Final_-_MLO_RE_Study.pdf

iii iv

Executive Summary

The National Renewable Energy Laboratory (NREL), in a partnership with the National Oceanic and Atmospheric Administration (NOAA) conducted a feasibility study looking at a variety of different renewable energy technologies for use at the Mauna Loa Observatory (MLO). The following technologies were considered.

Solar Photovoltaic (PV)

Solar Thermal

Biomass

Wind

Geothermal

Of the technologies that were considered, all but Solar Photovoltaic were eliminated upon a site visit by NREL staff. The following report summarizes the analysis that was conducted including performance, economics, site conditions, and general feasibility.

Seven sites in or near the site boundary of MLO were considered, all of which were found suitable for PV systems. The economics of the potential systems were analyzed using an electric rate of $0.36/kWh, as well as incentives that are offered by the State of Hawaii and by the serving utility, Hawaii Electric Light Company (HELCO). Table ES-1summarizes the system performance and economics of a potential system that would produce enough power to meet the entire site electrical load. The system laid out in the table would bring the site to Net Zero

Energy (NZE). The data is presented both with and without incentives that are available in

Hawaii.

Currently, Hawaii has a very attractive set of incentives. The state offers a 35% tax credit up to

$500,000 for commercial properties. This is in addition to the 30% federal tax credit incentive.

In order to take advantage of these tax credits, the system owner must pay taxes. There are methods through which NOAA could capture the tax credits, in order to improve the economics of the system. These methods are explained in section 4 of the report. A full list of incentives can be found in Appendix B.

The results of this feasibility study show that this is a very good candidate for a solar PV system.

The system payback periods are within a reasonable range with or without incentives, and implementation of a system would help to hedge against rising energy costs. The Mauna Loa

Observatory should consider PV energy projects for several reasons in addition to economic reasons. The projects could accomplish the following:

Reduce environmental emissions including carbon dioxide (CO2), oxides of sulfur (SOx), oxides of nitrogen (NOx), particulate matter (PM), and mercury (Hg) from regional power plants operated by HELCO.

Contribute to the requirement in the Energy Policy Act of 2005 that Federal agencies obtain 7.5% of their electricity from renewables.

v

Employ local trades to install and maintain the systems instead of spending that money to import energy into the district.

Inform visitors about these promising PV energy technologies.

Hedge against rising electric rates by guaranteeing an energy source for 25 years or more.

Set an example for the nation on real steps that can be taken to diversify the energy portfolio.

Provide high quality reliable daytime power for sensitive electronics

Two feasible courses of action can be taken to implement PV systems at the site. One is to use a power purchase agreement (PPA) to implement the PV system in an arrangement that can use the tax credits. Based on past experience at NREL, the smallest feasible system size for a PPA with

PV is 100 kW. Another version of a PPA is a solar lease, which involves making monthly payments to the solar contractor in exchange for the system. The solar lease may be a good path to take if the 1603 Treasury Grant is renewed after it expires on 12/31/2010. If the grant is not extended, the solar contractor will not be able to capture the tax credits for the system in place of the MLO site. Here are some possible next steps for setting up a power purchase agreement:

Talk to the utility about Rule 14h (Hawaii specific regulation), other interconnection issues and available incentives.

Investigate contract length options. Contract length is limited to 10 years under FAR Part

41. DOD has longer term authority. Other options include using Unicor, utility PPA and competitive ESPC for 25 year contract.

Investigate NEPA requirements

Investigate land use agreement options

Determine contracting office (internal or DLA Energy)

The second is to purchase the system outright and forfeit the tax credits. Based on NREL’s analysis, here are some possible next steps for purchasing a system outright:

Prepare a request for proposal (RFP) based on performance specifications which allow for the contractor to design the system using information from this report.

Submit the RFP to solar contractor community and review designs as they come in.

Accept the best proposal and commission the system upon installation.

Train staff on continued O&M of the systems.

DOE’s Federal Energy Management Program (FEMP) offers agencies assistance in each of these areas.

See Appendix C for a list of PPA resources.

The FEMP website with PPA resources.

http://www1.eere.energy.gov/femp/financing/power_purchase_agreements.html vi

Table ES-1. PV System Performance and Economics by System Type

System Type Potential System Size (kW) a

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

145 268,913 $96,809 $2,689 $865,742 9.2 $866,922 w/ incentives 145 268,913 $96,809 $2,689 $303,010 3.2 $1,472,472 a System is calculated to offset all electrical use at the 4 NOAA meters on site.

