(Reuters) - Germany's big four utilities -- E.ON, RWE, EnBW and Vattenfall [VATN.UL] -- are seeking nearly 25 billion euros ($27.8 billion) in various lawsuits related to the country's nuclear policy.

Germany's Constitutional Court, the country's highest, is holding a two-day hearing on March 15-16 in a case relating to Germany's landmark decision to abandon nuclear altogether by 2022.

Following is a list of all pending cases:

NUCLEAR EXIT:

ADVERTISEMENT

    - E.ON, RWE and Vattenfall have filed complaints with Germany's highest court against the government's decision, taken in the aftermath of Japan's Fukushima nuclear accident in 2011, to close all nuclear plants in Germany by 2022.

That reversed an October 2010 agreement to allow some plants to run beyond 2022.

- Following the two-day hearing, the Constitutional Court is expected to make a ruling later this year on the legality of the decision.

ADVERTISEMENT

    - E.ON is suing for 8 billion euros. RWE has not commented on the possible size of claims but analysts at Deutsche Bank estimate it could be about 6 billion euros.

    - Vattenfall, whose group headquarters are in Sweden, has also filed a lawsuit with the Washington-based International Centre for Settlement of Investment Disputes (ICSID), where it is seeking 4.7 billion euros in damages.

- As EnBW is majority state-owned, it has not sued the government over this issue.

THREE-MONTH NUCLEAR SHUTDOWN IN SUMMER 2011:

    - E.ON in 2014 filed a lawsuit seeking 380 million euros in damages over a moratorium on nuclear production at Germany's eight oldest reactors after the Fukushima disaster, that subsequently led to their permanent closure. These included E.ON's Unterweser and Isar 1 plants.

- EnBW in 2014 also filed a claim for damages against the state of Baden Wuerttemberg, seeking 261 million euros in damages for the closures of Neckarwestheim 1 and Philippsburg 1. A court said the claim has little chance of success.

    - RWE is seeking 235 million euros from the federal government and the state of Hesse for the enforced shutdown of its Biblis A and B plants. A court has signaled the company might get back much less than that.

- Vattenfall's two German reactors, Brunsbuettel and Kruemmel, were inactive in 2011, so did not become subject to the moratorium.

NUCLEAR FUEL ROD TAX:

- A fuel element tax, introduced in 2011 and due to expire this year, requires firms to pay 145 euros per gram of nuclear fuel each time they exchange a fuel rod, usually about twice a year. Germany's utilities have so far paid a total of 5.4 billion euros in the tax.

- The utilities argue they only agreed to pay this in return for being granted longer lifespans for their plants as was promised in the pre-Fukushima agreement.

- The German Constitutional Court is expected to present a separate final ruling this year on the matter and could theoretically scrap the tax.

- In June 2015, the European Court of Justice ruled that Germany's tax on the use of nuclear energy did not breach European Union laws, dealing a blow to utilities' hopes for a multi-billion euro refund.

    STORAGE OF REPROCESSED NUCLEAR WASTE:

    - E.ON and Vattenfall have filed lawsuits against three German states (Bavaria, Lower Saxony, Schleswig-Holstein) and the federal government, rejecting a 2014 law that banned transporting reprocessed nuclear waste to a central storage site at Gorleben in northwest Germany and stipulating it be stored at sites near nuclear reactors instead.

ADVERTISEMENT

The utilities say the transport ban is politically motivated and on-site storage incurs additional costs they should not have to bear.

- RWE has filed similar lawsuits concerning the sites of its Biblis, Lingen and Gundremmingen reactors in Hesse, Lower Saxony and Bavaria.

- As EnBW is majority state-owned, it will not sue the government over this issue.

($1 = 0.8993 euros)

(Reporting by Christoph Steitz, Vera Eckert and Tom Kaeckenhoff; Editing by Keith Weir)