Solar Roof-top On-Line Course

Lesson Set 3: A-Z Rooftop Solar Model and Building Portfolios

This lesson set walks you through a rooftop analysis beginning with establishing a portfolio from multiple installations to evaluating financing and the ability of the project to repay debt. Parts of the model and lesson are pretty standard but there are quite a few tricky issues. If you make it all the way through all of the lessons you may learn something about both modelling and finance. As different solar facilities on rooftops are assumed to be constructed at different times, the model involves evaluation of how to compute cash flow and production items when rates change over the lifetime of a project such as degradation. This set of videos and files also introduce you various other tricky modelling issues including using sumproduct for S-curves with asset portfolios, inflating in alternative periods, accounts receivable and bad debt when outstanding accounts receivable are longer than a month, allocation to interest during construction and difficult financing issues in a monthly analysis where cash flows can be positive or negative. Video links associated with the lessons are shown below. The second section includes the file with different sheets that should be used together with the videos.

If you really fill out each sheet for a modest fee of 40 Euro I will check your work and if you do a good job I will give you an official badge. (If you have ever taken one of my classes you do not have to pay this fee!). I have been told that the way the world works is that if you charge somebody a lot of money for something then they will feel really good about their purchase but if you give your product for free, then they will find it worthless. I think this is complete rubbish and I expect that you can get a lot more out of these exercises than other companies that spend a lot of money on marketing and being flashy. So, if you want to pay my fee of 40 Euro, I will give you an official badge and then even better you will be registered as a modelling expert on this website. You can then show the website page to your boss and ask for a raise or you can even go to an interview and put show the person who is interviewing you that you have a highly valuable certificate. If you want such a certification, sent me an e-mail to

Videos associated with Lesson Set 2: Rooftop Solar Model

Subject Sheet Name in Course File Video Links
Rooftop Model Overview — Introduction to Course File, Videos and Exercises Overview
Rooftop Model Inputs — Structure and Organisation Assumptions
Setting-up Portfolio Equations in Rooftop Model Portfolio Set-up Exercise
Computing Capacity and Generation for Solar Facilities Production Exercise
Degradation Part 1 – Vintage Array Degradation Example
Degradation Part 2 – User Defined Array Function Array Functions
Degradation Part 3 – Application of Function in Model Degradation Calculation
Calculation of Capital Expenditures and SUMPRODUCT Trick Capital Expenditures
Revenues, Periodic Inflation, Accrued Bad Debts Revenue Calculation
Working Capital in Monthly Model with Forward Calculations and OFFSET Accounts Receivable
Operating and Maintenance with Function to Compute by Age Operating and Maintenance
Compute Cash Flow, Depreciation and IRR and Operating Taxes Pre-tax and After Tax Cash Flow
Overview of Financing Financing
Financing 1: Cash Flow and Balance Sheet Financing
Financing 2: IDC and Fees with Financial Statements Financing
IDC Accounting and Cash Balance Issues Financing
Scenario Analysis Scenario Exercise