The incentives can only be captured through a PPA or solar lease.

iii

Table of Contents

Executive Summary ...................................................................................................................................... iii

Table of Contents .......................................................................................................................................... iii

List of Figures ............................................................................................................................................... iv

List of Tables ................................................................................................................................................. v

1 Study Location

2 PV Systems

2.1 Types of PV Systems

2.2 PV System Components

2.3 PV Size and Performance

3 PV Site Locations

3.1 Rooftop NDSC

3.2 Rooftop Keeling

3.3 South Area In Site Boundary

3.4 South Area Lava Barrier

3.5 North Area Near AMIBA

3.6 North Area Along Entrance

3.7 North Area Along Summit Access

3.8 Summary System that Could Offset MLO Energy

4 Economics and Performance

4.1 Assumptions and Input Data for Analysis

4.2 Incentives and Financing Opportunities

5 Conclusions and Recommendations

Appendix A. Assumptions for Calculations*

Appendix B. Renewable Energy Incentives* iv

List of Figures

Figure 1: Mauna Loa Observatory Aerial Image

Figure 2: Solar Resource in the Hawaiian Islands

Figure 3: Wind Resource in the Hawaiian Islands

Figure 4. Major components of grid-connected photovoltaic system

Figure 5: Potential System Placement Aerial Site Total

Figure 6. Rooftop NDSC: Recommended PV system placement

Figure 7. Rooftop NDSC: Roof Image of recommended PV array site

Figure 8. Rooftop Keeling: Recommended PV system placement

Figure 9. Rooftop Keeling: Roof Image of recommended PV array site

Figure 10. South Area In Site Boundary: Recommended PV system placement

Figure 11. South Area In Site Boundary: Ground view of recommended PV array site

Figure 13. South Area Lava Barrier: Recommended PV system placement

Figure 14. South Area Lava Barrier: Ground view of recommended PV array site

Figure 15. Solar Measurement South Area Lava Barrier

Figure 16. North Area Near AMIBA: Recommended PV system placement

Figure 17. North Area Near AMIBA: Ground view of recommended PV array site

Figure 18. North Area Along Entrance: Recommended PV system placement

Figure 19. North Area Along Entrance: Ground view of recommended PV array site

Figure 21. North Area Along Summit Access: Recommended PV system placement

Figure 22. North Area Along Summit Access: Ground view of recommended PV array site

Figure 23. Solar Measurement North Area Along Summit Access

Figure 24. Installation cost for grid-tied PV systems 2009-2010 v

List of Tables

Table ES-1. PV System Performance and Economics by System Type........................................ vi

Table 4. Energy Density by Panel and System Table 5. Rooftop NDSC System Options Table 6. Rooftop Keeling System Options Table 7. South Area In Site Boundary System Options Table 8. South Area Lava Barrier System Options

Table 9. North Area Near AMIBA System Options Table 10. North Area Along Entrance System Options Table 11. North Area Along Summit Access System Options Table A-1. Assumptions for Calculations Table A-2. Other Assumptions, including Assumptions for Costs and System Types

Table B-1. Renewable Energy Development Incentives and Financing Tools Applicable to

Photovoltaics

Table B-2. State Rebates for Commercial-Sector PV Projects Table B-3. State Tax Credits for Commercial-Sector PV Projects

Table B-4. State Policy and Incentive Comparisons: Massachusetts, North Carolina, and

Colorado

Table B-5. Key Policy Comparison for Subject States

1 Study Location

The Mauna Loa Observatory (MLO), located on the Big Island of Hawaii near the summit of the

Mauna Loa Volcano, is one of the premier climate study facilities in the world. The observatory has been in operation since the 1950s continuously collecting data relating to the atmosphere.

The remote location and lack of vegetation and human activities make this a nearly ideal location for these types of measurements. The facility is situated on a 4.05 acre parcel of land. The land surrounding the facility is managed by the Department of Hawaiian Home Lands. The remote location of the facility contributes to the high cost of energy at the facility and also increases the cost of construction at the site.

Figure 1: Mauna Loa Observatory Aerial Image

Mauna Loa Observatory Renewable Energy Resource Assessment

The purpose of performing this site assessment was to identify the most suitable renewable energy technology for a given set of geographic, economic, and regulatory parameters as well as customer specific requirements. The following are the results of the preliminary RE resource assessment for the Mauna Loa Observatory.

Solar

The solar resource at the Mauna Loa Observatory ranges from 4.92-6.42 kWh/m2/Day. This is considered an ―excellent‖ resource as compared to Phoenix, AZ which has an ―excellent‖ or

Portland, OR which has a ―fair‖ resource. See Table 1 below.

Table 1: MLO Solar Resource Comparison

Location Insolation (kWh/m

/Day)

Resource Classification

Mauna Loa Observatory

4.92 – 6.42 Excellent

Phoenix, AZ 4.88 - 7.54 Excellent

Portland, OR 3.5 – 4.0 Fair

To further define the solar resource at the Mauna Loa Observatory, a solar resource map can be seen below in Figure 2 showing the solar resource throughout of the Hawaiian Islands. As can be seen on the map, Mauna Loa has nearly the best solar resource in the islands.

Figure 2: Solar Resource in the Hawaiian Islands3

Based on a pre-screening calculation of the one minute wind resource data that was taken at the observatory, wind energy is not feasible at MLO. The wind data file was filtered and the values were used to put MLO into a wind resource class. Wind resources are rated on a scale of 1 to 7, with Class 1 being the lowest and Class 7 the highest. Class 4 and above is generally considered to be the range in which productive wind power is practical, with Class 2 as the lower limit for small turbines. At a height of 38 meters, MLO has an average wind speed of 4.49 m/s, which is classified as a wind power class rating of 1, making wind generation in the area impractical.

http://nreldev.nrel.gov/gis/pdfs/eere_pv/eere_pv_h_hawaii.pdf

MLO

Site http://nreldev.nrel.gov/gis/pdfs/eere_pv/eere_pv_h_hawaii.pdf

Table 2: Wind Power Classifications

Power 10 m (33 ft) 50 m (164 ft)

