1. Solar challenges in 2017 In it for the long term James Page
Head of Engineering

2. When does solar need subsidy ?
- in the absence of carbon taxation (or rationing)
- long term (40 year?) investment – society values future income more than individuals or companies

3. Step changes in FITS

4. Some back of envelope numbers:
Cost of system: typically £900-£1100 / kW
1kW will generate kWh / year
So ~ £1 / kWh for many years (degradation say 0.5% / year )
1 kWh brings 4p of FIT + 12p saving or ~7p PPA or 5p export

5. Rates of Return (50kW, London)
Installed Price
% electricity used on site
Can reach rates of return >15%
Should leave space for:
Returns to shareholders
Community Benefit
Attractive PPA price to host
May imply new types of communities ….
23/2/2017

6. Still a good investment even with lower FITs
Real 20-50kW systems

7. Return on investment: - location (& shading)
- system kWh/kW (& pitch etc)
- FIT rate (EPC/date/multiple)
- usage on site
- reliability

8. Microgrids
Financial benefits require selling kWh to users – either on or off site.
Export prices difficult to predict – low at the moment but move towards ‘time of use tariff’ with Smart metering roll out
2/23/2017

9. Return on investment – 20kW example
New FIT rates (4.59p) bring IRR from 16 to 12%, assuming 80% usage on site (and ‘deemed’ export.)
2/23/2017

10. Conclusion:
Replace individual meters with ‘private metering’ to increase % used on site.
Ideally meters would be located in one place, to ease cabling
2/23/2017

11. Limited roof space? East/West = more kWh

12. Science Museum , South Kensington

13. Shading analysis – Senate House, London

14. Comparing with actual weather data:

15. Measuring on site use

16. Measuring system performance: Bungay, 50kW

17. Do panels need cleaning ?
Relative performance before and after :

18. How often?
Performance change 1 and 2 weeks after cleaning ?

19. Thank you
“It is no longer a question of whether or not renewables can take the lion’s share of global power generation, but how long it will take to get there.” Eco-business
James Page