Many companies are concerned about their supply chain. In particular, they are concerned about how suppliers will cope with setbacks such as loss of power and they want a plan in place.
Moreover, some companies will not accept that you have a viable plan unless you have tested it.
One client was forewarned that power would be disconnected for several hours, so they arranged to hire generators. Come the day that power was lost, they found that their phone lines did not work; and they were in an area where mobile phone coverage was non-existant.
So, identify what could go wrong, have a plan in place and make sure it will work.
There's guidance on the SSS website on this, and we also show how we can help. See http://www.strategicsafety.co.uk/BusinessContinuityManagement.html