Class

Wind

Power Density

(W/m2)

Speed m/s (mph)

Wind

Power Density

(W/m2)

Speed m/s (mph)

1 0 0 0 0

2 100 4.4 (9.8) 200 5.6 (12.5)

3 150 5.1 (11.5) 300 6.4 (14.3)

4 200 5.6 (12.5) 400 7.0 (15.7)

5 250 6.0 (13.4) 500 7.5 (16.8)

6 300 6.4 (14.3) 600 8.0 (17.9)

400 7.0 (15.7) 800 8.8 (19.7)

1000 9.4 (21.1) 2000 11.9 (26.6)

Due to the high cost of electricity at MLO, the economics of a 50 kW system were calculated regardless of the poor wind class. See Table 3 for a summary of the calculation. Although the simple payback is not out of the realm of reasonable, the economics of solar technology are much better than wind.

Table 3. PV System Performance and Economics by System Type

Potential System Size (kW) a

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Small Wind 50 15,457 $5,595 $236 $101,742 19 $70,330

Further analysis of the potential for wind power in this immediate region is not recommended.

The wind resource in the Hawaiian Islands can be seen below in Figure 3.

Figure 3: Wind Resource in the Hawaiian Islands4

Geothermal (GT)

Due to the small heating load needed for the MLO campus and the difficulty associated with implementing a system in a lava field, further analysis of the potential for geothermal power or direct geothermal heating in this location is not recommended.

Biomass

Based on a review of NREL’s Geographic Information System (GIS) renewable resource maps, the biomass resource near MLO is negligible. The remote location and the poor quality of the roads leading up to MLO will result in an extremely high cost of fuel delivery. Further analysis of the potential for biomass power or heating is not recommended for MLO.

http://nreldev.nrel.gov/gis/pdfs/eere_wind/eere_windon_h_hawaii.pdf

MLO

Site http://nreldev.nrel.gov/gis/pdfs/eere_wind/eere_windon_h_hawaii.pdf

Based on the initial RE screening, the only significant RE resource available to MLO is solar energy. Using data that was gathered during the site visit, the remainder of the report will focus on the potential for solar PV energy and use various tools developed at NREL to predict the power output of these potential systems. This will allow for an economic analysis to be made to determine the feasibility of installing such systems. Areas identified as potential locations for

PV system placement for the feasibility study are discussed below in Section 3.

2 PV Systems

Solar photovoltaics (PV) are semiconductor devices that convert sunlight directly into electricity.

They do so without any moving parts and without generating any noise or pollution. They must be mounted in an unshaded location; rooftops, carports and ground-mounted arrays are common mounting locations. It is anticipated that PV systems will work very well at MLO where the average global horizontal annual solar resource is 4.92-6.42 kWh/m2/day. This number, however, is not the amount of energy that can be produced by a PV panel. The amount of energy produced by a panel depends on the several factors. These factors include the type of collector, the tilt and azimuth of the collector, the temperature, the level of sunlight and weather conditions. An inverter is required to convert the direct current (DC) to alternating current (AC) of the desired voltage compatible with building and utility power systems. The balance of the system consists of conductors/conduit, switches, disconnects and fuses. Grid-connected PV systems feed power into the facility’s electrical system and do not include batteries.

Figure 4 shows the major components of a grid-connected PV system and illustrates how these components are interconnected in a grid-connected PV system.

Figure 4. Major components of grid-connected photovoltaic system

PV panels are made up of many individual cells that all produce a small amount of current and voltage. These individual cells are connected in series to produce a larger current. PV panels are very sensitive to shading. When shade falls on a panel, the shaded portion of the panel cannot collect the high-energy beam radiation from the sun. If an individual cell were shaded, it would act as a resistance to the whole series circuit, impeding current flow and dissipating power rather than producing it. By determining solar access—the unimpeded ability of sunlight to reach a solar collector—one can determine whether an area is appropriate for solar panels. For this assessment, the NREL assessment team used a Solmetric™ solar path calculator to assess shading at particular locations by analyzing the sky view where the solar panels would be located.

If a site is found to have good solar access for a PV system, the next step is to determine the size of that system, which highly depends on the average energy use of the on-site facilities.

Providing more power than a site would use is generally not advisable due to the economics of most net-metering agreements. In the case of the assessed sites, all of the electricity generated at the site would be used to offset the site electrical usage. The serving utility is Hawaii Electric

Light Company (HELCO). The system size will be determined either by the amount of area that the site is able to utilize, the system size that HELCO is willing to interconnect, or the site electrical load.

2.1 Types of PV Systems

Ground-mounted Systems On a $/DC-Watt basis, ground-mounted PV systems are usually the lowest cost option. Several

PV panel and mounting options are available, each having different benefits for different ground conditions. Table 4 outlines the energy density values that can be expected from each type of system.

Table 4. Energy Density by Panel and System

System Type Fixed-tilt Energy Density (DC-Watts/Sq. Ft)

Single-axis Tracking Energy Density (DC-Watts/ Ft.

