TECHNICAL FIELD

The present invention pertain? to optimisation of electrical power production in an incineration plant In dependence of fJuclua ons in the price on ..electricity,

BACKGROUND OF THE E TION

it ^' is generally k o D in e art that incineration plants, which incinerate refuse, _; ma be configured to produce electricity and/or supply hot water. Generally, it has been unprofitable to generate electrical power from the incineration of refuse, partly because th price .of electricity is not constant, hut varies during the course of a day and even on the longer term in dependence of the seasons, whereas the incineration plants often, need to work at optimal capacity In order to dispose of the refuse delivered to them. in order to provide a more; profitable production, of electricity by incinerating refuse, it has been proposed in KR 100 905 742 to control the production- of electrical power in dependence of the time varying price on electricity:

KR IQO 905 742 discloses an incineration piant, which comprises: a _: controller thai receives, input from a server. This server comprises a table aver the time-varying price on electricity. Based on the price on electricity:, i..e, whether it is above or below a threshold value, the controller issues a control signal to a selection unit for either switching on or switching off the supply of steam to a steam turbine (which generates electrical power). When, the price of electricity: is low, only; hot water is produced and outputted rom the incineration plant.

The controller can control a combustion chamber in the incineration plant in order to increas or decrease the incineration of waste In dependence of the price on: electricity. This control is however based solemnly on mpiric&f data, it Is not regulation taking into account -unexpected fluctuations In the price on electricity. KR 100 905 742 is also silent regarding ho This increase or decrease in. Incineration may be achieved. Another problem associated with this known system Is that there is a rather large "waste" of fuel, because It needs to he operated at substantially full capacity all the time i order to be able to switc the turbine on and off in dependence: of the variation of the price on electricit , because if the turbine is switched off a a time tha coincides with a .time of the day wherein the demand for hot water is low, then this wi\\ lead to a waste of energy. Accordingly,, there is a need for a mor accurate regulation of the production of electrical power, where non-empirieat factors (such as. changes in th weather) Influencing the price.. of electricity may be accounted for.

-SUMMARY OF THE INVENTION

It is thus an object of the present invention to provide a method and system for a mare accurate regulation of the production of electrical power in an incineration- plant, where non-ernplricai factors influencing the price- of electricity may be accounted for; According to the present invention,, the above-mentioned and other objects -are fulfilled by .a rpe!hod for regulating the electrical power output of an incineration plant, the method, comprising the steps of;

^■■ feeding: fuel (e.g. refuse) into a combustion chamber of the incineration plant, ~ generating heat b incinerating the fuel within the combustion chamber,

- generating steam from, the heat for driving a steam turbine, which is configured, for providing electrical power,, and

- regulating the electrical power out t generated: by the steam, turbine In dependence of an estimate of indefermlnistic variations in the. price oh electricity In. addition to an estimation of @m iricai/determii¾istic variations in the price of .electricity.

Very, often it- i so unprofitable to generate eiecfricai power by an incineration plant incinerating for example- .refuse. However, b regulati g the electrical power output in dependence of an estimate of in deterministic variations - in addition to ernp!rP oas etermlnisflc variations - in the price on- electricity, _, it is possible to gain a more profitable use of the fuel, because it is used to generate electricity at times when it is most profitable. By incorporating indeterminlstic variations in the price estimates, the profit ma gin may be considerably- increased as coropared to those incineration plants that are only basing the electrical power generation on foreseeable variations in the price on electricity. The rice on elec r ci y varies greatly during the day, where the demand for - and thereby the price on ^■■■■ electricity in domestic use is at a peak value during the time when, cooking s clone. These empirically collected variations In the demand - and price ~ 015 electricity are statistically very stable arid therefore have a deterministic .§ nature. White: being deterministic, -these, variations may be very large, nd: regulation in dependence of these variations may therefore significantly increase the profitabilit ^y of an incineration plant. Thus, according to an emhodirnent of the method, the empirt- caf/determirtistic variations comprise- calculated variations of the price on; electricity over the course of a day.

ID

Similarly, there are seasonal changes in the demand. - and therefore: price - on electricity that are rather stable statistically. Thus, according to a further embodiment of the method, the empiricaf/deterministic variations comprise calculated seasonal variations of the price on electricity over the course of a year.

