American Institute of Physics Journal of Renewable and Sustainable Energy
Volume 4 Issue 4 (16 July 2012)

Technology and Information Management for Low-Carbon Building 
by Frank Dalene

Peer review of the following article.  

INTRODUCTION

All buildings worldwide combined use 40% of the global energy and are responsible for one third of global energy-related greenhouse gas (GHG) emissions.1 The majority of GHG emissions of buildings come from fossil fuel energy in several stages of the life cycle. The embodied or embedded GHG emissions comes from the processing of raw materials, manufacturing of products, transportation of materials and products in the supply chain and distribution system until it arrives at the jobsite. It includes labor and construction activities required for assembling, erecting buildings and how demolition and waste is handled. When construction is complete the operations stage begins. GHG emissions from operations come from heating, cooling, and electrical uses. Other GHG emissions though not being accounted for now, come from transporting occupants to and from the building, how waste is handled and the maintenance of the building.1,280%–90% GHG emissions of buildings are emitted in the operations stage during the life-span of the building; 10%–20% GHG emissions are from the embodied energy and other carbon emissions related to the construction stage.1 The greatest potential for low-hanging fruit in cost effective, quick, deep GHG reduction and mitigation is found in the construction industry.2 With currently available and proven technologies, reductions in energy consumption on both new and existing buildings are estimated to achieve 30%–80%. When the costs of implementing the energy reduction technologies are offset by energy savings, there is potential for a net profit over the life span of the building.1

Much has been done to study energy reductions, define GHG emissions, and develop metrics and protocols for measuring and reporting carbon emissions. This paper addresses the “How”; How energy consumption of a house was reduced almost 70%. How CO2 emission was reduced 44%. How embodied GHG emissions of the house were measured and certified carbon neutral. How U.S. Green Building Council (USGBC) LEED for Homes platinum certification was attained. How actual savings from energy reductions are able to pay back up-front cost of implementing technologies and begin earning a profit in fifteen years. How reducing electric consumption has the greatest impact in reducing energy costs and reducing CO2 emissions compared to propane and #2 fuel oil. How earning LEED points provided a surprise benefit of mitigating overall GHG emissions by earning carbon offsets. How these achievements and findings were accomplished in the reconstruction of one home.

Hamptons Green Alliance 

In March 2008, the Hamptons Green Alliance (HGA) was formed. It is a not-for-profit organization whose founding members are one builder and several trade contractors in residential construction. Through collaboration, the HGA finds practical solutions for green building technologies, implements these technologies, and educates the consumer. The HGA is believed to be the first of its kind organization in the country and received national recognition immediately.3

HGA House 

The HGA members began to understand, through collaboration, people plying the trades who possess practical knowledge of green technologies could achieve higher goals than if each attempted it individually. The HGA decided to test its ability by submitting a request to the architectural community seeking an opportunity to build a ultra-green luxury home. The HGA made the commitment to build the project at cost and solicit contributions from vendors. An architect came forward with a client that wished to reconstruct a house after a fire destroyed a large portion of the structure. A total gut renovation was required that would allow incorporating many new green technologies. An agreement between owner and builder, Telemark Inc. was executed to reconstruct the house, it became known as the HGA house.4 Figure 1 shows the existing house before work commenced and Figure 2 shows the HGA house completed.

Figure

Fig 1.

Before—existing house.


Figure

Fig 2.

After—current house.


THE GOALS 

Net-Zero Energy 

A building that produces equal or more energy than it consumes, preferably through on site, renewable sources is Net-Zero Energy. Fossil fuel based energy production is minimized, generally using heat sources from solar thermal and geothermal energy production systems together with renewable photovoltaic systems and wind generators. The building usually remains attached to the electric grid with a net-meter installed to measure the difference between electrical energy produced and electrical energy consumed over a period of time.5 Some buildings are off grid independent of publicly available energy sources.

Embodied Carbon Neutral 

Embodied carbon or embodied energy of construction activities, subcontractors, labor, transportation to the job site and materials are measured and calculated based on currently available data bases and carbon accounting protocols. A Phase I carbon audit was performed to determine GHG emissions associated with the construction stage of the building. The total GHG emissions were offset by carbon mitigation programs and certified carbon offsets were purchased. When the total GHG emissions are offset 100% by carbon mitigation offsets and purchased carbon offsets, carbon neutral status is achieved. It must be noted that there were no established metrics or protocols to measure and calculate embodied GHG emissions of the construction stage of a building at the time a commitment was made. A methodology was developed based on accepted protocols including carbon accounting of businesses, life cycle assessment (LCA), embodied carbon accounting of materials, offset mitigation, and offset projects. The firm Verus Carbon Neutral6 was retained to assist in measuring and calculating GHG emissions.

