REopt Lite | REopt Energy Integration & Optimization

The REopt™ Lite web tool allows users to:

Evaluate the economic viability of distributed PV, wind, battery storage, CHP, thermal energy storage, and geothermal heat pumps (GHP) at an existing site
Identify system sizes and dispatch strategies to minimize energy costs
Estimate how long a system can sustain critical load during a grid outage.

Watch REopt Lite Tutorial Videos

Step 0: Login and Gather Data

Logging in (optional) enables you to:

save your evaluations

create a custom electricity rate

build a critical load profile

manage typical and critical load profiles

Data needed for a Financial run:

location

electricity rate

load (interval data or building type)

fuel cost (if CHP or GHP is modeled)

Data needed for a Resilience run:

critical load assumptions

outage duration

outage start date and time

Step 1: Choose Your Focus

Optimize for financial savings or energy resilience?

Financial Resilience

Step 2: Select Your Technologies

PV Battery Wind Generator CHP Chilled Water
Storage Geothermal
Heat Pump

Step 3: Enter Your Site Data

Load Profiles (required)

* Required field

* Typical electrical load

How would you like to enter the typical energy load profile?

* Type of building

Building Details

Annual Monthly

Energy Consumption (kWh)

January

February

March

April

May

June

July

August

September

October

November

December

* Annual energy consumption (kWh)

* Total Energy Consumption (kWh)

Select Building Type	% of Total Energy Consumption

* Custom load profile

Year of load profile

Sample custom load profile

Download electric load profile

Chart electric load data

Electrical load adjustment

Adjust electricity consumption

100% of original consumption

* Typical heating system fuel load

How would you like to enter the typical thermal load profile?

* Type of building

Building Details

Annual Monthly

* Annual heating system fuel consumption (MMBtu)

Addressable load percent (%)

Monthly boiler fuel
consumption (MMBtu)

Addressable Load
Percent (%)

January

February

March

April

May

June

July

August

September

October

November

December

* Total annual heating system fuel consumption (MMBtu)

Select Building Type	% of Total Heating System Fuel Consumption (MMBtu)

* Custom heating boiler fuel load profile

Download heating system fuel load profile

Chart heating system fuel load data

* Typical cooling system thermal load

How would you like to enter the typical cooling thermal load profile?

* Type of building

Building Details

Enter custom annual or monthly thermal energy amounts

Annual Monthly

Monthly thermal energy consumption (tonhour)

January

February

March

April

May

June

July

August

September

October

November

December

* Annual thermal energy consumption (tonhour)

Enter custom annual thermal energy amount

Annual thermal energy consumption (tonhour)

Select Building Type	% of Total Thermal Energy Consumption (tonhour)

* Thermal energy consumption load profile

Annual Monthly

* Annual fixed percentage of total electric load (%)

Monthly fixed percentage of total electric load (%)

January

February

March

April

May

June

July

August

September

October

November

December

Download cooling load profile

Chart cooling plant load data

Electric cooling plant coeff. of performance (kWt/kWe)

Max. chiller thermal capacity as factor of peak cooling load

Resilience (required)

* Outage information

* Outage duration (hours)

* Outage start date

Autoselect using critical load profile

* Outage start time

Reset to default values

Financial

Analysis period (years)

Host discount rate, nominal (%)

Electricity cost escalation rate, nominal (%)

Existing heating system fuel cost escalation rate, nominal (%)

CHP fuel cost escalation rate, nominal (%)

Use third-party ownership model

Advanced inputs

Reset to default values

Emissions

Electricity Grid Emissions Factors

How would you like to enter the emissions factors?

Source of hourly grid emissions factors

Annual grid emissions factor (lbs CO2/kWh)

* Hourly emissions factors

Sample custom emissions profile

Download emissions factor data

Chart emissions factor data

Fuel Emissions Factors

Heating system natural gas emissions factor (lbs CO2/MMBtu)

CHP natural gas emissions factor (lbs CO2/MMBtu)

PV

System capital cost ($/kW DC)

Existing PV system?