15

According to a further embodiment of the method, the calculated: variations are based on historical data regarding the variation in demand ^' of electricity due to ^' household -and industrial applications,

20 Thus, according _, to a further embodiment: of the method, the empirical deterrninistic data further comprise a projected correction based on. historical changes in the price and/or demand of electricity, When regulating: the electrical power generation in an incineration plant there Is a dela in when this regulation will generate a change in the power generation of the plant. However, since a projected correction is included _, into

25 the estimation in. the price of electricity; t is possible: to initiate the regulation of the electrical power generation enough time in advance before the change in price sets in, thereby taking full ^' advantage of the price- change. This delay is typically between 15 minutes arid 20 minutes, but could also be as low as 10 minutes-..

30 Meteorological variations are notoriously unforeseeable and can significantly alter the demand for-- and thereby the price of - electricity. Similarly, technical data regarding the -electrical: power supply system may abruptly change, a id thereby abruptly alter the electrical power supply, leading to significant changes In the price on electricity. Thus, according to a further embodiment of the method, the !ndeterminist!e variations m the

35 price of electricity are estimated on the basis of meteorological data and/or technical data regarding the electrical power supply system. The technical data regarding the electrical power supply system may comprise any of: power grid failures, transformer station failures, power plant failures, whereas the meteorological data may comprise current temperature, and/or current wind speed conditions, and/or current precipitation (form; and magnitude thereof), and/or current cloud coverage, and/or floodings,

According to a further preferred embodiment of the method, the meteorological data comprises weather forecasts,, whereby JndeierrrsiPisiic variations in the price on electricity may at least In part be predicted/estimated. By incorporating knowledge from forecasts is would be possible to adjust the electrical power production in advance, whereby i will be possible to account for the inevitabl delay Itr initiation of eleetrica! power adjusting measures and when these measures eventually set in. As mentioned before, this delay is typically between 15 minutes and 20 minutes, but could also be as krw as Q minutes, The method may according to a further preferred embodiment comprise the step of establishing online access to a meteorological data server and/or technical data server for the provision of meteorological data and/or technical data regarding: the electrical power supply system. The method .may according to a further preferred embodimen comprise the step of estimating the Indeierrnlnistic variations in the price on electricity, in dependence of information from news sources. This informatio may fee used by a human operator to update the adjustment of the electrical power production accordingly. According to a preferred embodiment of the method according to the invention., the step of regulating th electrical power output com rises the ste of regulating the feed of fuel info the combustion chamber In dependence of an estiraate of indeterminlstlc variations in the price on electricity in addition to an estimation of em iri- cai/deterministie variations In the price on electricity. Hereby is achieved a method of optimizing the use of the available fuel, because the use of the available fuel is adjusted .independence of the Indetermlnisfic variations in the price on electricity in addition to an estimation of empirlcairdeterministio variations in the price on electricity. Hence, iwo objectives are achieved by this step: regulating the production of electricity to times when it is most profitable, and a more effective use: of the fuel, because the use of the fuel is regulated to times when it is most profitable to Incinerate It. Bot of δ these objectives ^' increase ^' the profitability of th ^■ incineration lant wherein the method is Implemented.

According to a further embodiment of the meihodj the ste of regulating the electrical bower output comprises the step of regulating: the type of fuel tha is fed into the combustion chamber in dependence of an estimate of indeferniinistic variation in the price on electricit in addition to an estimation of empirical/deterministic variations in the price on electricity. Hereby is achieved a method in which a more efficient usage of the energy content or "ineineraiion value" of the fee! is obtained, because fuel generating most heat when incinerated may be used at times when the price of electricity is a its highest.

According to a: further preteored embodiment of the method, the ste of regulating the electrical power output comprises the step of regulating a supply of combustion air into the .combustion, chamber in dependence of an estimate of ndeterministic variations in the price of electricity in addition to an estimation of e ical^

in the price of electricity. Hereby Is achieved a. method: by which it is possible to regulate th electrical power generation very quickly in order to account for a sudden change in the price of electricity, because a regulation of the supply of combustion air would generate a rather quick regulation of the best generated by the incineration process.

