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Green Buildings and their

Financial Feasibility

12 August 2010

By:Mili MajumdarThe Energy and Resources Institute (TERI)

Pollution�Water pollution �Air pollution �Soil degradation �Erosion�Solid waste

Environmental health

Resources�Water�Energy�Trees/vegetation�Land and soils

Conservation & augmentation

Dimensions of ecologically sustainable development

Green……..the way to build

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A Green Building…

•Minimizes depletion of natural resources during its

construction and operation

•Minimizes pollution: Water pollution, Air pollution, Soil

degradation, Erosion, Solid waste

•Uses minimum energy to power itself

•Uses efficient equipments: lighting, air conditioning, etc.

•Maximizes the use of renewable energy sources

•Uses efficient building materials and construction

practices

•Uses efficient waste and water management practices

• Provides comfortable and hygienic indoor environment

Benefits of Green Buildings

Minimal impact on site and surroundings

•Erosion control

•Storm water management

•Pollution control

•Tree protection

•Heat island control

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Benefits of Green Buildings

Saves water by upto 30-40%

•By reducing irrigation water requirement

•Use of efficient fixtures

•Rain water harvesting

•Waste water treatment on site

•Recycle and reuse of water

Benefits of Green Buildings

Saves energy by 40-50%

•Minimize building energy demand through:

Solar Passive Design

•Use of efficient building systems

• Maximum use of renewable energy

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Benefits of Green Buildings

Solid waste management

•Reduction in waste during construction

•Efficient waste segregation at source

•Suitable storage and disposal at building level

• Resource recovery from waste

Benefits of Green Buildings

•Use of recycled material: Fly ash, blast

furnace slag

•Adopting efficient technologies

•Use of low-energy materials

www.luxuryhousingtrends.com

Very high energy Aluminum, stainless steel, plastics, copper

High energy Steel, lead, glass, cement, plaster board

Medium energy Lime, clay bricks and tiles, gypsum plaster, concrete (in situ, blocks, pre-cast)

Low energy Sand, fly ash, blast furnace slag

www.science.edu/

Use of sustainable building materials

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Benefits of Green Buildings

Minimal negative impact on people

Healthy and productive work environment

•Clean environment for construction workers

•Day lighting/natural ventilation•Universal accessibility

Tool to facilitate design, construction, operation of a

green building ,and in turn ….measure “greenness” of a

building in India

National Rating System: GRIHA Green Rating for Integrated Habitat Assessment

Set of 34 criteria

100 (+4 innovation points)

point system with differential

weightage on various criteria

� 51 - 60

� 61 - 70

� 71 - 80

� 81- 90

� 91- 100

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All Green Building aspects covered under GRIHA Rating

What gets measured gets managed

Policies/programs to mainstream green construction

Why GRIHA ?

Energy Conservation Act 2001 enacted

Energy Conservation Building Code (ECBC)2007 launched

Star rating of existing buildings launched

Ministry of Power/Bureau of Energy Efficiency empowered to mandate ECBC

Environmental Clearance from the Ministry of Environment and Forests/State Environment Impact Assessment Authority mandatory for all large constructions

Resource (energy, water) efficiency integral part of clearance

Ministry of New and Renewable Energy incentivises GRIHA programme

National green building rating system “GRIHA” launched

National Action Plan on Climate Change

Mission on Sustainable Habitat

Convergence is crucial to implementation and mainstreaming

Site planning

17%

Water

15%

Waste

management

5%

Health and

well being

9%

Energy(end

use) and

Renewable

Energy

37%

Materials and

construction

technology

17%

GRIHA Scoring Weights

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Trees preserved and protected

Outdoor solar lights

N-S Orientation with shading (roof/window)

Lesser paving

Solar PV and Solar Thermal systems

Incremental cost 17%

Energy savings 52%

Payback period :3 years

5 Star Rated GRIHA Building in IIT Kanpur

• Sustainable site planning(compensatory afforestation, topsoil preservation, etc)

• Water efficient landscape by

adopting native species, efficient irrigation systems and limiting turf areas.

• Building water consumption reduced by use of high efficiency and low-

flow fixtures

• Energy efficiency measures such

as high performance glass, roof insulation, energy efficient lighting and variable refrigerant volume based air conditioning shall reduce the energy consumption of the apartments significantly

• Solar photo voltaic system is proposed to meet 10% of total energy

requirement for internal lighting

• Waste water recycling and solid waste management system are being planned

Common wealth Games Village

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Station cum commercial complex for Delhi Metro Rail Corporation(16 hour

/day use)• EPI (Base case):522

kWh/sq m /year• EPI (ECBC roof and glass):

469 kWh/sq m /year (10% savings)

• EPI (ECBC light power density): 424 kWh/sq m /year (18% savings)

• EPI (ECBC HVAC): 331kWh/sq m /year (36% savings)

• EPI (Heat recovery): 268 kWh/sq m /year (48% savings)

• Tonnage of AC brought

Challenges: Builder invests…tenant benefits (overcome through committed leadership)Design team may not accept change (overcome through continuous discussion process)Owner may not put up all the systems (overcome through laying down tenant/buyers’ guidelines)

• 7 green rated buildings selected as case studies

• Required building data collection (through primary survey,

consultation with subject experts, basic thumb rules for filling in data gaps)

• Green case and base case established

• Data analysis

Are Green Buildings Financially Feasible?

Description of study conducted by TERI

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• Life of building: 25 years

• Values used for calculation of present value factors

• Inflation rate: 4.9%

• Nominal discount rate:16%

• Real discount rate: 10.6%

• Escalation rates: 7.6%

• Costs

• Single costs: Initial investment costs, capital replacement costs and resale value of building

• Uniform annually recurring costs: Operation & Maintenance costs

• Non-uniform annually recurring costs: Energy costs of the building

Description of study conducted by TERI

Are Green Buildings Financially Feasible?

