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Article

Integrated Water–Energy–Food System for Rural Climate Adaptation: The Green Village Model in Oman

by
Sultan Al-Maskari
* and
Bachar Ibrahim
Chair of Public Law, in Particular Environmental and Planning Law, Faculty 5 for Economics, Law and Society, Brandenburg University of Technology Cottbus-Senftenberg, 03046 Cottbus, Germany
*
Author to whom correspondence should be addressed.
Climate 2025, 13(9), 195; https://doi.org/10.3390/cli13090195
Submission received: 23 July 2025 / Revised: 8 September 2025 / Accepted: 10 September 2025 / Published: 17 September 2025
(This article belongs to the Section Climate Adaptation and Mitigation)
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Abstract

Rural communities in arid regions face linked challenges of water scarcity, energy insecurity, and climate stress. This study develops a pilot-scale “Green Village” model for Dar Al-Sawda, Oman, integrating agrivoltaic solar generation with natural wastewater treatment and agroforestry to enhance resilience. We used a mixed-methods design: semi-structured interviews with residents and experts informed the system requirements, and PVsyst simulations and field monitoring quantified expected performance. The integrated design comprises two 15 m3 ReedBox® natural wastewater treatment units and a 75 kWp agrivoltaic array above olive orchards. The treatment system processes 26 m3 day−1 for irrigation reuse, while the solar plant is estimated to generate 147,700 kWh per year. Performance ratio (PR) results are reported explicitly: monthly PR simulated for 2024 ranged from 0.70 to 0.81 (mean 0.77), while the annual PR estimated by PVsyst under a clean-panel case was 0.85 (85%). The modeled energy supply covers the treatment units and essential community loads, reducing diesel use and reliance on trucked water. For approximately 120 residents, the Green Village concept improves water security, clean energy access, and local food production, helping to counter rural out-migration. The results demonstrate the feasibility and advantages of an integrated water–energy–food approach and offer a scalable blueprint for sustainable development in Oman and comparable arid settings.

1. Introduction

Global climate change and resource scarcity demand innovative, integrated solutions, especially in arid regions [1]. Following the Paris Agreement, Oman has articulated climate commitments and policy frameworks that emphasize resilience and decarbonization [2]. Oman Vision 2040 also highlights sustainability as a strategic national priority [3].
Despite these commitments, rising temperatures and shifting precipitation are already straining Oman’s water and energy systems [4]. Recent regional assessments report that the spatially averaged annual air temperature across Oman and the wider MENA region rose at 0.36 °C per decade during 1981–2020, reaching about 0.45 °C per decade in summer [5]. El Kenawy et al. documented a significant increase in drought frequency and severity in Oman since the late 1990s [6]. Rainfall is low and highly variable, with long dry spells in interior and mountain districts reliant on shallow aquifers and springs [7]. Water scarcity is acute across the country, with per capita freshwater availability well below the 500 m3 year−1 threshold for absolute scarcity [8].
These pressures are particularly severe in the Al Hajar mountains, where villages such as Jabal Shams experience worsening droughts and dwindling springs [7]. However, localized studies of adaptation strategies at the community scale remain scarce [7]. Oman’s policy framework recognizes the importance of integrated sustainability, emphasizing renewable energy, water reuse, and climate resilience [2]. Still, practical implementation in rural communities has so far been limited [3]. Past projects have often targeted single sectors—for example, solar electrification in remote areas [4]—or wastewater treatment in urban centers [9].
In contrast, an integrated water–energy–food nexus approach is increasingly recognized as essential for arid regions [10]. Such approaches show that treating and reusing wastewater for irrigation can reduce dependence on desalination [8]. Solar-powered irrigation systems can simultaneously strengthen both water and energy security [4]. These strategies are widely recommended for MENA countries facing intensifying resource constraints [10].
A unified “Green Village” model integrating renewable energy, wastewater recycling, and agroforestry in a remote mountain setting is proposed for the first time in Oman. Dar Al-Sawda, a small village in Al-Dakhiliyah governorate (population ~120), was selected as the pilot site. Qualitative field research was combined with technical simulations to identify local needs and to design a tailored solution [11]. On the basis of these insights, a system was configured that incorporates solar agrivoltaics, constructed-wetland wastewater treatment, and olive-tree agroforestry [9]. System performance was evaluated through PVsyst simulations and engineering estimates [12]. By demonstrating feasibility and multiple co-benefits, a practical template for sustainable rural development aligned with Oman’s climate adaptation goals is provided [2].

2. Literature Review

2.1. Hydro-Climatic Stress and Regulatory Design Basis in Oman

Peer-reviewed analyses show statistically significant intensification of droughts across Oman since the late 1990s, with longer and more frequent dry spells in interior and mountain districts reliant on shallow aquifers and springs [6]. These climate dynamics directly threaten rural livelihoods, particularly in farming-dependent communities where irrigation demand is high [7].
Within this context, safe wastewater reuse is a critical adaptation lever because it can stabilize irrigation supply while reducing freshwater withdrawals [8]. Oman regulates reuse through Ministerial Decision (MD) 145/1993: Regulations for Wastewater Re-use and Discharge, which prescribes microbiological and chemical thresholds for treated effluent used in agriculture [13]. These limits—summarized in Table 1—serve as the legal design basis for rural reuse systems [13]. Empirical work documents Omani reliance on treated effluent for irrigation and landscaping in water-scarce governorates, demonstrating feasibility under arid conditions [9]. Strategically, Oman Vision 2040 and the National Strategy for Adaptation and Mitigation of Climate Change both list wastewater reuse as a pillar for water security and climate resilience [2,3]. At policy level, this institutional framing legitimizes decentralized reuse investments in rural settlements [2].

