How homes using solar power can get set to sell electricity back to the grid

It’s surely sunshine all the way; the potential contribution of a feed-in-tariff (FIT) — environmentally sensibilities aside. 

With the current grant supports for domestic photovoltaic (PV) systems, only the relatively privileged can put the capital (or even a loan) into a meaningful household array that would significantly benefit from a PV system and FIT payments for their excess production.

I was advised by my installer in 2019, given my budget, that getting the best from my array for my investment meant tailoring a system to serve the house first and foremost. 

The MSS or FIT payments are likely to be reasonable, wholesale prices, but without a large excess gain from the roof, they will make a puny financial hit to a bill.

The proposed Clean Export Guarantee (CEG) tariff is the amount that FIT should raise per unit or kWh for currently an unknown amount but to be set by the Commission for Regulation of Utilities. 

The first c/kWh prices coming from suppliers recorded over a billing period via a Smart Meter, is falling somewhere between 13c/kWh and 14c/kWh. SSE has gone with 14c/kWh, and Pinergy will pay customers 13.5c/kWh. 

Offers will vary and may be tied to a particular contract. Most suppliers are gathering “declarations of interest” letters or assuring their customers with the required NC6 form (a declaration from the ESB that you are a grid-tied micro-generator) that they will “be in touch”.

All are still finalising the system for receiving export-data from ESB networks.

“All suppliers will make payment to eligible micro-generation customers by August 31, 2022, and this payment will be backdated as per the below guidelines. If you met all eligibility criteria on February 15, 2022, when the legislation was enacted, your payment will be backdated to this date,” states Electric Ireland.

If we go north of 13c for every kWh of excess PV units bled back to the grid, with 4.3kWp on the roof — the first bill I receive when the FIT payments kick in, will count. 

This is largely because the excess units sent back to the grid are being back-dated to February 2022. After that bill, the FIT units will take a welcome bite out of the hefty standing charges and Public Service Obligation (PSO) levy that no grid-tied PV household can escape. This will appear as a credit on my bill, significant for the brighter months of May to September. 

I am estimating a credit of €90 (€150pa) by 2023 at 13c-14c/kWh on my bill. I simply don’t let much solar power fall back to the grid, schooled on the old PV principle of “use it or lose it”. My battery, water diverter, and electric vehicle (EV) are fed first.

The findings by MaRIE include the potential influence of 3.2Kwp per sized arrays trickling split kWhs of sustainable power back to the grid. I have a larger 4.2kWp array and I run around here like a neurotic squirrel, making best use of it. Still, there is that cut in 135,000t of carbon emissions and €450 slashed off a standard household bill to consider, also projected by MaRIE. 

We are now deemed by Environment Minister Eamon Ryan, as “active energy citizens”. It’s the collective generation and grid return from all our PV arrays, however scanty for some, that makes MSS a future sustainable triumph.

There are only around 25,000 households using PV arrays in the Republic. Trust me, most of us are searching madly online for news about where FIT is headed. Just like getting PV for charging an EV, it’s vital to be realistic with FIT. To make €500 in one year on a generous 14c/kWh, you would have to generate 3,571kWh in excess. 

That’s the amount of power I use in my home in one year. If you are farming, there is now improved grant aid of up to 60% to install seriously big and productive arrays on agricultural sheds.

If there is a change to the Targeted Agriculture Modernisation Schemes rules (and there should be) this is where the big payouts tipping into actual profit from MSS will inevitably go: To medium to large commercial enterprises.

Incentives

Don’t invest in PV in the belief that you will make out like a bandit on FIT. FIT is one on a short list of incentives to make the costly transition. The future of FIT is uncertain. It’s maddening that it is low-income Irish households barred from PV by its price; who would benefit most from conquering horrific electricity bills with PV, a battery, and the additional FIT mechanism.

Putting in PV for an EV, or scaling the array up to partially charge one, doesn’t make economic sense. There are good kWh rates for EVs charging at night on NightSaver and smart meters — as low as 7c/kWh (Energia).

Installing a larger PV array is expensive, even with €2,400 from the SEAI. Improving PV is expensive with additional panels, with a potential up-scale to the inverter for your little power plant. This latter move will not be SEAI grant aided. 

It appears to me that for enthusiasts, the array cannot be big enough. Should you concentrate on exporting rather than storing? I was initially baffled to read the posts of potential PV householders on social media, buying huge arrays but eschewing batteries. Batteries don’t work in isolation, but segue with real-time solar gain and grid power to drop down the power you need during the day and night (load balancing).

If you are in the position to easily afford a battery — then chances are you will get a battery. When you’re out, you can be stashing free power into the battery (as we do n our house) and then take advantage of FIT payments once the battery is full. 

After 11pm in the winter, you can download more power at a low overnight tariff directly from the grid to your battery (load-shifting) to use the next day — which could be a dark day.

An array without a battery will send all excess not used instantly in the house, by a hot water-diverter or for charging an EV, back to the grid. With a big array of this FIT excess, it could offset your consumed grid power units to the point that you’re paying very little in the brighter months. It is possible over the year that you could pay zero — obliterating even the standing charge in FIT credit. 

This is superb if you have a huge array of 8kWp-plus, and it’s something of a boutique area for those able to cover their home and out-buildings with panels. This is not the situation of most families, and dare I mention the vagaries of the Irish weather. There’s an odd technical thrill for some buyers in over-sizing a PV array. even with long years of payback.

Where low-income households with medical needs receive an array (part of recent Government plans), at least with no battery in the house, they will get a squeak of collection credited to their bill through FIT gained on bright days.

The price of a battery is something that puts many householders off PV altogether, so it could be argued that with FIT, an economical SEAI grant-aided project will start earning its keep in excess in spring/summer.

I elected to get a Smart Meter in February thinking it would be the most economical in terms of a power deal, and to take advantage of the micro-generation scheme when it finally blazed to life.

Now as an EV owner with a rudely increased standing charge, and unable to access the best night-time rates offer by NightSaver meters, I have some regret. To take advantage of the micro-generation scheme, it’s generally obligatory to have a Smart Meter.

EV owners who are enjoying low day/night rates with NightSaver meters — take note. You will have to make a choice — the Smart Meter and FIT payments, or the NightSaver with the best night-time tariffs to charge your electric car.

• Next week we will explore how to get involved in microgeneration, how to choose PV-friendly power deals, and share stories of PV users