Sponsored by


SOLAR POWER


17


As well as improvements in


transmitting DC over distances, we are now seeing the growth of microgeneration, where businesses and homes are fitting more and more photovoltaic (PV) cells, wind turbines and even water turbines, all of which generate DC current. For all the above reasons, the Gree research and development laboratories in China are continuing their development of equipment that can make the most of these new circumstances. Already, the company is on the second generation of VRF equipment that is designed to work directly from PV cells with built in controls that mean no loss of power, with the ability to charge banks of ever improving batteries with DC power. If heating or cooling is not required over the weekend, that provides two days when the charge can go straight to recharging the


batteries. Charging can also take place over the week, as there is usually more charge from the PV than is required for the VRF. So far, experience has shown that this can save at least 30% of running costs. In my view, it is not going to be too far in the future before most buildings are going to come with built in microgeneration capacity – enough for their own use and more – and banks of high efficiency batteries, in much the same way as we now have built in ring mains and plumbing.


All of this will reduce


transmission power loss enormously and reduce the need to build ever more power stations to cope with our insatiable appetite for electricity; while admirable strides in efficiency means that individual appliances are taking less power, we are continually adding new electrical equipment to the list of things we use every day.


Obviously, the fewer power


stations the less carbon dioxide is generated. Even nuclear power stations, which do not use combustion, still have support vehicles. Also, reducing demand by relying more on microgeneration means there is a better chance of supplying the bulk of the power that must be generated centrally from tidal, wind and solar power. The other consequence of


moving to DC and microgeneration is that we will inevitably move still further towards heat pumps for heating and hot water, as well as cooling. It is the only really environmentally friendly form of heating that can take full advantage of microgenerated electricity. Biomass and gas heating, may, with technological improvements, be able to hold their own in the environmental stakes for a while, but not in the long-term.


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