2.2. Appropriate Technology Landscape for Arid, Off-Grid Villages

A growing body of research examines greenhouse-integrated solar envelopes that jointly deliver energy, water, and microclimate services [14]. Light-splitting semi-transparent heater roofs transmit photosynthetically active radiation (PAR) for crops while harvesting near-infrared (NIR) for low-grade heat and freshwater recovery, showing promise for arid greenhouses [15]. Complementarily, greenhouse + humidification–dehumidification (HDH) systems recycle internal moisture to usable irrigation water while moderating greenhouse microclimates in desert settings [16]. Semi-transparent PV can also curb greenhouse cooling loads in hot climates without compromising yields, offering an electricity-generating shade solution [14]. Beyond electricity alone, photovoltaic–thermal (PVT) hybrids co-produce low-temperature heat suitable for greenhouse or water-heating demands [17].
These concepts primarily target microclimate management and saline/brackish-water desalination, not treatment of domestic wastewater to agricultural reuse standards, so they would still require an additional treatment train to meet Omani effluent specifications [13]. In contrast, constructed wetlands and modular reed-bed systems are documented in Oman as low-energy, cost-effective options that consistently meet the microbiological and chemical thresholds for safe irrigation reuse [9].

2.3. Comparative Evaluation and Rationale for the Selected System

Because rural settlements generate domestic wastewater and must use limited land to produce both energy and crops, the most context-appropriate configuration is an agrivoltaics + constructed-wetland system [9]. Constructed wetlands provide robust, low-energy compliance with Oman’s reuse thresholds, enabling safe irrigation within village boundaries [13]. Overhead PV structures reduce evapotranspiration and moderate crop microclimates while supplying on-site electricity for pumps and controls, improving water-energy reliability in arid conditions [17]. A comparative overview of candidate technology options is summarized in Table 2. By comparison, greenhouse-integrated solar heaters and HDH units improve microclimate and freshwater recovery but leave the domestic wastewater treatment requirement unresolved without extra units, adding cost and complexity in rural settings [15,16]. PVT or roof solar-thermal systems can supply useful heat, yet they similarly depend on separate wastewater treatment to satisfy reuse regulations [18].

3. Materials and Methods

3.1. Study Area: Dar Al-Sawda, Oman

Dar Al-Sawda is located in the Jabal Shams mountain area of Al Hamra district, Oman (23.24° N, 57.19° E; 1950 m elevation). At the time of the research, the settlement was composed of 12 households (~120 people) scattered on a high plateau (authors’ field ob-servations, March 2022). A semi-arid climate was experienced, with average summer highs of ~25 °C and winter night temperatures below ~7 °C [19]. Annual rainfall was low (100–300 mm) and highly variable in the Al Hajar highlands [7]. Livestock herding and terrace farming (wheat and pomegranates) were reported to have declined under water scarcity (authors’ field survey, 2022). The area was designated a dark-sky reserve and attracts tourists for its canyon vistas [20]. Electricity was supplied by diesel generators or a small grid extension, and a municipal sewage network was absent; households relied on basic septic pits with potential leaching to groundwater (authors’ field observations, 2022). The geographic location of Dar Al-Sawda within Oman is illustrated in Figure 1.

3.2. Community Interviews

Semi-structured interviews were conducted in March 2022 with residents and stakeholders to inform system design. Purposive sampling was employed to capture variation in age, gender, livelihood, and water/energy contexts [11]. Fifteen individuals (eight male, seven female) were interviewed, including village elders, farmers, the local water caretaker, two government officers from Al Hamra, and engineers from a sustainable-technology company. The interviews were held in family homes or the communal majlis and were conducted in Arabic with translation to English provided by bilingual researchers. Each interview lasted 45–60 min under an IRB-approved guide (Appendix A) [11]. Open-ended prompts explored daily water use, energy access and costs, farming practices, perceived climate risks, and willingness to adopt new technologies [11]. The guide was developed from literature on rural sustainability and reviewed by two independent experts prior to fieldwork [19]. In addition to one-to-one interviews, a focus group with five key informants (village leaders and a female residents’ representative) was convened to cross-check priorities and clarify design implications [22]. Audio recordings (with consent) and contemporaneous field notes were produced, with anonymity and gender-sensitive arrangements implemented to promote candid participation [23]. Translations were prepared by bilingual researchers; ambiguous terms were checked against Arabic audio, and key quotations were back-translated for accuracy [11]. A summary of the living situations and attitudes toward renewable energy across the three villages is presented in Table 3.

3.3. Qualitative Data Analysis

Audio recordings were transcribed verbatim, and ambiguous passages were checked against the source audio [11]. De-identified transcripts were stored on an encrypted drive with restricted access [23]. A hybrid deductive–inductive thematic content analysis was applied following established guidance [19]. Deductive start codes were derived from the interview guide (water use, energy access and costs, farming practices, perceived climate risks, technology adoption), and inductive codes were added to capture unanticipated ideas [19]. A pilot subset (20% of transcripts) was double-coded independently, and a shared codebook (names, definitions, inclusion/exclusion rules, exemplar quotes) was developed [19]. Line-by-line comparisons were undertaken in Microsoft Excel until consensus was reached, and the reconciled codebook was applied to the full corpus [19]. Subsequent disagreements were resolved through discussion to ensure consistency, with credibility strengthened via member-checking summaries, constant comparison across participant groups, and an audit trail documenting coding decisions and reflexive notes [23]. Thematic saturation was monitored using a saturation grid, and no new substantive codes were observed in the final interviews and focus group [23]. Initial descriptive analysis included theme frequency counts, code co-occurrence matrices, theme incidence by participant role and gender, and a saturation curve of new-code emergence across interviews to indicate salience without statistical inference [19].

