Annex A - Solar Feasibility Study.pdf

The Department of Veterans Affairs

Solar Feasibility Report

VA Central California Health Care System Fresno, CA

July 23, 2015

Submitted by:

Gabel Associates, Inc.

417 Denison Street

Highland Park, New Jersey 08904 Phone: (732) 296-0770

BPA Contract Number: VA776-BP-0018 GSA Contract Number: GS-10F-0089S

Purchase Order Number: VA-701-15-Q-0029

TABLE OF CONTENTS

1. INTRODUCTION

2. SUMMARY OF FINDINGS AND RECOMMENDATIONS

3. TECHNICAL AND SITE REVIEW

a) Overview of Photovoltaic (PV) and Solar Thermal Systems

b) Types of PV and Solar Thermal Systems

c) Site Visit Review

d) PV Panel Location and Analysis

e) Solar PV System Sizing

f) Solar Thermal Panel Location and Analysis

g) Solar Thermal System Sizing

h) Electrical System and Interconnect Point

i) Calculation of System Production

j) Current Energy Supply Configuration of the Campus

k) Battery Storage

4. FINANCIAL ANALYSIS

a) Economic Feasibility

b) Summary of Financial Results

c) Calculation of Annual Energy Savings

d) Estimated Project Costs

5. FINANCING FOR SOLAR PROJECTS

6. DESIGN AND CONSTRUCTION REQUIREMENTS

a) Logistical, Site Related and Environmental Issues

b) Preliminary Project Timeline

c) Site Work and Preparation

7. ENVIRONMENTAL BENEFITS

8. CONCLUSION

ECONOMIC ASSUMPTIONS AND ATTACHMENTS:

i

LIST OF TABLES

Table 2-1: Economic Metrics of Total Estimated System Table 2-2: Comparative Economic Metrics for Solar Thermal System Table 2-3: Comparative Economic Metrics for Solar PV and Thermal Systems Table 3-1: Comparison of PV Panel Varieties Table 3-2: Comparison of Solar Thermal System Varieties Table 3-3: Recommendations for Potentially Feasible Roofs – Existing Structures Table 3-4: Recommendations for Potentially Feasible Roofs – Proposed Structures Table 3-5: Overview of Parking Lots Table 3-6: Parking Garage Canopy System Size Table 3-7: Summary of Carport Canopy PV Systems Table 3-8: PV System Characteristics

Table 3-9: Solar PV System Size Table 3-10: Solar insolation and temperature for Fresno, CA Table 3-11: PV Watts Parameters Table 3-12: PV System Output Calculations – Year 1 (833 kW dc) Table 3-13: Solar Thermal System Output Calculations – Year 1 (27 Panels) Table 4-1: PV and Thermal Savings Metrics Table 4-2: PV Savings Metrics Table 4-3: Thermal Savings Metrics Table 4-4: Electric Rate Forecast Table 4-5: Natural Gas Rate Forecast Table 6-1: Preliminary Project Timeline Table 7-1: CO2 Reduction by Proposed Project Type

Table 7-2: Solar PV Equivalency Result Table 7-3: Solar Thermal Equivalency Results

LIST OF FIGURES

Figure 3-1: Fresno VAMC Site Plan (Including Future Structures as per Option 3 of the 2023 Master Plan) Figure 3-2: Building 32 Solometric SunEye Skyline Figure 3-3: Building 32 Preliminary Solar Conceptual Layout Figure 3-4: Building 25 Preliminary Solar Conceptual Layout Figure 3-5: Building 24 Preliminary Solar Conceptual Layout Figure 3-6: PRRC Building Preliminary Solar Conceptual Layout Figure 3-7: CLC Extension Preliminary Solar Conceptual Layout Figure 3-8: Kern County Parking Garage, Bakersfield, CA Figure 3-9: Monthly Electrical Energy Facility Consumption Figure 3-10: Electrical Energy Generated by Existing PV System Figure 3-11: Monthly Natural Gas Facility Consumption

LIST OF ATTACHMENTS

ii

Attachment A: Economic Assumptions Attachment B: Solar Project Economics Summary Attachment C: Retail Electric Revenue Forecast Attachment D: Retail Natural Gas Revenue Forecast Attachment E: Site Layout Overlay

Gabel Associates Solar PV & Thermal Feasibility Study

VA Central California Health Care System

1. Introduction

Gabel Associates (Gabel) was contracted by the Department of Veterans Affairs (VA) to provide a feasibility study for solar photovoltaic (PV) and solar thermal energy projects at the VA Central California Health Care System (CCVAHCS) located in Fresno, CA and to recommend next steps for project development.

This study takes into consideration information collected during an onsite visit, data provided by the Contracting Officer’s Technical Representative (COTR), and other technical and economic considerations specific to the site and the California energy and incentive marketplace. The report provides technical and financial analysis regarding the feasibility of a solar system. This report will recommend whether a solution appears feasible for the site, will assess the potential for alternative financing approaches and will recommend “next steps” in project development, if appropriate.