Minimum new PV size (kW DC)

Maximum new PV size (kW DC)

Advanced inputs

Reset to default values

PV Costs

O&M cost ($/kW per year)

PV System Characteristics

Module type

Array type

Array azimuth (deg)

Array tilt (deg)

DC to AC size ratio

System losses (%)

PV generation profile

PV Station Search Radius (mi)

PV Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Database of state incentives for renewables

	Incentive based on percentage of cost (%)	Maximum dollar amount for incentive based on percentage of cost ($)	Rebate based on system size ($/kW)	Maximum dollar amount for rebate based on system size ($)
Federal	default = 26%	Unlimited	default = $0	Unlimited
State	default = 0%	default = Unlimited	default = $0	default = Unlimited
Utility	default = 0%	default = Unlimited	default = $0	default = Unlimited

Production Based Incentives

	Production incentive ($/kWh)	Incentive duration (yrs)	Maximum incentive ($)	System size limit (kW)
Total	default = $0	default = 1	default = Unlimited	default = Unlimited

Tax Treatment

MACRS schedule

MACRS bonus depreciation

Reset to default values

Battery

Energy capacity cost ($/kWh)

Power capacity cost ($/kW AC)

Allow grid to charge battery

Minimum energy capacity (kWh)

Maximum energy capacity (kWh)

Advanced inputs

Reset to default values

Wind

Size class

System capital cost ($/kW AC)

Minimum size desired (kW AC)

Maximum size desired (kW AC)

Advanced inputs

Reset to default values

	Production incentive ($/kWh)	Incentive duration (yrs)	Maximum incentive ($)	System size limit (kW)
Total

Generator

Install cost ($/kW AC)

Diesel cost ($/gal)

Fuel availability (gallons)

Minimum new generator size (kW AC)

Maximum new generator size (kW AC)

Existing diesel generator?

* Existing diesel generator size (kW)

Advanced inputs

Reset to default values

Combined Heat & Power

Prime Mover

Prime mover type

Size class

Change default prime mover & size class?

Minimum electric power capacity (kW)

Minimum non-zero power capacity (kW)

Maximum electric power capacity (kW)

Use single cost ($/kW) for all CHP sizes?

Size-Cost Pair 1

Size-Cost Pair 2

Electric power capacity (kW)

Total installed cost ($/kW)

Total installed cost ($/kW)

Minimum electric power capacity (kW)

Maximum electric power capacity (kW)

Steam turbine inlet pressure (psig)

Steam turbine inlet temperature (°F)

Steam turbine outlet pressure (psig)

Advanced prime mover inputs

Reset to default values

CHP Operating & Maintenance Costs

Fixed O&M Cost ($/kW/yr)

Variable O&M Cost ($/kWh)

CHP System Characteristics

Isentropic efficiency

Gearbox and generator combined efficiency

Net-to-gross electric power ratio

CHP Incentives

MACRS schedule

MACRS bonus depreciation

A default maintenance schedule has been selected based on your prime mover type and the year of your electric load profile.

Use the summary table and detailed table links below to view the details of the default schedule.

* Custom downtime schedule

Download schedule

View summary table View detailed table

CHP Costs

Fixed O&M Cost ($/kW/yr)

Variable O&M Cost ($/kWh)

CHP System Characteristics

Electric efficiency at 100% load (% HHV-basis)

Electric efficiency at 50% load (% HHV-basis)

Thermal efficiency at 100% load (% HHV-basis)

Thermal efficiency at 50% load (% HHV-basis)

Min. electric loading of prime mover (% of rated electric capacity)

Knockdown factor for CHP-supplied thermal to Absorption Chiller (%)

Supplementary firing maximum steam production ratio

Supplementary firing thermal efficiency (% HHV-basis)

Installed Cost of Supplementary Firing ($/kW)

CHP Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Database of state incentives for renewables

	Incentive based on percentage of cost (%)	Maximum dollar amount for incentive based on percentage of cost ($)	Rebate based on system size ($/kW)	Maximum dollar amount for rebate based on system size ($)
Federal	default = 10%	Unlimited	default = $0	Unlimited
State	default = 0%	default = Unlimited	default = $0	default = Unlimited
Utility	default = 0%	default = Unlimited	default = $0	default = Unlimited

Production Based Incentives

	Production incentive ($/kWh)	Incentive duration (yrs)	Maximum incentive ($)	System size limit (kW)
Total	default = $0.000	default = 1	default = Unlimited	default = Unlimited

Tax Treatment

MACRS schedule

MACRS bonus depreciation

Reset to default values

	Weekend (hrs)	Weekday (hrs)	Total (hrs)
Total
January
February
March
April
May
June
July
August
September
October
November
December

Maintenance Periods
Start Date & Time	End Date & Time	Length (hrs)

Hot Water Storage

Minimum size (gal)

Maximum size (gal)

Total installed cost ($/gal)

Advanced inputs

Reset to default values

Absorption Chiller

Absorption Chilling

Minimum size (ton)

Maximum size (ton)

Total installed cost ($/ton)

Advanced inputs

Reset to default values

	Weekend (hrs)	Weekday (hrs)	Total (hrs)
Total
January
February
March
April
May
June
July
August
September
October
November
December

Maintenance Periods
Start Date & Time	End Date & Time	Length (hrs)

Chilled Water Storage

Minimum size (gal)

Maximum size (gal)

Total installed cost ($/gal)

Advanced inputs

Reset to default values

Geothermal Heat Pump (beta)

Require GHP purchase in the solution

Total installed cost for heat pump ($/ton)

Total installed cost for building hydronic loop ($/sq ft)

Total installed cost for GHX ($/ft)

GHP incremental O&M cost increase over existing HVAC system ($/sq ft-year)

Advanced inputs

Reset to default values

GHP performance (COP) table

Default
Upload

Default GHP coefficient of performance (COP) versus entering fluid temperature for the heat pumps for both heating and cooling is provided.

