Electricity is generated by both hydro and nuclear power plants. Much of the hydro-power is generated on the Dnipro. Many nuclear reactors are west of the Dnipro.
Virtually all of Ukraine's limited oil and gas reserves are in the northeastern part of the country, east of the Dnipro, vulnerable to Russian attack. Thus, Ukraine's ability to produce sufficient liquid fuel to sustain its field forces for a war of any duration is in doubt.
Some military production capability should be moved to the western part of the country, particularly for the production of ammunition. At minimum, substantial stocks of liquid fuel will need to be held in western Ukraine. It may even be reasonable to investigate the possibility of producing liquid fuel from soft coal, though the investment costs may currently be beyond Ukraine's reach.
this is where the German General von Manstein had hoped to anchor his defense had Hitler approved his "counter-offensive" alternative to the abortive Kursk offensive. Once the German offensive at Kursk had ground itself to pieces, the Russians launched a massive counterattack that precipitated a virtual race to that river line. The Russians exploited the chaos of the German retreat to place their own bridgeheads across the river before the Germans could fully arrange their defenses. Given this inauspicious start, the Germans still managed to delay the Russians for more than two months along the Dnipro river
To recover most areas of Russian settlement however, the objective would be much more ambitious, and would include the entire oblasts of Kharkiv, Luhanska, Donetsk, and Zaporizhzhya, the Crimea, and Odessa. To establish a land bridge to Odessa, it would also be necessary to take Kherson and Mykolaiv. These 9 oblasts, which extend in a belt from north-east to south-central Ukraine, represent roughly 35-40% of the land area of the country. To ensure against counter-attacks it is easy to see how this strategy could grow to include simply all of Ukraine east of the Dnipro., plus Odessa and Mykolaiv.
Ukraine's fourteen odd heavy divisions and five brigades would have a very difficult time covering this front. A good rule of thumb is that a "medium sized/ medium technology" armored or mechanized division such as the kind the Ukrainians can probably field, can populate 25-35 km of front, on average terrain, with weaponry in sufficient density and depth to provide good prospects for a successful defense against a determined, well-armed, quantitatively superior attacker. If that attacker has enough resources, and if the defender has no reserves of additional units and weapons, the attacker will ultimately grind a hole in this force. Taking the high end of the estimate, the Ukrainian force can cover about 60% of the front with no reserves. This leaves it vulnerable to large scale flanking maneuvers. Or, Ukraine could cover the whole front at one division/60 km, with no reserves.
The emerging Ukrainian force structure is only partially adequate to the strategy outlined above. A western Ukrainian "bastion" will require far more effort than merely holding a mechanized, 6-division strategic reserve. The basic problem is that even this bastion needs to be defended; the Belarus border would generate about 500-600 km of front to be defended, and there would be an 800 km Dnipro River defense line to guard. The reorganized Ukrainian force of eighteen mechanized divisions would still be insufficient. Because many of them would suffer heavy attrition in the battles in the eastern part of the country, the real strength of Ukraine's mechanized forces, by the time they managed to cross the Dnipro (if they did), would be much less than when the fighting started.
Even within the CFE constraints, the Ukrainians ought to be able to organize a very large number of motorized infantry divisions with potent anti-armor and anti-aircraft defenses--neither of which are constrained by CFE. Other key assets that are constrained will have to be strictly rationed--especially tanks, infantry fighting vehicles, and artillery. Careful reorganization supplemented by limited procurement could yield a force of roughly 50 infantry divisions, with considerable defensive but little offensive power. These would be supported by 18 (small) mechanized divisions. A dozen of the latter would be committed to delay, and sovereignty-assertion missions in the east. The others would concentrate in the west to create the "bastion."
The rigorous slimming of these units would free up nearly 2500 guns and heavy mortars, 1400 tanks, and an equivalent number of infantry fighting vehicles to provide basic equipment for 50 infantry divisions. Some would say that this use of scarce armor is a mistake, but the historical record suggests that small armored tactical reserves greatly stiffen the defensive power of infantry units. Trucks and engineering assets for these divisions would need to be mobilized out of the civilian economy.
The less mobile air defense assets that Ukraine has inherited from the old Soviet strategic air defense system would provide the basis for air defense belts along the Dnipro and the Belarussian border. Anti-tank guided missiles (ATGM's) currently owned by Ukraine would be distributed across these divisions. As financial resources become available additional ATGMs would be acquired. Substantial numbers of more basic anti-tank weapons-- shoulder fired rockets, large caliber recoilless rifles, and towed high velocity anti-tank guns would be collected from existing military units, or manufactured. Finally, to compensate for the relatively sparse artillery assets in these units, very large numbers of medium mortars (82mm) would be acquired. (120 mm mortars would be better, but they are counted under the artillery ceilings in CFE, and thus Ukraine cannot acquire more of them.) A notional divisional TOE (table of organization and equipment) is presented below
This division should be able to populate with its units and weapons 20-25 km of front in depth with sufficient density, to create substantial problems for an attacker
A 50 division force of infantry divisions would permit a reasonably dense defense of some 1000-1250 km. This is not quite enough, given the 1400 km of northern and eastern perimeter that the bastion will have to defend. Thus, even this force will require very careful management. It may be true that some parts of both lines of resistance offer sufficiently difficult terrain that they can be defended even more economically. The Dnipro line will require a major water-crossing operation by Russian forces; some portions of the river appear to be virtual lakes on a map, and cannot simply be bridged.