Specifically, the report contains the following sections:

1. Introduction

2. Summary of Findings and Recommendations

3. Technical and Site Review

a) Overview of Photovoltaic (PV) Systems and Solar Thermal Systems

b) Types of PV Systems and Solar Thermal Systems

c) Site Visit Review

d) PV System Location and Analysis

e) Solar PV System Sizing

f) Solar Thermal System Location and Analysis

g) Solar Thermal System Sizing

h) Electrical System and Interconnect Point

i) Calculation of PV and Thermal Systems Production

j) Current Energy Supply Configuration of the Campus

k) Battery Storage

4. Financial Analysis

a) Economic Feasibility

b) Summary of Financial Results

c) Calculation of Annual Energy Savings

d) Estimated Project Costs

5. Financing Options for Solar Projects

6. Design and Construction Requirements

a) Logistical, Site Related and Environmental Issues

b) Preliminary Project Timeline

c) Site Work and Preparation

7. Environmental Benefits

8. Conclusion

Solar PV & Thermal Feasibility Study

9. Economic Assumptions and Attachments

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

2. Summary of Findings and Recommendations

Gabel evaluated the technical and financial feasibility of solar photovoltaic (PV) and solar thermal projects at the Department of Veterans Affairs (VA) site at the VA Central California Health Care System, 2615 E. Clinton Avenue, Fresno, CA 93703.

In order to determine the feasibility of a PV system and a solar thermal system, Gabel conducted a site inspection of the buildings and its operations, including interviews with facility personnel and undertook detailed technical and financial analysis.

It is important to note that the site already has PV solar systems installed on most existing building roofs and one parking lot. The systems are designed to occupy most of the area that is not shaded and free from roof obstructions. Therefore the analysis presented in this report discusses additional opportunities available on existing roofs as well as systems that can be installed on new buildings structures currently in construction or planned to be built in near future.

Solar PV and solar thermal projects were analyzed independently and are intended to be reviewed and implemented as separate expenditures and projects. As such, for purposes of this evaluation the economics are independent of one another and the installation of one does not affect the economics of the other. However, for the benefit of the VA’s understanding, we also provided economics of the combined solar PV and solar thermal systems.

The results of this review include the following key findings:

A conceptual design and layout of the proposed PV systems consist of roof-mounted arrays and carport canopy arrays. The existing facilities considered feasible for additional roof-mounted systems include buildings 24, 25, and 32. The future buildings included in this analysis include the following buildings: PRRC, CLC Extension, Building 3 and OPC West Addition. The parking area considered feasible for a carport canopy system includes a section of Parking Lot C and top deck of a future parking garage. The approximate location of the arrays has been outlined on the Preliminary PV Design Layouts in the attached appendices, and described in greater detail in Section 2(d) (PV Panel Location and Analysis).

In addition to the existing solar system, the new system would have approximately 2,923 panels totaling 833.1 kW and an estimated 1,260,406 kWh of annual production in year

1. The majority of the panels, approximately 70%, would be installed as part of a parking canopy-mounted system and the remainder, approximately 30%, would comprise the roof-mounted system.

An economic analysis of the two PV systems (i.e. roof, and carport), inclusive of estimates of savings and capital and operating costs was developed for a publicly owned PV solar system. The analysis indicates net present value (NPV) savings over the life of the project and an internal rate of return as follows:

The Solar PV systems are projected to have a 20-year project NPV of -$728,777 and an IRR of 0.5%. The analysis includes conservative estimates of project installation and maintenance costs, electric production, electric rates, and rebates. Table 2-1 provides a comparative breakdown of the economic metrics per each individual project and the entire project as a whole.

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Table 2-1: Economic Metrics of Total Estimated System

Metric Value Annual Cash Flow Year 1 $99,505

Total Construction Costs $2,475,553

Annual O&M Costs Year 1 $22,836

NPV Savings Over 20 yr -$728,777

Savings-to-Investment Ratio 0.85

Internal Rate of Return 0.5%

Adjusted Internal Rate of Return 0.3%

A conceptual design of a thermal solar system designed to preheat makeup water for existing steam boilers was considered. The system would consist of 27 collectors mounted on the roof of Building 22 (chiller building), and would save approximately 311 MMBtu’s of natural gas annually. A second thermal system designed to heat water for the hospital laundry services was also considered. However due to the lack of adequate roof area for solar collectors, it was removed from further consideration.

An economic analysis of the solar thermal system inclusive of estimates of savings and capital and operating costs was developed for a publicly owned solar thermal system. The analysis indicates a projected 20-year project net present value (NPV) of -$128,465 and an IRR of -12.2%. Table 2-2 provides a comparative breakdown of the economic metrics of the solar thermal system.

Table 2-2: Comparative Economic Metrics for Solar Thermal System

Metric Value Annual Cash Flow Year 1 $1,033

Total Construction Costs $151,250

Annual O&M Costs Year 1 $756

NPV Savings Over 20 yr -$128,465

Savings-to-Investment Ratio 0.28

Internal Rate of Return -12.2%

Adjusted Internal Rate of Return -8.3%

When combined together, the solar PV and solar thermal systems proposed herein result in a projected 20-year NPV of -$857,242 and an IRR of 0.1%. Table 2-3 provides a comparative breakdown of the economic metrics of the solar PV and solar thermal systems.