Preferably, the ste of regulating the supply of combustion air into the combustion chamber mm prises the substep of regulating the suppiy of nderfire air or overfire air, or both.

According to a further preferred embodiment of the method according to the Invention, the regulation of the electrical ow output generated by the steam turbine is initiated a predetermined time span in advance of the time when the indeiermlnictic and env pirica!/determinlstic variations in the price of electricity are estimated to set in. Hereby it is possible to take into account the inevitable delay in the measures (e.g, regulation of feed Of fuel and or regulation of the supply of combustion air) used Id increase or decrease the electrical power production, so that the: electrical power production will always follow the price as closely as possible, preferably,, by a suitable choice of said predetermined time span. Since different means being usable to regulate; the electrical power production leads to different delay times rega ding when the lull effect of such a regulation will be reached, the predetermined time span may preferably be chosen ih dependence of the means chosen: to regulate the electrical power output. in, some embodiments of the method, § the predetermined time span is between 1.0 minutes and 30 minutes, or between 15 minutes and 2 hours, e,g. between 2D minutes and i½ hours. The delay is maximally 4 hours

A further preferred embodiment of the method may .comprise the ste of comparing0 the estimated indeterministfc variations In fhe price of electricity to a first threshold value, and only initiate the regulation of the electrical power output if th numerical value of the estimated indeterminate, variations is larger than said first threshold value. Hereb is achieved thai th electrical power production is not regulated due to minor fluctuations in the price on electricity, because there will - a mentioned before § - .be an inherent delay in when the effect of such a ..regulation will set in, wherefrom ^' it follows that an immediate regulation due to. minor fluctuations will not increase the efficiency of the power plant.

A. further preferred embodiment of the .method may comprise the step of estimating for0 how large a, time span the numerical value of the estimated, indeterministic variations in the. price of electricity is larger than a second _: threshold value. Hereby is achieved a method, by which if is possible to account more accurately fo the delay in the regulation of ih¾ electrical power production, e,g. when to Increase and decrease it, and to •what extend it needs to be increased or decreased.

5

A- further preferred embodiment of the method may comprise the step of estimating for. how large a time span the numerical value of the: estimated ipdeterministic variations in the price of electricity is larger than a second threshold value, and only Initiate the regulation of the electrical power output if the numerical value of the estimated0 indeterministic variations Is larger than said second threshold value for predetermined ime span. Hereby is avoided that unnecessary up and down regulations of the electrical power feneration are initiated, which may ultimately lead to waste of valuable fuel instead of o timal usage of the fuel. 5 Preferably, fhe regulation of the electrical power output comprises the substeps of - incre sing the electrical ^' power: output of the incineration plant if the estimated indeterminfetic variations increase,, and the numerical value of the estimated indeter inisiic variations is larger than said first threshold value, or

- lowering the electrics! po r output of the Incineration plant if the estimated ^deterministic variation are -declining, and the numerical value of the estimated indeterminisiic variations is larger than said first threshold value.

According to a preferred embodimen of the .method, the steam is superheated in at least one, but preferably a series of super heaters before being supplied to the steam. turbine,

Preferably, the incineration plant is configured ^'" for generating both electricity and hot water, wherein the regulation, of the electrical power output generated by the steam turbine _, in dependence of an estimat of sndeterministie variations in the price of eleciriclfy in addition to an estimation of: empiricai deferrillrii iic variations in the price of electricity Is performed y changing the ratio between generation 0f electricity and hot water. Hereby is achieved a ver flexible method, wherein It is possible to at least in part shift between the generation of electrical power and hot water, thereby enabling the incineration plan to operate on a highe capacity at: ail times. Preferably, th changing of the ratio between the generation of electricity and ho! water comprises the subste of reducing or increasing the supply of steam: to. the steam turbine, for example b leading some of the steam through bypass tube: around the turbine and towards a. water tank, from which hot water is supplied to the users to are interconnected with the plant. Alternatively, or additionally, the changing of the ratio between the generation of electricity and hot water comprises the substep of increasing: the supply of cold water into the boiler.