3.4. System Design and Costing Approach

Design parameters and simulation inputs are summarized in Table 4. An integrated Green Village system was configured to include a ground-mounted photovoltaic array, a modular constructed-wetland treatment and reuse line, and an olive orchard for effluent irrigation under an agrivoltaic arrangement [9]. Photovoltaic capacity was sized to meet present household demand and wastewater-system loads with margin for growth [24]. The wastewater line was sized for a design flow corresponding to 200 L person−1 day−1 for 120 residents [12]. A high-density olive layout was adopted to utilize treated effluent via drip irrigation while retaining access aisles and adequate light within alleys [25].
Photovoltaic performance was modeled in PVsyst v7.2 using Meteonorm 8.1 typical meteorological year data [24]. Standard loss factors were included for wiring, soiling, inverter efficiency, and temperature derating, and a conservative degradation rate was applied [24]. ReedBox® blower loads and irrigation pumping were modeled explicitly, with pumping scheduled preferentially during photovoltaic generation hours [20]. A small battery was assumed to ensure continuity of nighttime aeration and controls under grid-tied operation, and existing diesel generators were retained for emergency backup [24]. Performance Ratio was calculated according to the international standard IEC 61724-1: Photovoltaic System Performance—Part 1: Monitoring [26], and Specific Yield was expressed in kWh kWp−1 year−1 [27]. Daily Light Integral within orchard alleys was estimated from ground-level photosynthetically active radiation using standard conversion factors, including a PAR fraction of shortwave radiation and a conversion of 4.6 µmol J−1 [28]. The division between household and irrigation water consumption was assessed by triangulating tanker delivery logs, well-yield records, and irrigation manifold meter readings, with monthly shares derived and uncertainty bands reflecting measurement error and missing data.
Cost assumptions and sources are summarized in Table 5. PV capital costs are derived from recent benchmarks for commercial PV, adjusted by documented agrivoltaic premiums. O&M uses NREL PV fixed-O&M benchmarks, while constructed wetland (CW) O&M assumptions are drawn from arid-climate CW literature. Battery costs and replacement intervals follow IRENA/NREL data [29,30,31,32,33,34].

4. Results

4.1. Community Needs and Current Practices

The interviews and field observations highlighted the interlinked challenges facing Dar Al-Sawda. Water scarcity is critical: villagers reported that by late summer, water rationing becomes severe, and agriculture largely halts. For example, one farmer noted “Our cistern ran dry for two months last year—we even bought water for our goats”. The absence of wastewater infrastructure further exacerbates water stress, as “every drop is lost in pits, nothing reused” (village elder, pers. comm.). Energy access, while better than water, is also a concern—the grid is unstable and many rely on generators at times. Women in the focus group emphasized the impact of fuel costs and outages on daily life (e.g., during cooking and washing). Encouragingly, attitudes toward sustainable solutions are very positive in Dar Al-Sawda. All interviewees were aware of solar energy’s benefits (some had relatives in nearby towns with rooftop panels). The community has in fact independently installed small PV-battery kits for lighting in a few homes. This existing uptake sets Dar Al-Sawda apart from neighboring hamlets like Karb (Table 1), where knowledge of renewables is lower. Villagers also expressed willingness to recycle water if safe: “If treated water can be made clean, we will certainly use it on our trees,” said a local farmer, reflecting a cultural openness to wastewater reuse for agriculture. These findings validated our integrated approach—there is both a pressing need and local buy-in for solutions combining water treatment, solar power, and agriculture. Practical considerations were also identified (e.g., space for the PV array was available on communal fallow land, and an old concrete water tank can be repurposed for storing treated water). In summary, the community input not only informed technical design choices (e.g., system capacity) but also indicated strong social acceptance, which is crucial for successful implementation.

4.2. Wastewater Treatment and Reuse

The two ReedBox® units are expected to effectively treat all village wastewater to irrigation standards. Each unit can handle up to ~15 m3/day; operating in parallel, they provide a safety margin above the average inflow (~25–26 m3/day). The system is certified for wastewater reuse by the Omani Environmental Authority under MD 145/1993, and independent studies of constructed wetlands report typical 70–95% BOD reduction, with effluent BOD and TSS generally ≤20–30 mg/L [36]. On this basis, the raw sewage BOD (~300 mg/L) [9] is anticipated to be lowered to <30 mg/L, and pathogen levels to comply with Omani reuse guidelines (BOD5 ≤ 15 mg/L; TSS ≤ 15 mg/L; thermotolerant coliforms ≤ 200 MPN/100 mL) [12]. The system will therefore produce nutrient-rich water suitable for crop irrigation, thereby closing the loop.
It is estimated that approximately ~24.6 m3/day of treated water will be available after accounting for minor evaporation and plant uptake losses in the wetland. This volume is sufficient to water about 300 olive trees, which at 8 m spacing would occupy roughly half a hectare under the solar panels. Olive saplings were chosen for their drought tolerance and local market value—the community can use or sell olives/olive oil, providing an economic co-benefit. By providing shade, the solar panels also reduce evaporation from soil and create a more favorable microclimate for the olive trees [18].
In essence, the agro-photovoltaic design synergistically links energy and agriculture: the panels generate power while the crops benefit from moderated microclimatic conditions, and neither significantly impedes the other’s output.

