An abiding memory of a day in August 2010, the first time my solar panels were connected to the grid, was of the builders downing tools and watching the electricity meter whiz round backwards.
It was a sunny day and they were supposed to be finishing the plastering and insulation, but the novel sight of the old-style electricity meter in reverse was too entertaining.
For the previous few months we had been refurbishing my new home, a 1930s bungalow, with some of the many “green” improvements that I had been recommending to Guardian readers during my 16 years as environment correspondent. Friends said I was “putting my money where my mouth had been”.
It proved more difficult than I imagined because there were so many options. In the end we settled first for super-thick insulation – three times the government recommended minimum – and a green roof over the flat roof extension for extra insulation. To add light to a dim interior, four triple-glazed skylights were built into the roof. We converted a double garage into a library, reinforcing the flat roof, and found space to install 10 solar panels facing south.
Of course, the electricity company soon rumbled the fact my meter was going backwards and dispatched a man in a fast van to swap it for a modern version that could only go forwards. He and they were cross.
Of all the “improvements” it is the solar panels that have been most beneficial, financially and for all the fun I have had out of them. The first cost – £12,000 for a 2.4kW system – was more than double the price a much better system would cost 14 years later. But the carrot for spending this hard-earned capital was that the government was prepared to pay householders 40p a unit for every kWh of electricity the solar panels produced – and that was index-linked and guaranteed for 20 years. This generous offer meant they paid me even if I used all the electricity myself.