In a further preferred embodiment of t e ¹ method, the changing of the ratio between the generation of electricity and hot water comprises- the substep of operating a. switching system, such that the supply of steam ie the: steam turbine is cutoff, for example by leading ail of the steam through a bypass tube around the turbine and towards a water tank, from which hot water is supplied to the users who are interconnected with the plant. In a further preferred embodiment of the method, the electrical: power output of the incineration plant may furthermore he regulated in dependence of the demand for hot water from the cosfu ers connected to the incineration plant ia _: central heating system.

The above mentioned and other objects are fulfilled by an incineration plant compris- ing a combustion chamber for incineration of fuel (e.g.. refuse) ^' , fuel feed system com rising a fuel chute and at least one pusher for pushing the fuel into the eornbus- fen chamber, the combust on chamber being configured for generating beat by incinerating the fuel within the Combustion chamber, the incineration plant further comprising means for generating steam from the heat for driving a steam turbine, which is configured for providing electrical power, wherein the incineration plant further ^' comprises means for regulating the electrical power output generated by the steam turbine in dependence of ah estimate of indeterminlsttc variations in the pride of electricity in addition to art estimation of erfipirical deterministic variations in. the price of electricity, |n an: embodiment of the incineralidn plant according to the invention, the eropirl- qal/deterrnlnistie variations .comprise calculated variations of the price of electricity over the course of day.

In a further embodiment of the incineration plant .according to the. invention, the empsri- cal/determirsistfc variations comprise calculated seasonal variations of the price of electricity over f e course of a year, in :a. further embodiment of the incineration, plant according; to the invention, the calculated variations: are based on historical data regarding the variation in demand: for electricity due to. household and industrial applications.

.In a r rther embodiment of the incineration plant according to the invention, the; empirical/deterministic data further comprise a projected ¹ correction based on historical changes in the price on and/or demand for electricity, in a further embodiment of the incineration plant according to the invention, the indetfirminisiic variations in th price of electricity are estimated; on the basis of meteorological data and/or technical data regarding the electrical power supply system. in a further embodiment of the incineration plant according to .the nden ion, the .technical data regarding the electrical ower supply, system .comprise any of: power grid failures, transformer station failures, and power pianifailures. In a further embodiment of the incineration plant according to the invention, the meteorological data comprise cnrreni temperature,, and/or current wind speed conditions, and/or current precipitation (form and magnitude thereof), and/or current cloud coverage, and/Of floodii gs. In a further embodiment of the incineration: plant according to the invention, the meteorological data comprise weather orecasts, whereby indeterniinistic variations in the price on electricity may at !east i part be predieted esfirriated.

The incineration - la i may according to a furthe embodiment comprise means for establishirsg online access to a meteorological data server ahd r technical data server for the provision of meteorological data and/or technical data regarding the etectricai power su ply system.

The incineration plant may according to a further embodiment comprise means for manually updating the: estimate of the fndetermtnfetic variation in th price of electricity m dependence, .of information from news sources. The information from the news sources may be used to adjust or calculate some of the parameters used hy the control unit to regulate the electrical power output. Srt further embodiment of the incineration plant according to the invention, the means for regulating- the electrical power output comprises means for regulating the feed of fuel into the combustion chamber in dependence of an estimate: of indetermir istic variations in the price of electricity in. addition to an estimation of empirical determlnistic variations In the price of electricity.

In a further embodiment of the incineration plant according to the invention, the means for regulating the electrical power output comprises means for regulating the type of feel that is fed Into the combustion chamber, in dependence of an estimate of indeterministie sanations in the price of electricity ^' in addition to an estimation of em- plnoal/determinlstic variations in the price of electricity. in a further embodiment of the incineration pfant according to the invention, the means for regulating the electrical power output comprises means for regulating a supply of combustion air into the combustion chamber In dependence of an estimate of indetarmi istie variation in the price of electricity i addition to. an estimation of em- pirical defer inistic variations in the price of electricity.

In a further embodiment of the incineration plant aceording to the invention, said means for regulating the supply of combustion air into the combustion chamber comprises means for regulating the supply of underfire air or ©ve.rfi.re air, or both,

The incineration plant may according; to further embodiment comprise a control unit comprising a processor, wherein said processor Is configured for initiating the regulation of the electrical power output generated by the steam turbine at a predetermined time spa In advanc of the time when the indeterrniniciic and empirical/deterministic variations in the price of elecihcfy ar estimated to set in.

