2.6.2. Carbon Credits

Carbon credits are awarded for the reduction in GHG emissions which can be traded in international market at their current market price. CO2 has been traded at € 21 per tonne CO2 eq [42] and each ton reduction in CO2 is a carbon credit earned [43]. The total carbon credits earned is described by Equation (12):

$$\text{Total carbon credit} \cdot \text{earned} = \text{Net CO}\_2 \cdot \text{migration} \cdot \text{price} \tag{12}$$

where,

*price* = Current market trading price

> The yearly carbon credits earned is described by Equation (13):

$$\text{Yearly carbon credit earned} = \text{Total carbon credits earned} / \text{T}\_{LS} \tag{13}$$

### *2.7. Financial Assessment of the Solar PV System*

While use of solar PV systems has increased, it is suggested that they need to become more price competitive to sustain further growth [36]. A grid connected solar PV system can reduce capital and maintenance cost by eliminating the need for battery with the grid acting as a storage bank [44]. The financial assessment of the solar PV system is based on current market prices of the project components.

A review of residential solar installers currently active in the Irish market, determined the approximate cost per kWp for a fully installed rooftop solar PV system was €1744 [35]. The Sustainable Energy Authority of Ireland (SEAI) in their payback calculator for domestic solar PV have considered the approximate cost per kWp to be €1900 [45]. Solar PV system cost can vary depending on the quality of solar PV panels and installation and after sales support. The project cost includes [36] the cost of modules; cost of inverters; miscellaneous costs {electrical items such as cables etc., installation cost, packing and freight etc.}; and cost of operation and maintenance.