LEED Platinum Certification 

“LEED, or Leadership in Energy and Environmental Design, is an internationally recognized green building certification system. Developed by the USGBC in March 2000, LEED provides building owners and operators with a framework for identifying and implementing practical and measurable green building design, construction, operations, and maintenance solutions.”7 LEED for Homes was released in 2007. There are four certification levels; Certified, silver, gold, and platinum. LEED for Homes rating system is based on points earned by meeting criteria in eight categories. A LEED for Homes score of 90 points or higher earns the platinum rating. To be considered green a house needs to be “right-sized.” The HGA house is too large therefore it needed to score 100 points or higher to attain a platinum rating.

CONSTRUCTION APPROACHES 

Integrated Design 

The traditional approach to design and construction process is “Design-Bid-Build.” The design team, generally an architectural firm, designs a building and defines it by drawings and specifications (construction documents). Some members of the design team may have construction experience but generally are not experts in construction. The design team generally creates the construction documents in a vacuum, with little input from construction experts. Engineers sometimes assist the design team on technical engineering issues. The construction documents are sent to several general contractors (GC) or construction managers (CM), who review the construction documents, interpret the content and provide the cost estimate associated with construction known as a bid. The GC and CM are held to the standard of a reasonable interpretation of the construction documents, not the highest and best interpretation. The bid process generally occurs with occasional questions of the design team for clarification on some unknown perhaps missing information. A GC or CM is selected and awarded the bid to begin construction. The process repeats itself when subcontractors bid their work. This fragmented approach many times causes miscommunication, misinterpretations, and confusion concerning the intent of the design team. It may cause adversarial relationships that inhibit further communication and collaboration. Many times miscommunication, misinformation, and misinterpretation cause additional cost and time to be added to the project as change orders or cost overruns. This is not the most efficient way to share and manage information. When integrating new green technologies, communication and collaboration needs to dramatically increase in order to achieve successful outcomes.

The American Institute of Architects (AIA) developed a concept of integrated design known as integrated project delivery (IPD).8 The LEED for Homes rating system awards points for implementing elements of integrated design. IPD brings the design team, owner, contractor, and trade contractors together during early stages of design phase to foster collaboration, teamwork, information sharing, shared risks, and shared rewards. Contributions early on in design by construction experts in each field allows for more efficient integration of new technologies, some of which require input from several trades at the same time. When all parties are in one room, information is managed more efficiently and effectively.

The cost benefit of coordinating trades while they are sitting at the table can be enormous compared to addressing issues in the field while men are standing around and work is stopped. The working environment, teamwork, collaboration is greatly improved since the causes of adversarial relationships are mostly eliminated. When collaboration is successful all parties contribute to the end result. This fosters a sense of ownership during the design process for all parties, making it more difficult to criticize or cast blame on a single person or entity. Differences in interpretation of contract documents are addressed in the design phase out in the open, around a table, not on the jobsite. When construction commences all focus is on building and little time is wasted on solving design issues. Information is managed more efficiently during design and during construction.

Systems integrated home 

The term “Systems Integrated Home” (SIH) was developed by the HGA based on the intensified complex interdependence of various building system required to meet set goals. SIH is the integration of multiple means and methods of design and construction to achieve maximum energy efficiencies. When the goal was set for net-zero energy it was not as simple as slapping photovoltaic panels on the roof. The architect threw the team a curve ball by deciding crystalline photo voltaic (PV) panels were not aesthetically pleasing to him. Instead he specified a building integrated photovoltaic (BIP) system known as thin-film. Electric output of PV varies significantly between manufacturers. Thin-film’s electric output is significantly less than Crystalline PV panel; the rule of thumb is that thin-film produces 50% less electricity. This caused the team to study reducing electrical consumption on a systems basis. Heating and cooling of the house is performed by a water source geothermal heat pump. The geothermal system uses a significant amount of electricity. The first course of action was to take the load off heating and cooling by super insulating the building envelope, installing energy efficient windows, doors and eliminating air infiltration. Installation of a variable speed well pump helped to reduce the amount of electricity to pump the water through the geothermal system.

An evacuated tube solar thermal system was installed to generate energy for domestic hot water production. It was thought that dumping excess hot water into the hot water coils of the air handlers in the winter would reduce the load further on the geothermal system. The lighting load was studied and it was found LED lighting produces the same light output but reduced electric consumption by 85% from incandescent lights.9 Fifty two LED recessed lights were installed. An integrated home energy monitoring system and other smart home technologies were installed to monitor energy usage and automate several systems.

Results Of Integrated Design And Systems Integrated Home 

Residential Energy Services Network (RESNET) developed a home energy rating system (HERS) to measure the energy efficiency by a series of tests and inputs from plan review. Obtaining a HERS Index is a prerequisite for the LEED for Homes rating system. The HERS Index is based off a standard new home built according to the 2006 International Energy Conservation Code. The HERS Index 100 equals the energy efficiency of that home. For each whole number less, it equals the same amount percentage of energy savings. For example: a HERS Index 90 is 10 less than 100, energy savings is 10% less than the 2006 Standard New Home.10 The HGA house earned a HERS Index 25, meaning a 75% energy reduction from the 2006 Standard New Home is projected.

