Tag Archives: MEPS

Saving energy on the small things

There are fundamental two ways to be “green” in regards to electricity; either reduce the demands on the planet to produce it, or use less. Examples of both can be found in some households. Solar panels can reduce the amount of CO2 produced to get the energy, while energy efficient lightning reduces the demand.

In recent years many┬ácountries have placed┬álimits on how much energy a device can use to do a specific job, for example a fridge. This is implemented via the MEPS(Minimum Energy Performance Standards) directive. Currently the MEPS directive is focused on a select group of large power hungry devices. Although Im sure this will be expanded there will always be a limit as are simply too many devices. There are also new types of devices popping up all the time. There will therefore always be “gaps”. It is these “gaps” in the regulations that I am particularity interested in here.

I thought it would be good to try to find away to push all devices to be more energy efficient; but how can that be achieved? Well its fair to say that independently assessing every new product would never work in the real world, the overhead in cost and time would be enormous. Though it may be possible to target specific aspects in the device which can be found in every product. One of these is the power supply. This can be a very large source of wasted energy in a product.

Its critical to note at this stage that making an energy efficient power supply is not always the most cost effective at low voltages. A typically inefficient linear regulator often costs less to make than a higher efficiency switching power supply; however in some situations a linear power supply can actually be more efficient. In some cases it is undesirable, or impossible, to use a switch mode power supply as it can generate more electronic noise (EMI). It is also worth noting that a switch mode power supply typically physically weighs more and takes up more space in a low voltage electronics design. Therefore the energy costs to build and transport it are more. In a nutshell unlike light-bulbs, you can’t just ban a particular item.

So how would this work then? Well as implied there are three aspects to consider.

1) The actual efficiency of power supply.

2) The amount of energy needed to make it

3) The amount of energy to transport it.

Their are already existing pressures to reduce the energy needed to make and transport a product, as a larger heavier items cost more to post and use up more material which also has a cost associated with it.

For the efficiency: Consider a product uses a linear power supply to power its electronics at 3.3V from a 9V battery. The efficiency of this power supply is 3.3V/9V = 36.6% efficient. If instead a switching power supply is used the efficiency might be as good as 90%. It is worth considering that many battery powered devices will themselves have a desire to increase, “battery life”, though this would not be the case for all of course is not a factor when considering mains powered devices.

Therefore if a small tax is added that is inversely proportional to the efficiency of the power supply then there would be a driving force at the design stage, making efficient powers supplies cheaper than inefficient ones. If a product absolutely needs an inefficient power supply, which can happen, then it pays the cost penalty. This hypothetical tax should not be set to high as it must not negate the energy costs manufacturing and shipping the product and in should therefore be optimized so that for the average product the cheapest way is the way that uses the least amount of energy.