C om pa rison of c ost/sqm for G re e n building vs C onve ntiona l building

15900

19075

23000

1803019239

14707

16674

20985

18335

17185

1411913636 13574

14293

5000

10000

15000

20000

25000

1 2 3 4 5 6 7

Co

st/

sq

m

C os t/s qm for Green buildings

C os t/s qm for C onventional building s

R ange of initia l inves tm ent cos t for G reen Building s = R s . 14707-23000/s qm

R ange of initia l inves tm ent cos t for C onventional B uildings = R s . 13574-19075/s qm

Comparison of initial cost ( per sq.m.) of Green vs conventional buildings

Study results

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Increment in Initial Investment for Green case as compared to conventional case

10%

17%

17%

32%

4%25%12%

0

100

200

300

1 2 3 4 5 6 7

Case Studies

Init

ial i

nve

stm

ent

cost

(C

rore

Ru

pee

s) Green Case

Conventional Case

Increment in initial cost of Green vs conventional buildings

Initial investment cost for Green buildings is higher as

compared to conventional buildings: incremental cost ranging from 4-32 %

Study results

Incremental cost components

Lighting & controls, 15%

Green rating & consultancy,

12%Envelope, 39%

Systems, 35%

Components of green building cost increment

Study results

Building envelope Roof & wall insulation, high performance glazing 39%

Systems (HVAC system, Electrical system, BMS)

Efficient chillers, motors & pumps, VFD, economizers, heat recovery wheel, BMS

35%

Lighting& controls Energy efficient lamps & fixtures, controls (Daylight & occupancy sensors)

15%

Towards green rating 12%

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Building envelope, Efficient systems and Lighting

Reduction in energy consumption due to these:

EPI (kWh/sqm per annum)% reductionBase building 605Envelope optimization 593 2Lighting optimization 476 21Efficient chiller 346 43Controls for HVAC system 312 48

605 593

476

346 312

2 21 43 48

0

100

200

300

400

500

600

700

ECBC interventions

EP

I (kW

h/s

qm

per

an

nu

m)

EPI (kWh/sqm per annum) 605 593 476 346 312

% reduction 2 21 43 48

Base building

Envelope optimization

Lighting optimization

Efficient chiller

Controls for HVAC

Base Case Final case Total % Reduction

EPI (kWh/ m2 per annum) 605 312 48

Study result: Green building cost increment-Major contributors

Study results

Maximum cost increment due to:

Efficient envelope, systems and lighting

•Which cause maximum energy savings, thus reduction in annual electricity bills

•Which are ECBC recommendations

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0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

conventional building

ECBC compliant building

GRIHA compliant building

Energy saving potential in a ECBC and GRIHA compliant building

37%45%

ECBC Compliance:•Insulation •High Performance glass•Controls•Efficient electrical , mechanical and lighting systemsIncremental cost: 15%Payback period < 5 years

GRIHA Compliance:•ECBC +•Passive principles (shading, orientation, controlled glass area)•Higher indoor design conditions (higher by 1 deg C)•Optimized lighting designNo further incremental costPayback period: < 4 years

kWh/yr

GRIHA Compliant Building= ECBC compliant+

Comparison of Life cycle costs over 25 years : Green vs Conventional Case

5

440

8 97

107

679

10 1181

139

38

170

43

0

100

200

300

400

500

600

700

1 2 3 4 5 6 7

Co

st (

Cro

re R

s.)

Life cycle cost - Green Case

Life cycle cost -Conventional case

Life cycle cost comparison of Green vs Conventional Building

Life cycle cost of Green buildings is lower as compared to

conventional buildings

Study results

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Comparison between payback periods of different case studies

2 2

1

2

3

2

1

0

0.5

1

1.5

2

2.5

3

3.5

1 2 3 4 5 6 7

Yea

rsPayback period

Discounted payback periods ranging from 1 to 3 years

Study results

Comparison of SIR & AIRR

1.9

19

2.33.023.61

4.1

5.3

15.3 20

21222324

29

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

3 7 4 2 6 1 5

SIR AIRR (%)

Financial feasibility assessment of Green Buildings

Savings to investment ratio ranging from 1.9 to 15.3

Adjusted internal rate of return ranging from 19-29%

Study results

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Low energy strategies: for low income groups

Silkworm rearing house: Bangalore

Thermal comfort requirement: Chawki room: 25 to 28 deg C with 70-90% RH

Rearing room: 23 to 25 deg C with 70-80% RH

Non uniform heating/cooling leads to loss in 50-70% of yield

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External methods used to decrease the temperature

False ceiling with

thermocolFalse ceiling with

thermocol

False ceiling with

thermocol

False ceiling with wooden

logsWet gunny cloth hanged in

corridor

Wet gunny cloth hanged in

door and windows

Wet gunny cloth hanged in

windows

Coconut leaves shading to

doors and windows

Wet sand bed with ragi

seeds sown near bottom

ventilators

�

�

Solar passive silkworm rearing house for enhanced productivity

Strategies for summer:

Roof pond with insulation

Insulated wall and roof

Wall shading

Solar chimney on south wall with adjustable vents (to improve ACH in the rearing room)

Air Inlet from north wall covered with wet gunny bags for added humidity

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South view of the rearing house

Architectural design of the rearing house

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Solar passive silkworm rearing house for enhanced productivity

Strategies for winter:

Insulated wall and roof

Retractable shading

Trombe wall on south wall with adjustable vents

Air Inlet from north wall closed

Thermal performance predicted

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TERI University: Usage of multiple low energy cooling techniques: (thermal storage, earth air tunnel, Variable

refrigerant flow system)

Thank You