ATTAINING THE GOALS 

LEED For Homes Platinum Certification 

Points were awarded for certain criteria met within each group below. The sum of the points equals the LEED score that determines the LEED for Homes rating. In the list below the first number is the number of points earned, the second number is the maximum number of points in each group.

·        Innovation and design process: 9/11

·        Location and linkages: 6/10

·        Sustainable sites: 10/22

·        Water efficiency: 13/15

·        Energy and atmosphere: 33/38

·        Materials and resources: 10/16

·        Indoor environmental quality: 20/21

·        Awareness and education: 3/3

The total number of points earned was 104. The minimum number of points to attain LEED for Homes platinum certification is 100. The HGA house was then certified LEED for Homes platinum.

Embodied Carbon Neutral 

Life cycle analysis (LCA) is the accounting of GHG emissions during the products entire life cycle, from gathering of raw materials to disposal at the end of the product’s life. Cradle-to-Gate LCA is the accounting for GHG emissions from the beginning of a products life until it reaches the consumer. Determining LCA data on building materials, products and buildings are in the infancy stage with only a few private companies that voluntarily perform LCA on their products. LCA standards created by the World Resources Institute remain in draft form and little information is available.11 Accounting for embodied GHG emissions in buildings is fragmented and contains data on embodied GHG emissions of materials. The common carbon metric measures only the energy used and GHG emissions of the operations stage of buildings.2 It is understandable to begin measuring GHG emissions at the operation stage since 80%–90% GHG emissions of a building occur then. The goal was to measure the GHG emissions embodied in the construction stage of the HGA house. A methodology was developed that may be the beginning of a framework to measure embodied GHG emissions in buildings.

Since there is little LCA data on manufactured products used in construction, the focus was on the embodied GHG emissions of materials incorporated in the products and materials that were used directly in construction. For example, there is no LCA data of a GE refrigerator, however, an estimate can be made of materials that are used in a GE refrigerator. Some data on embodied GHG emissions of materials exist. Some data is based on averages and others disclaim accuracy. While embodied GHG emissions of a house cannot be accurately measured at this time, estimates of GHG emissions are able to be made as well as the development of a framework. As LCA data becomes more standardized and readily available, accuracy will improve. Other well accepted protocols were used for measurements of GHG emissions in construction.12

This level of calculation is defined as “Phase I.” This includes the embodied GHG emissions of materials used, transportation to the job site, energy used in construction activities such as electric and heat, subcontractor Scope I, II, and III GHG emissions attributed to this project, demolition, waste disposal, and recycling. Since labor was subcontracted the measurement includes labor in the construction of the HGA house.

The members of the HGA committed to certify their businesses carbon neutral. The first reason to do this was to lead by example and walk-the-talk by certifying their business green. The second reason is a carbon neutral contractor will not have an emission impact on any project he works on for a period of one year. Scope I, II, and III carbon audits were performed by Verus Carbon Neutral. The HGA members purchased carbon offsets from Verus that were retired from the Chicago climate exchange (CCX) Registry to offset 100% GHG emissions and each member was certified carbon neutral.

For the remainder of the subcontractors, a pro-rata sum of their Scope I, II, and III GHG emissions were accounted for on this project. The pro-rata calculation was based on the percentage of their contract in relation to gross revenues. For example: If a subcontractor’s contract on the HGA house was $10,000 and gross revenues for the year was $100,000, then 10% of GHG emissions measured was attributed to the HGA house.

Carbon offsets were earned for GHG mitigation performed as a result of landfill avoidance. The EPA maintains an online calculation of carbon offsets in the waste reduction model (WARM).13 Earning LEED points for recycling materials provided a surprise benefit by also providing offsets to mitigate the cost of purchasing carbon offsets. Waste on the HGA house was significant since there was a fire and significant amount of deconstruction was required. Quantities of recycled waste documented during the LEED process was calculated providing 107 mt CO2e offset. The GHG emission values are summed and the EPA WARM offsets subtracted to find the total Phase I embodied GHG emissions is 957.43 mt. Table 1 identifies the GHG emission in each line item.

958 mt CO2e Offsets were purchased from Verus Carbon Neutral, retired from the CCX Registry and the HGA house certified Phase I carbon neutral.

Net-Zero Energy 

To claim a building is net-zero energy, the building needs to operate for one year while energy usage is monitored. If the building produces equal to or more energy than it consumes, the building is net-zero energy. We did not reach this goal. There are many reasons we believe we did not which we will address.

