What are the major effects of the Operations and support phase?

20.4.3.3 Operation phase

The operational phase starts when the EPC contractor turns over care and custody of the project to the O&M contractor. This usually occurs at IA and typically corresponds to the COD of the PPA. In most plants, the formal turnover of the complete plant to the O&M contractor signals the start of the final acceptance test (FAT) for the EPC contract, which may run for multiple years.

Even though the CSP plant has been tested for the provisional acceptance, it is generally considered necessary for CSP projects to evaluate the performance of a CSP plant over an entire year. This is because the position of the sun in the sky changes throughout the year, and the solar resource—and therefore, the plant efficiency—also changes. It is considered necessary to evaluate the performance of the plant over the year to make sure it performs to expectations. Additionally, experience has shown that it typically takes some time for the plant to be tuned to achieve peak operational conditions. Part of this is the learning curve needed by the O&M team.

When the project reaches commercial operation, the revenues from the sale of energy are income to the project company. From the income, the project funds the plant O&M, makes the principal and interest payments to the banks, and provides the returns to the equity holders. The operational phase runs for the full financial lifetime of the project, typically 20–30 years or longer.

Operations: monitoring, reporting and inspection

The operational phase of storage is subject to a regular process of monitoring compliance with conditions; reporting by the operator on operational matters; and inspection by the relevant authorities of the Member State. The key operational element of the permit is a series of plans which address any associated risks of operating the site, including post-closure storage. The plans must outline monitoring measures to assess site integrity and possible environmental impacts (in accordance with details set out in Annex II to the Directive); any remedial measures to be taken in response to CO2 seepage; risk of seepage or any risks to health or the environment; and any measures to be adopted post-closure.

The Directive makes provision for Member States to ensure that the operator monitors the storage and injection facilities and, 'where appropriate', also the adjacent environment (Art. 13). This is to check on the safety of the facilities, and for detecting CO2 leakage and any damage to the adjacent environment (Art. 13(1)). Annex II of the Directive lays down criteria on which a 'monitoring plan' must be based (Art. 13(2)). The operator must submit a report on the results of monitoring at least once per year to the authority, but national law may ask for more frequent reporting (Art. 14).

In case of 'leakage or significant irregularities' the operator must inform the authority and undertake 'corrective measures' (Art. 16). The corrective measures are agreed with the authority as part of the licensing procedure (Art. 7(7)). If the operator fails to undertake these measures, the national authority must step in and ensure that they are taken (Art. 16(4)). The authority may also ask the operator to undertake any corrective measures deemed necessary, including any not mentioned in the plan (Art. 16(3)).

The Directive obliges the Member State authority to undertake inspections of the storage facilities (Art. 15(1)). These should be routine, at least once per year, and non-routine in case of reported irregularities. Triggers would include a notification of seepage or risks of environmental harm (Art. 15(3)). The authority must prepare its own report after each inspection and publish the report within two months of the inspection (Art. 15(5)).

4.3 Operational Phase Research

During operational phase of micro-scale energy harvesting system, because of the variations in energy harvesting sources, systems still need to manage energy consumption and adapt themselves according to energy harvesting conditions and battery residual charge, i.e., to maintain energy neutrality. In order to do so, systems must have capability to change or adapt their power consumption:

Node layer: manages hardware components such as sensors, radio chips, sensor boards’ processors, and possibly energy storage subsystems using software. As such, a power management scheme at the node layer can adapt techniques such as duty cycling sensors, processors, and radio at highest possible rates to match energy consumption with energy supply from energy transducers.

Network layer: takes charge of sending packets from sources to destinations, selecting paths that ensure delivery and maintain energy sustainability in the network. Maintaining connection and communication is very important in a WSN. As nodes die, part of the network might be isolated and important events/emergency scenarios can be missed or undetected by base stations. The network layer therefore must take active responsibility to control the traffic and set up sustainable routing paths, not only adopting existing techniques from energy-efficient routing protocols but also exploiting inherent characteristics of renewable energy sources in space and in time.

OS layer: where tasks including sensing, processing, and communicating are scheduled by scheduling algorithms. Scheduling algorithms have the control of when and how tasks are executed so that systems can operate smoothly. For example, tasks can be delayed by OS scheduler until sufficient energy is harvested to execute the tasks. Dynamic voltage frequency scaling techniques could be helpful. A task can be executed at higher frequency to meet its deadline if it has been delayed for a significant amount of time or at lower frequency to save energy consumption at the trade-off of delayed finished time. How to deal with both time and energy optimally at the same time is still a challenge. Tasks with multiple versions of execution time and accuracy can be selected for the best system performance while meeting energy neutrality constraint.

