From Sandy Henderson, Dunblane, Stirling, UK
Surely it is not so much a question of whether we can get all our energy from renewable sources, but that we must. The only point to debate is how quickly.
It seems likely to me that production of hydrogen fuel using electricity to split water will be a major part of this process. The resulting supply of oxygen should be extremely useful – for example in the incineration of waste. This would avoid nitrogen being involved in the combustion cycle and could make it easier to keep the process clean. It would also give us electricity as a by-product, not to mention district heating by exploiting the low-grade heat.
Further, much of the biomass we grow, whether for food or energy, captures and stores under 2 per cent of the solar energy striking the land used for cultivation. In comparison, solar panels convert more than 12 per cent and could exceed 30 per cent within 20 years. It is not that plants cannot be efficient, but that they cannot always use what is available. It now seems possible that growing staple crops indoors under artificial lighting can produce more food from less land, even when land use for solar panels to power it is included.
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