The following table shows the generation of electricity by the solar panels for each month in 2011 in units (kW.hours). It also gives the units exported. As we do not have an export meter these are defined to be half the units generated. The last column gives an estimate of the units saved (i.e. used by us and not actually exported). The numbers do not add up! This is because in the winter virtually all the units are generated over a very short period around midday - this may be used by the heat pump if it is running then. In the summer it is more likely that the electricity will be generated when it can be used (i.e. mornings and evenings), but even then it is difficult to use more than half the electricity generated. We maximised our usage in the summer by only running the heat pump for about an hour around midday, and also only using the washing machine and dish washer when we were exporting electricity. Overall we used about one third of the electricity we generated. The total saving was £1678 for the year although £108 of this was assigned to the heat pump (based on 13.17p per unit).
| Month | Units generated | Units exported | Units Saved |
| January | 53.3 | 26.7 | 16 |
| February | 75.1 | 37.6 | 28 |
| March | 296.2 | 148.1 | 86 |
| April | 494.7 | 247.2 | 131 |
| May | 509.0 | 254.5 | 240 |
| June | 435.3 | 217.7 | 149 |
| July | 446.7 | 223.4 | 240 |
| August | 338.1 | 194.1 | 271 |
| September | 305.3 | 152.7 | 150 |
| October | 217.6 | 108.8 | 60 |
| November | 84.1 | 42.1 | 41 |
| December | 69.1 | 34.6 | 38 |
| Totals | 3374 | 1687 | 1317 |
| Value | £1453 | £52 | £173 |
This table is for 2012. The total saving was £1600 for the year although £125 of this was assigned to the heat pump (based on 14.36p per unit).
| Month | Units generated | Units exported | Units Saved |
| January | 95.8 | 47.9 | 51 |
| February | 149.1 | 74.6 | 58 |
| March | 333.4 | 166.7 | 99 |
| April | 348.3 | 174.2 | 116 |
| May | 414.7 | 207.4 | 149 |
| June | 373.5 | 186.8 | 235 |
| July | 395.0 | 197.5 | 189 |
| August | 399.3 | 199.7 | 177 |
| September | 325.9 | 163.0 | 113 |
| October | 146.3 | 73.2 | 65 |
| November | 102.3 | 51.2 | 40 |
| December | 62.7 | 31.3 | 34 |
| Totals | 3146 | 1573 | 1326 |
| Value | £1362 | £48 | £190 |
This table is for 2013. The total saving was £1714 for the year although £125 of this was assigned to the heat pump (based on 14.36p per unit).
| Month | Units generated | Units exported | Units Saved |
| January | 55.7 | 27.8 | 38 |
| February | 113.4 | 56.7 | 66 |
| March | 164.6 | 82.3 | 68 |
| April | 383.0 | 191.5 | 107 |
| May | 424.1 | 212.1 | 198 |
| June | 432.0 | 216.0 | 216 |
| July | 529.8 | 264.5 | 255 |
| August | 439.0 | 219.5 | 265 |
| September | 257.7 | 128.9 | 166 |
| October | 143.6 | 71.8 | 53 |
| November | 88.3 | 44.1 | 23 |
| December | 64.5 | 32.3 | 39 |
| Totals | 3096 | 1548 | 1494 |
| Value | £1449 | £51 | £214 |
This table is for 2014. The total saving was £1885 for the year although £121 of this was assigned to the heat pump. Note that a new import meter was fitted in July and the cost of electricity dropped to £0.1239 per unit in the same month (about the same as in March 2011).
| Month | Units generated | Units exported | Units Saved |
| January | 76.2 | 38.1 | 53 |
| February | 131.3 | 65.6 | 79 |
| March | 312.0 | 156.0 | 111 |
| April | 371.6 | 185.8 | 111 |
| May | 411.0 | 205.5 | 213 |
| June | 485.6 | 242.8 | 259 |
| July | 519.4 | 259.7 | 263 |
| August | 393.3 | 196.7 | 226 |
| September | 294.8 | 147.4 | 178 |
| October | 150.3 | 75.1 | 81 |
| November | 76.4 | 38.2 | 29 |
| December | 69.7 | 34.9 | 48 |
| Totals | 3386.0 | 1643.3 | 1642 |
| Value | £1627 | £55 | £203 |
This table is for 2015. The total saving was £1818 for the year although £140 of this was assigned to the heat pump. Note that the cost of electricity dropped to 12.16p per unit in April (about the same as in March 2011). By the end of the year the solar panels must have produced as much energy as was used in their construction, transportation and installation so they can be considered "green" from now.
