Picture: ISFH

Facil­i­tat­ing decen­tral­ized ener­gy tran­si­tion with dig­i­tal solutions

Stor­age facil­i­ties are of great impor­tance for bal­anc­ing out fluc­tu­at­ing elec­tric­i­ty feed-in from fluc­tu­at­ing renew­able ener­gies. In the recent­ly com­plet­ed research project ENERA, which was fund­ed by the Ger­man Fed­er­al Min­istry of Eco­nom­ics and Tech­nol­o­gy, the IT insti­tute OFFIS has shown how decen­tral­ized ener­gy sys­tems can act in this con­text. One part, coor­di­nat­ed by OFFIS, dealt with the self-orga­ni­za­tion of ener­gy stor­age sys­tems and their feed­ing of elec­tric­i­ty into the grid. From bak­eries to indus­tri­al enter­pris­es, var­i­ous com­pa­nies equipped with bat­tery stor­age sys­tems were sent on a field test to test so-called soft­ware agents. “Such soft­ware agents can make deci­sions inde­pen­dent­ly and they can also be con­trolled very well,” explains Dr. Mar­tin Tröschel, OFFIS co-group leader for “Dis­trib­uted Arti­fi­cial Intel­li­gence”, a sub-field of Arti­fi­cial Intelligence.

“There is no cen­tral author­i­ty that assigns a sched­ule to each stor­age facility”

Equipped with the guardrails drawn into the soft­ware by the OFFIS team, the agents were allowed to decide when the bat­tery stor­age units would release the charged ener­gy. A key cri­te­ri­on was peak shav­ing, i.e. the smooth­ing of load peaks at times of par­tic­u­lar­ly high elec­tric­i­ty demand. At such times, feed­ing elec­tric­i­ty into the grid from the stor­age facil­i­ty is par­tic­u­lar­ly attrac­tive due to the very high elec­tric­i­ty exchange prices. The dif­fer­ence com­pared to sys­tems com­mon­ly used today, which are cen­tral­ly con­trolled and trimmed for peak shav­ing: “The sys­tem suc­cess­ful­ly orga­nized itself com­plete­ly in the field test. There is no cen­tral author­i­ty that assigns a sched­ule to each stor­age facil­i­ty, as is the case in vir­tu­al pow­er plants,” Tröschel explains.

Co-group leader Ste­fanie Hol­ly also sees the decen­tral­ized mode of oper­a­tion of the soft­ware agents as a major plus and even a neces­si­ty for a suc­cess­ful ener­gy turn­around, giv­en the fur­ther increase in the num­ber of small­er pow­er gen­er­a­tion plants. “Cen­tral con­trol units will reach their lim­its with an increas­ing num­ber of pow­er gen­er­a­tors,” warns the OFFIS expert. For the future, she sees one of the tasks of applied research in tak­ing away the scep­ti­cism of elec­tric­i­ty man­agers towards soft­ware agents. “Already today, elec­tric­i­ty stor­age sys­tems are attrac­tive for many indus­tri­al com­pa­nies due to the some­times very high grid fees”, empha­sizes the OFFIS expert.

Use stor­age and heat pumps for opti­mised use of renewables

Increased region­al use of elec­tric­i­ty from renew­able ener­gies can have a lim­it­ing effect on the expan­sion of the elec­tric­i­ty grid and thus on increas­es in grid fees. Because elec­tric­i­ty con­sumed region­al­ly does not have to be trans­port­ed over long dis­tances. In addi­tion, elec­tric­i­ty con­sump­tion is like­ly to increase in the future due to the demand from e‑cars, but also from heat pumps that con­vert elec­tric­i­ty into heat­ing ener­gy. In the recent­ly com­plet­ed research project “Wind-Solar-Heat Pump Quar­ter”, also fund­ed by the Fed­er­al Min­istry of Eco­nom­ics, the Insti­tute for Solar Ener­gy Research Hameln (ISFH) inves­ti­gat­ed how the share of renew­able ener­gies in res­i­den­tial quar­ters can be increased in var­i­ous sce­nar­ios using ther­mal and elec­tri­cal stor­age sys­tems in con­junc­tion with heat pumps. Two exist­ing res­i­den­tial quar­ters, one in Low­er Sax­ony, one in Bavaria, were com­plete­ly mea­sured for this pur­pose in terms of elec­tric­i­ty and heat demand and gen­er­a­tion, as well as the yields of solar pow­er sys­tems in the set­tle­ments and the yields of wind tur­bines from the region. “As a result, it was shown that a very high region­al degree of cov­er­age with renew­able ener­gies can be achieved by a well-cho­sen oper­a­tional man­age­ment, exceed­ing the mark of 80 per­cent”, says Dr. Tobias Ohrdes, head of the ISFH work­ing group Elec­tri­cal Ener­gy Sys­tems. Accord­ing to the sim­u­la­tions, more than 60 per­cent of the elec­tric­i­ty can be cov­ered direct­ly by wind and pho­to­volta­ic pow­er. With bat­tery stor­age and intel­li­gent con­trol of the heat pumps, a fur­ther 20 per­cent of the elec­tric­i­ty demand can be cov­ered local­ly with wind and sun. If the heat pump oper­a­tion is coor­di­nat­ed among each oth­er in the whole neigh­bour­hood, the renew­able sup­ply increas­es by anoth­er four per­cent­age points com­pared to an unco­or­di­nat­ed operation.

Zuse Community DecentralizedEnergyTurn 600

Heat pump demand match­es well with wind power

How­ev­er, the results must take into account the con­di­tions for wind farms, whose elec­tric­i­ty is fed direct­ly into the medi­um-volt­age grid depend­ing on the cir­cum­stances and is there­fore not used per se for region­al demand. “The region­al use of wind ener­gy is sup­port­ed by the fact that its gen­er­a­tion over the course of the year usu­al­ly cor­re­sponds well with the require­ments of heat pumps in build­ings,” says Ohrdes. The tran­si­tion to the elec­tric­i­ty mar­ket of the future is par­tic­u­lar­ly tan­gi­ble in the Low­er Sax­ony dis­trict of the two neigh­bour­hoods stud­ied, as it is locat­ed on the south­ern slope of the Ohrberg near Hamelin, with­in sight of the Grohnde nuclear pow­er plant, which will be tak­en off the grid at the end of this year. Deriv­a­tives are now to emerge from the inves­ti­ga­tions. “We will make rec­om­men­da­tions for plan­ners on how best to com­bine the elec­tric­i­ty sup­ply from wind pow­er and solar plants with the demand from heat pumps for res­i­den­tial quar­ters,” Ohrdes explains and like­wise announces: “In coop­er­a­tion with the Cli­mate Pro­tec­tion and Ener­gy Agency of Low­er Sax­ony, we want to imple­ment five more heat pump quar­ters and thus bring our research results to bear.”

“The com­bi­na­tion of field stud­ies and sim­u­la­tions in the projects of OFFIS and ISFH as well as oth­er projects on the ener­gy tran­si­tion in the Zuse com­mu­ni­ty shows the impor­tance of dig­i­tal solu­tions for the elec­tric­i­ty mar­ket of the future. With increas­ing shares of green elec­tric­i­ty in the grids, such solu­tions are gain­ing in impor­tance,” explains Dr. Klaus Jansen, Man­ag­ing Direc­tor of the Zuse Asso­ci­a­tion. “The suc­cess­ful col­lab­o­ra­tive projects also demon­strate the impor­tance of effi­cient fund­ing and coop­er­a­tion between com­pa­nies and non-prof­it indus­tri­al research,” Jansen emphasized.