HOMER Version History

Version 2.76 (June 23, 2010)

• Fixes a bug related to batteries that do not use the kinetic battery model
• Added the Beacon Power Smart Energy 25 flywheel to the list of batteries in the component library
• Fixed a bug that prevented the HTML and XML reports from appearing.
  

Version 2.75 (April 23, 2010)

• Added the ability to model a flywheel.

• Added ability to model ZBB type batteries.

• Made battery capacity curve optional when specifying the properties of a new battery.

• Made battery lifetime curve optional when specifying the properties of a new battery.

• Added battery initial state of charge variable.

• Added the ability to schedule the operation of the electrolyzer.

• Added solar altitude, solar azimuth, and angle of incidence to hourly simulation results for all PV systems.

• Fixed bug in vertical-axis PV tracking logic causing erroneously low PV power output in tropical latitudes.

• Fixed bug that occasionally prevented HTML report from appearing in Firefox.

Version 2.68 beta (July 24, 2009)

• Updated contact information to reflect the licensing of HOMER from
  NREL to HOMER Energy, LLC.

Version 2.67 beta (April 21, 2008)

• Added the ability to model up to ten generators.

• Added the ability to compete up to ten battery types against each other.

Version 2.64 beta (December 27, 2007)

• Added battery string size.

• Added energy in, energy out, and losses to the battery tab of Simulation Results window.

• Added delta plot to the Hourly tab of the Simulation Results window

• Updated cost summary section of the HTML system report.

Version 2.63 beta (November 30, 2007)

• Added the ability to model the temperature effect on the PV array.

• Added the ability to import solar radiation and temperature data from TMY2 files.

• Made the reformer and the electrolyzer capable of supplying hydrogen to a generator as needed to serve an electric load.

• Added the ability to limit the excess thermal output.

• Added a constraint on net grid purchases.

• Added checkbox to System Control window allowing two types of wind turbines in a single system.

• Added a second thermal load.

• Added a new grid/battery control parameter prohibiting any battery charging above a certain grid power price.

Version 2.52 beta (August 31, 2007)

• Fixed bug that prevented the Plot button from working in the load and resource input windows.

• Fixed bug that caused incorrect calculation of grid sales in some grid-connected systems.

Version 2.5 beta (July 20, 2007)

• Added operating cost to Optimization Results and Simulation Results.

• Added rated power to wind turbine properties.

• New ability to calculate primary energy savings.

• New Cost Summary tab in the Simulation Results window.

• New scatterplot window to the Simulation Results window.

• New Compare Economics window, which calculates payback, ROI, and IRR.

• New ability to forecast wind power sales to the grid, and calculate resulting imbalance penalties when actual sales deviate from the forecasts.

Version 2.42 beta (May 21, 2007)

• Added a graph to the cash flow window.

Version 2.41 beta (May 10, 2007)

• Added the ability to simulate the system using any time step down to 1 minute.

• Added the ability to import time series data with any time step down to 1 minute.

• Added window showing the cash flow over the lifetime of the project.

• Changed cost of energy equation denominator to exclude grid sales.

• Changed calculation of PV power output to eliminate twilight power spikes.

• Changed PV derating factor from 90% to 80%.

• Fixed bug in solar azimuth calculation, which caused errors with tracking in the tropics.

• Added two control parameters for grid/battery systems.

• Made the grid stop charging the battery bank when it reaches the setpoint state of charge.

• Improved hourly results table and export file to show date/time rather than hour of year.

• Changed wind turbine power curve to accept two decimal places in wind speed.

• Fixed the bug that caused the y-axis label to disappear in metafiles copied from graphs.

• Allowed manual setting of graph axes.

• Allowed manual override of graph colors.

• Implemented new click-and-drag zoom feature in time series graphs.

Version 2.2 beta (October 26, 2005)

• Added ability to model flow batteries.

• Added ability to connect the PV panel to the AC bus.

• Allowed real-time (hourly) grid power pricing.

• Added threshold power price above which grid will not charge battery bank.

• Added threshold sellback rate below which the system will not sell power to the grid.