The early designs included a building integrated maglev, vertical access wind turbine (VAWT). The manufacturer claimed a maglev VAWT could be integrated into the house since no vibrations were generated to transmit through the building and the vanes of the turbine were designed to capture the additional wind energy deflecting up the roof slope. A wind anemometer was installed on the site and found the average wind speed to be nine miles per hour. The manufacturer could not substantiate electrical output at the average wind speed recorded. The team researched other manufacturers and made a recommendation to the owner to install a VAWT on a pole. The cost of the installed VAWT together with electric output data supplied by the manufacturer could not substantiate a reasonable pay-back period. The owner decided against moving forward with the VAWT. The team reluctantly concurred based on the premise that renewable energy technologies need to be reasonably cost justified. We are aware of developing technologies that create more efficient energy production of VAWT but they were not available at the time of this project. Integrating efficient wind energy generators are a key ingredient in this area since wind is present when the sun does not shine, sometimes in great quantities.

Incorporating the best designs, best engineering, and best green buildings technologies energy reduction relies on how efficiently building occupants use energy. Owners of green buildings are expected to make lifestyle changes through education and awareness. Increased awareness is reinforced with visual cues from energy monitoring technologies similar to Prius instruments giving feedback on gas mileage efficiencies, known as the “Prius Effect.” Raised consciousness of energy usage and emphasis on energy savings is expected to influence lifestyle changes of the occupants. Certain changes can be forced upon the occupants such as restricting flow from water faucets and using less water to flush a toilet. We are not able to control many energy uses. We installed technologies to automate energy usage such as automatically turning off lights, setting back heat or air conditioning when the alarm is set and other automated programs. How these systems are ultimately used will have an impact on the overall energy usage. Based on observations from online energy monitoring, lifestyle changes can be improved. This contributed to more energy use and is an area where possible energy reductions may occur in the future.

Lessons Learned 

We are beginning to believe a solar thermal system designed primarily to produce domestic hot water should not have a dual use. If solar thermal is to be used to supplement heating, a segregated system should be designed instead. This is partially due to conflicting demands on the system that is difficult to control. We believe a split system may have been a better option. We continue to work on solving this problem.

Emphasis to maximize electrical production from crystalline PV systems in lieu of thin-film for aesthetic choices need to be practiced to achieve maximum results to attain a net-zero goal. Technologies in building integrated photovoltaics need to improve electrical output to the extent there is little difference in electrical production compared to PV panel if they are to be considered as a design option.

Relying on energy savings from voluntary lifestyle changes in homes is difficult to realize. Renewable energy systems need to be over designed so energy usages of occupants are not impacting overall energy reduction goals.

Based on thirty years performing construction services under Design-Bid-Build, we believe it would be extremely difficult to integrate the new technologies and attain the results seen in the HGA house without using the IPD approach. The communication, coordination, and teamwork observed during design phase contributed significantly to construction efficiencies, cost and quality. Significantly fewer misunderstandings and claims for additional costs needed to be addressed during construction. This contributed to a more pleasurable working environment that increased productivity and a sense of pride and ownership by all participants. As a builder, we enjoyed the approach immensely. We hope our industry transitions from Design-Bid-Build to IPD.

ANALYSIS 

Energy Use Analysis 

This project is unique since there is energy data three years prior to the fire and re-construction of the house. Engineering is sufficiently advanced to accurately calculate and project energy efficiencies, production and consumption. Weather is a variable in renewable energy production and consumption as it relates to renewable energy, heating, and cooling. Weather cannot be controlled but the weather’s impact on energy consumption can be controlled by reducing energy loss in winter and solar heat gain in summer. How occupants operate a building is the variable in energy consumption the designers, engineers, and constructors cannot control. In commercial buildings, the variable can be entrusted to the building manager’s hands instead of occupants. In homes, it is very personal and energy use habits amongst family members can vary greatly. Certain family members conserve energy and others can be very wasteful. Sometimes maintaining peace between family members has priority over energy consumption behavior. It is difficult to determine what extent family behavior contributes to energy consumption however it is a factor.

The existing house was 3,780 square feet; it increased in size to 4,770 square feet. The increase in size is 26.2%. Three types of energy were used, electricity, propane, and #2 fuel oil. The owner provided us with three years of energy invoices. The usage and cost was averaged for yearly use comparisons. The current local price for energy cost on August 10, 2011 was used to calculate the current energy costs. The existing energy data was increased by the same 26.2% increase in the size of house. The average yearly cost of energy adjusted for increase in size and based on current costs of energy is $10,639.23. The breakdown of the calculation is seen in Table 2.

