https://www.foreignaffairs.com/ukraine/why-ukraine-should-keep-striking-russian-oil-refineries
The main points:
Scope and Impact of Strikes - Starting from October, Ukraine has conducted over 20 strikes on russian refineries, significantly reducing russia's oil-refining capacity. By March, around 14 percent of russia's refining capacity was destroyed, prompting russia to impose a six-month ban on gasoline exports.
Objective and Criticism - The strikes aim to disrupt fuel supplies to the russian military and cut off export revenues used for the war effort. However, the Biden administration has criticized these attacks out of concern for potential global oil price increases.
Effect on Global Energy Markets - Contrary to concerns, the strikes primarily affect russia's ability to refine oil, not its extraction or export volume. With reduced refining capacity, russia is forced to export more crude oil, potentially lowering global prices. The attacks have not significantly impacted international crude oil prices so far.
Impact on russia - The strikes have caused a decline in diesel and gasoline production in russia, leading to domestic fuel shortages and price hikes. The russian government may need to import fuel from neighboring countries and consider lifting restrictions on low-quality gasoline usage, which could strain its military capacity and incur economic and political costs.
Effectiveness of Strategy - Despite criticism, Ukraine's campaign has proven effective in inflicting economic and logistical pressure on russia, achieving objectives that Western sanctions have struggled to deliver. The strikes have highlighted the limitations of the price cap on russian oil exports and underscored the interconnectedness of the EU and G-7 shipping industry with russia's exports.
Ukrainian strikes on russian oil refineries are now doing what the sanctions regime has not. Without compromising global energy supply or driving up prices, the attacks are eating into russian revenues and curtailing russia’s ability to turn crude oil into the kinds of fuel that tanks and planes need to run. As long as Ukrainian forces avoid hitting crude oil pipelines or major crude oil export terminals, they can maintain this balance.
Ukrainian strikes on russian refineries are now doing what the sanctions regime has not.
The current strategy comes with limited risks. Ukrainian drones have generally been hitting their targets at night, causing few, if any, civilian casualties. As long as Ukraine continues to weigh potential harms to noncombatants every time it approves a strike, it should stay on the right side of international law. Targeting an industry that directly contributes to russian military power is a reasonable wartime measure—one that past belligerents, such as the United States, have employed before, including in its recent operations against the Islamic State.
Ukrainian strikes on russian oil refineries also seem unlikely to widen the conflict. At the very least, russia will struggle to escalate in kind, given its long-running and far broader campaign to destroy Ukraine’s energy infrastructure: its forces destroyed Ukraine’s Kremenchuk oil refinery within weeks of the 2022 invasion, and the Ukrainian energy minister has said that russian strikes earlier this year hit up to 80 percent of Ukraine’s conventional thermal power plants. Rather than threatening escalation in response to Ukraine’s strikes, the Kremlin has tended to play down their effects to avoid embarrassment.