Let the sunshine in: How to use solar energy to slash winter bills
With Dynamic Interact Kws And You Selling System Using In Battery, Farming Effectively Solax Get To And Grid, Your Picture: A Can Know The Solar Ways
Despite the annual fall in grant aid managed by the Sustainable Energy Authority of Ireland (SEAI), solar-photovoltaic panels are still popular in Ireland.
The figures show — we have the means to shine with this standalone renewable and prices for solar systems are increasingly competitive and highly transparent. Installations for the first half of 2024 were up by almost 50% compared with the same period last year.
Over 100,000 rooftop micro-generators have now been connected to Ireland's electricity network (ESB Networks). Our solar-PV capacity (farms, commercial installs and domestic rooftop solar) equates to 220 watts of solar PV per person, just behind the UK. At year’s end, this figure is expected to be 297 watts per person.
Around 90,000 of us are exporting our excess power from solar PV to the grid (from 30,000 in 2022).
According to the SEAI, the average system size continues to increase year on year, as panels become more efficient. The average system size installed in Q1 2024 was 5.5kWp. The median cost for solar PV before the grant during Q2 was €11,059.
A generous 5.2kWh array comes in well under €7,000 without a battery (after full 2024 grant aid of €2100) if the roof doesn’t need any structural repairs.
Offers/installers including utility suppliers, are offering attractive packaged deals, and low-interest home improvement loans have tempted householders to pay their renewable energy systems off over five years or more as this standalone magician steadily earns its keep.
Capital cost aside, if there’s one thing that still puts people off solar PV, it’s seasonal performance. There’s no getting away from the shorter days of winter, the lower arc of the sun in the sky and the dramatic drop in collection from October forward. Yes, there are householders with massive arrays and multiple batteries who will continue to pay for most or even all of their power via their solar PV.
Where they “suffer” is in a fall in the return on their payments for energy returned to the grid via the Microgeneration Support Scheme (MSS) launched in 2022 (feed-in tariffs or FIT). However, some cute householders have found a way to farm power in other ways.
As an early adopter back in 2019, the crash in gain in autumn 2019 really stung. I had been warned to expect it and to judge the performance of my East/West 4.2kWp system over twelve months, not five.
The 6.5kWh battery that had got us through the nights for nothing, became an idling ornament in the laundry room, blinking out no more than 15% collection on typical, miserable, wet and darker days. My annual saving in unit prices is in the area of 75%, with the system having paid for itself by next year. I’ve had no battery degradation after seven years of cycling, two resets to the system have been remotely handled and uncomplicated (my original installer was PV Generation). I’m not complaining now. I see the bigger, sunshiny picture as it is.
This seasonality with solar PV runs straight into some shadowy talk from industry-led promoters, who suggest that a solar array will contribute significantly to the running of a BEV or PHEV car or firing up a heat pump all year long. I was alarmed to see one site offering a search facility for systems claiming credit profits from the FIT, which would only be possible living in Nevada, not Cork. Huge arrays of 9kWp are promoted in a hysterically upbeat, salesman speak, way beyond the needs of most households.
Spoiler alert — with an EV, you will draw down just about all your charge from the grid during the night on a very economical kW/h deal. kWh excess in summer is far more profitable when returned to the grid, not dropped into your car unless you’re sticking with a standard 24-hour tariff of 25c per kWh or more.
Solar export payments should not be your first concern when commissioning an array. Expect to generate €200-€300 in savings using export payments with a typical array, enough to put a good dent in your standing charge.
With the grant award managed by the SEAI down to a maximum allowance of €1800 from January 1 (unless you’re already in contract from 2024) it’s important to manage expectations. I remain evangelical.
Where a roof can take it, or a piece of ground is available for a ground mount, every home should have a solar-PV system to future-proof and insulate every family against the vagaries of energy prices, and to improve our renewable energy clout as a country.
My solar is still covers at least 30% of my kW unit demand from October to February, but on a very dark day, it’s relatively useless. After the initial despair, system owners without batteries, run their appliances sequentially using some solar help and otherwise shrug until Spring. With a battery, however, there’s a useful hack using cheaper overnight kWh charges. With FIT payments in place, it’s easy to dismiss the need for a battery. Still, a battery allows you to interact with the grid in a very dynamic way.
You don’t need to be proactive, the technique can be scheduled on the digital touchpad of your inverter to run quietly in the background of your life. Welcome to grid-shifting.
If you have a day/night (night/saver) meter you at least have two-tier time-of-use tariffs you can rely on with Day and Night prices per kWh. With a smart meter, you can usually have three tariffs.
Just as someone with an EV would charge their car battery during the wee hours for as little as 5c per kWh (in a dedicated EV deal of three or four hours of charging), many PV-solar users charge up their domestic batteries overnight from the grid.
This means you start the day with a fully charged house battery which can be used alone before the sun comes up, segue into your feeble collection from the roof and combined with grid power (where needed for a big draw like an electric shower).
So, for instance, with a 6kWh battery, you might pay as little as 30c for 6kWh to deploy to the house, as opposed to €1.80 if we priced our day-time kWh at 30c in a time-of-use tariff deal (never mind those peak charges from 5pm to 7pm).
If you only have a standard night tariff, the saving is around 35% - 50% on daytime tariff prices. Check those unit prices in your current contract (inc. the VAT).
Frugal users (or those out at work all day), will still have some charge in their battery before nightfall, so charging overnight could cost even less if the battery is in double digits already.
Modern inverters have a setting that will handle this import schedule seamlessly. Current deals on low kWh prices include 7.5c/kWh (Energia) and 5c/kWh (Pinergy).
There are real enthusiasts who go even further. They are not just sending excess solar back from the roof year-round, but legally game FIT to fill multiple batteries from the grid overnight at extra low tariff prices of as little as 5c/kWh.
They then export the battery power back to the grid for the full FIT price of up to 25c per kWh. There’s no massive profit in doing this, but some householders are willing to double the cycles on their batteries to do it.
It’s worth noting that batteries remain expensive, generally doubling the cost of a PV-solar system, demanding a hybrid inverter and longer payback on your system for the investment.
Keep this in mind as unit prices from the grid are signalling a decline, and FIT unit prices paid to PV-solar owners on the MSS are open to change too.
That said, weigh the value of those solar export payments, if you have solar PV and you’re shopping for a supplier. Get more than one quote and look for experiences and recommendations on consumer sites including the excellent Irish Solar Owners Group on Facebook (62,000 members and counting).