Thursday, 12 October 2017

Can smart meters give us energy saving advice?

Would you like a smart meter that told you how much you can save by turning down your heating?  Current smart meters can't do this but researchers at the University of Bath reckon that it should be possible, with the aid of some extra sensors for temperatures and CO2 levels. They devised a system which could give you prompts such as 'We have noticed your thermostat is set to 23C. If you reduced the thermostat to 21°C you would save 11 kWh; this is equivalent to £1.43.'  (I think this must be per day and using electricity) [1]. They found that residents in their experiment were very likely to follow this advice. But all these extra sensors will be expensive - can we manage with less?

Wednesday, 4 October 2017

Recycling solar panels and PVCu windows

Over the years I have installed PVCu¹ windows to save energy (but actually mainly just to be warm) and solar panels for renewable energy - what will happen when they get old and have to be replaced? The way that we deal with materials at end of life can make a significant difference to the overall carbon savings. For example both panels and windows contain glass and other materials that take a lot of energy in manufacture. If they are recycled properly and reduce emissions from building the next thing, then the overall carbon emissions can be significantly reduced. Does this happen?

There are two issues with recycling that are slightly related:
  1. What is possible? How much material can be reused or recycled and how much energy can be saved by doing so?
  2. Does it happen? Is there a recycling supply chain that actually picks up most of the waste generated?

It turns out that for windows and for solar panels high levels of recycling are achievable. However, whether this actually happens or not is another question.

Monday, 2 October 2017

How to ramp up energy efficiency without subsidies

There are many things we can do to save energy at home but some of them take so long to pay back we can't afford to think that far ahead. If you factor in other benefits such as reduced carbon emissions and improved air quality that benefit society as a whole, then the finances look much better. But those costs (often called social costs) are not included in our energy bills and we would be very unhappy if they were, at least without some other compensation. Adding in the carbon cost to my gas bill would mean an increase of 25%! [1] We need a way of adding these costs to our bills without leaving us out of pocket. Maybe we need something like the Carbon Fee and Dividend. This would make a great deal more energy efficiency savings financially viable for households and businesses without subsidy.

Friday, 22 September 2017

Why I haven't installed a heat pump (yet)

If you read this blog you will know I am keen to promote heat pumps as a low carbon heating technology, so I feel a bit of a hypocrite not having one at home. Since we have insulated our house as much as we can it is a logical next step to a low carbon house. So I made enquiries with two heat pump installers - but no joy. This blog post is a personal story. Every house is different and doubtless you won't meet exactly the same issues, perhaps even none of them.

Friday, 15 September 2017

The cost of building too many solar farms

Solar panels give us plenty of power in the summer when we don’t need so much and not much in the winter when we do. Building solar is like going to the shops to buy a winter woolly and buying a stack of T-shirts instead. Last time I wrote about this I focussed on our pattern of energy demand and how that can best be matched to wind and solar generation patterns. I concluded that we need some solar now but less in the future. That post was criticised for ignoring costs. So this time I will discuss the extra costs of investing in the wrong sort of renewables.

Monday, 28 August 2017

How much water do power stations use?

It is world water week and the power generation sector is often blamed for high water consumption - how high is it really? First the headline figures. Current water consumption by UK power stations comes to around 13 l/person/day [1][2]. That is less than a tenth of the amount we use at home [3].

However, the amount of water used depends on the technology. Wind and solar power generation need no water at all but most nuclear and conventional power stations use water for cooling. Coal power stations use more water than gas, partly because they use water for cleaning sulphur out of the flue gases as well as for cooling. Nuclear power plants also use more cooling water than gas. This is partly because they are less efficient so they have to dump more heat and also because they don't generate any hot flue gases, so all their heat has to be dumped through the water cooling system.

Friday, 4 August 2017

Drawdown - review

My beloved has given me a copy of 'Drawdown - the most comprehensive plan ever proposed to reverse global warming, edited by Paul Hawken'. It is a superb book in many ways - incredibly ambitious and a real eye opener.

The book ranks 80 wide ranging strategies in terms of potential carbon savings, with estimates for up front costs and overall financial savings to 2050. Strategies range from wind power to vegetarian diets, from district heating to educating girls. There were some in the agriculture section I had never heard of such as silvipasture (growing trees and grass together for animals and tree products) and improved rice cultivation (a combination of improved planting schemes and intermittent drainage).

Some of the rankings are surprising - but on a closer inspection this is often due to their method of accounting, whereby only carbon savings over the business as usual scenario are included. This increases ranking for strategies that are not currently widespread, which is a good way to bring them to our attention.