Crystalline Silicon 4 3.3

Thin Film 1.7 1.4

Hybrid HE* 4.8 3.9

* Because hybrid high efficiency (HE) panels do not represent a significant portion of the commercial market, they were not included in the analysis. Installing panel types that do not hold a significant portion of the commercial market would not be feasible for a large-scale solar generation plant.

For the purposes of this analysis, all fixed-tilt systems were assumed to be mounted at latitude with a tilt of 19 degrees. To get the most out of the available ground area, considering whether a site layout can be improved to better incorporate a solar energy system is important. If unused structures, fences, or electrical poles can be removed, the unshaded area can be increased to incorporate more PV panels. When considering a ground-mounted system, an electrical tie in location should be identified to determine how the energy would be fed back into the grid. For this report, only fixed tilt ground-mounted systems and fixed tilt roof mounted systems were considered.

Fixed-tilt systems are installed at a specified tilt and are fixed at that tilt for the life of the system.

Single-axis tracking systems have a fixed tilt on one axis, and a variable tilt on the other axis.

The system is designed to follow the sun in its path through the sky. This allows the solar radiation to strike the panel at an optimum angle for a larger part of the day than can be achieved with a fixed-axis system. A single-axis tracking system can collect nearly 30% more electricity per capacity than can a fixed-axis tracking system. The drawbacks include increased operations and maintenance costs, less capacity per unit area (DC-Watt/ft2), and greater installed cost

($/DC-Watt).

Roof-mounted Systems In many cases, a roof is the best location for a PV system. Roof-mounted PV systems are usually more expensive than ground-mounted systems, but a roof is a convenient location because it is out of the way and is usually unshaded. Large areas with minimal rooftop equipment are preferred, but equipment can sometimes be worked around if necessary. If a building has a sloped roof, a typical flush-mounted crystalline silicon panel can achieve power densities on the order of 11 DC-Watt/ft2. For buildings with flat roofs, rack-mounted systems can achieve power densities on the order of 8 DC-Watt/ft2 with a crystalline silicon panel.

Typically, PV systems are installed on roofs that either are less than 5 years old or have over 30 years of life left.

2.2 PV System Components

The PV system considered here has these components:

PV arrays, which convert light energy to DC electricity

Inverters, which convert DC to alternating current and provide important safety, monitoring and control functions

Various wiring, mounting hardware, and combiner boxes

Monitoring equipment

PV Array The primary component of a PV system, the PV array, converts sunlight to electrical energy; all other components simply condition or control energy use. Most PV arrays consist of interconnected PV modules that range in size from 50 peak DC-Watts to 300 peak DC-Watts.

Peak watts are the rated output of PV modules at standard operating conditions of 25°C (77F) and insolation of 1,000 Watts/m². Because these standard operating conditions are nearly ideal, the actual output would be less under typical environmental conditions. PV modules are the most reliable components in any PV system. They have been engineered to withstand extreme temperatures, severe winds and impacts. ASTM E1038-05 subjects modules to impacts from one-inch hail balls at terminal velocity (55 mph) at various parts of the module. PV modules have a life expectancy of 20–30 years, and manufacturers warranty them against power degradation for 25 years. The array is usually the most expensive component of a PV system; it accounts for approximately two-thirds the cost of a grid-connected system. A large choice of PV manufacturers is available.

Inverters PV arrays provide direct current power at a voltage that depends on the configuration of the array. This power is converted to alternating current at the required voltage and number of phases by the inverter. Inverters enable the operation of commonly used equipment such as appliances, computers, office equipment and motors. Current inverter technology provides true sine wave power at a quality often better than that of the serving utility. The locations of both the inverter and the balance of the system equipment are important. Inverters are available that

ASTM Standard E1038, 2005, "Standard Test Method for Determining Resistance of Photovoltaic Modules to Hail by Impact with Propelled Ice Balls ," ASTM International, West Conshohocken, PA, 2005, DOI: 10.1520/E1038-05.

http://www.astm.org/Standards/E1038.htm Go Solar California, a joint effort of the California Energy Commission and the California Public Utilities

Commission, provides consumer information for solar energy systems. See http://www.gosolarcalifornia.org/ equipment/pvmodule.php.

http://www.astm.org/Standards/E1038.htm http://www.gosolarcalifornia.org/equipment/pvmodule.php http://www.gosolarcalifornia.org/equipment/pvmodule.php include most or all of the control systems required for operation, including some metering and data-logging capability. Inverters must provide several operational and safety functions for interconnection with the utility system. The Institute of Electrical and Electronic Engineers, Inc

(IEEE) maintains standard “P929 Recommended Practice for Utility Interface of Photovoltaic

(PV) Systems,‖ which allows manufacturers to write ―Utility-Interactive‖ on the listing label if an inverter meets the requirements of frequency and voltage limits, power quality, and non-islanding inverter testing. Underwriters Laboratory maintains ―UL Standard 1741, Standard for

Static Inverters and Charge Controllers for Use in Photovoltaic Power Systems,” which incorporates the testing required by IEEE 929 and includes design (type) testing and production testing. A large choice of inverter manufacturers is available.

Due to the unique conditions that exist at MLO, the solar resource can exceed the test conditions that the solar panels are tested at, allowing the panels to produce power above the nameplate capacity of the panel. In order to allow the inverter to have enough capacity to accept all of this power, the nameplate rating of the inverter in this location should be sized 20% above the nameplate rating of the PV system.

