How the sunny side up can lead to solar energy savings

Last spring nine households in my neighbourhood, ourselves included, decided to invest in rooftop photovoltaic (PV) panels in an effort to reduce our electricity costs and our carbon footprint.

We discovered that less than 12 sq m of PV panels is planning exempt and that they can be installed on all sorts of roofs such as slate, tiles (both cement and recycled rubber), standing seam and flat roofs. While a south-facing orientation is best they will produce electricity facing east and west but they won’t work if they are overshadowed. They produce electricity silently.

On the bright July day that our household’s panels were put in place the whole process was as easy as the installers Construction PV had promised in their prior assessment and quotation.

They attached the panels to our roof, ran metal ducting down the back of the house, drilled a hole through the wall and hooked the panels up to an inverter, a neat white box with a read-out panel that they attached to our utility room wall.

Sandyford semi grows in size and price, €355K-€800K in a year

---

What €350K buys in Terenure, Lucan, Stoneybatter and Sligo

---

Mosse mugs and snail plates - what sold at Mary Robinson country home sell off

---

By then it had started to drizzle. Much to my amazement, our panels were generating 450W of electricity.

The realisation that our family home had in one short morning become a micro-power plant caused a ripple of excitement – our seven-year-old burst in the office door the next day exclaiming: “Mummy, we generated 2072 watts!”

We became obsessed with how much electricity we use and how to use as much of our solar electricity as possible when it’s being generated.

Eco programmes

We dug out electrical appliance manuals and searched online to discover that eco programmes really do save electricity, that one ceramic hob ring on our old cooker demands 1700W and that my computer uses 106W or a little less when idle.

The biggest revelation was that even on the sunniest summer’s day our south-facing PV panels would not generate enough electricity to boil our kettle. Why? Because they produce a maximum of 2200W and our kettle needed 2600W.

We promptly ordered a 650W kettle! We also started running washes and charging up appliances in bright daylight hours, rather than at night.

Our determination to maximise the use of our solar electricity is driven by the fact that we have no way of storing our excess capacity (currently batteries cost more than the panels) and we don’t get paid for the electricity that we send to the grid. It’s a case of use it or lose it.

The recent citizens’ assembly that considered climate change overwhelmingly recommended legislative support for domestic micro-generators to sell back into the grid with a so-called feed-in tariff.

The Minister for Communications, Climate Change and the Environment, Denis Naughten, says he is "committed to finding a correct mechanism for developing small and micro-scale generation in Ireland" but has excluded support for micro and small-scale renewable generation from his new renewable electricity support scheme.

Optimistic

Despite the lack of a feed-in tariff Robert Goss, director of Solar Electric Ireland, is optimistic about domestic PV installation. "Compared to keeping €5000 in the bank, investing €5,000 on your roof is very beneficial. If you do the calculation on payback of PV and include 5per cent electricity price inflation the payback comes down very rapidly."

There are currently two Sustainable Energy Authority of Ireland schemes under which PV can be grant-aided although neither is open to individual householders and both prioritise energy efficiency rather than production. There’s the deep retrofit pilot scheme and the better energy communities scheme that my neighbours and I went for, with up to 50 per cent grant aid.

Support for PV can also fall under the superhomes scheme run by Tipperary Energy Agency in which individuals can retrofit their homes to an A1 building energy rating (BER). Domestic PV panels improve your BER and may push your home up a grade.

Annual savings

PV installation qualifies for the Revenue’s home renovation incentive scheme as advertised by Electric Ireland as part of its solar PV package. Qualifying customers can install a six-panel 1750W system for €3,980 including VAT and can save around €240 annually depending on location, roof angle and orientation, according to the company.

It was particularly easy to incorporate a PV system into our house so our total cost before grant aid, which has yet to be reimbursed, was €2,800 including VAT. Soon after installation our SSE Airtricity monthly budget plan was recalculated from €72 to €55, so a saving was immediately apparent. Our online monitoring gismo tells me we've reduced our emissions by over 300kg of CO2 equivalent compared to using predominantly fossil fuel-generated electricity from the grid.

While we now pay less attention to our PV panels than during those first heady weeks, we hope to keep improving usage of our solar electricity. Top of the list is a low wattage slow cooker. Then come storage batteries and an electric car.

In the meantime the kettle takes longer to boil but on a bright day it’s worth the wait.