Environmental aspects and social acceptance

Environmental Impacts of geothermal projects

Most stages of development of a geothermal project potentially produce an impact on the environment.

Environmental Impacts of geothermal projects

• surface-visual effects (land use, landscape, flora and fauna);
• physical effects (induced seismicity, subsidence, geological hazards);
• acoustic effects (noise during drilling, construction and management);
• thermal effects (release of steam in the air, ground heating and cooling for fluid withdrawal or injection);
• chemical effects (gaseous emissions into the atmosphere, re-injection of fluids, disposal of liquid and solid waste).

EIA is the assessment of the possible impact (positive or negative) that a proposed project may have on the environment, together consisting of the natural, social and economic aspects.
EIA studies are required by authorities at various project phases (to various degrees of details).

Atmospheric emissions

Mostly power production, negligible at low temperature resources (heating/cooling).

Sources:

• Geyser, fumaroles, diffuse emissions
• Wells (during well testing operation)
• Power plants

Noise

-Well drilling and testing phase
-Plant construction and equipment installation
-Power plant commissioning and operation

The intensity of the generated noise depends on the installed capacity and other acoustic parameters. 

Visual impact and land use

Exploration phase: removal of vegetation, preparation of the areas, construction works, infrastrctures (e.g. new roads).

Operation phase:  presence of pipelines, power plant.

How  to minimize visual impacts?

• avoid tourist areas, locations of natural/historical value, ecologically sensitive areas; 
• apply good architectural principles in the design and layout of facilities;
• enclose the wellheads in small structures integrated well with the surroundings; 
• prefer areas with tall trees that mitigate the visual impact;
• use reforestation with native plant species type;
• paint the pipelines green and brown; 
• underground the power transmission lines, except in wooded areas (to limit the deforestation).

Land subsidence

Extraction of large amount of fluid from the underground. Surface deformations can cause damage not only to facilities and infrastructure but to homes, if present in the vicinity of the field.

Larderello:
25-35 mm/a
(Rosi e Agostini, 2013)

Liquid and solid waste

• fluids (drilling mud and other drilling fluid additives like cement slurry, diesel and lubricant leakages, lubricant spill, cleaning fluid waste);
• solids (earth and rock excavation, construction wastes, like waste timber, metallic waste, packing, cement);

Generally these wastes are "not dangerous"

The contractor doing the work should be made responsible by contract for cleaning and transporting away all such waste to an approved waste dump after his work is completed. Such a performance should also be prescribed in a health, safety and environment (HSE) management program for the whole project. 

Water pollution

The extraction, reinjection, and discharge of geothermal fluids may affect both the quality and quantity of surface and groundwater resources.

The well casing is the first barrier against pollution of groundwaters. Damaged casings may allow brines to mingle with fresh water aquifers: to install and cement multiple casings at shallow depths to provide extra barriers.
fluids discharging during well testing must be stored in impermeable holding ponds;

Monitoring wells strategically located in the well field to rapidly detect any problems.

Completion of a hydrogeologic and water balance assessment during the project planning stage to identify hydraulic connections between the geothermal extraction and reinjection points and any sources of drinkable water or surface waters.

Induced seismicity (EGS)

Hydraulic fracturing to incresae permeability. Normal operation produces microseismic activity (low magnitude events), at no risk.

Often difficult to discern natural from induced seismic events:

• collect baseline data prior to field development 
• seismic monitoring
• establish a traffic light system (threshold definition, Go-No GO set up)

Potential damages to the built environment: public acceptance 

Social acceptance 

„Social acceptability is attained if the project activities do not result in drastic changes from the regular conditions of the area, and if the affected sectors can see some advantages issuing from the project” (de Jesus, 1995)

Figure 1: The triangle of social acceptance of renewable energy innovation (Wüstenhagen, Wolsink and Bürer 2007)

Social acceptance: a multiple stakeholders approach

Actions to win social acceptance

Public relations and information campaign during the planning /execution stage of the project:  

• Contacts with public administrators of the area concerned, not only to provide them with information on the project objectives, but also to start having an idea of the peoples attitude towards the new initiative; 
• Preparation of public opinion through a plain and timely information campaign on duration of works, potential impacts of the construction and benefits during the operating phase;
• Presentation to regional authorities, public administrators, and important entities of the area, of a brochure outlining the project objectives, the environmental measures in program, and the social benefits that the project is expected to produce; 
• Study tours, help-desk (information).