Operation and Maintenance (O&M) The PV panels come with a 25-year performance warranty. The inverters, which come standard with a five-year or ten-year warranty (extended warranties available), would be expected to last

10-15 years. Over the 25 year expected life of a solar PV system, it can be assumed that the inverter of a will fail at least once. Although the cost of this inverter replacement is included in the O&M cost of system, the cost is spread out evenly over the 25 year analysis period. This will result in smaller than predicted O&M costs for most of the system life, and large costs around year 10 & year 20 for the cost of a replacement inverter. Inverters cost approximately $0.49/W, equating to $70,582 to replace the inverters if the 145 kW system is implemented. For this reason it may be beneficial to keep the O&M budget for the PV system separate from the site

O&M budget. In order to be sure that a system does not require maintenance, system performance should be verified on a vendor provided web site. Wire and rack connections should be checked. For this economic analysis, an annual O&M cost of 0.25% of total installed cost is used based on O&M cost of other fixed-axis grid tied PV systems. For the case of single-axis tracking, an annual O&M cost of 0.35% of total installed cost is used based on existing single-axis tracking systems O&M.

2.3 PV Size and Performance

The PV arrays must be installed in unshaded locations on the ground or on building roofs that have an expected life of at least 25 years. For this assessment, the predicted array performance was found using a PV production calculation tool for grid-connected PV systems created in

NREL’s Integrated Applications Office. The tool used one minute solar data that was collected at the site and supplied to NREL staff by the NOAA staff. The performance data was used to calculate the amount of money that could be saved on utility bills each year. The project economics were based on this analysis and the calculations can be found in Appendix A.

ANSI/IEEE Std 929-1988 IEEE Recommended Practice for Utility Interface of Residential and Intermediate

Photovoltaic (PV) Systems (http://standards.ieee.org/reading/ieee/std_public/description/powergen/929-

1988_desc.html) Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy

Resources: UL 1741 (http://ulstandardsinfonet.ul.com/scopes/1741.html) Go Solar California approves inverters.

http://standards.ieee.org/reading/ieee/std_public/description/powergen/929-1988_desc.html http://standards.ieee.org/reading/ieee/std_public/description/powergen/929-1988_desc.html http://ulstandardsinfonet.ul.com/scopes/1741.html

3 PV Site Locations

The site was visited by NREL staff on July 30th, 2010. The seven separate locations were identified as potential areas in which PV systems could be placed. Four of the areas identified are located within the 4.05 acre site boundary, while the other three areas are located outside the boundary. The areas that are located outside of the site boundary would require an agreement to be made with the Department of Hawaiian Home Lands in order to be implemented. All proposed system locations are shaded in orange in the figures.

Figure 5: Potential System Placement Aerial Site Total

Site Boundary

3.1 Rooftop NDSC

The NDSC building is located centrally on the site, and houses various laboratories, offices, and meeting rooms. This building has a significant amount of equipment that results in high electrical use in the facility. In addition to the laboratory space, there is a rooftop deck where several measurement devices are located. Although some of the rooftop area is used for this equipment deck, there is still a reasonable amount of south facing roof available. The roof is sloped at approximately 18 degrees, which is nearly the optimal tilt for a fixed tilt solar array in

Hawaii. According to measurements that were taken at the site, this location has approximately

1180 square feet of rooftop area available. The roof on the NDSC is the original roof that was installed 1997. The roof is in good condition, and is not slated for replacement at this time. The roof material is tin, and with proper maintenance it should last an additional 25 years. The roof has a great orientation, and it is not expected to be significantly shaded from surrounding structures. The NDSC building has a main electrical panel rated at 400 amps, and a main panel breaker rated at 400 amps. In the current configuration, the panel could accept an additional 80 amps of rated current from a solar array. If more capacity is required, either the main breaker would need to be reduced in size, or the panel would need to be upsized. In order to reduce the size of the main breaker, the existing circuits in the building would need to be assessed to determine if they could be carried by a smaller breaker.

Assuming the usability percentage of the site to be 90%, the available area is 1062 square feet.

Table 5 outlines the PV system possibilities. The system size is limited by the available roof area, and would be able to supply 8% of the site load. The potential system is laid out below in

Figure 6. The cost for this system would be $6.96/W.

Figure 6. Rooftop NDSC: Recommended PV system placement

Table 5. Rooftop NDSC System Options

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

12 22,218 $7,999 $222 $83,213 10.7 $59,944 w/ incentives 12 22,218 $7,999 $222 $29,124 3.8 $114,033

Figure 7. Rooftop NDSC: Roof Image of recommended PV array site

Aspect: Looking West Credit: Lars Lisell, NREL

3.2 Rooftop Keeling

The Keeling building is located across the parking lot from the NDSC building. This building is used to house computing equipment at the site, and also contains work stations for Observatory staff both permanent and temporary. The equipment in the building uses a significant amount of energy. The Keeling building has a relatively small roof, but it could potentially be a very good location in which to place a solar array. Like the NDSC, the roof is sloped at approximately 18 degrees. According to measurements that were taken at the site, this location has approximately