Table 2-3: Comparative Economic Metrics for Solar PV and Thermal Systems

Metric Value Annual Cash Flow Year 1 $100,538

Total Construction Costs $2,626,803

Annual O&M Costs Year 1 $23,592

NPV Savings Over 20 yr -$857,242

Savings-to-Investment Ratio 0.81

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Internal Rate of Return 0.1%

Adjusted Internal Rate of Return 0.0%

Both the Solar PV, and the Solar Thermal projects, either individually or when considered together, have weak economics that would likely limit interest by third party investors that could offer a PPA or similar structure;

As a result, the primary path for project implementation would be a "self-own" structure under which the VA finances the system(s) itself. In this case, however, the economics will be particularly weak and Gabel does not consider the project(s) economically attractive;

If the VA is able to secure additional funding, or alternatively, if the VA were permitted to monetize the renewable energy certificates associated with the generation of the solar PV array, the associated economics would be greatly improved and would provide a positive investment for the facility; and

If adequate additional financing can be arranged or if renewable energy certificate incentives can be collected, the VA should take the steps to implementing the solar projects.

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

3. Technical and Site Review

a) Overview of Photovoltaic (PV) and Solar Thermal Systems

Photovoltaic Overview

Photovoltaic (PV) cells convert energy from sunlight directly into electrical energy through the use of semiconductors, diodes and collection grids. PV cells are then linked together in a single frame, or module, to become a solar panel. This conversion occurs without any moving parts and without generating any noise or pollution.

Rooftops, carports and ground-mounted arrays are common mounting locations for solar PV projects. To be effective, solar panels must be mounted in a non-shaded location. The angle of inclination of the PV panels, the amount of sunlight available, the orientation of the panels, the amount of physical space available and the efficiency of the individual panels are all factors affecting the amount of electricity that is generated.

Under full sun, and as measured under standard test conditions1, each panel produces direct current (dc) electricity at about 12% to 21% efficiency. However, under real conditions, this efficiency also depends on the tilt and azimuth of the collector, and weather conditions (the temperature and the level of sunlight). The overall PV system efficiency at this location is estimated to be between 14 and 15% based on PV Watts calculations and assumptions. This percentage will vary based upon panel selections, weather conditions, efficiency of final system design as well as other factors.

An inverter then converts the dc to alternating current (ac) at the desired voltage and phasing compatible with building and the utility power systems. The balance of the system consists of conductors/conduit, combiner boxes, switches, disconnects and fuses.

PV system installation typically includes the installation of a remote web-based monitoring system that will display real-time data such as instantaneous kWh generation, cumulative kWh generation, dollars saved, on-going environmental savings associated with the system and current weather data. In addition to web access, this information can also be displayed on a flat panel monitor that can be installed at a location selected by the VA.

The most common type of solar panels are crystalline panels, which can be mono-crystalline (mono-Si) or poly-crystalline (p-Si). A typical crystalline panel is approximately 39 inches high and 65 inches wide, and their efficiencies vary from 12-21%. Panels are linked in strings, and are covered by a protective glass panel. An alternative solar PV technology is “thin film” solar panels, which consist of a solar cell that is made by depositing one or more thin layers (thin film) of photovoltaic material on a substrate. The thickness range of such a layer is wide and varies from a few nanometers to tens of micrometers. Thin Film solar is lightweight and durable as compared to crystalline panels. Per square foot, thin film panels are less efficient than their crystalline counterpart, however, the advantage to crystalline panels is found in their light-weight, easy to install design and the productivity on large scale installations where space constraints aren’t a limiting factor. A comparative table of PV panel options is outlined below:

1 STC specifies temperature of 25 °C, irradiance of 1000 W/m2 and an air mass 1.5 (AM1.5) spectrum.

http://en.wikipedia.org/wiki/Solar_cell http://en.wikipedia.org/wiki/Thin_film http://en.wikipedia.org/wiki/Photovoltaic http://en.wikipedia.org/wiki/Wafer_(electronics)

Table 3-1: Comparison of PV Panel Varieties

Type of PV Panels

Advantages Disadvantages

Mono-crystalline

High efficiency (15-21%)

Long life expectancy

More efficient in low-light conditions as compared to poly-crystalline

More efficient in high-temperature conditions

Uniform look (more aesthetically pleasing)

Most expensive

Low performance if a portion of a panel is covered by shading, snow or dirt

Generates more silicon waste during manufacturing process

Poly-crystalline

Less wasted silicon during manufacturing than mono-crystalline panels Less expensive

Efficiency lower than mono-crystalline (13-16%)

Requires more space than mono-crystalline

Thin-Film

Cheaper to produce than crystalline-based panels

Uniform look

Flexible, easy to install

Less sensitive to shading and high temperature

Lowest efficiency (7-9%)

Requires significantly more space

Lower life expectancy – degrade faster than crystalline panels (shorter warranty)

Grid connected photovoltaic (PV) systems are designed to shut down when the power from the utility is cut off, in order to prevent back-feed to the grid that could endanger utility line crews working to restore power, and because the PV systems rely on utility power to balance solar power in order to maintain a constant voltage for appliances and other electrical loads. However, there have been advances in battery technology over the last few years that can provide continuous emergency power and the ability for solar to keep generating when the grid is down.

Adding battery backup to PV systems would allow the PV system to continue to operate and provide a level of continuous emergency power available from a combined PV-battery system that automatically isolates from the grid and operates independently during power outages. The systems are in full compliance with all the traditional safeguards against grid back-feed.

PV-battery systems could generate power for critical loads such as lights, heat circulating pumps and fans, computer etc. Batteries store and release power produced by the PV system and with management of critical loads, and the sun shining, batteries are continually recharging as the system continues to operate when the grid is down.

