Sometimes a table of numbers or elegant prose doesn't get the message across where a graph or a chart gets straight into the brain. Renewable energy is not exempt from this truth.
For example, I've being trying to understand how the carbon intensity of the UK's electricity grid changes with time (by hour/week/month) and even my feeble attempts at charting have really helped me understand.
Can We Live on Renewables in the UK?
Even ignoring issues of supply intermittency, Chapter 18 of MacKay's book illustrates with simple red and green stacks of consumption and generation the difficulties of living on 'our' renewables in the UK, even including PV farms in remote deserts, and other generous assumptions.
I'm trying to make this even easier to understand by making it more of a 'what-if' tool, usable by almost anyone, but good enough for policy makers and decision takers!