4.3. Solar Energy Generation

The 75 kWp solar array is projected to produce 147,708 kWh per year, substantially exceeding the village’s current annual consumption (~50,000 kWh). This surplus will accommodate future load growth (e.g., more electric appliances or cooling as living standards rise) and can potentially support nearby villages or feed into the regional grid. The specific yield is about 1969 kWh/kWp/year, reflecting the excellent solar irradiance at the site [24]. For context, this is higher than typical PV yields in central Europe (~1000 kWh/kWp) and on par with other high-irradiance locations.
The simulated performance ratio (PR)—a measure of system efficiency—averages 85.2% annually. This PR is quite high, indicating that losses are kept low despite the hot climate (thanks to the elevation, panel ventilation, and quality components). Monthly PR variation is minimal, ranging from ~0.70 in December to ~0.81 in April (Figure 2). These small differences are explained by seasonal factors.
In the coolest months (Dec–Jan), the PR dips slightly mainly due to lower sun angles and occasional cloudy days, which cause the inverter to run below optimal load some of the time. In the peak of summer, high air temperatures (occasionally >30 °C even at this altitude) induce heat-related efficiency losses in the PV modules, preventing PR from rising above ~0.80. The highest PR occurs in spring (March–April) when irradiance is strong and temperatures are moderate—ideal PV operating conditions.
Overall, the PR staying within a narrow 0.70–0.81 band across the year indicates a well-balanced system with consistent performance. This is an advantage of the design: unlike regions where winter snow or monsoon clouds cause drastic drops in PR, Dar Al-Sawda’s climate allows the PV system to operate near optimally year-round.
The power output profile of the PV system shows a peak power of about 60 kW during clear midday hours, with April exhibiting the highest midday output, and near-zero output at night (Figure 3). The distribution of output frequencies indicates that for much of the daytime the system operates at 20–50 kW depending on sun intensity [2]. This aligns well with the load profile: daytime power can directly run the ReedBox® units and meet household needs, reducing reliance on batteries or grid draw.
A small battery bank (20 kWh) was included in the design to cover nighttime power requirements for the treatment aerators, but the majority of solar generation will be used in real time or exported. The daily energy correlation with sunlight is very strong. Figure 4 illustrates the linear relationship between daily global horizontal irradiation and daily PV output. The correlation coefficient is above 0.95, indicating that on sunnier days, energy production rises proportionately. The best-fit line has an R2 ≈ 0.96, confirming the model’s accuracy in predicting output based on irradiance. Minor scatter around the line results from temperature effects and a few outliers (e.g., days with passing clouds).
Overall, the PV system is highly responsive to solar resource availability, as expected. This reliable generation gives confidence that even in lower-sun periods (winter), enough energy (~300–400 kWh/day) is produced to meet essential demands—the ReedBox® uses ~16 kWh/day; the rest can supply ~50 households at 6–8 kWh each. Any surplus in high-sun months (up to ~500 kWh/day in May) can be used to charge batteries or stored as water (by pumping extra groundwater, if available).
From the simulation, the annual output (147.7 MWh) far exceeds the ReedBox energy requirement (~5.8 MWh/year) and current village use (~50 MWh/year), leaving roughly 90 MWh/year for additional usage or export. This margin could electrify around 30 more homes or be fed into Oman’s grid under net metering policies. The treated water (≈9000 m3/year) will support the growth of olives, which after a few years could yield an estimated 1–2 tons of olives annually, creating new livelihood opportunities (e.g., olive oil production, agri-tourism). Importantly, the integrated system enhances climate adaptation on multiple fronts: it bolsters water security by reusing wastewater, improves food security through local agriculture, and achieves energy self-sufficiency with clean solar power. These outcomes address key Sustainable Development Goals (SDGs) relevant to Oman (in particular SDG 6: clean water and sanitation, SDG 7: affordable clean energy, SDG 11: sustainable communities, and SDG 13: climate action). The co-location of systems also optimizes resource use (land, energy) and minimizes the environmental footprint compared to separate, conventional solutions (e.g., diesel generators + septic trucks + imported produce).

4.4. Agrivoltaic Olive Yield, Spacing Check, and Irrigation Adequacy

To accelerate establishment, advanced nursery trees will be planted so that a first modest harvest is expected from year 3 and commercial bearing is reached by years 3–4; extension data also indicate full production by about year 5 [25]. The orchard layout consists of 300 olive trees on 0.5 ha (≈600 trees/ha) at 4.0 m × 4.17 m spacing.
Peer-reviewed sources report that mature, well-managed irrigated olive orchards commonly produce on the order of 8–12 t ha−1 [30,37]; long-term trials further report fruit yields between ≈7.1 and 12.9 t ha−1 depending on cultivar and site [38]. Olive shading experiments show that the crop is moderately sensitive to light reduction during critical phenological phases [18], supporting the use of a conservative yield decrement under partial shade. Therefore, a 10–15% fruit-yield penalty is applied for low-to-moderate effective shading, giving a mature planning band of 3.4–5.4 t year−1 on 0.5 ha (≈6.8–10.8 t ha−1), which lies within reported ranges [38]. With advanced plant material, early production begins by year 3 and typically rises further as the canopy closes during years 4–5 [25].
For drip-irrigated olives in southern Portugal, full irrigation requirements are reported at roughly 3500–4000 m3 ha−1 year−1 [39]; regulated deficit irrigation (RDI) strategies down to ≈45% of ETc have been successfully scheduled using plant-based control [34]. The designed reclaimed-water supply of 24.6 m3 day−1 (≈8979 m3 year−1) corresponds to ~18,000 m3 ha−1 year−1 on 0.5 ha, indicating ample availability to support ETc-based RDI with seasonal storage and operational flexibility [39,40].

4.5. Cost Summary

The integrated system requires an initial capital investment of approximately USD 295,000, comprising USD 100,000 for the 75 kWp agrivoltaic PV installation, USD 150,000 for two modular constructed wetland units (ReedBox®-class), and about USD 45,000 for battery storage, pumping, control systems, and civil works. Annual operating expenditure (O&M) is modest, estimated at ≈USD 5000 yr−1, including PV cleaning/inspection (USD 1300 yr−1) and wetland operation (USD 3700 yr−1). Over a 20-year lifetime, scheduled component replacements—including inverters, pumps/blowers, and one battery renewal—amount to ≈USD 28,000.
The corresponding 20-year total cost of ownership is therefore ≈USD 423,000 (CAPEX + O&M + replacements). These results are consistent with published agrivoltaic cost premiums, PV O&M benchmarks, and evidence of low-intensity O&M requirements for constructed wetlands in hot–arid climates.

