Articulo

Progress in Nuclear Energy, Vol.29 (Supplement),pp. 217-223,1995

Pergamon

1995 ElsevierScienceLtd Printedin GreatBritain 0149-1970/95$29.00

0149-1970(95)00046-1

A S T U D Y OF A N E W ELECTRICAL E N E R G Y S T O R A G E S Y S T E M IN WHICH N U C L E A R E N E R G Y IS U S E D FOR M E T H A N O L P R O D U C T I O N

S. Sato,* H. Nagata,t R. Notomi,~ I. Minatsuki§ and S. Uchida §* Tokyo Electric Power Company at present with JANUS, 1-3 Uchisaiwaicho, 1-chome, Chiyoda-ku, Tokyo 100, Japan t Mitsubishi Research Institute, Inc., 3-60temachi, 2-chome, Chiyoda-ku, Tokyo 100, Japan :~Mitsubishi Heavy Industries, Lid, 1-1 Akunoura-machi, Nagasaki 580-91,

Japan
§ Mitsubishi Heavy Industries, Ltd, 3-1 Minatomirai, 3-chome, Nishi-ku,

Yokohama 220-84, Japan

ABSTRACT Thesignificance of nuclear energy is increasing because it has the potential to solve a number of problems concerned with shortages of fuels and environmental degradation in the 21st century. Therefore the uses of nuclear power should be widened so that it can be used as a source of heat energy as well as just being used for electrical generation. A concept for utilizing nuclear energy effectively hasbeen studied for an electric power company. A new electric energy storage system has been proposed which stores power by producing a synthetic fuel, methanol. The methanol is made from coal gas and hydrogen which is produced by excess off-peak electricity and high temperature heat from a HTGR. The system is not only technically feasible, but is also cost-competitive with other storage systems.KEYWORDS HTGR; methanol; nuclear energy; electrical energy storage; SOSE

INTRODUCTION The significance of nuclear energy is increasing because it has the potential to solve a number of problems concerned with shortages of fuels and environmental degradation in the 21st century. Therefore it needs to be used for a wider range of energy applications as well as for the generation of electricity. Anumber of concepts for utilizing nuclear energy have already been studied in which process heat is supplied by LWRs or HTGRs but these are not so effective because the market for process heat is far from nuclear power plant sites. The objective of this study was to propose an efficient system of using nuclear energy and to demonstrate its feasibility from the view point of both technology andeconomics. The paper focuses on the use of reactors and methods of utilizing thermal energy which are available today or which will become practical in the near future.

217

218

S. Sato et al.

A CONCEPT FOR UTILIZING NUCLEAR ENERGY EFFECTIVELY The multipurpose use of nuclear power by an electrical power company was studied from the point of view of the products which could be produced andthe market for them. The products should be easily transported and should also be usable by the power company itself and for this reason general purpose fuels such as methane, methanol and hydrogen are suitable. These synthetic fuels are promising because the energy market is far from the nuclear power station site. Also the users need to have flexibility in their demand for energy and theutility does not want to have its production tightly linked with the users' demands. The pattern of energy usage is changing with a higher proportion being used at peak times. On the other hand, with more power generated by nuclear plants and fossil fuel units for which the fuel has already been purchased by long term contracts, it becomes desirable to store electrical power to help equalize the daytimeand night time power requirements. From the point of view of an electrical utility, one of the most effective approaches is to produce synthetic fuels such as methanol and hydrogen by using excess off-peak power and heat from a HTGR at night. This will help to make an electrical power system more flexible in future.

COMPARISON OF ELECTRICAL ENERGY STORAGE SYSTEMS A number of systems for...