• Allowed hydrogen demand to be specified hourly.

• Added calculation of levelized cost of hydrogen.

• Changed formula for battery energy cost to account for discharge efficiency.

• Added fixed and marginal generation cost to generator page of Simulation Results window.

• Added battery wear and energy cost to battery details page of Simulation Results window.

Version 2.19 (June 14, 2005)

• Fixed bug causing some infeasible deferrable load-serving systems to be counted as feasible.

Version 2.18 (June 1, 2005)

• Fixed bug in renewable fraction equation causing an incorrect calculation when excess electricity served the thermal load.

• Fixed bug preventing browser launch with Firefox as default browser.

• Added constraints, emissions, and generator control sections to the HTML input report.

• Added excess electricity to monthly thermal production graph.

Version 2.17 (May 16, 2005)

• Fixed bug causing boiler emissions costs to be double counted in calculation of total net present cost.

• Changed equation for levelized cost of energy to subtract the cost associated with serving the thermal load.

Version 2.16 (April 8, 2005)

• Fixed bug preventing HOMER from recalculating results after a change to the grid rate schedule.

• Fixed bug preventing HOMER from recalculating results after a change to the emissions constraints.

Version 2.15 (April 5, 2005)

• Made the units of the emissions factors on the Boiler Inputs window correspond to the fuel units.

• Fixed a problem that prevented the creation of the HTML report before the document was saved to disk.

Version 2.14 (January 25, 2005)

• Fixed several bugs in the XML import facility.

• Changed to new kind of install file created with Inno Setup. This avoids the error that occurred when running the old install file on some versions of Windows stating "The system file is not suitable for running MS-DOS and Microsoft Windows applications."

Version 2.13 (December 16, 2004)

• Fixed bug where HOMER did not properly consider the emissions costs when controlling dispatchable power sources.

• Fixed bug causing incorrect column headings in text export of the tabular sensitivity results table.

Version 2.12 (December 13, 2004)

• Fixed bug where total electrical production value excluded grid purchases.

• Fixed bug causing erroneous extraterrestrial solar radiation calculation at midnight in polar latitudes during 24 hours of daylight.

Version 2.11 (December 1, 2004)

• Added Furhländer and Windside wind turbines to the default component library.

• Added Hoppecke and Vision batteries to the default component library.

• Fixed bug in pie charts where legend occasionally disappeared.

• Added Import XML button to Create New Battery window.

• Fixed a few minor interface problems in the Create New Battery window.

• Changed HTML input summary to show annual average load profile rather than January load profile.

• Improved the FAQ page in the help file.

Version 2.10 (November 8, 2004)

• Changed calculation process to avoid recalculating existing results. This can dramatically reduce run times.

• Added ability to specify daily, weekly, and seasonal variations in grid power cost.

• Added ability to schedule generator operation.

• Added link to solar resource database.

• Added ability to calculate, penalize, and limit emissions of CO2, CO, SO2, NOx, particulate matter, and unburned hydrocarbons.

• Added fuel curve calculator window.

• Added HTML reports summarizing inputs and simulation results.

• Added XML import/export capability.

• Added ability to create spider graphs of sensitivity results.

• Added ability to model an external hydrogen load and a steam reformer.

• Added variable for initial hydrogen tank level.

• Added constraint on final hydrogen tank level.

• Replaced wind speed scaling factor with anemometer height and turbine hub height.

• Replaced power curve scaling factor with altitude.

• Added additional pages to Simulation Results window showing detailed operation of the wind turbine, hydro turbine, PV array, hydrogen tank.

• Fixed bug in net metering logic causing incorrect calculation of annual energy charge.

• Fixed bug causing incorrect economic calculations when the interest rate was zero.

• Fixed bug causing unmet load in setpoint mode with undersized generator.

Version 2.09 (February 18, 2004)

• Fixed bug that in some situations caused HOMER to ignore the battery setpoint state of charge.

Version 2.08 (February 11, 2004)

• Fixed bug that in some instances caused HOMER to be unable to initiate a license.