5. Discussion

The Green Village model was demonstrated to be technically feasible and to provide significant advantages over siloed approaches. By integrating the three subsystems, synergistic benefits were observed: the PV array powered the water treatment, the wastewater nourished agriculture, and the crops improved PV efficiency through shading and cooling. These interactions exemplify the water–energy–food nexus in action [10].
It was found that even a relatively small solar plant (75 kW) was capable of sustaining an isolated community’s basic needs while producing surplus energy, thereby highlighting the viability of clean energy for rural electrification in Oman. A performance ratio of approximately 85% was achieved in the simulation, which is considered notably high for PV in hot climates. This indicates that careful system design (optimal tilt, ventilation, and component quality) can mitigate thermal losses. The simulated PR was shown to be comparable to, or better than, reported values in similar agrivoltaic projects in other arid regions (typically 75–85%) [41]. These findings suggest that agrivoltaics could be implemented in Oman without significant efficiency penalties, and it is possible that vegetation may even improve summer performance by limiting extreme panel heating—an aspect that requires confirmation in field trials.
Consistency was also observed with recent agrivoltaic olive studies in the Mediterranean, where careful orchard layout limited fruit-yield penalties to ~0–15% while maintaining high land productivity, consistent with the conservative planning penalty applied in this study [41]. In MENA contexts, geospatial and policy analyses have identified high technical potential for agrivoltaics in arid conditions, supporting the transferability of the concept to Oman’s highlands [42]. For PV systems in hot–dry climates, reported performance ratios generally fall in the 0.75–0.85 range under well-designed and ventilated conditions [43], and the modeled PR for Dar Al-Sawda lies at the upper end of this range. This suggests that thermal losses can be effectively contained with appropriate mounting and spacing [41]. With respect to wastewater reuse, constructed wetlands in arid regions have routinely achieved effluent BOD/TSS concentrations ≤ 20–30 mg L−1 [43]. Large-scale reuse programs in Morocco have been reported to save multi-million cubic meters annually, which underscores the relevance of decentralized reuse in water-scarce settings [44]. Taken together, these analogs confirm that the Dar Al-Sawda configuration is consistent with, and extends, the emerging literature on integrated WEF-nexus solutions in the region [44]
On the water side, the ReedBox® system was shown to provide a decentralized, environmentally friendly solution aligned with sustainable practices. In many remote villages, the absence of wastewater treatment has resulted in pollution and water loss. By contrast, in Dar Al-Sawda wastewater would be treated as a resource. Approximately 9000 m3/year of recycled water could be made available for irrigation and potentially for aquifer recharge, thereby reducing dependence on desalinated imports. This outcome is consistent with the findings of Maftouh et al. (2022), who reported that water reuse and agricultural improvements are preferable to the expansion of energy-intensive desalination in MENA regions [10].
In addition, the natural wetland process of the ReedBox® system was noted to require low operation and maintenance costs and to avoid the use of chemicals, enhancing cultural and environmental suitability. Social acceptance of wastewater reuse on olives indicated that community outreach and education efforts have been effective, a key dimension for success.
The integrated model also demonstrates promising economic potential. Although the required capital investment is considerable (≈USD 295,000; ~USD 100,000 for the agrivoltaic PV system, USD 150,000 for two ReedBox® units, and ~USD 45,000 for ancillary components), long-term benefits include avoided diesel expenditures, reduced costs of water trucking, and additional income from agriculture. Over a 20-year project horizon, these gains are likely to offset the initial costs, particularly where financing support is available through governmental programs or international climate funds. Alignment with Oman’s Vision 2040 sustainability agenda further increases the feasibility of securing funding under climate-adaptation and rural-development initiatives [3]. Furthermore, the model was identified as both scalable and replicable. Similar mountain villages (e.g., in Jabal Akhdar or Dhofar) could adapt the blueprint, scaling PV and ReedBox® capacity to population size. At larger scales, the concept could be expanded to cluster-level systems serving multiple villages. The proof-of-concept demonstrated in Dar Al-Sawda therefore provides a foundation for wider application of integrated resource management in Oman’s rural context.
Some limitations must also be acknowledged. The results relied on simulations, and real-world performance may vary due to panel soiling, irregular household demand, and fluctuations in wastewater inflows. Field trials with monitoring would thus be necessary to validate both PV yield and ReedBox® efficiency. The qualitative interview data reflected a small, time-bounded sample, and community views may evolve over time, requiring continued engagement. While indicative economic estimates were provided, full techno-economic or life-cycle assessments were not conducted, and these will be required for policy and investment decisions. Long-term sustainability would also depend on the training of local operators and the establishment of supply chains for spare parts.
Despite these limitations, the potential of the integrated approach to strengthen community-level climate resilience was clearly demonstrated. By simultaneously addressing water scarcity, energy access, and livelihood needs, compounded benefits were achieved that would not be realized through sector-specific interventions. Additional contributions were observed for climate mitigation through diesel displacement and reduced wastewater methane emissions, while adaptation was simultaneously enhanced—an outcome aligned with global calls for synergistic climate action [1].
In summary, the findings affirm that an integrated renewable energy, wastewater reuse, and agroforestry system is both feasible and advantageous for Dar Al-Sawda and comparable rural contexts. The approach offers a pathway to meet essential needs sustainably, improve livelihoods through agriculture, and reduce environmental impacts. Future work should prioritize piloting monitored installations, scaling the model to other villages, and undertaking detailed techno-economic and life-cycle analyses to inform national policy.

