© Research Centre Jülich

Solu­tions for green­house gas neutrality

Flood dis­as­ters in Ger­many, dev­as­tat­ing for­est fires in Cal­i­for­nia, droughts and floods: The stricter cli­mate pro­tec­tion law, which was sued before the Fed­er­al Con­sti­tu­tion­al Court and came into force in August of this year, is cer­tain­ly not com­ing too soon. “Net zero” is the goal. Ger­many is com­mit­ted to becom­ing green­house gas neu­tral by 2045. Emis­sions are to be reduced by 65 per­cent by 2030 com­pared to 1990. Is that still fea­si­ble? And how much is it going to cost? Jülich sys­tems researchers have analysed what is need­ed to achieve these ambi­tious goals — and to do so as cost-effec­tive­ly as possible.

The analy­ses of the Jülich sys­tems researchers show that it is pos­si­ble to achieve green­house gas neu­tral­i­ty by 2045, both tech­ni­cal­ly and eco­nom­i­cal­ly. But it won’t be easy. “Com­pared to the pre­vi­ous reduc­tion tar­gets, the new tar­gets of the Cli­mate Pro­tec­tion Act rep­re­sent a turn­ing point,” explains Prof. Detlef Stolten, Direc­tor of the Jülich Insti­tute for Tech­no-Eco­nom­ic Sys­tems Analy­sis. “They require a dynam­ic of change that is fun­da­men­tal­ly dif­fer­ent from the devel­op­ment of the past years. What is need­ed is the imme­di­ate intro­duc­tion of mea­sures in all sectors.”

The Jülich sys­tems researchers have spent months cal­cu­lat­ing and mod­el­ling with com­put­er mod­els spe­cial­ly cre­at­ed for this pur­pose to find out what the solu­tions and paths to green­house gas neu­tral­i­ty might look like. In their study, they present a sci­en­tif­i­cal­ly sound analy­sis of the nec­es­sary mea­sures and strate­gies, gen­er­a­tion paths and inter­ac­tions — down to the last detail: from region­al wind pow­er and pho­to­volta­ic expan­sion pos­si­bil­i­ties to future inter­na­tion­al import and export networks.

The cor­ner­stones: elec­tric­i­ty and hydro­gen from renew­able energies

Fos­sil ener­gy sources, the mod­el­ling shows, must be replaced as far and as fast as pos­si­ble. As a result, elec­tric­i­ty con­sump­tion will increase sig­nif­i­cant­ly in the future — in all sec­tors. There­fore, the con­ver­sion of the Ger­man elec­tric­i­ty sup­ply to CO2-free pro­duc­ers is one of the basic pre­req­ui­sites for achiev­ing net zero. “This requires a mas­sive expan­sion of renew­able ener­gies,” explains Stolten. “Today’s onshore wind pow­er capac­i­ty needs to be quadru­pled. Com­pared to today, future plants will be larg­er, so the total num­ber need­ed for this only needs to be increased slight­ly. Pho­to­volta­ic instal­la­tions would need to be expand­ed on a large scale — com­pared to the aver­age expan­sion rate over the last ten years, annu­al expan­sion rates here would need to increase by more than a fac­tor of four. We can show that there is suf­fi­cient poten­tial in Ger­many for the required expan­sion of wind pow­er and photovoltaics.”

Hydro­gen is a cen­tral ele­ment on the way to green­house gas neu­tral­i­ty. It is intend­ed to replace fos­sil fuels on a large scale, serve as a stor­age facil­i­ty for renew­able ener­gies, enable mobil­i­ty and link the var­i­ous ener­gy sec­tors with each oth­er. While its use is one option among many in some sec­tors, it is manda­to­ry in some areas of indus­try. This applies in par­tic­u­lar to steel pro­duc­tion and the chem­i­cal indus­try, which togeth­er are cur­rent­ly respon­si­ble for over 40 per­cent of indus­tri­al CO2 emissions.

Ener­gy sav­ing and CO2 storage

Sav­ing ener­gy in all sec­tors is anoth­er build­ing block on the road to green­house gas neu­tral­i­ty. The mod­els devel­oped by the Jülich sci­en­tists show that final ener­gy con­sump­tion can be reduced by just under a third through mea­sures such as insu­la­tion, heat pumps or more effi­cient house­hold appliances.
Sim­ply reduc­ing addi­tion­al green­house gas emis­sions is no longer enough. Resid­ual emis­sions will still remain until 2045, main­ly from indus­try and agri­cul­ture. “To achieve net zero, these resid­ual emis­sions must be com­pen­sat­ed by remov­ing car­bon from the nat­ur­al cycle. This requires that around 50 to 90 mil­lion tonnes of CO2 be per­ma­nent­ly stored each year, for exam­ple in suit­able geo­log­i­cal for­ma­tions,” explains Peter Marke­witz, co-author of the study.

Reduced depen­dence on ener­gy imports

The restruc­tur­ing of the ener­gy sup­ply will reduce ener­gy con­sump­tion by around 40 per­cent by 2045. This will also reduce ener­gy imports, from about 74 per­cent today to about 22 per­cent in 2045. In addi­tion to the eco­nom­ic advan­tage, there is a geopo­lit­i­cal plus point: depen­dence on future ener­gy import­ing coun­tries is reduced, as are the price risks of inter­na­tion­al ener­gy markets.

The trans­for­ma­tion of the entire ener­gy sys­tem pos­es enor­mous chal­lenges in almost all areas. The Jülich researchers show that there are solu­tions to this prob­lem. The annu­al addi­tion­al costs in 2045 will amount to about 139 bil­lion euros. “These are obvi­ous­ly notable addi­tion­al costs,” Detlef Stolten said. “How­ev­er, they are both pre­dictable and man­age­able, as well as finan­cial­ly viable. Sub­se­quent adap­ta­tion costs to cli­mate change are like­ly to be many times higher.”

Fur­ther information:

Overview of the main find­ings of the study:
On the IEK‑3 web­site (right col­umn under downloads)