The existing house used propane and #2 fuel oil for heating, propane for cooking and clothes drying, and electricity for cooling. The current house uses electric for heating and cooling performed by a geothermal system, propane for cooking and clothes drying. Energy type use differs from existing to current house. Since most energy in the current house is electricity the conversion of other fuel types into the equivalent energy content of electricity in kWh is necessary for comparison. The energy unit, British Thermal Unit (BTU) was used because of its common use in design and construction. The energy conversion calculations in Table 3 are based on methodologies developed by Dr. Dennis Buffington at Penn State, College of Agricultural Sciences.14 The assumptions used for the conversions are also used in this methodology.15

The efficiency of the combustion equipment is calculated in the “Energy Content BTU/Unit” column in Table 4 by dividing the energy content by efficiency (for propane: 91,600/0.85 = 107,765 BTU/gal). The energy content in equivalent kWh in the existing house is increased by the same 26.2% of the increase in size of the completed house. The adjusted equivalent energy content based on three year actual energy data of the existing house is 97,890 kWh. The current average cost per kWh is $.20; it is multiplied to 97,890 kWh to equal $19 578. This is the equivalent cost of energy if only electricity were used. Table 4 identifies the details of the calculation.

The current house uses propane for cooking and drying clothes. Nine months of propane use was given by the owner. We averaged monthly use and projected it to be 187 gallons for the year. Propane use is then converted to equivalent kWh as we did in Table 4. Table 5 details the calculation.

Table 6 sums the actual energy of the completed house used over a one year period of time. We received electric invoices for one year after the project was completed. The propane energy is converted to equivalent kWh. The cost of propane is the actual cost of propane projected for the year. 29,933 equivalent kWh of energy was used at an actual cost of $5203.92.

The following conclusions are made from the data in the above tables:

·        67,957   Less equivalent kWh used: (97,890 equiv. existing—29,933 kWh equiv. current)

·        $14,374.08  Less equivalent cost: ($19,578 existing cost—$5,203.92 current actual cost)

·        69.42%   Less energy usage: (97,890 equiv. kWh compared to 29,933 equiv. kWh)

·        $5,435.31  Adjusted annual energy savings: ($10,639.23 existing—$5,203.92 current house)

·        51.09%  Adjusted annual energy savings: ($10,639.23 existing to $5,203.92 current house)

The HGA house was rated with a HERS Index of 25 which indicates a projected 75% energy reduction from the HERS Standard Home. The actual energy reduction is 69.42%. It is interesting to note the projected energy reduction is very close to the actual energy reduction. We do not know if this supports the HERS indexing system methodology or this is purely coincidental. Further analysis of the existing home in comparison to the HERS Standard Home will need to be done to establish an equivalent baseline for comparison. No conclusion can be made in the scope of this paper.

The cost of energy reducing technologies used in the HGA house amounted to $85,240 inclusive of current incentives. The adjusted energy cost savings from the conclusions above is $5,435.31. The pay-back period for the energy reducing technologies used is 15.7 years if the energy savings average continues on the same track as the first year and energy costs remain the same. If we use 30 years (30 year mortgage) for the life span of a home (we know houses last longer) then energy savings begin making a net profit after 15 years or within half the life span of a house. The premise made in the second paragraph of this paper is upheld: “With currently available and proven technologies, reductions in energy consumption on both new and existing buildings are estimated to achieve 30%–80%. When the costs of implementing the energy reduction technologies are offset by energy savings, there is potential for a net profit over the life span of the building.”

The cost of energy reducing technologies used without tax rebates and Long Island Power Authority rebates is $189,244. The pay-back period would have been 35 years if incentives were not available. It is more difficult to justify a 35 year pay-back period than 15 years and supports the importance of continuing with incentive programs.

CO2 Emissions Analysis 

The CO2 data value, kg CO2/unit for electric, propane, #2 fuel oil and the methodology to measure GHG emissions of the operations stage of a building as seen in Table 7 originates from the common carbon metric.2 This is a draft protocol to calculate GHG emissions in the operational phase of buildings. The data for electricity is given by country for CO2 emissions only. For that reason CO2e, carbon equivalent (six greenhouse gases) is not used. To be consistent, only CO2 values were used for electric, propane, and #2 fuel oil. The emission source of the existing house is the quantity of energy used adjusted for the increase in size of the house. The source of CO2 values in the common carbon metric comes from the International Energy Agency (IEA), CO2 emissions from fuel combustion, 2008.2

11.36 Metric Tonnes CO2 reduction from fossil fuel based energy in first year (The existing house CO2 emissions in metric tonne minus the current house CO2 emissions in metric tonne equal 11.36 mt). The calculation is Scope I and II CO2 emissions for the operational stage of the house. Scope I emissions are direct combustion of fuels and Scope II is indirect combustion from offsite emissions such as electric production. Table 7 identifies the details of the calculations.