6. Conclusions

A sustainable Green Village model was developed and assessed for Dar Al-Sawda, Oman, integrating solar power, wastewater treatment, and agroforestry to address intertwined climate challenges in an arid mountain community. A mixed-methods approach—combining community engagement with technical simulation—was effective for a locally tailored and technically sound design.
A single integrated system can meet village water, energy, and food needs. A 75 kWp agrivoltaic installation was simulated to power wastewater treatment (ReedBox®) and essential household loads, while treated water irrigates ~300 olive trees. The modeled output is ~147 MWh year−1 with a simulated PR ≈ 0.85; two ReedBox® units were sized to treat ~26 m3 day−1, supplying ~24.6 m3 day−1 of reusable water compliant with MD 145/1993.
Wastewater recycling improves water security; clean solar power strengthens energy independence; olive cultivation supports food security and income—together reducing vulnerability to drought and fuel costs. The approach aligns with Oman Vision 2040 and is replicable in similar MENA rural settings.
Among the first village-scale demonstrations in Oman to combine advanced solar, nature-based wastewater treatment, and agroforestry in a synergistic, participatory design.
Findings are based on simulations and qualitative data; a pilot is recommended to monitor energy output, water quality, olive growth, and social acceptance. Future work should include storage integration, alternative crops/aquaculture, climate-scenario testing, and detailed techno-economic and life-cycle assessments, alongside enabling policies and capacity-building for long-term O&M.
In sum, the Green Village model provides a practical pathway for climate adaptation: treating wastewater as a resource, harnessing solar energy, and revitalizing agriculture to address water scarcity, reduce emissions, and improve livelihoods. The modular, proven, and regulation-compatible design is feasible and scalable; stakeholders are encouraged to support pilot projects and knowledge-sharing to refine and expand this approach across arid regions.

Author Contributions

Conceptualization, S.A.-M. and B.I.; methodology, S.A.-M.; software, S.A.-M.; validation, S.A.-M.; formal analysis, S.A.-M.; investigation, S.A.-M.; resources, S.A.-M.; data curation, S.A.-M.; writing—original draft preparation, S.A.-M. and B.I.; writing—review and editing, S.A.-M. and B.I.; visualization, S.A.-M.; supervision, B.I.; project administration, B.I.; funding acquisition, B.I. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Data is contained within the article.

Conflicts of Interest

The authors declare no conflicts of interest.

Appendix A. Interview Guide (Dar Al-Sawda “Green Village” Study)

This appendix outlines the semi-structured interview prompts used with Dar Al-Sawda residents and stakeholders (March 2022). The interviews were conducted in Arabic, but the English translations of guiding questions are provided below. The interviews were conversational and open-ended; not all questions were asked verbatim or in this order, but all topic areas were covered. The aim was to understand current challenges and attitudes regarding water, energy, and agriculture, to inform the system design.
Water Supply and Use:
Can you describe your household’s current sources of water? (Prompt: Do you use a well, spring, or trucked water? How reliable are these sources?)
How much water do you typically have available per day, and is it sufficient for your needs?
What challenges do you face regarding water? (Prompt: Have you experienced water shortages or rationing? How do you cope during dry periods?)
Do you practice any form of water storage or rainwater harvesting? If not, why (e.g., lack of rain, lack of tanks)?
How is wastewater or sewage currently handled in your home? (Prompt: septic tank, pit, direct disposal, etc.)
Are you concerned about wastewater or environmental sanitation issues here?
Energy Access and Use:
How does your household get electricity or energy for appliances and lighting? (Prompt: grid connection, diesel generator, solar kit, none?)
Is the current electricity supply reliable and sufficient? (If not, what problems occur—e.g., frequent outages, high cost of fuel?)
What do you mainly use electricity for, and do you have unmet needs (devices you wish to power but cannot)?
How much do you spend on fuel (diesel/gasoline) or electricity per month, approximately?
Have you heard of or considered solar power for your home or village? (If they have solar: ask them to describe their system and satisfaction; if not, gauge interest.)
What is your attitude towards adopting solar energy here? (Prompt: Do you think it would work well? Any concerns about it?)
Agriculture and Livelihoods:
Do you or others in the village currently practice farming or livestock rearing? If yes, what crops or animals, and how has this changed over time?
(If not currently farming) Did the village cultivate crops in the past? What changed or why did farming decline?
How does water availability affect agriculture here? (Prompt: is lack of water the main reason for not farming? What about soil or other factors?)
Would you be interested in growing certain crops if water and resources were available? (Prompt: which crops? Why those? For home use or sale?)
Are there any community gardens or attempts to irrigate plants presently? If so, describe them.
(For officials/experts) What do you see as the main opportunities for improving agriculture or livelihoods in Dar Al-Sawda?
Perceptions of Climate and Environment:
Have you noticed any long-term changes in climate or weather patterns here (e.g., rainfall, temperature) during your lifetime?
How do these changes impact your daily life or the village (water, farming, etc.)?
Do you consider climate change a concern for your community?
In your opinion, what are the biggest environmental challenges facing the village?
Proposed Solutions—Attitudes and Willingness:
We are exploring an idea to improve the village’s water, power, and agriculture together—for example, using solar panels for electricity, treating wastewater to use for irrigation, and planting trees or crops. What are your initial thoughts about this concept?
Specifically, how would you feel about using treated wastewater for irrigating trees or crops? (Gauge any cultural or health concerns, and whether they’d use such water on food crops versus non-food crops.)
How would you feel about having a small solar farm in or near the village that provides power to everyone? Any concerns (e.g., land use, aesthetics, reliability)?
If such a project provided opportunities (like maintaining the system or farming a communal plot), would you or others in your family be interested in participating?
What do you see as potential benefits of such an integrated project for your household and for the community?
What do you see as potential challenges or obstacles for implementing it?
Do you have any suggestions on how to make sure the community accepts and supports such a project? (Prompt: involvement in planning, fair distribution of benefits, etc.)
Miscellaneous and Closing:
Are there any local customs or regulations we should consider when introducing a new water/energy system here?
Is there anything else you’d like to share about your needs or ideas for improving water, energy, or livelihoods in Dar Al-Sawda?
(For officials) What support could government agencies provide to make a project like this successful?
Would you personally support and use the systems (solar power, recycled water irrigation) if they were implemented?
Thank you for your time and insights. (Interviewer would then explain next steps, e.g., how the information will be used to design the project, and assure follow-up with the community.)
The questions were framed to be respectful and to empower participants to share their experiences. The openness of responses was crucial in designing a solution that fits the social context of Dar Al-Sawda.

