Archive for transmission
Intermittent energy source – From Wikipedia, the free encyclopedia
Posted by: | CommentsLatest version – feel free to comment or edit – strangely, has a large number of refrences from the claverton site.
Erie Shores Wind Farm monthly output over a two year period
An intermittent energy source is a source of electric power generation that may be uncontrollably variable or more intermittent than conventional power sources, and therefore non-dispatchable, and is usually used to refer to sources of renewable energy such as wind and solar generated electricity.
At present, the penetration of intermittent renewables in most power grids is low, but wind for example provides nearly 20% of the electricity generated in Denmark (where plans are underway to increase this substantially) [1][2] and 7% in Germany.[3] The use of small amounts of intermittent power has little effect on grid operations. Using larger amounts of intermittent power may require upgrades or even a redesign of the grid infrastructure.[4][5] However, it should be borne in mind that large amounts of large inflexible plant, such as nuclear or supercritical coal or coal plant equipped with CCS will also require significant grid upgrades to deal with the inflexibility.
Technological solutions to deal with intermittency already exist and studies by academics and grid operators indicate that the cost of compensating for intermittency is expected to be low even at levels of penetration substantially higher than those prevailing today. [6][7] Large, distributed power grids are better able to deal with high levels of penetration than small, isolated grids. For a hypothetical European-wide power grid, analysis has shown that penetration levels as high as 70% are viable,[8] and that the cost of the extra transmission lines would be only around 10% of the turbine cost, yielding power at around present day prices [9] Smaller grids may be less tolerant to high levels of penetration.[4][10]
Matching power demand to supply is not a problem specific to intermittent power sources. Existing power grids already contain elements of uncertainty including sudden and large changes in demand and unforeseen power plant failures. Though power grids are already designed to have some capacity in excess of projected peak demand to deal with these problems, significant upgrades may be required to accommodate large amounts of intermittent power.But again, large amounts of large inflexible plant will also require grid upgrades and increased interconnection – ie the French nuclear programme necessitated its 2 GW HV link ot UK, and increased imports and exports to neighbouring countries.[4] The International Energy Agency (IEA) states: “In the case of wind power, operational reserve is the additional generating reserve needed to ensure that differences between forecast and actual volumes of generation and demand can be met. Again, it has to be noted that already significant amounts of this reserve are operating on the grid due to the general safety and quality demands of the grid. Wind imposes additional demands only inasmuch as it increases variability and unpredictability. However, these factors are nothing completely new to system operators. By adding another variable, wind power changes the degree of uncertainty, but not the kind…”[11]
Popularity: 13% [?]
ZERO EMISSION HYBRID RAILCAR
Posted by: | CommentsUltra Light Rail – the Fast Track to Fuel Cells
Introducing Fuel Cells to the Commercial Public Transport Market
Fuel cells are now recognised as a key technology in the process of weaning the modern world from its dependence on fossil fuels and leading it into a new age of alternative energy. The principal obstacle still to be overcome is the high cost of fuel cells. In transport, for example, one kilowatt from a fuel cell costs around $3,000, compared with $30 per kilowatt for an internal combustion engine. Somehow a reduction of two orders of magnitude has to be achieved if fuel cells are to compete with alternatives in the commercial market for transport.
There are two complementary approaches to achieving this reduction. The first and most obvious is to increase the efficiency of the fuel cell in producing electricity from hydrogen. But producing electricity is not an end in itself. It is rather a means to enable us to achieve the end objective, which is to provide people with useful services such as heat, light and mobility. The cost of mobility can therefore be reduced just as much by increasing the energy efficiency of the system in which the fuel cell is used, as by increasing the efficiency of the fuel cell itself.
Ultra Light Rail is a transport system designed to eliminate the two orders of magnitude gap between the fuel cell and the internal combustion engine. The first step is to increase the efficiency of the vehicle system in which the fuel cell is used. This can be done in a number of ways but the most dramatic “step change” in energy efficiency can be achieved by using a vehicle running with steel wheels on steel rails. This immediately reduces the energy requirement by a factor of three, since the lower rolling resistance allows a tram to use only one third of the energy required by a similar sized bus.