43.82% reduction of fossil fuel based energy CO2 emissions in first year. It is interesting to note energy reduction was 69.42% while CO2 emission reduction is only 43.82%. This is due to significantly higher CO2 emissions per BTU in electricity from the grid than other fuel types. The current house uses proportionately more electricity compared to other fuel types than was used in the existing house. The current house actually uses 6982 kWh more electricity, 1359 gallons less propane, and 627 gallons less #2 fuel oil. A higher CO2 emission in electricity per BTU results in less percentage reduction in CO2emissions when compared to the percentage of energy reduction. The greatest impact in reducing CO2 emissions in building operations is achieved by reducing electricity usage from the grid. This is better understood when CO2 emissions per BTU of different fuel types are compared with one another as illustrated in Table 8 and Figure 3.

Figure

Fig 3.

CO2 emissions/MM BTU.

The cost per BTU for electricity is approximately two times that of propane and #2 fuel oil. An additional benefit of focusing on grid electricity for CO2 emissions is that it will also have the greatest impact on energy cost reduction. Or if one prefers, it can also be said, focusing on electricity for cost reductions there is an added benefit of attaining greater CO2 emission reductions. This is also better understood when cost per BTU of different fuel types are compared with one another as illustrated in Table 9 and Figure 4.

Figure

Fig 4.

COST/MM BTU.

CONCLUSION 

To borrow from the old adage: “There’s no accounting for taste.” Taste in architecture varies greatly from one individual to another and changes over time. We consistently resist change. As new technologies are integrated into architecture, there is resistance to accept them. To attain transformational change of our energy from fossil fuel to renewable energy, there needs to be a paradigm change. Taste is based on past experiences, aesthetic appeal is learned. We should learn to base aesthetic appeal on attaining energy independence, freedom from fossil fuels and reduction in GHG emissions. Then we will be able to accept change more readily.

This study shows that reducing electricity from the grid has the greatest impact on both reducing energy cost and reducing CO2 emissions in the operation of buildings. Whenever renewable energy is contemplated priority should be on reducing electrical usage from the grid compared to other energy types. This will have the greatest impact over the life span of a building. When the cost of implementing energy reduction technologies are offset by energy savings they start earning a net profit within 15 years, well before the expected life span of a house. Applying lessons learned from this project can greatly improve the pay-back period making the additional up-front cost to implement technologies easier to accept.

Landfill avoidance through recycling required to earn points for LEED platinum had a surprise benefit of creating 107 mt CO2e offset when calculating embodied GHG emissions of the house. Having an awareness of GHG emissions contributed to all HGA companies becoming carbon neutral. We are certified carbon neutral for two years and we made a commitment to continue being carbon neutral. Our new found awareness of GHG emissions helped us see an opportunity by recycling sawdust from the millwork shop into wood pellets to be used to heat the shop and our homes. This will generate carbon mitigation offsets to further reduce our GHG emissions next year. If this proves successful, we may expand the operation by grinding our clean wood waste on the jobsite to make wood pellets. This illustrates how raising awareness on emissions leads to other ways of reducing GHG emissions.

APPENDIX: LIST OF TECHNOLOGIES IN HGA HOUSE 

New Technologies Integrated 

1.      LED lighting

a.      CREE LR-6 Recessed Lights. Using only 12.5 W of input power to deliver 1000 lumens, the LR6-DR1000 has unmatched fixture efficacy of up to 84 lumens per watt. It consumes half the energy of a typical CFL down light while delivering the same light output

2.      Micro inverters for solar thin film PV

3.      Building integrated photovoltaics (BIPV)

4.      Solar thermal winter mode heat dump

5.      Whole house monitoring system—The energy detective (TED), “The Prius effect”

Technologies Used 

1.      Architect’s design

a.      Passive features—increased soffits to maximize solar gain in winter and maximize shading in summer

b.      South facing orientation

2.      High efficiency windows

a.      Green Mountain Windows (U-Value: .26–.29)

3.      Spray foam insulation

a.      Closed cell in all 2 × 6 roof rafters, exterior 2 × 4 walls, headers (R-Value/Inch = 6)

b.      Open cell in exterior 2 × 6 walls (R-Value/Inch = 3.8)

c.      24″ spacing between roof rafters; floor joists to maximize insulation; minimize material and thermal transfer as per LEED

d.      Low expansion foam around windows; doors

4.      HERS rating

a.      Checks for air leakage in ducts and the house

b.      All ductwork is to be in conditioned space

c.      All ductwork is to be sealed

d.      Caulk all joints to decrease air infiltration

5.      Low flow fixtures

a.      Kohler dual flush toilets

b.      1.5 gpm fixtures

6.      Rainwater harvesting tank

a.      Collect rainwater from gutters used for irrigation

7.      LED lighting

a.      CREE 6″ LED recessed lights, using 85% less energy than incandescent, 50% less energy than CFL

8.      Smart house technology

a.      LED screens on first and second floor to monitor house readings

b.      Program certain systems to turn on and off with the alarm

c.      Pre wire all rooms and electronics with CAT 5 for future technologies

d.      Home energy monitoring

9.      High efficiency wood burning fireplace

a.      Clean and efficient burning to minimize heat loss

b.      Produces 50 000 BTU/h.