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Figure 1. Map of Oman showing the location of Dar Al-Sawda (red marker) in Al-Dakhiliyah Governorate. Dar Al-Sawda is situated on the Jabal Shams plateau (~1950 m elevation), approximately 36 km northeast of Al Hamra town and 240 km from Muscat. Base map source: JRC (ECHO, EC), licensed under CC BY 4.0 via Wikimedia Commons [21].
Figure 1. Map of Oman showing the location of Dar Al-Sawda (red marker) in Al-Dakhiliyah Governorate. Dar Al-Sawda is situated on the Jabal Shams plateau (~1950 m elevation), approximately 36 km northeast of Al Hamra town and 240 km from Muscat. Base map source: JRC (ECHO, EC), licensed under CC BY 4.0 via Wikimedia Commons [21].
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Figure 2. Monthly performance ratio (PR) of the 75 kWp solar PV system, as simulated by PVsyst [36]. Each bar represents the fraction of incident solar energy converted to usable output in that month (values range from 0.70 to 0.78, averaging 0.77 over the year). The minor seasonal variation reflects slightly lower PV efficiency in the hottest and coldest months.
Figure 2. Monthly performance ratio (PR) of the 75 kWp solar PV system, as simulated by PVsyst [36]. Each bar represents the fraction of incident solar energy converted to usable output in that month (values range from 0.70 to 0.78, averaging 0.77 over the year). The minor seasonal variation reflects slightly lower PV efficiency in the hottest and coldest months.
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Figure 3. Distribution of the PV system’s AC output power over one year (PVsyst simulation) [36]. The curve shows how often the system operates at a given power level. It peaks around 50–60 kW on sunny midday hours and tapers off toward zero at night. This indicates the system spends a significant time at mid-range output, matching typical daytime consumption patterns.
Figure 3. Distribution of the PV system’s AC output power over one year (PVsyst simulation) [36]. The curve shows how often the system operates at a given power level. It peaks around 50–60 kW on sunny midday hours and tapers off toward zero at night. This indicates the system spends a significant time at mid-range output, matching typical daytime consumption patterns.
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Figure 4. Daily input–output relationship for the PV system [36]. Each point represents one day, plotting global solar irradiation on the PV plane (x-axis, kWh/m2/day) vs. the useful energy generated (y-axis, kWh/day). The tight clustering along a line (R2 ≈ 0.96) demonstrates a strong linear correlation:, e.g., days with ~8 kWh/m2 produce ~550 kWh, while 4 kWh/m2 days yield ~300 kWh. This verifies that system performance is primarily driven by solar availability, with minimal unexplained losses.
Figure 4. Daily input–output relationship for the PV system [36]. Each point represents one day, plotting global solar irradiation on the PV plane (x-axis, kWh/m2/day) vs. the useful energy generated (y-axis, kWh/day). The tight clustering along a line (R2 ≈ 0.96) demonstrates a strong linear correlation:, e.g., days with ~8 kWh/m2 produce ~550 kWh, while 4 kWh/m2 days yield ~300 kWh. This verifies that system performance is primarily driven by solar availability, with minimal unexplained losses.
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Table 1. Omani treated-effluent thresholds for agricultural reuse (design basis, per MD 145/1993) [12].
Table 1. Omani treated-effluent thresholds for agricultural reuse (design basis, per MD 145/1993) [12].
ParameterUnitLimit (Max, Any Sample)Monthly Average (over Any 4 Consecutive Weeks)Notes
BOD5 (5-day)mg/L1510Biological oxygen demand.
TSSmg/L1510Total suspended solids.
TurbidityNTU52Point of compliance.
Free residual chlorine (after 60 min)mg/L≥0.5≥0.5Disinfection safeguard.
pH—6–96–9Acceptable range.
Total dissolved solids (TDS)mg/L15001000Salinity control for crops/soils.
Total coliformsMPN/100 mL23 (single-sample cap)2.2 (7-day geometric mean)Microbiological safety.
Viable pathogenic—None detectableNone detectableParasitological safety.
Table 2. Comparative analysis of candidate technologies for a rural “Green Village” configuration.
Table 2. Comparative analysis of candidate technologies for a rural “Green Village” configuration.
TechnologyPrimary FunctionWater-Recovery or Treatment PathwayLand-Use EfficiencyComplexity and CostRelevance to Omani Rural Context
Proposed: Agrivoltaics + constructed wetlandEnergy and food production; wastewater reuseOn-site domestic wastewater treatment (reed-bed/constructed wetland); reuse for irrigationHigh (dual use: crops under PV)Moderate–High (modular CW + PV; scalable)High: meets MD 145/1993; reduces ET; supplies local energy [3,12]
Semi-transparent PV greenhouseElectricity with crop-compatible lightNone inherent; shade lowers ET; requires separate reuse/desal unitHigh (within greenhouse envelope)High (specialized glazing; structure)Improves microclimate/energy but does not treat wastewater [7,9]