Version 2.07 (January 15, 2004)

• Fixed a bug where HOMER considered electricity produced by a hydrogen-fuelled generator to be non-renewable. HOMER now considers such electricity to be 100% renewable.

• Fixed a problem with the behavior of generators fuelled by stored hydrogen and operating under the cycle charging dispatch strategy.

• Fixed a calculation error that occurred when a generator operating under the influence of a setpoint state of charge ran out of fuel.

• Added the ability to graph the amount of hydrogen in the storage tank.

Version 2.06 (October 21, 2003)

• Fixed bug relating to the calculation of carbon emissions.

Version 2.05 (August 26, 2003)

• Added the ability to import .tpc files into the Create New Wind Turbine window.

Version 2.04 (August 5, 2003)

• Fixed bug that could cause HOMER to crash when opening a file containing fewer than 8760 hours of primary load data.

Version 2.03 (July 30, 2003)

• Fixed bug in grid sales logic.

Version 2.02 (July 24, 2003)

• Fixed bug causing Search Space Usage window to crash in certain circumstances.

Version 2.01 (July 22, 2003)

• Fixed bug in deferrable load logic.

Version 2.0 (July 10, 2003)

• Added ability to model grid-connected systems.

• Added ability to model both AC and DC electric loads.

• Added ability to model thermal loads and cogeneration.

• Added ability to model as many as three generators.

• Added ability to model electrolyzers, hydrogen storage, and hydrogen-fueled generators.

• Added ability to model operating reserve.

• Added a clickable schematic diagram to the main window.

• Redesigned all input windows.

• Rewrote battery module and allowed battery bank size to be specified in terms of number of batteries, rather than kWh of nominal capacity.

• Allowed generators to be fueled by pure biogas

• Added carbon tax.

Version 1.58 (March 26, 2002)

• Fixed bug causing certain systems to be mistakenly omitted.

• Changed default wind turbine lifetime from 20 yrs to 15 yrs.

• Changed default biomass carbon content from 50% to 0%.

• Changed default battery maximum charge rate from 1 A/Ah to 0.1 A/Ah.

• Changed default real interest rate from 10% to 6%.

Version 1.57 (October 24, 2001)

• Minor bug fix.

Version 1.56 (October 3, 2001)

• Minor bug fix.

Version 1.55 (September 13, 2001)

• Increased length of temporary license from 60 to 180 days.

Version 1.54 (September 12, 2001)

• Made the PV slope and azimuth default to values appropriate to the latitude.

Version 1.53 (September 11, 2001)

• Changed default hourly and daily noise values to 15% and 25%.

Version 1.52 (June 22, 2001)

• Added ability to copy and save graphic images in metafile format.

• Made symbol size and line width in graphics configurable by user.

Version 1.51 (June 6, 2001)

• Added asterisk to the document title when modified.

• Added version number and remaining days to the splash screen.

Version 1.5 (May 11, 2001)

• Added ability to model small modular biomass systems.

• Improved procedure for fitting kinetic battery model constants to a discharge curve.

• Added capability to identify file version of an invalid-format .hmr file.

• Changed units of output variable carbon emissions to t/yr from kg/yr.

• Improved scroll bar operation and eliminated flicker in time series plots.

Version 1.4 (March 1, 2001)

• Added capability to model small hydro systems.

• Changed image file format from bitmap to PNG (Portable Network Graphics).

• Added protection from low values of Kt in the solar data generation algorithm.

• Fixed bug causing crash when writing large .hmr files.

Version 1.3 (November 9, 2000)

• Stored hourly values of inverter power and rectifier power.

• Added primary load efficiency analysis capability.

• Added linked sensitivities.

Version 1.2 (July 31, 2000)

• Changed to compressed binary .hmr file format.

• Included imported load and resource data in the .hmr file.

• Added maximum diesel run time and minimum battery life constraints.

• Added carbon emissions.

• Allowed the resorting of the sensitivity results list control.

Version 1.1 (June 27, 2000)

• Added superimposed variable to surface plots and OST graphs.

• Added ability to simulate on demand so all systems appear to have hourly data.

Version 1.0 (February 14, 2000)