500 square feet of rooftop area available. The roof on the Keeling building is the original roof that was installed on the building in 1957. The roof appeared to be in good condition, but it is unclear whether it will last for an additional 25 years. According to the site staff, building rooftops last a very long time at MLO. A system should not be implemented on the Keeling building unless it is determined that the roof will last an additional 25 years, or if the roof is replaced. The roof has a great orientation, and it is not expected to be significantly shaded from surrounding structures. The Keeling building is connected to the meter on the south side of the

Butler building, which has a main electrical panel rated at 400 amps and a main panel breaker rated at 400 amps. In the current configuration, the panel could accept an additional 80 amps of rated current from a solar array. If more capacity is required, either the main breaker would need to be reduced in size, or the panel would need to be upsized. Assuming the usability percentage of the site to be 90%, the available area is 450 square feet. Table 6 outlines the PV system possibilities. The system size is limited by the available roof area, and would be able to supply

3% of the site load. The potential system is laid out below in Figure 8. Figure 9 shows a ground view of the Keeling building.

Figure 8. Rooftop Keeling: Recommended PV system placement

Table 6. Rooftop Keeling System Options

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

5 9,366 $3,372 $94 $36,620 11.2 $23,728 w/ incentives 5 9,366 $3,372 $94 $12,817 3.9 $47,531

Note: System should only be implemented if the roof is replaced or evaluated

Figure 9. Rooftop Keeling: Roof Image of recommended PV array site

Aspect: Looking Northwest

3.3 South Area In Site Boundary

In the southwest corner of the MLO site, there is a large open area that has been flattened and is currently not being utilized. This area has a couple of minor obstructions in the form of a boardwalk and tower guide wires, but the vast majority of the area is open. This area would make an excellent area in which to implement a PV system. The area beyond the area of this parcel is a very rugged lava field that would require extensive site leveling before it would be suitable for a system. Due to the flattened condition of the parcel, a ballast mounted system could be implemented with little or no site preparation. A ballasted system requires no ground penetrations, and stays in place using weights stacked on the PV mounting racks. The racks sit on top of the ground. The proposed area is inside of the MLO site boundary. The electricity produced by the system could be fed into either the meter on the south side of the Butler building, or into the NDSC meter. The area in the image was found using Google Earth.

Figure 10. South Area In Site Boundary: Recommended PV system placement

Table 7. South Area In Site Boundary System Options

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

145 268,913 $96,809 $2,689 $865,742 9.2 $866,922 w/ incentives 145 268,913 $96,809 $2,689 $303,010 3.2 $1,472,472

Assuming the usability percentage of the site to be 90%, the available area is 30,420 square feet.

Table 7 outlines the PV system possibilities. The system size is limited by the available area, and would be able to supply 100% of the site load. The potential system is laid out in Figure 10.

Figure 11 shows a ground view of the site. The area has very few sources of shading, with the only significant source along the eastern boundary of the potential site from the NCAR high altitude observatory. The shading from the high altitude observatory will have a minimal impact on the production of the system as can be seen below in Figure 12.

Figure 11. South Area In Site Boundary: Ground view of recommended PV array site

Aspect: Looking Southwest

Figure 12. Solar Measurement South Area In Site Boundary

3.4 South Area Lava Barrier

Just south of the site boundary is an area that has been modified to re-direct the flow of lava in the event that Mauna Loa erupts. The area has been flattened, and the rock has been piled up into large berms in the shape of a ―V‖ to re-direct lava around the MLO site. The result of this action has left a nicely leveled area to the north of the berm. This site would work nicely as a place to implement a ballasted mounted PV system. Since this land is outside of the MLO boundary, it may difficult to get approval to utilize the land. The land outside of the MLO boundary is managed by the Department of Hawaiian Home Lands, so they would need to agree to allow MLO to utilize the land for the life of the system (25 yrs). The electricity produced by the system could be fed into either the meter on the south side of the Butler building, or into the

NDSC meter. The area in the image was found using Google Earth.

Figure 13. South Area Lava Barrier: Recommended PV system placement

Table 8. South Area Lava Barrier System Options

System Type

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings ($)

Annual O&M

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

150 276,869 $99,673 $2,769 $889,873 9.2 $894,055 w/ incentives

150 276,869 $99,673 $2,769 $311,455 3.2 $1,429,655

Note: This system was sized to use all available area. The production will exceed the site usage.

Assuming the usability percentage of the site to be 90%, the available area is 31,320 square feet.

Table 8 outlines the PV system possibilities. The system size was limited by the available area and would be able to supply 103% of the site load. It should be noted that the site will likely forfeit any electricity produced above the site load. In the case of this system, 3% of the power generated would likely be forfeited. The potential system is laid out in Figure 13. Figure 14 shows a ground view of the site. The area has very few sources of shading, with the only significant source along the western boundary of the potential site from the berm. The shading from the berm will have a minimal impact on the production of the system as can be seen below in Figure 15.