In a further embodimen of the incineration plan according to the invention, the predetermined time span is chosen in dependence of the means chosen to regulate the electrical power output.

In a further embodiment of the incineration plant according: to the invention., _, the predetermined time span is betwee 10 minutes and 30; minutes, or tw ' 5 minutes and 2 hours, e.g. batween 20 minutes and 1½ hours. The predetermined time span is maximally 4 hours.

The incineration plant may according to a further embodiment comprise a control unit comprising g processor,; wherein sa d processor is GOfTfigur d for comparing the estimated indeteratiinisiic variations in the price of electricity to a first threshold value, and ^• only initiate the regulation of the electrical power output if the numerical .value of the estimated Indeferministic variations is larger than said first threshold value.

The incineration plant may according te ¾ further embodiment comprise a control unit comprising a processor, wherein said processor is configured for estimating for how large a time span th numerical value of the estimated indeterministic variations in the price of e!ectncity is iarger than a second threshold: value. The incineration plant may according to. a further embodiment comprise a control unit comprising a processor, wherein said rocessor is configured for estimating for how large a time span the numerical value of th estimated indeterministic variations in the price of electricity, is. larger than a second threshold value, and only initiate the peguia- tion of the electricai power output if the numerical value of the estimated indeteriTiinisfiG variations s larger than said second threshold value fo a predetermined time span,

In a further embodiment of the incineration plant according to the invention, the pn cesser is configured for:

- increasing the electrical power output of the- incineration plant if the estimated indeterrninistic variation increase, and the numerical value of the estimated indeterrninistic variations: is larger than sa d first threshold ^. value-,- o

- lowering th electrical power output of the incineration plant if the estimated indeter inisfie variations are declining,, and the numerical value of the estimated indeterrninistic variations i larger than said first threshold value.

The incineration plant may according to a further embodiment comprise at least one, preferably several superheaters, wherein the steam i superheated: before being sup- p lied to the. steam turbin e:.

The incineration plant may according to a. further embodiment, comprise means for generating both eleGificity and hot water, and further comprise a control unit comprising a processor, wherein said processor is configured for changing the: ratio between the: generation of electricity and hot water in dependence of an -estimate of indeterrninistic variations in the price of electricity in addition to an estimation of em- pirieai/deterministie variations in the price of electricity.

The incineration plant may according to a further embodiment comprise a switching system operatlyei connected to the processor,, said switching system comprising means for increasing or reducing the supply of. steam to the turbine;, whereby the change of the ratio between the generation of electricity and hot water is facilitated by reducing or increasing the supply of steam to the steam turbine. in a further embodiment of the incineration plant according to the invention, the processor furthermor Is operatlveSy connected to means, for increasing or reducing the sUppiy of cold water into the _. boster, whereby changing: of th ratio between the generation of electricity and hot water Is facilitated by increasing the supply of cold water into the ripper,

5 In- - further embodiment of the incineration plant according to the invention, the changing of th ratio between the generation of electricity and hot water is facilitated by cutting off the supply of steam lo the stearn turbine.

The incineration .plant may according to. a -further embodiment comprise means f r- 1.0 regulating the electrical power output of the incineration plant lh dependence of the demand for hot wafe from the consumers connected to the incineration plant via a central heating system:.

15 BREiF DESCRIP ION OF THE DRAWINGS

A, further understanding of the nature and advantages of the present invention may toe realixed b reference to the remaining portions of th specification and the drawings, in the .following,, preferred embodiments of the invention are explained in more detail with reference to the drawings, -wherein:

'J ft

Fig, 1 shows an embodiment of an incineration plant according to the invention, Fig; 2 shows, a. close-up view of combustion chamber of an embodiment of an incineration plant according to the invention, and

Fig, 3-: shows, a flow diagram of an embodiment of a method- according to the Invention:

25

DETAILED DESCRIPTION

The present invention will now toe described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the inventio are