In addition to providing back-up power and reliability, additional savings and revenues may be realized with the addition of batteries. VAMC may have the opportunity to minimize demand charges and realize additional demand savings on utility bills. The battery provides the ability to strategically reduce loads and thereby offer the potential to offset these charges and realize significant demand savings. Unfortunately, the timing of peak demands (typically late afternoon) does not always correlate with peak PV production. If a solar system has battery storage, the ability to use the stored solar generation during periods of peak demands provides reductions to on-peak demand charges that were unable to be provided without the storage capability.

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Solar Thermal Overview

Unlike PV systems, solar thermal systems utilize solar collectors and a storage tank. A pump is used to circulate heat-transfer fluid (water or glycol) to and from the solar collectors to extract heat which can be used in the building for space heating, pool heating or domestic hot water heating.

Solar thermal systems can be 46% to 74% efficient, an efficiency that is much higher than that of PV systems. The downside of a solar thermal system is that the only time that the system is effective is when the heat is actually being used unless large storage tanks are installed, whereas a PV system will generate electricity which can be net-metered effectively storing the savings for later use. However, applications such as swimming and rehabilitation pools do not require large storage tanks, as they provide a ready heat ‘sink’ that can immediately use the extracted energy to compensate for heat loss.

b) Types of PV and Solar Thermal Systems

i. Roof mounted PV

The most common roof mounted system is referred to as a “fixed tilt” system typically mounted to a metal rack that is fixed at a specific angle (tilt). The tilt is determined by considering the geographic location, total targeted kWh production, seasonal electricity requirements and weather conditions such as wind and snow. Experience with many installations has shown that roof-mounted PV systems are typically installed at a tilt of 10 degrees or lower, thus minimizing issues with wind while maximizing total system size. The azimuth (or orientation of the panels) illustrates the direction in which the panels will be facing (180-degrees is due south). The type of PV panels and equipment used to mount the system are determined based on wind conditions and structural integrity of the roof, determined during the design phase of the project. In general, penetration/tie-down systems, non-penetrating ballasted type systems, or a combination of the two can be considered.

For areas with high winds and a potential for hurricanes and tornadoes, a roof penetrated system would be recommended for all roof-mounted PV systems.

ii. Canopy System PV

In order to mount PV panels over parking spaces, a “carport” type construction using steel support members is needed.

Experience has shown that properly designed and laid-out supporting structures do not interfere with the flow of traffic or with snow plowing or de-icing operations, where applicable. Carport canopy systems should always be designed with geographic area, climate and local weather in mind. For example, areas of the country with snowfall should include considerations for snow guards and ice damming prevention. In

Solar PV & Thermal Feasibility Study

VA Central California Health Care System addition, under-canopy lighting should always be included and light levels should meet or exceed existing light levels of the parking lot. It is also recommended that high efficiency lighting be used where possible. Each parking space typically accommodates four to six PV panels. Column spans and canopy heights can vary. Canopy designs accommodate specific requirements of the parking lot. For example, school parking lots are commonly designed such that the canopies allow school busses to park underneath (Note: 13’ 6” is the legal max height of any vehicle on the road, however, for passenger cars and trucks this height can be lower). The span of the columns also depends on the design and materials used, with column span typically 3-4 parking spaces (24-30 feet). Depending on the parking lot size and orientation, carport canopies can be designed as a single post cantilever construction or multi-column structure (typically referred to as an “area canopy”) where only parking spaces or an entire parking lot area is covered. The cost of a carport canopy system will also be heavily impacted by the design selection ie certain more aesthetically pleasing single post cantilever designs can cost significantly more on a cost per watt basis than an area canopy. The type of carport canopy design, PV panels, equipment used to support the system, and any alterations or additions to the parking lot lighting are determined during the design phase of the project.

iii. Ground Mounted PV

Ground mounted systems are designed to stack multiple panels together in a rack and position them with a higher tilt (20-30-degree) in order to maximize kWh production.

Spacing between racks depends on number of stacked panels and panel tilt and is determined based on a shading analysis for a particular location. Ground mount designs typically require concrete and steel support posts or “screw-type” helical anchors to withstand wind loads and other factors. Finished installations result in racks that can be as low as 3 feet or as high as 8-10 feet in height at the tallest point. Ground mounted systems can be “fixed-tilt” or “tracking”. Tracking systems change orientation of the panels to maximize sun exposure to the panel and therefore increase total kWh production. They can be 1-axis or dual-axis systems. Both systems require significantly more space than fixed-tilt systems as they have to be spaced out to prevent inter-row shading from each other. In addition, an increase in kWh production of the tracking systems is somewhat offset by higher operations and maintenance costs as compared to fixed-tilt.

iv. Solar Thermal Systems

The two main types of Solar Thermal systems are evacuated tube and flat plate. Typically flat plate collectors are more efficient at 61% to 74% while evacuated tube collectors are 46% to 57% efficient.

Evacuated tube collectors can produce higher temperature water than flat plate collectors and may be necessary depending on the application. These systems can be set up with either drain back systems or an anti-freeze solution to prevent damage to the system from freezing. Both systems require a storage tank to hold the heat absorbed by the system. Typically solar thermal

Solar PV & Thermal Feasibility Study

VA Central California Health Care System systems are mounted on roofs. Following please find a comparison chart of various solar thermal systems.

