Qwhen do you talk about solar panels for own consumption it is necessary to gather some elements and do the math, because if the period of return on the investment approaches ten years, it may not be worth it. In Portugal, the Government will provide another 30 million euros to make homes more efficient, using efficient windows and solar panels, it should be noted. And the second phase of the funding program to improve the energy and environmental performance of buildings is launched today.
With this in mind, DECO PROTESTE analyzed the proposals of the EDP Comercial, Ei (Galp), Iberdrola and IKEA, to know the best energy that will be supplied. Now look.
Before you start, to know how many kilowatt-hours (kWh) you consume, you need the electricity bills you’ve collected over more than a year. After knowing the annual consumption, it is necessary to check how it is distributed throughout the day, in order to know the energy that will have to be supplied by the photovoltaic system. The simplest is to set the count when you leave the house in the morning and, again, when you come back at the end of the day, for about two weeks, it supports consumer protection.
Finally, it is necessary to have an idea of the quantity and power of appliances used simultaneously, as they will influence some of the system requirements to be installed, such as the inverter output power.
DECO PROTESTE Study
In order to use the same situation in all simulators, DECO defined a scenario of a family, of two people, who live in a house with one floor and four rooms, in the Porto area, renovated in 2005 and with a low level of thermal insulation.
The couple is telecommuting and because they are at home all day, they have two consumption peaks, at lunchtime and at night. They contracted a power of 6.9 kVA and have an average annual consumption of 4850 kWh. The tariff is that of SU Eletricidade and they usually pay 88 euros per month.
For the study, DECO consulted the proposals of EDP Comercial, Ei (Galp), Iberdrola and IKEA. To determine consumption, simulators start by asking for the address or indication of the house on a map. Then, they request the amount of the monthly electricity bill.
Cost and estimated annual savings
The annual savings estimate differs between 95 and 498 euros. Although in the case of EDP Comercial the proposals include two panels and in the case of Ei (Galp) and IKEA three units, with an impact on the performance of each system, savings almost triple or even quintuple, makes note of consumer protection.
© DECO PROTEST
EDP Comercial’s proposal presented an annual consumption (4750 kWh) close to that defined for the DECO scenario: 4850 kWh. Ei’s (Galp) was also not far away (5000 kWh), but the distribution of consumption throughout the day was unadjusted, as it implied that all the electricity produced would be consumed. The IKEA proposal estimates an annual consumption much higher than the real one (5652 kWh) and a very optimistic panel production.
The results of the proposals show the importance of doing more calculations, especially to find the real period for the return on the investment. ten years is the limit that DECO considers acceptable.
Also Read: Supports to make houses more efficient is in phase 2. What changes?