30 shown. The Invention may, however, be embodied in different forms and should hot be construed as limited to the embodiments set: forth herein. Rather, these embodiments aro provided so that this disclosure will foe thorough and complete, and wilt fully convey the scope of the invention to those skilled In the art. Like reference numerals refer to like elements throughout. Like elements will, thus, not: be described in detail with

35 re s pecf to th e description of each % u re. }ρ

Fig, 1 shows the overall ^' outline of an embodiment of an Incineration plant 2 according to the Invention. The illustrated, incineration plant 2 is configured for incineration of refuse, such as ousehold, solid waste, or commercial and industrial waste, which forms the fuel 4 for the .combustion; The incineration plaat 2 receives fuel 4 for example in the form of refuse from garbage trucks 6\ which d l ve th refuse to a large fuel silo 8, The heat value of the refuse in the silo 8 may vary a lot because it comprises so many different kind of industrial and household refuse. Therefore a operator will overlook the silo 8. from the operator room 10 and manually steer the crane 12. in order to mix the refuse, so that a mor even heat value may be achieved. The process of Tilling the hopper 13 with fuel 4 is performed automatically t>y the crane 12. The hopper 13 is formed i such a. way that si's cross sectional area widens towards the bottom. This precludes the possibility of jamming of the hopper l The quantity of fuel: 4 in. the hopper 13 acts as a buffer for the In-feeding of fuel 4 to the . grates 14, 1 S, 20, so that a continuous supply of fuel 4 to the grates can be: ensured.

At the bottom of the hopper 13 is placed a plurality of pusher pistons 22, which operate in a backward a d fos vard movement in order to push the fuel 4 onto the moving grates 14, 18 and 20, The fuel 4 forms a layer on the grates 14, 18,, 20, where said fuel 4: is fed: forward and subjected to successive drying, ignition,, combustion and outbyrrsing. The incineration plant 2 also comprises an air supply 16 configured for supplying primary air for the combustion from; beneath the. movable grates 14, 18, 20 and through th layer of fuel 4. This is. often referred: to as underfire air. Also schematically is shown an ai tube .2? for overfire air, which is connected to the air supply via the air tube 29. In praxis there is a plurality of overfire air tubes 27 placed adjacent, to each of the grates 14, _, 18: and 20.

The incineration plant 21s fed with water 32, which is preheated: in a preheater 31 by the escaping flue gasses 38, and then led into a steam drum 33.. This steam is then superheated in a series of superheating sections 30, This superheated steam is sent to a steam turbine 24 as indicated by the arrow 34, The steam turbine 24 drives a generator 38 for the production of electrical power, which is supplied to a consumer via wires 40.

Fig. 2 shows a close-up schematic Image of the combustion chamber 28. The pusher pistons 22 push the fuel 4 onto th grates 14, 18, 20 where It undergoes successive drying, igniiion, combustion and outburning. The remains are discharged through the stag discharge chute 42.

Referring to Fig. 1 again, there is s own- a .-control unit 44 comprising a processor 52 5 (preferably a plurality of processors).. The control unit 44 is in the illustrated: embodiment operatively connected to a plurality of valves 46, 48 and 50 for individually controlling the air supply IS to each of the grates 14, 18 and 2 Hereby the control unit 44 may regulate the supply of combustion air .into the combustion chamber 26 in: dependence- of an estimate .of-indeiermirslst ^' ic variation in the. price of electricity in addition to G an estimation of empirical/deterministic variations in the price of electricity.

The control unit 44 may In an alternative: (hot illustrate embodiment) be operatively connected to a valve controlling t e stream of overfir© air through the overfire air tube 27, whereby the. supply of combustion air into the combustion chamber- 26 may be5 regulated by regulating the supply of underfire air or overfire. air, or both. in. the illustrated: embodiment, _, the control unit 44 is also operatively connected to the pushe pistons 2 for controlling the feed of fuel ^' ; 4 into the combustion chamber 26 through the Inlet 28. The _: control unit 44 is configured for regulating the teed of fuel into0 the combustion chamber 26 in dependenc of an estimate of indeferministic variations in the price of electricity in addition to an estimation of empirical/deterministic variations in the: price of electricity (by e.g. regulating, the operation of the pusher pistons 22). Hereby the production of electrical power by the steam turbine 24 is; regulated by a regulation of the feed of .fuel into the combustion chamber 28.