10.   Energy Star appliances and electrical systems

11.   Geothermal system

a.      Open loop

b.      Two stage, variable speed

c.      Insulate and seal all ductwork with 181 tape required by HERS rater

12.   Solar thin film

a.      South facing

13.   Solar panels

a.      East and West facing roof

b.      Maximize LIPA rebates

14.   Solar thermal

a.      Summer mode

                                                    i.     Priority—domestic hot water

                                                   ii.     Heat Dump—pool heat

                                                  iii.     Mixes with the return water from pool

b.      Winter mode

                                                    i.     Priority—domestic hot water

                                                   ii.     Heat dump—geothermal system—excess hot water goes to hot water heating coils, ductwork distributes heat as primary heat source for house

Tables

Table I. Embodied GHG emissions.

GHG emission source

Metric tonne CO2e

Materials

14.91

Material deliveries

5.61

Electric usage

4.41

Propane usage

9.50

Subcontractors

1030.00

WARM offsets

(107.00)

Total

957.43

Table II. Existing house energy used.

Existing House 3 Year Average Energy Usage

Energy Type

Aver. Usage/Yr

Aver. Cost/Yr

Current Unit Cost

Electricity - kWh

13,506.00

$2,971.32

$2,701.20

Propane - Gallons

1,224.66

$3,318.83

$3,661.73

#2 Fuel Oil - Gallons

497.00

$1,481.06

$2,067.52

Total Average Yearly Energy Usage

$7,771.21

$8,430.45

House Size Increase 26.2%

$2,036.06

$2,208.78

Usage Adj. for Increase in Size

$9,807.27

$10,639.23

 

Table III. Assumptions used converting energy units.

Assumptions Used Converting Energy Units

Fuel

Energy Content

Efficiency

Electricity

3,412 BTU/kWh

100%

Propane

91,600BTU/gal

85%

#2 Fuel Oil

139,400 BTU/ gal

80%

Table IV. Energy analysis of existing house.

Energy Analysis of Existing House Energy Usage Adjusted for 26.2% Increase in Size of House

Energy Content Conversion to BTU; Conversion to Equiv. kWh; Average Cost/ kWh −$0.20

Energy Type

3 Yr Average Per Energy Type

Energy Content BTU/Unit

Total Energy Content BTU

Conversion to Equiv. kWh

26.2% Increase in Size - kWh

Equiv. Cost $.20/ KWH

Note: Size of House Increased from 3780 sqft to 4770 sqft. 26.2% Increase in Size.

Electric- kWh/yr

13,506.00

3,412

46,082,472

13,506

17,045

$3,408.91

Propane - gal/yr

1,224.66

107,765

131,975,125

38,680

48,814

$9,762.76

#2 FuelOil-gal/yr

497.00

174,250

86,602,250

25,382

32,032

$6,406.33

TOTAL

77,567

97,890

$19,578.00

 

Table V. Propane energy conversion to kWh.

Propane Energy Content Conversion to kWh

Gallons Propane

Energy Content BTU/gal

Energy Content E BTU

Energy Content BTU/kWh

Conversion to Equiv. kWh

187

107,765

20,152,000

3,412

5,906

Table VI. Total current energy usage.

HGA House Current Electric Net Usage - Total Energy Usage

Date

kWh Used

Total Charges

Days/Inv.

kWh/Day

Cost/ Day

Cost/ kWh

6/16/10-7/30/10

1,869

$398.16

44

42.48

$9.05

$0.21

7/30/10-9/7/10

2,001

$420.21

39

51.31

$10.77

$0.21

9/7/10-10/7/10

870

$183.29

30

29.00

$6.11

$0.21

10/7/10-11/4/10

1,083

$213.74

28

38.68

$7.63

$0.20

11/4/10-12/7/10

2,753

$533.43

33

83.42

$16.16

$0.19

12/7/10-1/6/11

4,132

$788.38

30

137.73

$26.28

$0.19

1/6/11-2/11/11

5,306

$974.64

36

147.39

$27.07

$0.18

2/11/11-4/7/11

4,529

$839.57

55

82.35

$15.26

$0.19

4/7/11-5/12/11

887

$170.55

35

25.34

$4.87

$0.19

5/12/11-6/7/11

161

$37.68

26

6.19

$1.45

$0.23

6/7/11-6/16/11

436

$88.27

9

48.44

$9.81

$0.20

Total Electricity

24,027

$4,647.92

365

62.94

$12.23

$0.20

Propane Conver.

5,906

$556.00

Average

Average

Average

Total Electric Equiv

29,933

$5,203.92

 

Table VII. CO2 emissions reduced.

