Micro-CHP: a power station in your home

Combined heat and power (CHP) systems are a common feature of modern power stations where the waste heat from the boilers is utilised nearby for factories or district heating. They are very popular in Denmark where they have an extensive heat distribution network. The increased efficiency of the system and the financial savings has propelled the technology into large buildings and is often seen in hospitals, universities and large offices where the heat can be efficiently used locally.

cooling-towers-sm.jpgA power station in your home

Now the technology has made the leap to the domestic market. Domestic or Micro-CHP systems save primary energy use by converting natural gas to both heat and electricity. The waste heat of the system is captured and contributes to the total thermal efficiency of the system. The main types of micro-CHP systems are internal combustion (IC), sterling engines and fuel cells. The domestic units favour natural gas as the primary fuel due to the extensive infrastructure and low price, although there are systems now that can utilise biomass [1]. Due to the use of fossil fuels the systems are generally not dubbed "renewable" but the efficiencies and savings over traditional heating systems can offset greater fossil fuel consumption and are therefore "low carbon".

Harness a whirlwind

A new renewable energy technology called the Solar Vortex system promises to harness the power of the whirlwind. A whirlwind, dust-devil or "whirling dervish" is created when there is a difference in temperature between hot air close to the ground and cooler air just above it. The hot air rises and through the convection currents between the layers a small vortex develops.

The Solar Vortex system

The Solar Vortex system, created by Mark Simpson and Ari Glezer at Georgia Institute of Technology in Atlanta USA, creates the perfect conditions for a vortex to start. The system creates the convection through a hot, sun-baked metal sheet and channels the air currents through an array of vanes attached to a turbine to generate electricity. The system uses the natural convection currents to start and as the warm air rises more air rushes in to fill the void and produces a sustainable process.

The Renewable Heat Incentive

Rapidly depleting fossil fuel resources and international agreements to lower the anthropogenic carbon-footprint have led the UK to respond with promises to lower the country’s carbon emissions by 80 per cent by 2050.

heating accounts for 47% of the energy consumed in the UK

One of the ways in which the UK intends to meet this target is by providing the world’s first financial scheme to encourage renewable heating in domestic and non-domestic sectors known as the Renewable Heat Incentive (RHI). Currently, heating accounts for 47% of the energy consumed within the UK and 46% of the UK carbon emissions.

The RHI was introduced by the UK government in March 2011 to encourage companies and individuals to invest in approved renewable heating technologies.

Domestic biomass ... the low down

Burning wood to keep warm and cook food is as old as humanity itself. The traditional open fire, while still popular, is inefficient and wasteful. So now new energy efficient and "renewable" heating systems are available; from the ubiquitous wood-burning stove to state of the art automatically fed central heating boilers.

the warming glow of a real fire

So what is "Biomass"? Well it is just a modern term for non-fossil fuels obtained from organic material. The most common type is wood, such as timber from managed forests, timber industry waste or short rotation coppice (SRC), although other forms such as Miscanthus (elephant grass) or straw also can be used. The fuel is usually delivered as logs, wood chips or sawdust compressed into pellets. Although wood chips are not widely used in small domestic systems due to the large volume and low energy density for storage1.

setsuden: energy efficiency in Japan

Energy efficiency is not as glamorous as new cutting edge renewable energy technologies, but it may well prove to help reduce our reliance on fossil fuels sooner rather than later.

24 hour energy demand in Japan's neon capital

An encouraging case study is that of Japan. The huge earthquake in March 2011, and the subsequent tsunami severely reduced the energy supply potential of the country. The tsunami brought destruction of the Fukushima Diiachi nuclear power plant and led to the shutting down of the all the remaining plants for testing. Japan had previously supplied 30% of its energy through nuclear power, and this shut down left a large hole in the country's supply.

The case for domestic micro-generation

Micro-generation technologies, such as solar photvoltaics, heatpumps and biomass, show the potential to provide upto 40% of domestic energy by 2050 2. Due to the mainly renewable nature of micro-generation, it could also contribute to reductions in domestic carbon emissions by up to 18% in 2050 2.

solar photo-voltaic panels are a common micro-generation technology

However before everyone embarks on a crusade for micro-generation, passive energy reduction procedures, such as loft and cavity wall insulation, energy efficient lighting and appliances should be installed and behaviour be changed 3. Without increased efficiency, the full gains from new micro-generation technology may be wasted.

mobile phone charger controversy

Lots of energy saving websites will tell you to switch off your mobile phone charger when it is not in use (for example here, herehere and even here), they are also now saying not to leave your phone plugged in once it is fully charged (Energy Saving Trust).

charger.jpgThe demon phone charger

Any smartphone user will know that their shiny gadget rarely lasts more than 24 hours per charge with standard use. In my normal day I plug the phone in to charge as I go to bed at night, and have it fully charged and waiting for me in the morning when I start the day. I am an energy conscious person, and I understand the idea that the phone will take 2-3 hours to charge but will be left plugged in overnight for about 8 hours. That sounds like it is wasting 5-6 hours being plugged in that is not needed. So about 2 weeks ago I decided to try the advice to only charge the phone for the time that is needed and see how I get on.

insulated pylon cross-arms increase capacity

Energy efficiency at a grid scale is large step in increasing capacity and reducing loses without new infrastructure. A new device developed by The University of Manchester and EPL Composite Solutions Ltd. could help increase the capacity of the UK grid which could in turn provide savings to the customer and enable cheaper connections to new renewable energy projects.

pylons.jpgElectricity pylons are the backbone of the grid

The new product is an insulated cross-arm which, according to modelling carried out at the university, could increase the carrying capacity by up to 2.5 times. This increase in capacity would reduce the need to install more pylons which is often fiercely fought by local residents and can take years in the planning process.  With more capacity in the existing network the addition more pylons or expensive underground lines would not be needed, and these savings could be passed onto consumers.

The "Green Deal", could it save you money?

The government's energy saving "Green Deal" scheme starts on Monday 28th January. The basic premise is that homeowners can borrow money for energy saving improvements to their home and then pay off the loan through the "savings" in their energy bills. The government is even trying to sweeten the deal by offering upto £1,000 cashback for early adopters.

Victorian/Edwardian terraced housing is a prime target for The Green Deal

The Green Deal loan is a type of unsecured loan that is attached to your electricity bill.  If you move you stop paying off the loan but the new owners must take over the payments. The official rate set by the government is 6.9% but various providers charge between 6-9%.

The humble room thermometer

This cold snap has prompted me to write a little about the perception of temperature and how the humble thermometer can help save you energy.

The joy of thermometers

Since the mass uptake of central heating systems in the 1970s the average internal temperature of households has increased from 12°C to 17.5°C (BRE, Domestic Energy Factfile, 2008). This is mainly due to the heating of unoccupied and previously unheated areas of the property, such as hallways and spare bedrooms. A simple change in behaviour to turn down the temperature in these areas can instantly save energy and money. Although it is the perception of the temperature and how people react to it that really waste energy.

"how green am i?" is now mobile ready

To make tracking your energy use even easier, the howgreenami website is now mobile ready!  You can add your meter readings, view your usage and compare yourself with the other site members directly from your smartphone in an easy to read format.

Simply go to www.howgreenami.co.uk in your mobile browser or scan the QR code in the image below.


8 energy saving tips that cost nothing

There is a lot of advice on saving energy but a lot of the time they will cost you money to set up. So here is a list of 8 simple energy saving tips that will cost you nothing to implement, but could save you money straight away.

green savings say oink

1. Turn down your thermostat

Just by turning it down by 1°C could reduce your energy use by 10% and can typically save you around £60 a year (Energy Saving Trust).