| Month | Units generated | Units exported | Units Saved |
| January | 84.2 | 42.1 | 67 |
| February | 111.4 | 55.7 | 66 |
| March | 275.9 | 138.0 | 111 |
| April | 455.2 | 227.6 | 240 |
| May | 434.5 | 217.3 | 238 |
| June | 503.0 | 251.5 | 265 |
| July | 417.3 | 207.8 | 273 |
| August | 332.3 | 166.2 | 215 |
| September | 321.4 | 160.7 | 203 |
| October | 161.4 | 80.7 | 49 |
| November | 49.9 | 24.9 | 6 |
| December | 32.9 | 16.4 | 15 |
| Totals | 3179.4 | 1589.7 | 1748 |
| Value | £1552 | £54 | £212 |
This table is for 2016. The total saving was £1804 for the year although £122 of this was assigned to the heat pump (based on 12.16p per unit).
| Month | Units generated | Units exported | Units Saved |
| January | 61.7 | 30.9 | 48 |
| February | 137.0 | 68.5 | 105 |
| March | 271.7 | 135.9 | 120 |
| April | 381.8 | 190.9 | 135 |
| May | 467.8 | 233.9 | 241 |
| June | 342.6 | 171.3 | 146 |
| July | 457.2 | 228.6 | 240 |
| August | 445.2 | 222.6 | 230 |
| September | 258.0 | 129.0 | 177 |
| October | 178.5 | 89.3 | 79 |
| November | 93.8 | 46.9 | 31 |
| December | 60.9 | 30.5 | 39 |
| Totals | 3156.2 | 1578.1 | 1588 |
| Value | £1557 | £54 | £193 |
This table is for 2017. The total saving was £1846 for the year although £133 of this was assigned to the heat pump (based on 14.03p per unit).
| Month | Units generated | Units exported | Units Saved |
| January | 80.8 | 40.4 | 61 |
| February | 91.3 | 45.6 | 42 |
| March | 263.7 | 131.9 | 79 |
| April | 430.1 | 215.0 | 172 |
| May | 405.1 | 202.6 | 200 |
| June | 484.2 | 242.1 | 216 |
| July | 436.7 | 218.3 | 233 |
| August | 412.1 | 206.1 | 209 |
| September | 253.7 | 126.9 | 143 |
| October | 140.4 | 70.2 | 50 |
| November | 96.4 | 48.2 | 39 |
| December | 44.2 | 22.1 | 32 |
| Totals | 3138.7 | 1578.1 | 1476 |
| Value | £1583 | £56 | £207 |
This table is for 2018. The total saving was £1891 for the year although £107 of this was assigned to the heat pump (based on 16.88p per unit). In April the net cost of producing a unit (55p - total cost/no. of units) dropped below the income per unit (56.47p) for the first time.
| Month | Units generated | Units exported | Units Saved |
| January | 56.6 | 28.3 | 45 |
| February | 165.9 | 83.0 | 102 |
| March | 169.6 | 84.8 | 100 |
| April | 303.3 | 151.7 | 124 |
| May | 520.9 | 260.5 | 241 |
| June | 520.3 | 260.2 | 245 |
| July | 507.3 | 253.7 | 246 |
| August | 382.0 | 191.0 | 229 |
| September | 312.6 | 156.3 | 111 |
| October | 200.4 | 100.2 | 85 |
| November | 74.0 | 37.0 | 49 |
| December | 44.3 | 22.1 | 29 |
| Totals | 3257.2 | 1628.6 | 1606 |
| Value | £1710 | £60 | £271 |
This table is for 2019 The total saving was £2007 for the year although £157 of this was assigned to the heat pump (based on 16.84p per unit). The total net cost of electricity including cooking and heating is £981 since the system was installed or about £100 per year (excluding fixed charges).
| Month | Units generated | Units exported | Units Saved |
| January | 73.3 | 36.7 | 57 |
| February | 149.9 | 74.9 | 72 |
| March | 233.1 | 116.6 | 112 |
| April | 370.1 | 185.0 | 154 |
| May | 437.9 | 219.0 | 220 |
| June | 401.3 | 200.7 | 217 |
| July | 451.9 | 225.9 | 223 |
| August | 432.5 | 216.3 | 217 |
| September | 297.0 | 148.5 | 161 |
| October | 145.9 | 73.0 | 43 |
| November | 76.6 | 38.3 | 29 |
| December | 56.8 | 28.4 | 41 |
| Totals | 3126.3 | 1563.1 | 1575 |
| Value | £1682 | £60 | £265 |
This table is for 2020. The total of income from generation and savings on domestic use (excluding the heat pump) exceeded the actual cost of installation on 12 August. The total saving was £2011 for the year although £151 of this was assigned to the heat pump (based on 16.75p per unit). The total net cost of electricity including cooking and heating is £882 since the system was installed or about £90 per year (excluding fixed charges).