Figure 14. South Area Lava Barrier: Ground view of recommended PV array site

Aspect: Looking South

Figure 15. Solar Measurement South Area Lava Barrier

3.5 North Area Near AMIBA

Just east of the AMIBA structures is an area that has been flattened, leaving a circular area that would be a good site in which to incorporate a PV system. This area is designated as an emergency helicopter landing pad, but is not frequently used. In order to utilize this area the site would need to leave sufficient area in which to land a helicopter, or designate a new area in which to use as an emergency landing pad. This site would work nicely as a place to implement a ballasted mounted PV system. Since this area is partially outside of the MLO boundary, it may difficult to get approval to utilize the land. The land outside of the MLO boundary is managed by the Department of Hawaiian Home Lands, so they would need to agree to allow MLO to utilize the land for the life of the system (25 yrs). The electricity produced by the system could be fed into either the Ground Winds meter or the GONG meter on the north sides of the site.

The area in the image was measured using Google Earth.

Figure 16. North Area Near AMIBA: Recommended PV system placement

Table 9. North Area Near AMIBA System Options

Type

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings ($)

Annual O&M

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

39 71,604 $25,777 $716 $249,774 10.0 $211,586 w/ incentives

39 71,604 $25,777 $716 $87,421 3.5 $373,938

Assuming the usability percentage of the site to be 90%, the available area is 8,100 square feet.

Table 9 outlines the PV system possibilities. The system size is limited by the electrical load, and would be able to supply 27% of the site load. The potential system is laid out in Figure 16.

Figure 17 shows a ground view of the site. The area has very few sources of shading, and it is anticipated that shading will have a minimal impact on the production of the system.

Figure 17. North Area Near AMIBA: Ground view of recommended PV array site

Aspect: Looking Northeast

3.6 North Area Along Entrance

To the west across the entrance road from the AMIBA structures, is an area that has been leveled, and could potentially be used as an area in which to implement a ballast mounted PV system. This area has a slight slope, but it could still be used as a place for a small PV system.

This location is located on the MLO site, so it would allow the system to be implemented without a land easement or lease. A small option of this area may spill over the property boundary, but the majority of the system falls on the MLO site. If the site would like to move forward with this site, the system layout should be adjusted to fall within the MLO boundary.

The electricity produced by the system could be fed into either the Ground Winds meter or the

GONG meter on the north sides of the site. The area in the image was measured using Google

Earth.

Figure 18. North Area Along Entrance: Recommended PV system placement

Table 10. North Area Along Entrance System Options

Type

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings ($)

Annual O&M

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

30 55,692 $20,049 $557 $197,245 10.1 $161,589 w/ incentives

30 55,692 $20,049 $557 $69,036 3.5 $289,798

Assuming the usability percentage of the site to be 90%, the available area is 6,300 square feet.

Table 10 outlines the PV system possibilities. The system size is limited by available area, and would be able to supply 21% of the meter load. The potential system is laid out in Figure 18.

Figure 19 shows a ground view of the site. The area has a small amount of shading present from the surrounding building, but the shading will have a minimal impact on the production of the system as can be seen below in Figure 20.

Figure 19. North Area Along Entrance: Ground view of recommended PV array site

Aspect: Looking Southwest

Figure 20. Solar Measurement North Area Along Entrance

3.7 North Area Along Summit Access

The north area along the summit access road appears to be the location where the fill was hauled as each building was constructed at the MLO site. This has resulted in a large flat area that could potentially be utilized with a ballast mounted PV system. This area is outside of the MLO boundary, but due to the disturbed state of the area it could potentially be less difficult to get the

Department of the Hawaiian Home Lands to agree to allow the space to be utilized. The electricity produced by the system could be fed into either the Ground Winds meter or the

GONG meter on the north sides of the site. The area in the image was calculated using Google

Earth.

Figure 21. North Area Along Summit Access: Recommended PV system placement

Table 11. North Area Along Summit Access System Options

Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings ($)

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

115 214,812 $77,332 $2,148 $700,842 9.3 $683,240 w/ incentives 115 214,812 $77,332 $2,148 $242,295 3.3 $1,138,788

Assuming the usability percentage of the site to be 90%, the available area is 24,300 square feet.

Table 11 outlines the PV system possibilities. The system size is limited by available area, and would be able to supply 80% of the meter load. The potential system is laid out in Figure 21.

Figure 22 shows a ground view of the site. The area has a small amount of shading present from the surrounding structures, but the shading will have a minimal impact on the production of the system as can be seen below in Figure 23.

Figure 22. North Area Along Summit Access: Ground view of recommended PV array site

Aspect: Looking Northwest

Figure 23. Solar Measurement North Area Along Summit Access

3.8 Summary System that Could Offset MLO Energy

Seven sites in or near the site boundary of MLO were considered, all of which were found suitable for PV systems. The economics of the potential systems were analyzed using an electric rate of $0.36/kWh, as well as incentives that are offered by the State of Hawaii and by the serving utility, Hawaii Electric Light Company (HELCO). Table 12 summarizes the system performance and economics of a potential system that would produce enough power to meet the entire site electrical load. The data is presented both with and without incentives that are available in Hawaii.

Table 12. PV System Performance and Economics by System Type

System Type Potential System Size (kW)

Annual Energy Output (kWh)

Annual Cost Savings

Annual O&M ($)

System Cost ($)

Simple Payback (yrs)

Net Present Value ($)

Fixed-tilt w/o incentives

145 268,913 $96,809 $2,689 $865,742 9.2 $866,922 w/ incentives 145 268,913 $96,809 $2,689 $303,010 3.2 $1,472,472

4 Economics and Performance

4.1 Assumptions and Input Data for Analysis

For this analysis, the following input data were used. The installed cost of the PV system was estimated based on system size. Through tracking of installed costs on all of the projects that the integrated applications office is involved with, a cost curve vs. system size was developed. This cost curve can be seen below in Figure 24. The data was adjusted based on the location cost index for Hawaii.

