Now you have to remember, God does not need the sun, moon, and stars to provide light. God is light and we see it at Creation and throughout the Bible.
John 8:12
Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.
John 8:12
Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.
He is the light and generates energy that is in the universe and what was there at Creation.
Genesis 1
1 In the beginning God created the heaven and the earth.
2 And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
3 And God said, Let there be light: and there was light.
4 And God saw the light, that it was good: and God divided the light from the darkness.
5 And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
God Himself was the light for the first three days of Creation, just as He will be in the new heavens and new earth.
Revelation 21:23
And the city had no need of the sun, neither of the moon, to shine in it: for the glory of God did lighten it, and the Lamb is the light thereof.
Revelation 22:5
And there shall be no night there; and they need no candle, neither light of the sun; for the Lord God giveth them light: and they shall reign for ever and ever.
Until He created the sun, moon, and stars, God of divine power provided light during the “day”, now what this 'energy' encompasses, we will have to see when we get to heaven.