| Month | Units generated | Units exported | Units Saved |
| January | 53.7 | 26.8 | 41 |
| February | 105.6 | 52.8 | 73 |
| March | 288.3 | 144.2 | 107 |
| April | 482.8 | 241.4 | 186 |
| May | 588.4 | 294.2 | 244 |
| June | 442.8 | 221.4 | 232 |
| July | 440.4 | 220.2 | 220 |
| August | 383.9 | 191.9 | 227 |
| September | 305.0 | 152.5 | 156 |
| October | 123.4 | 61.7 | 37 |
| November | 66.9 | 33.4 | 5 |
| December | 41.7 | 20.9 | 71 |
| Totals | 3322.0 | 1661.5 | 1569 |
| Value | £1834 | £64 | £262 |
This table is for 2021. The total income from generation (excluding savings) exceeded the actual cost of installation on 26 April, but this ignores inflation and lost of interest so we are still £9598 worse off at the end of the year. The total saving was £2160 for the year although £192 of this was assigned to the heat pump (based on 16.75p per unit). The total net cost of electricity including cooking and heating is £1262 since the system was installed or about £115 per year (excluding fixed charges).
| Month | Units generated | Units exported | Units Saved |
| January | 46.1 | 23.1 | 41 |
| February | 97.6 | 48.8 | 39 |
| March | 241.0 | 120.5 | 87 |
| April | 462.9 | 231.5 | 191 |
| May | 407.1 | 203.5 | 243 |
| June | 417.4 | 207.8 | 216 |
| July | 428.2 | 214.1 | 211 |
| August | 336.8 | 168.4 | 187 |
| September | 259.2 | 129.6 | 126 |
| October | 136.2 | 68.1 | 53 |
| November | 74.8 | 37.4 | 6 |
| December | 27.1 | 13.5 | 21 |
| Totals | 2934.4 | 1467.2 | 1421 |
| Value | £1642 | £58 | £238 |
This table is for 2022. The income per unit was 64.47p from 1 April, while the cost per unit increased from 16.75p to 36.51p on 1 April. This sudden increase has resulted in the net cost to us of producing one unit 0.26p is for the first time less than the cost of purchasing it. The cost per unit fell slightly on 1 October to 35.32p but the government rebate reduced it further to 24.81p but because the rebate is fixed the cost per unit varies with the number of units used. The daily electricity consumption excluding heating has fallen from 15 to 14 units per day partly because the second freezer (bought in 1981) failed at the start of July and will not be replaced, and secondly due to the gradual change to LED light bulbs.
| Month | Units generated | Units exported | Units Saved |
| January | 64.2 | 31.2 | 42 |
| February | 122.5 | 61.3 | 66 |
| March | 288.2 | 144.1 | 86 |
| April | 431.7 | 215.8 | 193 |
| May | 434.9 | 217.5 | 276 |
| June | 453.1 | 226.5 | 264 |
| July | 504.2 | 252.1 | 296 |
| August | 435.5 | 217.8 | 229 |
| September | 260.2 | 130.1 | 201 |
| October | 170.8 | 85.4 | 47 |
| November | 62.8 | 31.4 | 23 |
| December | 36.4 | 18.2 | 19 |
| Totals | 3262.7 | 1631.4 | 1742 |
| Value | £1945 | £68 | £300 |
This table is for 2023. The cost of electricity with a government rebate of £67 per month for the first three months and another £200 in February reduced it to 31.13p in January, 13.61p in February, 29.73p in March, 35.32 from April to June, and 31.16 from July with a £150 penalty. We generated the 40th MWh on 24 June.
| Month | Units generated | Units exported | Units Saved |
| January | 57.3 | 28.6 | 39 |
| February | 104.4 | 52.2 | 64 |
| March | 143.8 | 71.9 | 64 |
| April | 350.9 | 175.5 | 150 |
| May | 487.2 | 243.6 | 299 |
| June | 545.7 | 272.8 | 309 |
| July | 368.3 | 184.2 | 280 |
| August | 367.1 | 183.5 | 281 |
| September | 293.5 | 146.0 | 220 |
| October | 153.7 | 76.9 | 125 |
| November | 62.8 | 31.4 | 23 |
| December | 36.4 | 18.2 | 19 |
| Totals | 3262.7 | 1631.4 | 1742 |
| Value | £1945 | £68 | £300 |