These prices include the PV array and the balance-of-system components for each system, including the inverter and electrical equipment, and installation. The economics of grid-tied PV depend on incentives, the cost of electricity, and the solar resource, including panel tilt and orientation. For this analysis, the cost of electricity was taken from the site utility bills from 2008-2009. The consumption and rates were averaged to produce a value of $0.36/kWh that was used for the analysis. An electrical escalation rate of 0.2% per year was used. This value is conservative for Hawaii, due to the fact that electricity is generated with diesel generators. This results in a price of electricity that is tied to the price of diesel fuel which traditionally escalates much faster than electricity.

A system DC to AC conversion of 79% was assumed. This includes losses in the inverter, wire losses, PV module losses, and losses due to temperature effects, for example. Figure 24 summarizes average system installation costs for grid-tied PV systems in based on bids that have come through NREL in 2009-2010. A PV production calculation tool developed at NREL was used to calculate energy performance.

Figure 24. Installation cost for grid-tied PV systems 2009-2010

2008 ―RS Means Building Construction Cost Data‖ y = 6.7637x-0.061

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

$7.00

$8.00

$9.00

0.0 500.0 1000.0 1500.0 2000.0 2500.0

In st al le d C o st

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System Size (DC-kW)

PV Cost Data

Series1

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Identifying and leveraging state incentives and grants is an important part of making PV systems cost effective. A private, tax-paying entity that owns PV systems a can qualify for a 30% federal business energy investment tax credit (ITC) and accelerated depreciation on the PV system, which are worth about 15%. The total potential tax benefits to the tax-paying entity are about

45% of the system cost. Alternatively, the tax-paying entity can opt to receive a cash payment of up to 30% of eligible project costs from the U.S. Department of Treasury Section 1603 program once the eligible system is in service. The American Reinvestment and Recovery Act

(ARRA) of 2009 allows for this cash payment in lieu of the ITC. To receive the payment from

Treasury, construction of the property must begin no later than December 31, 2010. Because the federal government does not pay taxes, private ownership of the PV system would be required to capture tax incentives or Section 1603 grant payments

4.2 Incentives and Financing Opportunities

The Database of State Incentives for Renewables and Efficiency (DSIRE) provides a summary of net metering, interconnection, and other incentives available to Hawaii utility customers. The utility for the MLO is Hawaii Electric Light Company (HELCO).

Renewable energy systems, including commercial solar PV, are subject to interconnection rules promulgated at the state level. Interconnection rules were found on the DSIRE Web site that requires that customers send in an application the HELCO to receive approval for a system interconnection prior to system implementation. The utility should be contacted directly to determine what requirements are in place. Hawaii has an aggressive renewable portfolio standard

(RPS). It sets the goal of 40% of total electricity generation from renewable energy by 2030.

This standard does not have a set-aside for solar energy.

Hawaii has a net-metering policy for residential and commercial systems up to 100 kW in capacity that generate electricity using photovoltaics (PV), wind, biomass, hydropower or small hydropower. Net excess generation will be carried over to a customer-generator's next bill, for up to 12 months, as a kilowatt-hour (kWh) credit (DSIRE). In order to determine if a larger system could potentially be entered into a net metering agreement, the utility should be contacted directly. By spreading the electrical production over the four meters located at MLO, all systems implemented can be kept under the 100 kW limit for net metering.

Currently, Hawaii has a very attractive set of incentives. The state offers a 35% tax credit up to

$500,000 for commercial properties. In order to take advantage of these tax credits, the system owner must pay Hawaii state taxes. However, through power purchase agreements, an outside tax-paying entity can capture the credits and then sell the electricity to the site for an agreed upon price. The same thing goes for the 30% tax credit federal incentive. A full list of incentives can be found in Appendix B.

There are several options for financing a solar PV system. A potential alternative financing option is the third-party ownership, power-purchase agreement. The agreement works by having a solar contractor install, finance, and operate the system, while the site purchases the electricity generated by the system. The system is financed by the solar contractor, the payments are paid

This program was codified in Section 1603 of the American Recovery and Reinvestment Act of 2009.

http://www.dsireusa.org/incentives/index.cfm?re=1&ee=1&spv=0&st=0&srp=1&state=WV.

http://www.dsireusa.org/incentives/index.cfm?re=1&ee=1&spv=0&st=0&srp=1&state=WV by the electricity, and the RECs that are sold to the utility. This way, the economics of the system can be improved as the solar contractor is able to capture the tax credits. In this configuration, the land that the solar system is on would need to be leased to the third party owner of the system for the duration of the contract.

5 Conclusions and Recommendations

The sites considered in this report are all feasible areas in which to implement solar PV system systems.

It is recommended that the party ultimately responsible for facilitating the implementation of a

PV system contact HELCO ahead of time and get the paperwork started on interconnection and net-metering agreements to identify if there will be any barriers before the system construction…