To supplement the solar PV/refrigeration project during the winter months I'm also looking at wind generation and LPG storage and LGP generator technology. Perhaps even more outlandish than the cost effectiveness of solar PV claims are claims about how much domestic micro wind generation can save. I've seen manufacturers claims that it can save 30% on a domestical annual electricity bill. The reality is of course highly dependant on the wind avialable on site. The cost of installing a wind generator is prohibative for me for the actuall power it generates due to sheltered location. A wind generation installation is also expensive (similar to the cost of Solar PV) and requires planning permission.

A portable LPG generator might be worthwhile such as the Honda EU10i LPG portable generator for backup electricity generation if there was a grid failure.

http://www.hartindustrialtools.co.uk/acatalog/EU10i.html

A couple portable heaters running on 15Kg Butane bottles might be worthwhile to have as a backup if the electricity grid failed during the winter.

http://www.lpg-portable-heaters.co.uk/provence-living-flame-heater.htm

The cost of bottle LPG for heating is actually competative when compared to daytime electricity but about twice as expensive when compared the to the night time electricity tarrif when I use electrical storage heaters. One 15Kg bottle of LPG is enough to supply heat for around 7 days use in winter. A 15Kg bottle (almost 200KWhr of energy or 60KWhrs of generated electricy @ 30% efficiency) may be enough to produce enough electricity (intermittant generation to charge the 200A battery) for domestic refridgeration, lighting and entertainment for possibly a month.

Using an LPG generator to produce electricity in not very efficient i.e 70% will be waste heat with around 30% as electricity generated. Does anyone know of a domestic LPG generator installation which could use a heat exchanger to all least transfer some of that waste heat emission into the hot water system? i.e. a combined supplemental LPG gas heat/solar heat/Solar PV cell hot water/electricity generation system.