Monday, 17 October 2016

If we had infrastructure like the Dutch, how many of us would be cycling?

I have been having fun with the PCT (Propensity to Cycle Tool) which estimates how many commuters would cycle, based on a different scenarios. Cambridge has a high proportion of cyclists already but there is still scope for improvement.

Looking at Cambridgeshire as a whole, as of the 2011 census 9.7% of commuters cycle but if we behaved more like the Dutch it would be 23.7%. You can use the map view to drill down into specific routes. In the snapshot below I have activated the popup on a section of the Madingley Road. In the Go Dutch scenario we could have 80% more cyclists.
Screenshot of the PCT showing potential for increased cycling on the Madingley Road in the Go Dutch scenario

Sunday, 16 October 2016

An overview of energy storage - where we are now.

We know we need energy storage, but what does that actually mean? How much is enough? What are our options? This is a large subject but I am going to try to give a birds eye view of the main issues because Transition Cambridge Energy Group are going to discuss this soon. I am primarily concerned here with electricity, though heat is also useful. There are three parts to this post: a bit of economics, a run through of the technologies and some examples of (mostly) existing installations. Northern Ireland now has grid scale examples of both compressed air storage and flywheels while England has a pilot liquid air energy storage system and some inter-seasonal heat storage. Battery storage is important but it is not the only game in town.

Tuesday, 11 October 2016

My flood story - why we need smart water meters too

I am somewhat obsessive about energy use and read our meters weekly, as I have said before. But I am not so diligent regarding water use. If I was, I could have saved us £100s on our water bill due to a massive leak we did not notice!
Our water bills should say:
Your consumption:

This period: 230 litres/day
Last period: 200 litres/day

Your consumption has increased 15%

Sunday, 2 October 2016

Can you fit carpets with underfloor heating?

Through OpenEcoHomes I recently visited two homes with underfloor heating and was surprised to find that one had a rug covering most of the floor and another had wall to wall carpet. I used to think that carpets were very bad with underfloor heating because they tend to block the heat coming up from the floor. However, many carpet manufacturers cite research commissioned by the Carpet Foundation that shows that carpets and underlay with a combined TOG value of up to 2.5 'allow underfloor heating systems to work efficiently'. For example Jacaranda quotes the research here. Is this really true? As usual, the answer is 'it depends'. In this case, it depends on what is supplying the heat. If you have a gas boiler, fine. If you have a heat pump then carpets are a bad idea.

Thursday, 15 September 2016

Does the UK need solar electricity?

I am not against solar PV panels in other countries where the pattern of demand is different, but in the UK our peak heating demand is in the winter time when solar power is low. Wind on the other hand peaks in the winter too so is a natural fit for our demand pattern. But does wind generation really match our demand well, or do we need mix of other types of generation? The answer was not as clear cut as I expected.

Saturday, 10 September 2016

How to make sense of your meter readings - and make them useful

I have been taking gas and electricity meter readings on a regular basis for about 5 years now and I can use this data to make some pretty graphs, showing energy use through the year. However, heating energy depends on the weather which makes year by year comparisons rather meaningless. Adding in temperature data as well makes it much more interesting and genuinely useful.

Thursday, 25 August 2016

Electricity is getting cleaner - should you heat or drive with electricity now?

Increasing renewable electricity (and less coal) in our mix is having a real impact on the carbon emissions from electricity. I used to say that electricity cost (roughly) three times as much as gas and generated three times as much carbon emissions - but now electricity is only twice as much as gas for carbon emissions. This has implications where you have a choice of fuels. For example, heat pumps for heating will now generate less carbon emissions than gas even if their performance is well below average. Also it increases the benefits of switching to electricity for cars. However, decisions made today are often based on out of date carbon factors.

Carbon emissions factors for grid electricity. DUKES is most up to date - DEFRA lags by 2 years (other differences are described below). Natural gas is added for comparison, based on gross calorific value (as appropriate for a condensing boiler)