reedbeds, scrapes used by passage waders, notable breeding bird assemblages. | |
| Negligible | Usually widespread and common habitats and species. Receptors falling below local value are not normally considered in detail in the assessment process. |
Potential Impacts – Natural Heritage
Impacts on natural heritage can affect either a site, or a species that uses the site (e.g. protected bird species). The following table provides an approach to valuing ecological receptors. This may change and for issues of high sensitivity you should get the professional opinion of a qualified ornithologist or ecologist.
Regulatory Issues – EIA Regulations
It is unlikely that any park-based ground or water source heat pump project is likely to require an Environmental Impact Assessment, but if it involved drilling boreholes and the area of works exceeds 1 hectare of is within 100 metres of any controlled waters, then it falls within the descriptions and applicable thresholds and criteria for ‘Schedule 2 Development’ under EIA Regulations.
If either of these criteria apply to the operational geothermal system, you’ll need to request a Screening Opinion from the Planning Authority. It is anticipated that EIA will not be required, but specific environmental and technical studies may still need to be undertaken to support a planning application.