Further cost reductions in the vehicle system can be achieved by introducing an on-board energy storage system in a hybrid electric drive train, similar, in principle, to that used in the Toyota Prius and other cars and even in some buses. This makes possible a lower rating for the prime on-board power source which is required only to run at its optimum level, in order to keep the energy storage system topped up. It also allows for the energy from braking to be recaptured and used, rather than dissipated in heat vented to the atmosphere. Still more efficiency can be introduced by integrating the electric motors into the wheels. The overall weight of the vehicle can be reduced by each of these innovations whilst the body itself can be manufactured from carbon fibre composite materials in a monocoque form. The whole process, using standard proven technology, creates a spiralling cost reduction, resulting from each innovative feature.
Using only some of these features, practical test work carried out by Sustraco Ltd, with support from a Carbon Trust grant, has shown that a 25 kilowatt fuel cell would be sufficient to power a light tram with similar capacity to the fuel cell buses tested in London under the EU’s CUTE programme. These buses have done an invaluable job in demonstrating to the public that fuel cells are no different to internal combustion engines in performance and safety. However the buses themselves are grossly inefficient in commercial terms, costing, as they do, some five times as much as a similar diesel bus and requiring 250 kilowatts fuel cell to operate them. The next logical step in commercialising the operation of fuel cell powered public transport vehicles must therefore be to integrate the fuel cell into an energy efficient tram.
The full report can be found by following this Link.
Popularity: 15% [?]
Time is running out for UK flagship wind project London Array
Posted by: | CommentsGregory Barker, the Shadow minister for climate change writing in the Sunday Times, 1st Feb, “Brown has a Power Failure” points out that unless a decision is made soon to go ahead with the London Array in the Thames Estuary, then National Grid will miss the slot allocated to upgrade the Grid in time.
Apparently National Grid will soon be devoting all their efforts to sorting out the supplies for the Olympics in 2012, and after that NG will be fully booked on other projects.
Barker says that the decision to invest or not, must be made in the next few months, or possible weeks. With the fall in the pound, and most of the stuff priced in Euros, the economics have gone against the scheme. Meantime the government report into how to better support Renewables won’t be published till next April.
Another example of the folly of assuming that markets can deliver the kind of energy infrastructure we will need in years to come.
It clearly requires some sort of central planning from independent engineers and economists who know what they are talking about, and not left to the whims and interests of the large energy players (who are off course all foreign owned in the main) and generalist (and influenceable by the unspoken thought of lucrative non-exec directorships in energy companies on retirement) civil servants. We could call the results of such planning an Energy Policy. The suggested mechanism to create such a Policy is here.
This also shows how daft it would be, to assume that we can get on building as many renewables as possible and worry about the European Super Grid later – since the Super grid will take at least a decade or two, you have to start planning and building it now, on the assumption that the renewables will come along later to populate it, since these typically only take around 3 years.
Popularity: 10% [?]
(Some clarifications and extensions made since earlier version)
A number of people have made comments similar to this:
“I have found Czisch’s plan for an Inter-Continental Grid, with Europe as its centre, unrealistic, politically. The idea that Europe should rely on power imports from Africa and the Middle East is completely barmy.
The recent panic over supplies of natural gas from Russia, coming through the Ukraine, show just what might be expected. And of course electricity can be turned off at the drop of a switch.”
Others have said that it is “madness” even in principle to consider importing electricity from North Africa. Read More→
Popularity: 12% [?]
European Super Grid – press release
Posted by: | Comments
Expert unveils plan for a European-wide renewable electricity solution
At the fourth Claverton Energy conference, hosted by Wessex Water, Bath, international energy expert Dr Czisch outlined his strategy for a European-wide super grid that would supply all of Europe with entirely renewable electricity. Speaking at the conference Dr Czisch of Kassel University, Germany, also said the move to a renewable electricity system could cost the UK consumer the same as what is currently being paid, and, if there is the political will, he added that it could in theory be achieved in decades.
Dr Czisch, who has conducted research of world weather patterns and European electricity consumption on an hour by hour, day to day basis, says Europe could ensure its energy security, slash its CO2 emissions and have a sustainable, renewable electricity supply by employing a network of wind turbines that stretch across the continent from Siberia to North Africa, where the wind is most constant. This would be supported by biomass, coupled with an extended transmission system and existing hydropower plants providing storage capacity. In Dr Czich’s Czisch’s system wind would account for 70% of the electricity mix. Biomass and hydro would provide storage and back up and the biggest part of the remaining electricity production. All of this is the result of a mathematical optimisation that allows for maximum objectivity in searching for the lowest cost renewable electricity supply for Europe and its neighbourhood. Read More→
Popularity: 28% [?]
