The RETScreen Clean Energy Project Analysis Software is a decision support tool developed with the contribution from government, industry, and academia. It was originally developed in 1996 by Natural Resources Canada. The software, provided free-of-charge from , can be used worldwide to evaluate the energy production and savings, costs, emission reductions, financial viability and risk for various types of Renewable-energy and Energy-efficient Technologies (RETs). The software (available in multiple languages) also includes product, project, hydrology and climate databases, a detailed user manual, and a case study based college/university-level training course, including an engineering e-textbook. Approximately 1,000 people download the model every week with a total so far of more than 200,000 downloads.
Fundamental to RETScreen is a comparison between a “base case”, typically the conventional technology or measure and a “proposed case” i.e. the clean energy technology. RETScreen is ultimately not concerned with the absolute costs, but rather the costs of the proposed case that are in excess of those for the base case. In the RETScreen Software, the energy benefits are the same for both the base case and the proposed case. If, for example, a proposed on-grid wind farm generates 50,000 MWh per year, then this compared to 50,000 MWh of electricity from conventional sources available through the grid. On the other hand, the costs will not, in general, be the same for the base case and the proposed case: typically, the proposed case will have higher initial costs and lower annual costs (i.e. savings). Thus RETScreen’s analysis task is to determine whether or not the balance of costs and savings over the life of the project make for a financially attractive proposition. RETScreen’s greenhouse gas emission reduction analysis adheres to this same analysis approach. RETScreen can analyse up to a 50-year time-horizon in monthly or yearly time-steps. The software can be applied to any energy system, ranging from individual projects to global applications. In addition the model considers all sectors of the energy system except the transport sector. RETScreen uses a five-step analysis for every model: (1) The Energy Model: User enters location of the energy project, the type of system used in the base case, the technology for the proposed case, the loads (where applicable), and the renewable energy resource (for RETs). RETScreen then calculates the annual energy production or energy savings. All thermal generation and renewable technologies can be accounted for using RETScreen. However, the only storage device considered is BES, and it cannot model any hydrogen or transport technologies. (2) Cost Analysis: User enters the initial, annual, and periodic costs for the proposed case system as well as credits for any base case costs that are avoided in the proposed case (alternatively, the user can enter the incremental costs directly). (3) Greenhouse Gas (GHG) Analysis (optional): Determines the annual reduction in GHG emissions stemming from using the proposed technology in place of the base case technology. (4) Financial Summary: User specifies financial parameters related to the avoided cost of energy, production credits, GHG emission reduction credits, incentives, inflation, discount rate, debt, and taxes. From this, RETScreen calculates a variety of financial indicators (e.g. net present value, etc.) to evaluate the viability of the project. (5) Sensitivity & Risk Analysis (optional): Identifies how uncertainty in the estimates of various key parameters may affect the financial viability of the project.
Previously RETScreen has been used to assess the feasibility of wind farm development in Algeria , the feasibility of solar water heating in Lebanon , the viability of solar PV in Egypt , as well as identifying the potential of a building-integrated PV system  and GHG reductions in the residential sector . Finally, a more detailed assessment of the projects and results completed using RETScreen is also available .
- RETScreen International, National Resources Canada, 26th April 2009, http://www.retscreen.net/
- Himri, Y., Boudghene Stambouli, A. & Draoui, B., Prospects of wind farm development in Algeria.Desalination, 239(1-3), pp. 130-138, 2009.
- Houri, A., Solar water heating in Lebanon: Current status and future prospects. Renewable Energy, 31(5), pp. 663-675, 2006.
- El-Shimy, M., Viability analysis of PV power plants in Egypt. Renewable Energy, 34(10), pp. 2187-2196, 2009.
- Bakos, G. C., Soursos, M. & Tsagas, N. F., Technoeconomic assessment of a building-integrated PV system for electrical energy saving in residential sector. Energy and Buildings, 35(8), pp. 757-762, 2003.
- Kikuchi, E., Bristow, D. & Kennedy, C. A., Evaluation of region-specific residential energy systems for GHG reductions: Case studies in Canadian cities. Energy Policy, 37(4), pp. 1257-1266, 2009.
- Leng, G. J., Monarque, A., Graham, S., Higgins, S. & Cleghorn, H. RETScreen International: Results and Impacts 1996-2012. Minister of Natural Resources Canada, 2004, http://www.retscreen.net/ang/impact.php.