Use the performance table link below to view the details of the default performance.

* Custom GHP performance table

Download GHP Performance Table

View performance table

GHP System Characteristics

Heat pump capacity sizing factor

Borehole depth (ft)

Heat pump can serve the domestic hot water load

Ground thermal conductivity (Btu/hr-ft-deg F)

Maximum allowable GHX return water temperature (°F)

Minimum allowable GHX return water temperature (°F)

GHX simulation years (year)

Borehole spacing distance (ft)

Borehole spacing type

Borehole diameter (in)

Grout thermal conductivity (Btu/hr-ft-deg F)

Ground density (lbm/cubic ft)

Ground specific heat (Btu/lbm-deg F)

GHP nominal flow rate of GHX fluid (GPM/ton)

Ground Heat Exchanger (GHX) System Characteristics

GHX fluid pump power (Watt/GPM)

GHX fluid pump minimum turndown

GHX fluid pump power curve exponent

GHX pipe diameter (in)

GHX pipe wall thickness (in)

GHX pipe thermal conductivity (Btu/hr-ft-deg F)

GHX pipe centerline distance between upwards and downwards u-tube legs (in)

GHX fluid density (lbm/cubic ft)

GHX fluid specific heat (Btu/lbm-F)

GHX fluid thermal conductivity (Btu/hr-ft-deg F)

GHX fluid dynamic viscosity (lbm/ft-hr)

GHX header depth (ft)

GHX simulation solver tolerance (°F)

GHX simulation solver initial guess (ft/ton)

GHP Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Database of state incentives for renewables

	Incentive based on percentage of cost (%)	Maximum dollar amount for incentive based on percentage of cost ($)	Rebate based on system size ($/kW)	Maximum dollar amount for rebate based on system size ($)
Federal	default = 10%	Unlimited	default = $0	Unlimited
State	default = 0%	default = Unlimited	default = $0	default = Unlimited
Utility	default = 0%	default = Unlimited	default = $0	default = Unlimited

Tax Treatment

MACRS schedule

MACRS bonus depreciation

Reset to default values

Entering Fluid Temperature (F°)	Cooling COP (kWt/kWe)	Heating COP (kWt/kWe)
20	11.023	3.351
30	11.023	3.639
40	11.023	4.161
50	10.481	4.681
60	9.168	5.081
70	7.263	5.678
80	5.826	6.047
90	4.803	6.341
100	3.9	6.341
110	3.279	6.341
120	2.707	6.341

Reset to default values

The REopt™ Lite web tool allows users to:

Watch REopt Lite Tutorial Videos

Step 0: Login and Gather Data

Step 1: Choose Your Focus

Step 2: Select Your Technologies

Step 3: Enter Your Site Data

Location

Electrical

Fuel

Solver settings

* Typical electrical load

Electrical load adjustment

* Typical heating system fuel load

* Typical cooling system thermal load

* Critical electric load

* Outage information

Electricity Grid Emissions Factors

Fuel Emissions Factors

PV Costs

PV System Characteristics

PV Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Production Based Incentives

Tax Treatment

Battery Costs

Battery Characteristics

Battery Incentives and Tax Treatment

Capital Cost Based Incentives

Tax Treatment

Wind Costs

Wind Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Production Based Incentives

Tax Treatment

Generator Costs

Generator Characteristics

Prime Mover

CHP Operating & Maintenance Costs

CHP System Characteristics

CHP Incentives

CHP Maintenance Schedule

CHP Costs

CHP System Characteristics

CHP Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Production Based Incentives

Tax Treatment

Hot Water Storage

Hot Water Storage Costs

Hot Water Storage System Characteristics

Tax Treatment

Absorption Chilling

Absorption Chiller Costs

Absorption Chiller System Characteristics

Tax Treatment

Tax Treatment

GHP performance (COP) table

GHP System Characteristics

Ground Heat Exchanger (GHX) System Characteristics

GHP Incentives and Tax Treatment

Capital Cost or System Size Based Incentives

Tax Treatment