Thinking Energy

Discussing how to make intelligent decisions about energy

Thinking Energy Manifesto

This manifesto is a call for the four principles I believe we should always apply when undertaking energy engineering or analysis generally but in the built environment particularly around CO2 emissions and energy efficiency. At present  these factors are often overlooked or ignored and this has or will have the impact of increasing CO2 emissions

Analysis should be undertaken over a realistic period – For example if calculating the CO2 emissions savings of a solar farm/roof or new boiler then those calculations should use the appropriate emission factors over the realistic lifetime of that system, such as 20 years. This would enable the projected change in emission factors to be accounted for over the lifetime. This is absolutely crucial as our electrical system is decarbonising rapidly and our mains gas is actually slightly carbonising.

Analysis should be on the the real impact on our energy system – At present in our calculations, (for buildings related issues) we use a standard emission factor (kg CO2 per kWh) for gas, electricity, etc. Years ago this may have made sense, it doesn’t any more. You can save or generate a kWh in many different ways and they have greatly varying benefits. For example solar power generates during daylight, mostly in the summer when we need that power least; an LED lamp that saves the same amount more often during hours of darkness and in the winter, when we need energy most. As energy at peak demand periods is generally more expensive and CO2 intensive the saving is much more substantial. On this basis an LED lamp that saves 1kWh is much more beneficial than a solar array that generates 1kWh and yet our system does not notice that.

Always consider “Real World” performance – We should seek to understand what the likely “real world” performance is likely to be, often known as “in-use” factors. Some systems perform very closely in line with projections and some don’t. For example solar power systems generally perform at 100% of projections, (often slightly higher), the same can be said for wind farms; on the other hand district heating networks, MVHR systems and particularly retrofitted energy efficiency measures, such as insulation are well known and shown to perform much less well than projected.

Consider the impact on other issues – When we undertake analysis energy efficiency and/or CO2 emissions are not the only relevant criteria; issues such as affordability and air quality, energy security and the impact on the wider energy system should be considered. For example when we deploy systems in our cities that are gas/oil based, such as CHP engines or gas boilers they emit air pollution and yet many policies and analysis are not taking this into account. There is a similar issue with solar power, where its use necessitates additional stand-by/spinning power generation that isn’t accounted for when a system is deployed.