Application layer: Many applications have flexibility in the scheduling of their activities and tolerance of certain error margin in the results. Exploiting this flexibility and tolerance, applications can tune their parameters, algorithms to meet energy constraint, and at the same time satisfy application requirements.

Middleware for quality-aware and cross-layer power management: Middleware layer which provides a neat and effective cross-layer management is desirable in micro-scale energy harvesting systems. Middleware layer is aware of both application and system requirements, hence tuning or adaptation by middleware layer will not only meet the energy neutrality constraint but also maximize quality of services for both systems and applications.

In conclusion, this section presents important research problems, classified into three groups: design phase research, deployment phase research, and operational phase research. These researches are extremely useful in achieving sustainability of WSNs in smart spaces by applying energy harvesting technologies.

3.2.9.4.4 Operational noises

During the operational phase, the sound waves generated by the generator and gearbox, is transmitted through the walls of the tower resulting in the propagation of sound waves under water. However, the sound waves emitted by the transformers and wind turbines have shown negligible effects on the overall noise level under water. The noise produced by the wind turbines under water is not higher than the ambient level of noise, in frequency range of about 1 kHz. In the close vicinity of the foundation of wind turbine, increased noise level can have pronounced effects on the marine mammals, fish, and benthic fauna. In a recent study, the operational noise level of wind turbine (having the maximum power rated capacity of about 1.5 MW) was measured in Utgruden, Sweden at the approximate distance of 110 m. At the wind speed of 12 m/s, the one-third octave sound pressure was found to be in between 90 and 115 decibels.

Anthropogenic sound waves can have strong influences in both physiological and behavioral responses of marine animals. These behavioral impacts include (1) either attraction or repulsion from the sound producing areas and (2) sudden panic attacks and increased intensity of vocal communication. Some recent reports regarding the impacts of noise on the fish have shown various effects ranging from physiological impacts to the avoidance behavior. These changes in the behavior can force the fish to: (1) migrate from the specific route, (2) spawn the areas, and (3) vacate the feeding locality. The case studies regarding the effects of noise pollution on the planktonic organisms and invertebrates, have only few known effects unless the organisms are very close to the powerful sources of noise. As per the recent environmental reports, the wind power plant having the installed capacity of about 1500 KW does not have the damaging effects on the hearing system of marine animals.

In the second major portion of the same report, it has been mentioned that it is not very clear, whether the sound waves produced by the wind turbines have significant influences on the marine animals or not. Larger marine ships are used for the construction of huge wind parks, and also found to be functional during the operational phase of larger wind turbines and platforms, for the proper maintenance and working. The sound waves produced by the ships, depends upon the speed and size of ship. There are huge variations in the different types of ships and boats used for this purpose. The medium size ships produce the sound waves of 130–160 decibels, in frequency ranging from 20 Hz to 10 kHz at the area of 1 m. Therefore, development and adoption of standardized approaches is of great significance, to obtain the noise certificates at constructional sites.

7.6.3 Use or operational phase (stage B1–B3)

This phase covers the operational phase of the building however long that might be—20, 50, 100 years. It includes all impacts during the use phase of that building including maintenance, repair, replacement, refurbishment, operational energy use, operational water use.

When it comes to materials, the importance in the operational phase involves the construction and performance of the building envelope. Timber-framed and clad systems are regularly used as the construction material in insulated lightweight wall systems which are used extensively throughout Europe and North America in both cold climate zones, to keep heat in, and warm climate zones, to keep heat out. The Canadian Wood Council (CWC, 2009) advises that “Wood is 400 times better than steel and ten times better than concrete in resisting the flow of heat. This means more insulation is needed for steel and concrete to achieve the same performance as with wood framing”.

Wood-framed windows also provide a more environmentally thermally efficient alternative to more thermally conductive materials. An LCA study on the comparative service life of window systems (Howard et al., 2007) investigated 51 window archetypes made from four different frame materials: standard aluminium (nonthermally broken), PVC, timber and aluminium-skinned timber. Key findings from the report included that “timber framed windows, whether aluminium skinned or without aluminium skin had consistently lower embodied impact per m2 of window expressed either in terms of embodied CO2 or eco-points – initial, over the life or for energy implications”.

Maintenance, repair and replacement are also key factors in the operational phase and of particular importance to wood-based products used externally, such as cladding (siding), decking, windows, etc. The key here is proper selection of timber species of appropriate durability class (discussed previously).

