一個句子的意思 - 翻譯

前幾天看報紙看到的,不太清楚是什麼意思,還請各位指教,謝謝
附上前後原文,文章來自於METRO報紙

Developers believe if installed in every home and office,the bulbs could
cut the proportion of electricity used for lighting from 20 to 5 percent
a year.

'This could well be the holy grail in terms of providing our lighting needs
for the future' --->不懂啥意思

That wont just be good news for the environment. It will also cut energy
bills.

謝謝

--