Table 3-2: Comparison of Solar Thermal System Varieties

Solar

Thermal

System Varieties

Advantages Disadvantages

Evacuated Tubes

Can produce higher temperature

More efficient during cold and cloudy conditions

Suitable for both DHW and space heating Aesthetically pleasing

Easier installation

More expensive

Potential problems with overheating during summer months

Flat Plate

More efficient overall, especially in milder climates

Less expensive

Not good for space heating

Bigger and heavier, more difficult to install

More sensitive in windy conditions due to larger surface area

Please note that for northern part of U.S. using solar collectors may not be the most cost effective way to heat hot water. Instead, using a photovoltaic system to generate electricity and then connecting the PV system to a heat-pump water heater may be more economical.

For this study, the VA requested that Gabel review the feasibility of solar PV located on existing building roofs, roofs of buildings that are planned to be built in near future and carport canopies located on existing parking lots and future parking garage. For solar thermal VA requested the feasibility study for a system located on existing boiler room used to pre-heat boiler makeup water and for a second system used to pre-heat domestic water used in the hospital’s laundry.

c) Site Visit Review

Gabel conducted a site walkthrough of the facilities on March 10, 2015. The purpose of the site walkthrough was to assess roof availability and orientation, potential carport canopy locations, review shading considerations, access to electrical interconnection points, access to mechanical rooms that have domestic hot water units, and positioning of the solar panels relative to the movement and track of the sun. The walkthrough consisted of an inspection of the site’s overall electrical systems throughout the campus, along with an inspection of the hospital’s boiler room.

d) PV Panel Location and Analysis

System location and sizing is preliminary in nature and subject to change. Actual sizing and placement will be determined during the design phase. The sizing and feasibility of the solar systems are also subject to conducting final due diligence on roof condition, wind load testing and structural stability. Reference the Appendices for a detailed Preliminary Solar Conceptual Overlay.

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Roof-Mounted PV Systems

Roofs of all existing buildings consist mostly of flat, horizontal areas constructed either as built-up non-ballasted or single-ply membrane roofs. These roofs vary in age, size and amount of equipment installed. Buildings 1 (main hospital), 24 (admin/education), 31 (CLC), and Outpatient Clinic (OPC) already have roof-mounted PV solar system installed. Roofs of most other buildings have previously been excluded from PV system consideration due to the presence of HVAC equipment, exhaust fans, ventilation pipes or other obstructions or because of shading from taller structures. An overview of roofs with PV systems installed as well as other potentially feasible roofs are presented in the table below. Please note that the buildings under 500 square feet are excluded from consideration due to insufficient roof size.

Table 3-3: Recommendations for Potentially Feasible Roofs – Existing Structures

Building Function Roof type Note

OPC 1

Outpatient Clinic

Flat, Built-up

PV solar system already installed on this roof.

No space available for additional panels.

OPC 2

Outpatient Clinic

B-1 Main Hospital Flat built-up & membrane, multi-level

Higher section (east) already has a PV system installed. Lower section (west) contains large number of HVAC – not recommended for PV.

B-2 Boiler Plant Flat built-up

Boiler stacks located along the eastern edge of the roof create shading in morning hours.

Not recommended for PV.

B-3 Engineering

Shops Flat built-up

New engineering building planed at this location. PV not recommended on existing structure.

B-4 Pump House and Emergency

Generator

Flat, metal corrugated roof

Building may not be structurally sound to support a PV system. Not recommended for

PV.

B-7 Engineering Warehouse

Flat, metal corrugated roof

Building may not be structurally sound to support a PV system. Not recommended.

B-8 Engineering Warehouse

Flat, metal corrugated roof

Building may not be structurally sound to support a PV system. Not recommended.

B-22 Chiller Plant Flat, Built-up

After existing cooling tower is removed, the roof may be used for either PV or solar thermal

B-24 Admin/Education

Building

Flat, membrane roof

Some sections of the roof already have a PV system installed. Other sections not recommended due to shading from taller structures.

B-25 Mental Health 1 Flat, membrane roof

North section of the roof is occupied by HVAC units. Available open space is affected by shading from a parapet wall. Building not recommended for PV.

B-31

Community

Living Center

(CLC)

Flat, Built-up PV solar system already installed on this building

B-32 Warehouse Flat, Built-up

North section of roof is recommended. Other sections not recommended due to significant shading from B-1

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

B-34 Mental Health 2 Flat, membrane roof

North section of the roof is occupied by a large HVAC unit. South section may be shaded at times by building 1 located to the south.

Roof not recommended for PV.

Buildings currently in construction or planned to be built in near future are presented in Table 3-

4. The analysis of PV systems that can be installed on these structures is based on available building plans or approximate square footage of the roofs as estimated by VA personnel.