Photovoltaic–thermal (PVT) collectorsElectricity + low-grade heatHeat can drive HDH/pasteurization only with added subsystemsModerate–High (roof-mounted)High (thermal circuits; higher CAPEX/O&M)Adds complexity; separate wastewater treatment still needed [10,11]
Solar-thermal collectors (roof)Thermal energy (space/water)Can drive HDH desalination; no domestic wastewater treatmentVariable (possible PAR impacts)Moderate–High (thermal plumbing)Heat-focused; misaligned with primary reuse need [10]
Solar desalination greenhouse (SDGH)Freshwater + cultivationHDH desalination of saline or brackish sourceHigh (dual-use envelope)High (HDH hardware; corrosion-resistant)Best for saline/coastal settings; domestic wastewater remains untreated [8,11]
Table 3. Information on living situations collected in interviews.
Table 3. Information on living situations collected in interviews.
VillageNo. of Houses (People)Water AvailabilityAttitude Towards Renewable Energies
Al-Khitaym3 (approx. 30)Water sourced from transport tanks; lack of rainwater in recent years; little to no irrigation possible.Open to renewable energy but not very familiar; financial support needed.
Krub8 (approx. 80)Water from dam and transport tanks; only 12 L per person per day reported.Skeptical; concerns about reliable supply.
Dar Al Sawda’a12 (approx. 120)Unreliable precipitation patterns; well occasionally provides limited water.Strongly supportive; already using solar battery.
Table 4. System design parameters and simulation inputs.
Table 4. System design parameters and simulation inputs.
ParameterValue/Description
Location (site)Dar Al-Sawda, Oman (23.24° N, 57.20° E; altitude 1958 m)
Climate dataMeteonorm 8.1 (1991–2007, satellite-derived); GHI 2260 kWh m−2 year−1; mean ambient temperature 18 °C; summer highs 30 °C
Photovoltaic array75.0 kWp; fixed tilt 26°; south-facing; elevated table height 3 m; row pitch 5.0 m
Inverters and ratio5 × 15 kW string inverters; total AC 75 kW; DC/AC ratio 1.00
Estimated energy demand50 MWh year−1 for households and 5.8 MWh year−1 for wastewater line operation
Wastewater treatment2 × ReedBox RBX-15 constructed-wetland modules (15 m3 each) in parallel
Design flow and reuse26 m3 day−1 influent design flow; usable effluent directed to orchard drip irrigation
Effluent quality targets (reuse)BOD5 not more than 15 mg L−1; TSS not more than 15 mg L−1; thermotolerant coliforms not more than 23 MPN 100 mL−1 (per MD 145/1993)
Orchard and irrigation0.5 ha; 300 olive trees at 4.0 m × 4.17 m spacing; drip irrigation at 80 L tree−1 day−1 peak; access aisles preserved
Loads modeledReedBox blowers 0.33 kW each (8 kWh day−1 per unit); irrigation pump scheduled in daytime
Battery and operationBattery 20 kWh for night aeration continuity; grid-tied operation with diesel backup for resilience
Simulation tool and lossesPVsyst v7.2; losses included wiring, soiling, inverter efficiency 98%, temperature derating; conservative degradation applied
Performance metricsPerformance Ratio (IEC 61724-1), Specific Yield (kWh kWp−1 year−1), Daily Light Integral estimated from PAR fraction
Table 5. Costing assumptions (point estimates, USD 2025).
Table 5. Costing assumptions (point estimates, USD 2025).
ComponentDescriptionEstimate (USD)Source
PV agrivoltaic system (75 kWp)Elevated agrivoltaic structure with modules, inverters, and balance-of-system components; cost derived from European elevated APV benchmarks (≈€1234 kW−1)100,000[29,31]
Wastewater treatment (2 × modular CW units, ReedBox®-class)Two vertical subsurface flow units (~30 m3 d−1 total); vendor documentation validated against CW cost studies in arid settings150,000[35]
Battery and pumping/controls20 kWh lithium-ion storage system with pumping and control hardware; cost aligned with recent storage benchmarks15,000[34]
Civil works and contingencySite preparation, piping, foundations, and general allowances30,000[34]
Subtotal CAPEX 295,000—
Annual O&M—PVRoutine cleaning and inspection; benchmarked at ≈$22 kW_AC−1 yr−1 (ILR ≈ 1.3; ~58 kW_AC)1300 yr−1[32,33]
Annual O&M—CWOperator time, minor consumables, and low energy use, typical for constructed wetlands in arid climates3700 yr−1[9]
Scheduled replacements (20 years)Inverter renewal (yr 12–15), blower/pump overhauls (7–10 years), and one battery replacement (10–12 years)28,000[33,34]
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Al-Maskari, S.; Ibrahim, B. Integrated Water–Energy–Food System for Rural Climate Adaptation: The Green Village Model in Oman. Climate 2025, 13, 195. https://doi.org/10.3390/cli13090195

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Al-Maskari S, Ibrahim B. Integrated Water–Energy–Food System for Rural Climate Adaptation: The Green Village Model in Oman. Climate. 2025; 13(9):195. https://doi.org/10.3390/cli13090195

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Al-Maskari, Sultan, and Bachar Ibrahim. 2025. "Integrated Water–Energy–Food System for Rural Climate Adaptation: The Green Village Model in Oman" Climate 13, no. 9: 195. https://doi.org/10.3390/cli13090195

APA Style

Al-Maskari, S., & Ibrahim, B. (2025). Integrated Water–Energy–Food System for Rural Climate Adaptation: The Green Village Model in Oman. Climate, 13(9), 195. https://doi.org/10.3390/cli13090195

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