Dave Elliott: Solar power prospects are looking good, but for solar heat as well as solar electricity. It is clear than solar photovoltaic power generation is booming around the world, with over 580 GW of PV solar installed by the end of 2019, and much more expected, but it’s worth noting that there is also a large amount of direct solar heating system capacity in use (470 GW thermal), and that too is also growing. Most of this capacity is in the form of standard roof-top solar heat collectors, with China in the lead (330 GWth), but large community-scaled solar heating arrays have been developed in Europe and elsewhere, some of them linked to large inter-seasonal heat stores, allowing summer heat to be used for winter warming via local district heating networks. Denmark has been a leader in this field, with its flagship 13.5 MW Marstal project and many others. The heat stores typically involve large lined pits with floating insulating covers for heat retention. In most cases, the solar input augments heat supplied by other means, including from biomass combustion, but new approaches are being adopted which enhance the solar and bioenergy input using large heat pumps. Although (fossil) gas fired heating still often has the edge, solar heating with heat stores can be competitive with other heating sources if district heating networks already exists, as they do in Denmark. And of course the carbon emissions associated with using fossil gas are then avoided.
Renew Extra 2nd May 2020 read more »