5

In- the illustrated embodiment, the. .control unit 4 is also .operatively connected to the crane 12 for filling fuel into the hoppe 13.. By controlling the crane 12, the control unit 4 may regulate the type of fuel that. is fed into the combustio chambe 2.6 in dependence- of an estimate of inde erministic variations in the price of electricity In addition to0 an estimation of empirical/determinisiic variations in the price of electricity.

The. illustrated controlle 44 may also (or alternatively) be operatively connected to a bypass valve (not shown) for leading the steam through a bypass tube (not shown) around the -turbine 24, and into a ^' hot water tank (net shown). This valve could be an5 on/off .valve or ¾ valv which may be gradually opened, and closed In order to differen- date the- ratio between hot water production, and steam production in the incineration plant 2,

When regulating the electrical power output of the steam turbine 24 by regulation of § the: feed ofimi 4 (8 _; g... by controlling the pusher pistons 22), or a regulation of the ty e of fuel (e.g. by ^' controlling the crane 12), or a. regulation of the air suppl 16 e.g.- by controlling the ives 44, 48, 50). there is an inevitable delay associated with each of these regulation measures befor a regulation leads to increased/decreased heat production within the combustion chamber 2Q, and . thereby before ft would lead to an in¬o qreased decrsased steam production, in the steam drum 33, and before it will affect the super heaters 30 and eventually lead to an increase/decrease in electrical power production by the steam turbine 24. Therefore, th processor 52 is configured far initiating the regulation of the electrical power output generated: by the steam turbine 24 at a predetermined time spaa In advance of the time when the indefer inicfic and empirl- S cal/deferminlsfio variations in: t e prise of electricity are estimated to set in. Preferably, the predetermined time span is chosen in dependence of the means {p _; g, regulation of the crane 12, and/or pusher pistons 2 and/or valves 44, 8, 50) chosen to regulate the electrical ^' ower output. In some embodiment this predetermined time span is between 10 minutes and 30 minutes, or between 15 minutes and 2 hours, e.g. .be-0 tween .20 minutes and 1 ½ hours. The predetermined time span is maximally 4 hours..

The processor 52 Is configured for comparing the estimated indeterministic. variations in the price of electricity to a first threshold value, and only initiate the regulation of the electrical power output if fhe _: numerical value of the estimated indeterministic ^■ variations6 is larger than said first: threshold value. The processor 52 may also be configured for estimating for how large a tim span the numerical value of the estimated Indeterministic variations in the price of: electricity is larger tha a second threshold value. The processor 52 is preferably configured for estimating for how large a time span the numerical value of the estimated indeterministic variations in the price of0 electricity is larger than a second threshold value and only initiate the regulation of the electrical power output if the: numerical value of the estimated Inrieferminsstic variations is larger than s id second threshold value for a predetermined lime span.

Specifically the illustrated: processor 52 Is configured for:

§ - increasing the etee ^' eai power output of the incineration -plant 2 if the estimated indeterministic variations in the price of electricity increase, and the numerical value of the: estimated indeferrninistlc variations i the price of electricity is. larger than sas s first threshold value, or

- towering the electrical power output of the incineration plant 2 if the estimated indeferministlc variaiions in the price of electricity are declining, and the numerical value of the estimated indeterminfeiic -variations in the price of electricity is larger than s id first threshold value. n . an alternative not illustrated embodiment of the incineration plants, according to the Invention, the processor 52 is furthermore Operatlveiy connected to means for increasi g or reducing.-the supply of cold water into the boiler (steam drum 33).

Fig, 3 shows a- flow diagram 54 of : embodiment of a method according to the present invention. The iilustrated .rnef Pd comprises the steps of:

- feeding fuel (e.g. refuse) 4 into a combustion chamber 28 of the incineration plant 2, indicated by the block 56,

- generating heat by incinerating the fuel 4 within the combustio chamber 26, indicated by the block 58,

- generating steam from the heat for driving : steam turbine 24, which Is configured for providing: electrical power, indicated by the block 60,

- estimate the: Irsdeterminlstio variations in the price of electricit in addition to an estimation, of empirical/deterministic variations in the price of electricity, indicated by the block 62,

