<dealing with one of many points> > (5) Transmission: With the present fossil-fuel-powered > system, transmission lines from the large-scale fossil fuel > or nuclear power plants to the consumers are needed. This > transmission and distribution network has tree structure: > electricity always flows in one direction, from the > generator to the consumers. Some renewables are > distributed, they are close to the consumption and need no > transmission at all but a more intelligent distribution > system; others are large scale (concentrating solar, > offshore wind), they need transmission to get to the > consumers, but instead of a one-way tree-shaped transmission > net, a more interconnected net which at night may bring wind > energy from Nebraska and during the day bring solar energy > from Arizona. With better local storage options and higher > penetration of renewable energy, these transmission lines > may not have to be very long or thick. It is not clear > at this time how everything will play out, this will > depend on how technology develops.
If wind and solar become a major part of the griid, they will require large scale transmission regaurdless of whether they generated in an extremely dentralized manner. For example San Diego is very suitable for rooftop solar generation. good supply of solar energy due to low latitude desert location. Low density, high ratio of rooftop to demand. (still might need to add parking lots to generate 100% of demand. Peak demand is during the daytime. However, a San Diego that covered its rooftops with solar cells would still ned to import wind energy from distant states at night if it was going to be supplied by 90% or better renewable energy. In return it would make sense for San Diego to produce excess solar during the day to supply power to wind generating states in return. Storage yes, but storage would not only have to be cheap, but unbelievably cheap for long distance transmission not to make sense. Even with long distance transmission, even at todays storage costs it would make sense to have storage equal to about an hour of peak generation, possibly even more. Renewables can avoid the need for long distance transmission only by having extremely cheap storage or keeping the percent of renewable supply below a certain level. While I think it likely that storage will get cheaper, I think it unlikely that it will get enough cheaper to reduce renewable's needs for long distance transmission. If we want a mostly or entirely renwable grid we will need more transmission, not less.. On Sat, Mar 24, 2012 at 11:35 AM, <[email protected]> wrote: > > It has often been said that renewable energy needs a > different infrastructure than fossil or nuclear energy. > Here is an attempt to spell out what this means. > > Right now electricity generation can be split into base > load, load following, and peak load generators. > > Base load is always turned on (except for maintenance) and > covers the minimum demand. It must have high reliability > and low marginal cost, ie cheap (dirty) fuel and it must be > large scale to get economies of scale, which requires heavy > equipment. This makes it difficult to increase or decrease > electricity output on the fly. But since its capacity > factor is high it can have high capital outlays. It is > typically coal and nuclear. > > Load following plants can easily be started and regulated to > account for the variability of the load. This requires > lighter equipment and since it is not always on, its > marginal cost is not so important, it can be simpler > equipment using more expensive fuel. It is typically > natural gas. > > Peak load power plants cover exceptional needle peaks in > demand, but most of the time they are turned off. They are > typically diesel. > > More information about this at > http://www.grist.org/renewable-energy/2011-05-26-how-to-get-to-a-fully-renewable-power-system > and > http://en.wikipedia.org/wiki/Load_following_power_plant > > > > Some renewables are base load (hydro and geothermal) or > dispatchable (hydro and biofuels), therefore they fit into > the above framework. > > But the main renewables, wind and solar, are neither base > load (because they are intermittent) nor load following > (because they are not dispatchable). On the other hand they > have practically zero marginal costs and high capital costs. > > With increasing penetration of wind and solar energy, a > series of things happen: > > (1) Since it becomes more difficult to adjust electricity > supply to demand, it becomes more important to adjust demand > to supply, i.e. demand side management (DSM). DSM is > already relevant today for peak shaving, will become even > more relevant in the future and it will require a smart grid > and smart appliances. > > (2) base load will become more and more uneconomical because > it will happen more and more often that all demand is > covered by renewables, which have lower marginal cost than > base load. In the future energy system base load plants > are of little use. > > (3) Instead of base load or load following, fossil fuels > (especially natural gas) will be needed for "residual load" > which is highly dispatchable. It is like peak load because > it only takes a minute or two to start up or shut down, in > order to cover demand when the sun does not shine or the > wind does not blow, but it must be more efficient and > cleaner and cheaper than diesel because it will be needed > much more often. > > (4) More and more often, total renewable electricity > generation will exceed total demand. This electricity will > be available for energy storage, so that in the long run the > residual load does not come from fossil natural gas but from > energy stored during the times of excess renewable supply. > Now energy storage can take many forms, some of them > unexpected. > > (5) Transmission: With the present fossil-fuel-powered > system, transmission lines from the large-scale fossil fuel > or nuclear power plants to the consumers are needed. This > transmission and distribution network has tree structure: > electricity always flows in one direction, from the > generator to the consumers. Some renewables are > distributed, they are close to the consumption and need no > transmission at all but a more intelligent distribution > system; others are large scale (concentrating solar, > offshore wind), they need transmission to get to the > consumers, but instead of a one-way tree-shaped transmission > net, a more interconnected net which at night may bring wind > energy from Nebraska and during the day bring solar energy > from Arizona. With better local storage options and higher > penetration of renewable energy, these transmission lines > may not have to be very long or thick. It is not clear > at this time how everything will play out, this will > depend on how technology develops. > > (6) Transportation fuels. So far we only talked about > electricity. Transportation must either be electrified > (electric railroads, electric cars) or must use biofuels or > hydrogen produced by electrolysis from renewable > electricity. > > (7) Space heating and air conditioning, water heating, > cooking: New buildings will be much more energy efficient, > they will not need natural gas for heating and cooking but > electricity (ground-sources heatpumps) and water will at > least be pre-heated by the sun. > > (8) Combined heat and power will become the rule instead of > the exception. Natural gas facilities for residual power > will be smaller and cleaner than today's large scale base load > generators; therefore they can be located in populated areas > and the waste heat from the electricity can be used for area > heating, greenhouses, etc. Initially this will use fossil > natural gas, but over time it will switch to biofuels. > > (9) How all these things will play out depends on > technology: whether and when there will be a breakthrough in > battery technology, various storage technologies, fuel > cells, also energy saving technologies for end users (LED > lights). For climate reasons it will also be necessary to > extract CO2 from the air and sequester it, i.e. CCS may play > a role even after all coal-fired power plants have been > phased out. > > (10) It will also depend on political constellations. The > fossil fuel and nuclear industries are fighting tooth and > nail against being superseded by renewables. They try to > maintain the fairy tale that there is not enough renewable > energy or that it is too expensive. Not true. The > construction industry is fighting against stricter home > efficiency standards and higher in-home technology which > will make pre-fab homes necessary, the auto companies will > fight against electric vehicles because electric motors last > 20 times longer than internal combustion engines, etc. > > (11) There is absolutely no need to use nuclear energy, > neither fission nor fusion. It is too expensive and too > dangerous (especially in times of political turmoil). > > This is how I see it. I may have overlooked things. > Please comment. > > Hans > _______________________________________________ > pen-l mailing list > [email protected] > https://lists.csuchico.edu/mailman/listinfo/pen-l -- Facebook: Gar Lipow Twitter: GarLipow Solving the Climate Crisis web page: SolvingTheClimateCrisis.com Grist Blog: http://grist.org/author/gar-lipow/ Online technical reference: http://www.nohairshirts.com _______________________________________________ pen-l mailing list [email protected] https://lists.csuchico.edu/mailman/listinfo/pen-l
