Understanding the financial projection
The projection are determined by the system cost, system output and your financial settings - you can set the projection period, inflation rate, degradation rate and discount rate. You can also set how the import and export rates will change with inflation. Select Financial inputs in the top right to adjust these for individual projects and edit your financial settings for all future projects.
Income and savings
- Electricity savings: this is how much we project the customer will be able to save now they will not be spending this on their electricity bill, using the annual generation and import tariff (using the customers old tariff if they are switching tariffs).
- Export benefits: this is how much we project that the customer will be able to earn from exporting unused electricity to the grid.
- Additional savings: this models any additional savings that aren't factored into the MCS or Easy PV model.
Note that if you have forced battery charging and discharging configured, you may find the electricity savings are negative. Provided the total income and savings is still greater than how much they were spending on electricity, this is not a problem. If your electricity savings are negative, we will just so the total benefit in this section.
Loan and running costs
The loan and running cost graphs will show any costs that they will incur in the first year and beyond. These will be factored into the total cost of the system across the period and used in the payback calculation.
If you have set up a finance option, you can select this from the right side bar to see the impact this has on the projection.
Bottom line
This section gives an overall indication of the benefits of the system and whether it is a worthwhile investment for the customer. Below are some key definitions.
Discount rate: A discount rate is a means of determining the current value of something (like income or savings from a PV system) that you'll receive in the future. This is set in your project financial settings.
How is this discount rate used?
Discount rate is used to reflect that money earned in the future is less valuable than money earned now.
In Easy PV, we calculate the discounted benefits. Discounted benefits are just the year by year benefits scaled down by half of what the discount rate is. This is halved to reflect the average across the year, for example for a 4% discount rate, at the start of the year the discount rate would be 0% and at the end the rate would be 4%, so we take the midpoint.
Net Present Value: This is the difference between cumulative benefits and the cumulative costs of the system across the projection period, both factoring in discount rate. A positive NPV indicates the system is a good investment.
Internal Rate of Return: This is the discount rate that, when used to calculate NPV (Net Present Value), makes NPV 0. A higher IRR is an indication a project is more profitable.
How do we calculate the IRR and NPV?
We need to calculate the IRR rate of return for the final year of the projection period. This cannot be calculated exactly, so for year 1, rates between 0% and 40% are tested and the value that gets the NPV closest to 0 is chosen. This year 1 value is then used to calculate the IRR of the next year until we reach the final year of the projection period.
Then to calculate the NPV we do the following:
Present year's NPV = previous year's NPV + (benefits - costs) * IRR factor
where present year refers to the current year being calculated and
IRR factor = 1/((1+IRR)^years)
To calculate the final IRR, we use the NPV calculated for the final year of the projection period, again finding the IRR that makes the NPV closest to 0.
Payback: This is how long it takes for the benefits of the system (savings on bills, earnings from exports) to outweigh the costs (initial cost, loan payments, maintenance costs). The graph shows the year by year costs (red) and benefits (green) of the system, including any income, savings, running costs and finance payments. When plotted against each other, where the costs equal the benefits gives the payback period.
Payback period coming out longer than you'd expect? Read here for things you can do to help with that.
If you have any additional questions about the financial task, take a look at our guide on using the financial task and our financial FAQs or reach out at help@easy-pv.co.uk or help@easy-pv.ie.