£9bn due to not having built more cheap onshore wind, £5bn due to poorly insulated homes, £5bn due to low solar deployment, £3bn because new homes were built less efficient.
Link me to a heat pump that produces water for central heating at 70C or more. Typically, flow temperature is closer 40C, which won’t heat the average house unless you increase (possibly double) the size and/or number of radiators. Which is expensive and not always feasible. You can run heat pumps at higher flow temperatures, but that reduces their efficiency. Don’t get me wrong, i think they are great. But successfully retrofitting to old UK housing stock needs expertise that is in short supply.
Houses that can’t be further insulated simply need a bigger pump and larger radiators to make it work. No need for 70 degree flow temps at all, though 50 is easily achievable. With the government grant Octopus are currently charging not much more than a gas install.
I’m not saying it can’t be done. But a larger heat pump and replacing all radiators drives up the cost, there is not always space for a bigger radiator, (and water tank), and while higher flow temperatures are possible, it tend to reduce efficiency. Sometimes it’s just not worth the investment, not helped by the big gap between gas and electricity prices in the UK