- compare the. estimated indeterrniriistic variations in the price of electricity to a ^" fst threshold value, indicated by the block 64,

- regulate the electrical power output generated b the steam turbine 24 in dependence of an estimate of sndeterminisiie riations in the price of electricity, in addition to an estimation of emplf al/determlnistsc variations. In the price, of eiectrkiiy, as indicated . y th block S6 wherein said regulation comprises:

- Increasing the electrical power output of the incineration plant if the estimated iridefermiriistic ^' variations increase, and the numerical ^' value of the estimated indetermlnistic variations i larger than said first threshold value,, as indicated by block 88, or

- lowering the electrical power output of the incineration plant if the estimated indsterrninlstlc variations are declining, and the numerical value of the estimated ^deterministic variation is larger than said first threshol value, as indicated by block 70, As indicated b the dashed, optional block 76, the indetermlrfefle variations in the price of electricity are -estimated on the basis of meteorological data and/or technical data regarding the electrical power supply system. The technical data regarding the electrical power supply system rrsay comprise any of; power grid failures, transformer station failures, power plant failures, whereas the meteorological data may comprise current temperature., and/pr ^' curr^nt ^' -vsti d speed conditions, and/or current precipitation I t arid magnitude thereof), and/or current cloud coverage, and/o ftoodings. The meteorological data may also comprise weather forecasts.

As indicated by the arrow 72 : leading, back to th block 56, the regulation of the electrical power output may be achieved by regulating th feed of fuel 4 into the combustion chamber 26> Hereb is achieved method of optimizing the use. of the available fuel 4, because the use of the fuel is adjusted in dependence of the indeterminisfic variations in the price: of electricity In addition to a estimation of empirical/deterministic variations in the price of electricity.

As indicated by the dashed arro 78, the method may also {or alternatively) comprise the step 74. of regulating a _: supply of combustion air (overfire air and/or uiiderfire air) info- the combustion chamber 26 in dependence of an estimate of indeter iriisfic variations in the price of electricity in addition to an estimation of empirical/deierrninistic variations in the price of electricity. Hereby Is achieved a method by which it is possible to regulate the electrical powe generatio very quickly In order to account for a sudden change in the price of electricity, because a regulation of the supply of com- bu.stl.on air would generate a rathe quick regulation of the heat generated by the incineration,, process.

The method may also preferably comprise a ste of estimating fo how large- a time span the: numerical value of the estimated indeter inisiic variation in. the price of electricity is larger than a second threshold: value. Hereby s achieved a method by which it Is possible to account more accurately for the delay in the ^' .regulation of the electrical power production, e.g, when to Increase and decreas it and to what extend it needs to: foe increased or decreased, LIST OF REFERENCE; MU BERS

In the following Is given a list of reference numbers t ai am used In the detailed description of the. invention,

garbage truck,

fuel slio,

operator .room,.

crane,

chute with boppe

16 air supply.

22 pusher pistons.

2 steam turbine,

26 combustion chamber.

2? schematic overfire air tube

:26 fuel inlet.

29 air tube,

30 super heater,

32 water iniel

33 steam drum,

34 steam outlet.

38 escaping flue gasses,

38 generator,

40 electrical wires.

42 slag chute,

44 contra! unit,

41, 4 8, 50 valves for air supply,

52 processor,

flow diagram,

56 step of feeding fuel into the combustion chamber,

58 step: of generating heat by incinerating the fuel,.

60 step of generating steam from the heat,

82 ste of estimating the i-ndete rrri i n stSc variations in addition to deierminis- tic variations in the price of electricity, 84 step of comparing the estimated indeierrninistic variations in the price of electricity to a first threshold v lla,

W step of reg ulating the electrical power output generated: by the steam turbine,

68 step of increasing . the electrical power output,

JQ step of lowering: the electrical power output,

72 step of regulating the feed of fuel into the combustion chamber,.

74 step f regulating the supply of combustion m into the combustion Cham*

bar,

?§· step of basing the estimation of the lncieterniinlsfic variation of the price on electricity on the basts of meteorological data and/or technicai data reg r ing the electrical piWi r supply system, and

78 arrow indicating the feedback loop for regulating the air supply.