Table 3-4: Recommendations for Potentially Feasible Roofs – Proposed Structures

Building Function Roof type Note

PRRC

Psychosocial

Rehabilitation and Recovery

Flat, membrane roof

CLC

Extension

Community

Living Center

Sloped, shingle roof

B-3 Engineering

Building N/A Building plans not available

OPC –

West

Addition

Outpatient Clinic

N/A Building plans not available

Parking

Garage Parking N/A Building plans not available

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Figure 3-1: Fresno VAMC Site Plan (Including Future Structures as per Option 3 of the 2023 Master Plan)

Solar PV & Thermal Feasibility Study

VA Central California Health Care System

Building 32

Building 32 has a flat, single-level built-up ballasted roof of a rectangular shape. VA personnel estimated the roof’s age is likely more than 10 years, in which case we would caution the VA to investigate closely the condition of the roof and its long term ability to last the equivalent life of a solar system. The building is adjacent to Building 1 to the south which creates significant shading especially during winter months (see Figure 3-2). In addition, the roof has a 4-foot parapet wall, which further reduces the amount of panels that can be installed. In order to avoid shading, we recommend the panels be installed in the north-east section of the roof only. The total size of the system is estimated at 16 kW dc.

Figure 3-2: Building 32 Solometric SunEye Skyline

Solar PV & Thermal Feasibility Study

Figure 3-3: Building 32 Preliminary Solar Conceptual Layout

Building 25

Building 25 has a flat, single-level roof of irregular shape. The roof surface appears to be new and in very good condition. A large section of the roof is occupied by HVAC rooftop units, its ductwork and piping. The remaining area is free from obstructions, however is it relatively small and the area suitable for a PV system installation is further reduced by the presence of a tall parapet wall around the roof perimeter. The total size of the system for this location is estimated at 8.5 kW dc.

Solar PV & Thermal Feasibility Study

Figure 3-4: Building 25 Preliminary Solar Conceptual Layout

Building 24

Building 24 has a flat, multi-level roof of irregular shape. The roof surface appears to be new and in very good condition. A small PV solar system is already installed on lower, southern section of the roof. Most of the remaining roof is either occupied by HVAC rooftop units and exhaust fans or shaded by taller structures such as building 1 and penthouse of building 24. However, a portion of the penthouse roof may be considered for additional PV installation. The total size of the additional system that can be installed here is estimated at 7.1 kW dc.

Solar PV & Thermal Feasibility Study

Figure 3-5: Building 24 Preliminary Solar Conceptual Layout

PRRC Building (currently in construction)

This buildings was in the early stages of construction at the time of our visit, therefore, a PV system that could be installed was based on available architectural plans. As per the plans, the roof is of irregular shape and will have a minimally pitched slope (1/2 inch per foot), covered with a roofing membrane. Apart from a large vestibule in the north-east section, it is assumed that no other HVAC units will be installed on the roof. Based on these assumptions, the total size of the system is estimated at 34.2 kWdc.

Solar PV & Thermal Feasibility Study

Figure 3-6: PRRC Building Preliminary Solar Conceptual Layout

CLC Building extension (future)

The existing CLC Building has a flat, single-level built-up roof of irregular shape. The roof already features a fixed-axis solar PV system rated at 70.98 kWdc. As per VA personnel, an extension to the building is planned to be built in near future. As per preliminary construction documents, the new building will have a low-pitch, two-sided roof covered with asphalt shingles. Sections of the roof will be occupied by ventilation fans, chimneys and dormers. Also, a smaller section of a south facing roof will be covered with solar thermal collectors for domestic hot water production. On the other hand, no HVAC equipment will be installed on the roof. For the purposed of this study, Gabel considered installation of solar panels on east, west and south-facing surfaces. Based on these assumptions and as indicated in the layout below, the total size of the new roof-mounted PV system is estimated at 70.4 kW dc.

Solar PV & Thermal Feasibility Study

Figure 3-7: CLC Extension Preliminary Solar Conceptual Layout

Building 3 (future)

As per VA personnel, a new engineering building will be built at the location of the existing Building

3. At present there is no further information available regarding the overall size, height and type of roof as this construction is still in programming phase. Assuming that the building will have a flat roof approximately 15,000 square feet in size, no significant shading from adjacent structures (Building 1 and Building 24) and that ½ of the roof will be occupied by HVAC units, exhaust fan units and other obstructions, the total size of the roof-mounted system that can be installed on this building is estimated at 43.9 kW dc. Please note that these are preliminary numbers and it is recommended to perform additional solar analysis when the building construction documents become available.

OPC West Addition (future)

According to the Site’s Master Plan, an extension to the OPC building is planned to be built to the west of the existing building occupying a portion of parking lot C. However, it was also indicated by the VA staff that this building will be built in stages over an extended period of time. For the purpose of this study it was assumed that the building extension will be similar to the OPC building with respect to number of floors, type of roof etc. The total size of the new roof is estimated at

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VA Central California Health Care System approximately 18,000 square feet. Based on the assumption that ½ of the roof will be occupied by HVAC units and other obstructions, the PV system size was estimated at 65.8 kW dc.

Canopy PV Systems There are a total of 7 parking lots at this location. The lots significantly differ in size, overall shading from trees and buildings and their orientation with respect to sun exposure. Currently a smaller portion of parking lot B is covered by a canopy PV solar system rated at 110.88 kWdc. An overview of all lots is provided in Table 3-5 .

Table 3-5: Overview of Parking Lots

Parking

Lot

Number of parking spaces Note

A 175

Most spots are shaded by trees. Installation of a PV system will require removal of large trees.

B 165

Most parking places currently not covered by a car canopy are shaded by trees planted along E Clinton Avenue. A smaller parking canopy may be feasible in the northwest section of the lot.