Metric Tonne CO2 Emissions Reduced

Existing House Energy Adjusted for Increase In Size

Current House Energy

Emission Source

Exist. House Adj.

kg CO2/unit

Existing CO2mt

Current House

kg CO2/ unit

Current CO2 mt

Electricity-kWh

17,045

0.55866

9.52

24,027

0.55866

13.42

Propane-gal

1,546

6.09451

9.42

187

6.09451

1.14

#2 Fuel Oil-gal

627

11.12911

6.98

0

11.12911

0.00

Total

25.92

14.56

Note:

11.36

Metric Tonne CO2 Reduced

43.82%

Less CO2 Emissions

Table VIII. CO2 emissions/MM BTU.

CO2 Emissions Per M ill ion BTU

Energy Type

BTU/Unit

kg CO2/ unit

kg CO2/ M M BTU

%CO2< Electric

Note: Propane has 65.46% less CO2 emissions per BTU than electricity. #2 Fuel oil has 60.99% less CO2 emissions per BTU than electricity.

Electric-kWh

3,412

0.55866

163.73

Propane-gal

107,765

6.09451

56.55

65.46%

#2 Fuel Oil-gal

174,250

11.12911

63.87

60.99%

 

Table IX. Cost/MM BTU.

Cost Per Million BTU

Energy Type

BTU/Unit

Cost/Unit

Cost/MM BTU

%Cost< Electric

Note: All unit costs for energy type are local costs in the Hamptons, Long Island, New York on August 10, 2011. Propane cost 52.67% less per BTU than electricity. #2 Fuel oil cost 59.27% less per BTU than electricity.

Electric - kWh

3,412

$0.20

$58.62

Propane - gal

107,765

$2.99

$27.75

52.67%

#2 Fuel Oil - gal

174,250

$4.16

$23.87

59.27%

 

References (15)

1.      UNEP, UNEP SBCI Sustainable Buildings and Climate Change, BUILDINGS AND CLIMATE CHANGE—Summary for Decision Makers (UNEP DTIE Sustainable Consumption & Production Branch, UNEP, 2009). 

2.      UNEP, UNEP SBCI Sustainable Buildings and Climate Change, World Resources Institute, COMMON CARBON METRIC—Protocol for Measuring Energy Use and Reporting Greenhouse Gas Emissions from Building Operations, UNEP (2010).

3.      S. L. Miller , Hamptons Builder Forms Local Green Alliance. Custom Home Magazine, March 20, 2008. 

4.      S. L. Miller , Ultra-Green Demonstration Home Rises in the Hamptons, Custom Home Magazine, September 3, 2009. 

5.      P. Torcellini, S. Pless and M. Deru, and Crawley , Zero Energy Buildings: A Critical Look at the Definition, Pacific Grove, CA: NREL National Renewable Energy Laboratory (2006) pp. 4–5, NREL/CP-550-39833.

6.      Verus Carbon Neutral, About Verus Carbon Neutral. Verus Carbon Neutral [Online] [Cited: August 10, 2011.], http://www.verus-co2.com/about.html. 

7.      U.S. Green Building Council, What LEED is, USGBC [Online] [Cited: August 10, 2011], http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1988.

8.      AIA National, AIA California Council, Integrated Project Delivery: A Guide, The American Institute of Architects. s.l.: AIA, 2007, Guide. 

9.      CREE LED Lighting, The CREE Difference. CREE LED Lighting [Online] [Cited: August 10, 2011], http://www.creeledlighting.com/The-Cree-Difference/Efficiency.aspx. 

10.   RESNET, Residential Energy Services Network, What is Home Energy Rating? RESNET [Online] [Cited: August 10, 2011], http://www.resnet.us/home-energy-ratings.

11.   World Resources Institute, World Business Council for Sustainable Development, The Greenhouse Gas protocol Initiative, Product Life Cycle Accounting and Reporting Standard, World Resources Institute, 2009, Review Draft for Stakeholder Advisory Group. 

12.   World Resources Institute, World Business Council for Sustainable Development, The Greenhouse Gas Protocol—A Corporate Accounting and Reporting Standard, Revised Edition, World Resources Institute, Washington, DC: World Resources Institute, World Business Council for Sustainable Development, 2004. 

13.   US Environmental Protection Agency, Climate Change—Waste, Waste Reduction Model (WARM) [Online] [Cited: August 10, 2011], http://www.epa.gov/climatechange/wycd/waste/calculators/Warm_home.html. 

14.   D. E. Buffington , Performing Energy Calculations—English Units, Agricultural and Biological Engineering, Penn State, College of Agricultural Sciences, 2008, Fact Sheet. 

15.   D. E. Buffington , Energy Cost Calculator Spreadsheet. Penn State, College of Agricultural Sciences [Online] 2009 [Cited: August 10, 2011], http://energy.cas.psu.edu/smartdecisions.html.

 

© 2012 American Institute of Physics


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