Showing posts with label Electric vehicles. Show all posts
Showing posts with label Electric vehicles. Show all posts

Thursday, 12 November 2015

Electric Cars - How Green Are They ?

Two blog posts today from guest posters - one on electric cars and the other on wind farm layouts.

Electric Cars - How Green Are They ?

by David Whitehead. BA(Mod. Nat.Sc.)TCD, FIMMM, C.Eng.






Electric cars  have to be charged using electricity purchased  from the state generating monopoly ( the ESB) which generates  about   90% of the electricity sold  annually  from  burning fossil fuels ( See SEAI website).

 The efficiency of the Irish fossil fuel plants is published by SEAI every year along with the CO2 intensity  is about 42%, as a lot of plants are Combined Cyle Gas Turbines, which will do 55% efficiency.
 
 A diesel engine  converts fuel to motive power at the rate of 3.3 kilowatt hours( kWh) per litre  but  a thermal power plant converts only at the rate of 3.0 kwh per litre or  90% of the efficiency of the diesel engine.  Transmission and transformation losses  amount to of about 5% of the electricity generated and  the efficiency of a battery charge/discharge system is reckoned at 84% .  An electric motor   converts electricity  to motive power  at  90% efficiency. Thus the overall energy efficiency  of the electric car in this system is   around 67.6%. 

Consequently in order to generate the same  motive power the  electrical  generating system has to burn  more  fuel than the diesel engine  - ie  1.48 litres per 3.3 kWh.  In Ireland this results in the emission of  close to 50%  MORE CO2 than would be emitted by burning the  equivalent  amount of  fuel  in a  diesel automobile.  

For the scheme to be  even  CO2 neutral  every electric car which was brought into service would have to have a shaft horsepower substantially less than a  diesel powered car AND one diesel  car  would have to be simultaneously  be removed  from service. If both of these conditions are not fulfilled  the total CO2 emissions simply increase.

The benefit to the owner  of an electric car is that he/she  has their road tax subsidised by by the owners of  fossil fuel powered cars. It is just like the users of fossil fuel generated electricity subsidising the owners of wind turbines. Quite apart from that the reticulation of charging points  that will be paid for by all road users/taxpayers whether or not they  make use of  it.

“the policy agenda on climate change has been driven recently more by ideology and target-setting rather than being informed by a rational assessment of what is possible and what is in Ireland’s interest, given the costs and benefits involved” 

Thursday, 18 December 2014

Response to Ernest & Young


Ernest & Young, the accountancy firm, made a submission on the Green Paper, which I found interesting, as apart from the financials aspect, I'm not sure what expertise they have in the energy sector and specifically, electricity generation.

Over time, encouraging the acceleration of electric vehicles will increase the load for variable generation at times where theremay be surplus wind generation (i.e., at night), thus providing additional benefits to the electricity system and simultaneously driving down transportation costs.

This is a common misconception. Firstly, wind is a product of the sun, so the best wind generation tends to occur during the day. Secondly, they fail to mention that transportation costs may go down but electricity costs will increase. Costs are simply transferred from one sector to the other.  But the main problem with this is that it would lead to demand for additional dispatchable capacity*. One night there might be high levels of wind generation. The next night there might be zero levels of wind generation. On the second night, dispatchable plant will be required equal to every MW of wind generation capacity. So a duplicate system would need to built and funded by the consumer instead of one. I shudder to think of what our electricity bills will look like then.

Over time and as technology solutions evolve, allowing electric vehicles to inject surplus electricity onto the grid (i.e., whenparked), will provide additional ancillary services to the system.
I am completely baffled by this concept. Perhaps someone can enlighten me ? Surely if I want to drive from Dublin to Cork tomorrow morning, the last thing I want to do, as I leave my car parked outside the night before, is to have it exporting electricity to the grid ?

Replacing Moneypoint as a baseload generator when it reaches the end of its useful life will be a key challenge to the market.The options will be to convert to other fuel types, upgrade it to include carbon capture facilities, or ensure that there is sufficient diversification and availability of other types of generation such that it does not need replacing. This latter option would be the ideal from an energy security and sustainability perspective but will require significant innovation around the operating and design of the future electricity system.

The latter option would not be ideal from a stability and reliability point of view as the Grid Regulations states:
There must be at least one Moneypoint unit on load at all times. Required to support the 400kV network. 
So Moneypoint most definitely needs to be replaced. It simply is not an option to do otherwise unless one wants to create blackouts in West Ireland. Biomass, SMRs (small nuclear reactors) or indeed cheap coal power are some of the options. It is a cop out to try to say otherwise. In economic terms, its like saying that we don't need to increase taxation or reduce spending when there is a budget deficit. Friends of the Earth made a similar suggestion regarding Moneypoint - it might sound nice and fluffy but the laws of physics do not respond well to emotions.

However, I don't disagree with everything in their submission:
Natural gas is the friendly fossil fuel with least environmental impact. The [Compressed Natural Gas] technology is well tested as there are over 14 million natural gas vehicles (NGVs) worldwide with around 11% growth per annum in Europe. The use of CNG as a transport fuel will have a positive impact on the energy security as it will reduce the dependence upon oil imports. Also, supply of natural gas through pipelines connected with the UK beneath the Irish Sea is more stable than oil supply from the Middle East. The national grid infrastructure can be used to ensure effective distribution. The option of blending CNG with bio methane will provide additional diversification of fuel mix and therefore additional energy security. NGVs produce about 13–21% fewer GHG emissions than comparable gasoline and diesel vehicles.If bio methane is blended with natural gas in a 10/90 ratio,the carbon emissions reduce further. Using pure bio methane reduces carbon by roughly 90%

Compressed Natural Gas (CNG), is certainly something worth looking at. In Delhi, India, all city buses operate on CNG resulting in less city pollution. For those interested, a summary of Delhi's transition from diesel to CNG can be found here:

By 1st December 2002, the last diesel bus had disappeared from Delhi’s roads, as part of a programme to improve public transport by offering more busses, and only busses running on CNG.
How was this achieved? Companies could either buy new CNG busses, at a cost of 1’600’000 Rupees (16 lakh), replace the engines of existing busses at a cost of 700’000 Rupees, or convert the diesel engine of existing busses to CNG, at a cost of 400’000 Rupees.
The majority of business went for the option of buying expensive new CNG busses; 2’800 opted for the cheapest solution of engine conversion; no existing busses were equipped with new CNG engines.
It is interesting to note that only 3’000 busses are operated by the Delhi Transport Corporation, the majority of the busses in Delhi are run by private operators. Approximately one thousand additional busses that link Delhi with neighbouring States still run on diesel; they are allowed to enter Delhi for a distance of 16 km maximum.
With the introduction of CNG came problems of conversion quality and maintenance quality; 12 busses caught fire. Foreign experts were called in to examine the problem[2], and a new regulation on CNG safety was published. One main problem was the absence of stress relief loops on CNG installations – a problem not limited to CNG and India, which led to the banning of LPG cars in Europe not equipped with pressure relief equipment.

Apparently, some city bus fleet in Cork have already been tested with encouraging results :


If only all new energy concepts were carried out on a trial basis.......



*Dispatchable plant is plant that can be switched on or dispatched when required to do so and includes fossil fuel, biomass and nuclear sources of generation.