C 30

Most of the parking lot is currently occupied by temporary buildings (trailers). Depending on the final building plans, this area may be considered for a PV system

E 14

Small parking lot used by engineering staff.

This area will be redesigned as part of new Building 3 construction. As a result, the lot most likely will be shaded by building 3.

F 12 Small parking lot used by engineering staff.

Shading from nearby buildings.

G 18 Used by CLC patients and staff. PV system may be too small for a car-canopy system.

H 19

This parking lot is currently not available as it is used for construction of the PRRC building.

Shading from medium size trees during afternoon hours.

At present time, there is a large number of mature trees planted at parking lot A and along E Clinton Avenue, which provide shading for both sections of parking lot A and B. As per VA personnel, removal of these trees will most likely not be considered resulting in no opportunity of additional PV car-canopy systems. On the other hand, parking lot C which is currently used for temporary trailers has minimal shading from nearby trees and buildings, may be used for carport canopies once the trailers are removed from the site. Other smaller parking lots (E, F, G and H) were excluded from the study due to small overall size or shading from existing and future campus buildings.

Parking Lot C (Future Parking) – This area is free from shading from trees and buildings throughout the day. However its future purpose is unclear at the moment and as per VA personnel the lot will most likely be used as a site for a new parking garage or OPC building west addition. Based on the 2023 Site Master Plan, north section of the lot may still be used as surface

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VA Central California Health Care System parking, while the south section will be used for OPC addition. Therefore only the north section area is considered in this study. The section would be able to accommodate approximately two cantilever carport canopies, each canopy covering about 30 parking spaces and ideally oriented with panels facing south. The total size of the PV system is estimated at 125.4 kW dc.

Parking Garage (future) – As per VA staff, there is a plan to build a new parking garage on site.

The location and the size of the garage has not been determined yet, however for the purpose of this study, it is assumed that it will be built in Parking Lot B as per 2023 Master Plan (see Figure 3-1). Gabel Associates considered the installation of a system mounted on the top deck of the garage. The garage is assumed to utilize most of existing parking lot B and be approximately 300 feet long and 130 feet wide. There are two distinctive canopy systems available that can be installed on garage roofs: a cantilever canopy that would cover parking spaces only, or an ‘area’ canopy that would cover the entire roof of the garage. An approximate size of a PV system for both canopy types is provided in the Table 3-6. An aerial overview of the cantilever canopy system is shown in Figure 3-11

Table 3-6: Parking Garage Canopy System Size

Cantilever canopies “Area” canopies PV size 315.8 kW 461.7 kW # of panels 1,108 1,620

Figure 3-8: Kern County Parking Garage, Bakersfield, CA

Table 3-7: Summary of Carport Canopy PV Systems

Area PV size

(kW)

Number of

Canopies

Parking lot C 125.4 2 (cantilever)

Parking garage 461.7 1 (area)

Ground-Mount PV systems

No ground–mount systems were considered at this site due to lack of available areas.

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VA Central California Health Care System

e) Solar PV System Sizing

For purposes of developing estimates for PV system capacity, Gabel assumed the installation of a south facing, non-tracking, fixed tilt system for both roof-mounted and carport canopy systems.

The calculations were based on utilizing a mono-crystalline panel such as the SolarWorld Sunmodule Plus SW285 mono (rated at 285 watts dc). The azimuth and panel tilt assumptions are as follows:

Table 3-8: PV System Characteristics

System Type Azimuth Panel Tilt Roof mount – flat roofs 180° 10°

Roof mount – pitched roofs 90, 180 and 270 degrees, depending on roof orientation.

Same as roof tilt (13 degrees for CLC extension)

Car canopies 180° 5°

The preliminary analysis shows that a total PV system array(s) of up to 833 kW (dc), consisting of approximately 2,923 panels, can be installed across the roofs and parking lots on the campus.

Factors taken into consideration include proximity to the potential electrical interconnection points, orientation and layout of buildings and parking lots, and potential shading of the PV panels.

This analysis did not assume removal of any trees on site; however, depending on the final location and size of the parking garage, some trees along Clinton Avenue may be necessary to remove/replant. The preliminary analysis results are shown in the following table:

Table 3-9: Solar PV System Size

Proposed PV System System Size Estimated Number of

Panels

Roof-Mounted Array 246 kW dc 863

Carport Canopy Array 587 kW dc 2,060

Total Campus-Wide Array 833 kW dc 2,923

f) Solar Thermal Panel Location and Analysis

Based on inputs and suggestions from VA personnel, two separate solar thermal projects are considered in this study:

Solar thermal system used to preheat steam boiler make-up water.

Solar thermal system used to preheat domestic hot water for hospital laundry services.

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VA Central California Health Care System

Boiler make-up water preheat

This solar thermal system will be used to preheat makeup water for steam boilers located in the central boiler plant in Building 2. Makeup water is added to boilers as a result of leaks of steam and condensate from the steam distribution system or other water losses such as boiler blowdown. As per boiler make-up data provided by VA personnel, the average annual boiler makeup at this site is about 3,350 gallons per day. The boiler plant consists of a total of three dual-fuel steam boilers, each rated at 10,042 MBH output. Typically one or two boilers are required to satisfy the campus thermal load. Two 2,000 gallon storage tanks located outside of building 2 provide source of makeup water in case of a water outage.

