Glossary

The unique 11-digit number identifying your electricity connection point, printed on your electricity bill. You need it to register on the ESB Networks customer portal and access your half-hourly meter data.

The CSV export from ESB Networks containing one Active Import reading every 30 minutes, in kW, covering up to two years. This is the file Home Battery Planner needs to generate a battery recommendation.

The rated power output of a solar PV panel or array under standard test conditions (1,000 W/m² irradiance, 25°C cell temperature). In Ireland, a south-facing system at the optimal tilt generates around 900–950 kWh per kWp per year.

Annual energy output per unit of installed solar capacity — a measure of how productively a system uses its rated size. South-facing arrays in Ireland achieve roughly 900–950 kWh/kWp; east/west-facing arrays achieve around 750–800 kWh/kWp.

The percentage of a battery's nameplate capacity that can safely be used before recharging. Home Battery Planner models 90% DoD — a 10 kWh battery has 9 kWh of usable capacity.

The ratio of energy retrieved from a battery to the energy used to charge it. Home Battery Planner uses 90% — meaning 10 kWh of solar sent into the battery yields 9 kWh back out.

The share of your own consumption you meet without buying from the grid. Reported month by month in the seasonal section of the report. Not the same as self-consumption: a dark December can score high on self-consumption (you use nearly all of the little solar you produce) while covering very little of what you actually consume.

The share of the solar you generate that you use yourself rather than exporting to the grid. This is the curve the solar-led battery recommendation is sized against — the knee is the point where a bigger battery stops capturing meaningfully more of your surplus.

The inflection point on the self-consumption vs. battery capacity curve where adding more capacity yields diminishing returns. Home Battery Planner recommends the smallest battery size where the next step up adds less than 3 percentage points of self-consumption.

The share of solar generation consumed on-site — directly or via battery — rather than exported to the grid. A self-consumption rate of 80% means 80% of all solar energy produced stays in the home.

The percentage of a household's daily consumption that a fully-charged battery could cover. Relevant for night-rate arbitrage: charge cheaply overnight from the grid, discharge during the day to avoid peak import rates.

The SEAI scheme under which Irish households with solar PV can sell surplus electricity to their supplier at a guaranteed export rate — currently €0.135/kWh. Home Battery Planner includes MSS earnings in its payback calculation.

A solar inverter that manages both the PV array and a battery bank in a single unit, handling charging, discharging, and grid export. Replaces the need for a separate battery inverter and is the standard choice for new solar + storage installs in Ireland.

Small-scale on-site electricity generation. In Ireland, residential solar PV systems up to 50 kWp qualify as microgeneration and are eligible for the SEAI MSS export tariff and a grid connection under the non-firm access rules.

The ESB Networks form used to notify the grid operator of a new micro-generation install (typically up to 6 kVA single-phase or 11 kVA three-phase). It is submitted before the system is energised — usually by the installer on the homeowner's behalf — together with a type-test certificate confirming the inverter meets the IS EN 50549-1 standard. Submitting an NC6 is what registers the install for smart-meter export readings and is a prerequisite for claiming the SEAI Microgeneration Support Scheme (MSS) export payments.

An electricity plan that charges different unit rates depending on the time of day — typically a cheap night rate and a higher day or peak rate. Smart tariffs incentivise shifting consumption to off-peak hours and are the main reason a battery can pay back faster: charging from the grid overnight at the low rate and discharging during the expensive band is pure arbitrage. Home Battery Planner models tariff-specific battery charging strategies in the tariff comparison.

A promotional rate reduction offered by Irish electricity suppliers to new customers, typically lasting 12 months. Welcome discounts reduce your first-year bill but expire after the introductory period. Home Battery Planner shows first-year costs as small text in the tariff comparison and uses the ongoing (post-discount) cost as the main figure so the savings arithmetic is consistent across years.