3.3.3 Postoperational phases

By the end of the operational phase of the facility, the cementitious SSC’s are aged and need to be managed in a way to ensure the protection of the worker and the environment. Consideration and technologies used to manage the cementitious SSC’s during postoperational phases of nuclear facilities are illustrated in Chapters 13–171314151617. This is not the case for radioactive waste disposal facility, where during postclosure phase the cementitious should continue to work safely as designed. In postclosure phase, cementitious SSC’s are subjected to different environmental stressors. These stressors include thermal stresses, fluctuation of water content, presences of aggressive components, and long-term interaction with host environment. Usually, unsaturated conditions represent the normal operational phase of the disposal in which the disposal is working as built and slight evolution in the barriers occurs that does not affect the overall behavior of the disposal practice. However, saturated conditions present the worst-case scenario that is studied to ensure that the disposal system will work efficiently even under accidental conditions. The behavior of cementitious SSC’s under these conditions will be presented in Chapters 6 and 7.

4.4.4.2 Acidification and eutrophication

The direct emissions from the operational phase can contribute in part to acidification and eutrophication (i.e., mainly associated with NH3 emission). Among sulfur-bearing gaseous emissions, H2S is by far the most dominant. Although not directly associated with the acidification effect, it is the subject of local environmental concern because of its odor and potential toxicity. However, when dissolved in water aerosol, H2S reacts with oxygen to form amore oxidized sulfur-bearing compounds such as SO2, thus indicating its secondary acidification potential. Fig. 4.6 shows the characterized impact on the acidification of different geothermal technologies. The Italian experience in this context has demonstrated that the abatement of mercury and hydrogen sulphide systems (AMIS) is very effective in the reduction of H2S (and Hg) [22]. In addition to this, in some peculiar fields where the NH3 emissions are most abundant, also a treatment system based on scrubbing with SO2 needs to be employed to reduce ammonia emissions.

Waste treatment processes, especially from drilling activities, might have a significant contribution to the eutrophication freshwater impact category. However, this type of process is often modeled using already existing processes from databases that might not be adequately representative of the geothermal sector. In some cases, for instance, the waste treatment and management processes included in databases account for part of the waste (i.e., muds, excavated soil, etc.) to be spread on soil as a fertilizing agent with a consequential high impact due to leaching of phosphorus (and other metals) into the soil. However, in most situations dealing with geothermal activities, using drilling wastes as a soil amendment is not allowed. Therefore, it should not be modeled by the general waste treatment process, but by a specific one that should be used instead.

11.5.5 Inspection and maintenance

To ensure low maintenance costs during the operational phase, a detailed inspection plan for the concrete structures was prepared, specifying inspection periods, test procedures and systematic recording of observations. The inspection plan also specified the types of monitoring to be installed on the structure, and they included an overview of actions to be taken after inspection, such as modified inspection frequencies, initiation of cathodic protection and repair or replacement of elements. The inspection requirements for the principal structures are briefly summarized next (for a description of the inspection types and their actual frequency, see Section 11.8).

The immersed tunnel is mainly exposed to chlorides, which may lead to high chloride contents at both faces of the exposed elements. The tunnel entrances are also subjected to freezing and de-icing salting. The potential for chloride induced corrosion must be monitored to permit timely activation of the cathodic protection so that extensive damage can be avoided. Cores cannot be taken from the tunnel faces exposed to external water pressure, but other samples may be taken where possible and be used to verify the chloride transportation and lifetime models.

The tunnel ramps are exposed to chlorides, freezing and de-icing. The structures are prepared for cathodic protection and equipped with corrosion monitors for activation of the cathodic protection before the onset of extensive damage. Cores and other samples may be taken where possible for model verification.

The roadway bridge deck and the railway containment troughs are exposed to freezing and, to some extent, to chlorides from de-icing salts. The drainage of water from all concrete surfaces is to be monitored. The waterproofing of the bridge deck will reduce the aggressiveness of the environment, but the edge beams will be highly exposed and therefore are subjected to detailed inspection. Minor repairs of edge beams may be envisaged, with replacement being considered as an alternative to larger repairs.

The bridge piers and pylons are exposed to chlorides, to freezing up to some distance above the bridge deck, and also to de-icing salts at the deck level. The exposed parts of the pylons are prepared for cathodic protection and equipped with corrosion monitors for timely activation of the cathodic protection. Cores and samples may be taken where possible, particularly at the splash zone, for verification of the chloride transportation model.

The bridge abutments and viaduct are in some areas exposed to chlorides, freezing and de-icing salts. Where possible, they are prepared for cathodic protection and equipped with corrosion monitors for activation of the cathodic protection in due time. Cores and other samples may be taken to verify the chloride transportation model. The viaduct beam elements are less exposed, and repairs may be envisaged of edge beams only. Replacement of severely damaged beam elements shall, however, be considered as an alternative to more extensive repairs.

What is the best stated objective of the Operations and support O&S phase?

What is conducted during the production and deployment phase?