In order to utilize thermal solar for boiler make-up water, solar collectors and a storage tank with integral heat exchanger coils would have to be installed. A closed-loop piping system would run between the collectors and the hot water storage tank, where make-up water would be pre-heated. Given that winter temperatures rarely drop below freezing in this area, an anti-freeze agent and/or a drain back system may not be required as part of the solar hot water system, however further analysis will be required to determine this and other specifics of the system. The areas available for installation of the collectors include roofs of Building 2 (boiler plant) and Building 22 (chiller plant). Please note that at present time there is a large cooling tower on the roof of Building 22, however as per facility personnel, this unit will be relocated to the roof of a new chiller building (future extension of Building 22).

Energy required to pre-heat boiler makeup water depends on volume of water and temperature difference (T). Based on the information gathered during our site visit, Gabel estimated the current energy used to heat the makeup water from 60 F to 130 F at approximately 946.5 million Btu per year. However, not all of this energy can be substituted by the solar system. When solar energy is not available (cloudy weather and during nighttime) and energy captured in the storage tank is depleted, the makeup water will have to be reheated using existing fuel source (natural gas or oil). Another consideration when designing a solar thermal system is to minimize the possibility of reaching a stagnation point2 of the solar collectors, which may happen during very hot weather or when the boilers are not used for a prolonged amount of time.

Solar thermal for hospital laundry services

Gabel Associates was also tasked with a feasibility study to determine the technical and financial viability of a solar thermal system designed and built to preheat domestic hot water used for laundry services in Building 1. Currently, the existing domestic hot water (DHW) system consists of steam-to-water heat exchangers where steam is supplied from the central boiler plant in Building 2.

In order to utilize thermal solar for this application, the system would require installation of solar collectors on the building’s roof and a storage tank with a heat exchanger close to the existing steam-to-hot water heat exchanger in the basement. A closed-loop piping system would run between the collectors and the hot water storage tank. However, upon the closer investigation it was determined that there is insufficient space available on the roof of building 1. Additional area was also considered on the roof of building 34, however, due to the presence of large HVAC unit

2A stagnation point is referred to as any condition when the heat transfer fluid is not circulating and a solar collector cannot reject heat generated from solar energy. In hot weather, a solar system may generate more heat than is needed which can result in an uncontrolled increase of internal fluid temperature above a desired maximum level.

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VA Central California Health Care System and possible shading from building 1 this area was excluded as a possible site for solar collectors.

No additional analysis was performed and this task was eliminated from further consideration.

g) Solar Thermal System Sizing

Boiler make-up water preheat

Given the design constraints explained above, Gabel Associates considered the installation of a number of flat plate collectors, such as the SolarHot S-SC-126P32. The area of each collector is 32 square feet (4’ by 8’) where the collectors will be installed at 37-degree tilt and 180-degree azimuth. Based on the building 2 (boiler plant) and building 22 (chiller plant) roof configurations, existing obstructions and available area, the solar thermal size was estimated at approximately 27 solar collectors. The thermal output of the system will fluctuate based on outdoor conditions such as insolation and ambient temperature as estimated in the table below. Please note that the output of the system during months of December and January will be negligible due to low outdoor air temperature. It may be necessary to drain the system to prevent possible damage to the panels caused by freezing. The total thermal output of the system is estimated at 245.5 MMBtu annually. Assuming a 5% distribution loss of the solar system and an average efficiency of 75% for the steam boiler, the total energy offset from steam boilers is estimated at 311.0 MMBtu/year.

In short, the solar thermal system would offset a minimal amount of the thermal demand of the make-up preheat, meaning that there would still be substantial reliance on energy provided from the gas-fired boilers.

Table 3-10: Solar insolation and temperature for Fresno, CA

Month Insolation Average

Temperature kBtu/(ft2 day) F

Jan 3.00 49.4

Feb 4.54 54.0

Mar 5.85 59.4

Apr 6.79 68.1

May 7.08 76.7

Jun 7.25 85.3

Jul 7.42 90.2

Aug 7.49 87.3

Sep 6.91 81.3

Oct 6.09 73.1

Nov 4.43 56.0

Dec 2.77 49.9

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VA Central California Health Care System

h) Electrical System and Interconnect Point

Analysis of the existing electrical system and possible interconnection points for the PV system is performed using the site’s electrical one-line diagrams, drawings for the existing PV system installed at the site and information gathered during the onsite visit. The Central California VA Health Care Center is currently primary metered from the utility company at 12,470 Volts. This primary feed voltage is stepped down to 480/277 or 208/120 Volts through a number of transformers located throughout the campus.

Interconnection Point - Roof-Mount Systems

Building 32 – The Solar PV System is estimated to be 22.8 kW (DC.) The roof of this building is very close to the hospital’s main electrical room in Building 1 which may be used as an interconnection point for the system. Please note that the existing solar system located on the roof of Building 1 has already been connected at this point utilizing line-side connection at the main secondary switchboard (MSS). The specifications of the MSS and other switchboards in this room will need to be reviewed to determine where a new point of connection can be made in accordance with the current National Electric Code (NEC) rules.

Building 24 – The Solar PV System is estimated to be 7.13 kW (DC). Please note that there are already two systems installed on this building (Main roof and Auditorium) rated at 5.04 and 6.93 kW respectively.