Our World in Data (and many others) tell us that wind and solar have fallen dramatically to well below the cost of coal- and gas-fired electricity. But their data look suspect for anyone who remembers the wholesale price of electricity in the mid-2000s. The claims for wind and solar have received a lot of well-justified scrutiny. They are nonsense. In this article, we look at another element - the cost of coal-fired electricity. It has apparently remained almost constant at around $110/MWh from 2009 to 2019. In reality, it was a fraction of that in 2009. The cost of coal has varied dramatically over the period, which will have produced much more variation in the cost of coal-fired generation than indicated by OWiD's misleading charts. When you look at how the costs and shares of various electricity technologies have varied over the period, it is impossible to square the claimed costs with the volumes and prices (wholesale and retail).

Clean energy advocates think we can use the batteries in an electrified road transport system to balance the supply of intermittent renewable electricity with the demand for electricity, including electrified heat and transport. They are wrong. It can work to a small extent, but it barely touches the sides of the problem.

Green armchair experts see interseasonal energy storage as the technology that will bring their plans together, and think it is just a matter of investment and technological progress. Most sceptics also think it's about technology, but believe there are insuperable technical barriers. In reality, the main barrier is economic not technical. We explore this fundamental economic challenge with reference to a recent announcement regarding one of the more promising technologies.

Labour's energy and climate-change proposals in their 2019 manifesto are vastly more expensive than they recognise - probably £1bn by 2030 and £1.5-2bn ASAP in the 2030s. This spending would reduce carbon emissions by less than 50% by 2030. One unintended consequence is that, despite so much infrastructure spending, electricity supply would occasionally be insufficient to meet the radically increased demand.

The decline of coal-fired electricity highlights important challenges for a network relying more heavily on intermittent generation.

A report from the Offshore Renewable Energy Catapult (OREC) notes that the value to the economy of offshore wind is less than the subsidy, but claims this will reverse. We question this.

The costs of the support mechanisms for renewable electricity are rising inexorably. From £0.5bn in 2011/12, the UK's environmental levies are now expected to hit £13.6bn in 2021/22.

Efforts to encourage renewable electricity and renewable transport do not have much effect on the overall levels of renewable energy. It is the levels of renewable heat that most strongly influence the overall delivery of renewable energy.