Green Electricity? Not really...

Monday 22nd October, 2012
The topic of electric cars being environmentally friendly comes around so often, I felt the need to explain it all over again for those that missed it the first time (and indeed the 2nd, 3rd, 4th etc.)

For years ecologist, conservationists, governments and even power companies have been encouraging us to switch to low energy light bulbs and to turn off appliances when they aren't in use. There's a good reason for that, electricity needs to be generated and electricity generation can create lots of emissions. Here enters all the talk about carbon footprints and AAA rated refrigerators.

Now the world is being turned upside-down due to the constant talk about electric cars and how they help the environment. They're apparently "zero emissions" and buying one will save the planet. There's talk about green electricity tariffs, solar panels and wind turbines which ensure electric vehicle (EV) owners don't create any power station emissions from their overpriced car. So why do I constantly tell people that I think this is utter bollocks? Let me explain...

Every day of the year, we usually have enough wind to turn a few turbines. These generate a bit of electricity and this is fed into the National Grid. As I type this post, wind turbines are apparently generating some 648MW of electricity. Sounds impressive. At the same time, we may have some hydro-electric power being generated from tide, waves and other sources. Apparently this is currently generating around 605MW of electricity. On top of that, during daylight hours at least, we generate some electricity from solar panels on the rooftops of buildings and homes. Some companies even have stand-alone solar "farms" to capture as much sunlight as they can.

All of this electricity is green, in that it has a carbon footprint of zero once the generator has been built and installed, and helps reduce the overall carbon footprint of the National Grid. All of this is good stuff, we should have more of it, and if you have a solar panel or other such device you should give yourself a hearty pat on the back.

So what happens to all this green power? It gets pumped straight into the National Grid for everybody to use. Yes, everybody. Not just people on a green tariff? No, power is power and the National Grid doesn't care where it comes from - they just supply power to meet demand all day every day. Monday to Friday demand is higher, industry uses a lot of electricity, so they have to supply more. They do this by buying it in from power companies. This whole supply and demand thing is where it all gets a bit tricky for green power.

Solar power only works in the day. Wind power only works when it's windy and hydro electric power has its own limitations. It's not exactly, as they used to say in the British Gas adverts, turn-off-and-on-able. When the sun is shining, those solar panels will feed the grid and the units sold to the highest bidder. Likewise the wind turbines will keep turning as long as somebody, anybody, will buy that electricity. It can't be stored until the solar panel owner gets home from work to charge their EV, so it's sold for use in a chemical plant, office block or to anybody really - whether they care about what a carbon footprint is or not.

At the moment we're generating around 1200MW of electricity from green sources and all of it is being used. Some of it might be being burned in the computer on which I am typing this post, even though I'm not on a green tariff. Unfortunately, however, current demand is around 45,000MW and this green electricity represents less than 3% of all that electricity currently in use. So where does the rest come from?

Currently, 13.2% of electricity is coming from nuclear power stations. These, like our green sources, run 24x7 to try and supply as much electricity as they can. As with green, however, supply still can't meet demand though and we have to fill the gap from somewhere else. But where?

The answer is that 80% of all electricity currently being used is coming from either coal fired or gas turbine power stations. These create CO2 and other emissions into the atmosphere. They are "brown" sources of electricity and exactly why we need to turn stuff off that isn't being used.

100% of green electricity is being utilised. 100% of nuclear electricity is now being utilised. If I now turn a light on, where will the National Grid get the power from? Chances are that they'll tell a guy in a power station up north to throw a few more coals on the fire. As long as demand for electricity exceeds green electricity supply, this will always be the case. The ONLY place to get additional electricity from is a brown source.

So what if I rush out and buy an electric car? Where will the electricity come from? There is only one place...and it stinks.

  1. 1) Mike Said: (29/04/2013 18:01:41 GMT) Gravatar Image
    Green Electricity? Not really...

    Holding the view that you can't have 100% Green from a mixed source on one hand, yet saying an EV is 100% coal even when powered from the same mixed source, is a very special skill. It's view that many find hard to hold. It is right to say that one supply wire contains a mix of power sources but equally you must also accept it must have a mix of supply emissions too.

    The marginal power argument completely fails to take into consideration any change in existing demand, and fails to accommodate any changes in the supply mix. It is purely an instantaneous worst case adding to a status-quo.

    Why does Marginal power fail? because In in a week where 4.5MW of renewable wind power has been added to the grid and 1MW of electric car demand has been added the quality of the mix has improved for everyone, and street level emissions are reduced too.

    As long as we are adding greener sources to the mix at a greater rate than we are increasing demand, then we are still pushing the average in the right direction.

    Electric cars would only be detrimental when they are added at a faster rate than the rate that we are cleaning our supply.

    You could equally make a corollary argument that the UK has a finite amount of coal generation, if demand were to exceed that, the only option would be to build new power stations, which would be strictly governed by current emissions regulation, Which would then also benefit the mix. (over the hump and down the other side). I don't foresee this happening but the argument is equally valid.

  2. 2) Ben Rose Said: (01/05/2013 07:16:00 GMT) Gravatar Image
    Green Electricity? Not really...

    Hi Mike,

    Changes in the supply mix are important but, until green supply exceeds total demand, we're always going to need fossil fuels to fill in the gap. You turn on an extra lamp in your living room, you increase demand for electric, which comes from fossil fuels. You turn the lamp off, demand goes down, they turn the fossil fuelled power stations down a bit and the grid gets cleaner.

    In a week where 4.5MW of wind renewables have been added to the grid but 1MW of EV has also been added, you've got a net renewable gain of 3.5MW.

    How many would you have if you hadn't plugged in the electric car? 4.5MW, some 28% more.

    How much renewable would we have if those 1MW worth of electric car owners had invested the cost of their car into a wind turbine? Even more than 4.5MW.

    What if the government hadn't subsides those cars and put the money into renewables? You'd have even more green electric.

    What if you hadn't built an electric car assembly plant and battery factory in Sunderland? Guess what? We'd have even more green electricity.

    There is indeed a finite amount of fossil fuel generation, that's why we've open more gas fired stations in recent times and we are planning some, but not enough, nuclear. Having a newer fossil power station helps a little, but it doesn't stop the carbon footprint - that's the issue here and EVs add to it.

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