The Solar Bucket - The Next Step

The lesson of the Solar Bucket can be summed up as solar is not a straight swap for the fossil/nuclear grid.  The fossil/nuclear grid supplies vast quantities of energy on demand (that is what it is meant to do), renewables like wind and solar provide modest quantities of energy when the weather permits.

One approach to using renewables as a step towards a cleantech energy economy, is to separate them from the fossil/nuclear grid and start again.

To use renewables successfully, requires:

The load should be consistent with supply.  The average domestic electricity consumption in the UK is around 4,700 kwh/year.  A typical PV solar installation produces between 1,000 and 2,500 kwh/year.  However, it is desirable to get consumption down to less than 2 kwh/day (approx 700 kwh/year)

The system should include some form of storage.  Batteries and the associated management system are a significant element of the system cost.

A back-up supply is needed.  The lower the level of consumption the easier it is to arrange a back-up.

Since I started messing with this stuff, there has been the idea of taking the back-office part of my very small business off-grid.  With the experience of Solar Bucket 1 and the knowledge gained from writing modelling software, there are some clues as to how this might be achievied.

Select computing equipment with very low energy consumption.  It should be possible to find something that consumes significantly less than 10 watts/day.  At the time of writing, conventional laptops have been rejected and the focus is on one of the basic Intel motherboards with an Atom processor.

Solar panel selection will be left until the load is fully understood.  An interesting part of this process will be determining the economics of operating during the winter months.

Storage will be some form of lead-acid battery.  Part of the decision will be the operating voltage.  It maybe that 6 volts offers advantages over 12 volts.

Apart from basic safety functions, the computer will be responsible for energy management.

Safety was not an issues with Solar Bucket 1, however, it needs to be taken into account if the equipment is being used within the home/office - Is there any appropriate safety standard for low voltage systems.

The plan is to get some form of design in place by then end of 2010 in time to see how things work during dark and gloomy months of Jan/Feb 2011.