At 4,961,538,207 shares of National Grid PLC available on the London Stock Exchange, and their latest dividend payout of 16.35p per share, that would be £811,211,497. Or £811 million in easier terms.

It fluctuates each year.

Also bare in mind each individual energy provider which also profits from infrastructure investment.

Also also bare in mind that both National Grid and the energy providers are usually multinationals with shares in more than one stock exchange.