Use-your-own boost for solar power
Electric car firm Tesla sees solar power as a key energy source for the future and this house shows - or rather hides - one key feature. Tesla has created a Smooth Glass Tile, fitted to the roofs here, glass-coated solar panels that cover the whole roof and will last a lifetime. They even come in a French slate pattern and will be brought to the market later this year at "about the same cost as a normal roof".
Anyone planning to fit solar panels has been given a powerful incentive as parliament has approved a law to allow households to use energy direct from their panels at the same time as the government revealed new grants for roof installations.
Previously, house-owners had to sell the power to energy suppliers such as EDF but the feed-in tariff for this had fallen so much – down last quarter to 23.54 centimes from 58 in 2011 – that solar take-up slumped.
Now, there could be a new impetus as the government grants available make the sums start to add up again.
With €800 grant offered for every 1kW of solar panel output in residential projects, that would mean that a typical 3kW installation for a three/four person household, costing an average of €12,000, would get €2,400 aid. This brings the cost down to €9,600 and should be paid off over nine years.
Each year about 25,000 families install solar panels and the government hopes that two measures will help double this number as part of the transition to renewable energy.
Environment Minister Ségolène Royal said low energy prices had slowed down the change and she hoped the new measure would provide new impetus.
She also hopes more local councils will start to see so-called autoconsommation, self-consumption as a way to cut costs in social housing and other public areas.
Using power from their own solar panels gives households a double boost as they are selling excess energy for more money than they pay when they use it and they save on the cost when they use self-produced energy.
However, in real terms, solar energy firms such as Bosch estimate that the natural self-consumption rate is only about 20% for a one-person household and 40% for a five-person household with a 5kW system.
That means the ‘useful’ period of self- consumption – when panels are in full sun and at peak 5kWp output – is actually quite limited in most homes with limited energy demand during the day for powering the washing machine or air-conditioning and no energy production at night. So the feed-in tariff is a vital way to subsidise costs.
In public buildings, however, this could make a big difference as excess energy could be diverted to heat hot- water tanks or even swimming pools.
The government has also set new measures to encourage public installations of up to 100kW and a special tax regime is being prepared for solar farms with output of under 1MW.
Despite the feed-in tariff falling from 58 centimes to 23.54, France is still much better than the UK where over the years it has fallen from 49p to 4.4p.
Advocates of self-consumption say that using batteries to store some of the energy created by solar panels is a way to live “off-grid” completely and could also mean families could turn towards smaller systems that are more adapted to their needs and not the feed-in rate.
Avoiding negotiating feed-in contracts with EDF or other companies would be a big plus for battery storage but the general technology is still not very advanced.
One company making big strides is electric car firm Tesla, which is starting to commercialise its Powerwall 2 system where its 14kWh battery can power a house for a whole day.
The snag is the price as the Powerwall 2 costs €6,300 with €1,100 for installation – €7,400 total (inc €1,250 VAT).
