I have about 1 acre of lawm to compost.
What I want to do is set up a cold compost.
What I want to do is generate enough compost to spred about a 1/4" of compost in the spring and again in the fall.
For compost I have and abundance of leaves.
My question is,how large of a compost pile do I need?
How long will it take for these leaves to decompose,should I set up a couple of bins? One for spring and one for fall?
Help..
Thank You.

My friend, there are literally dozens of ways to compost leaves and grass clippings. The fast active way or the slow passive way. You can do it bins, or you do it in piles. You can do it a sheet or trench composting method by just burying or laying your greens and browns just on or in your garden beds.

If you add more nitrogen materials like food scraps, grass clippings, coffee grounds, etc. to your leaf piles, you can get it ready in under 2 months. If not, it can take 3-6 months, or longer.

The more moisture, constant aeration, nitrogen, and living aerobic microbes you got breeding in your greens and browns material, the faster and hotter the piles will get, and the greater the decomposition rate.

With my own personal methods and techniques, I can produce about a ton of mature compost every 2-3 weeks, from my several 3' tall, 20' long compost stockpiles on my farm.

Leaves all by themselves take a long time to compost--maybe two years. You can speed it up by shredding them with a shredder or by running over them. Also you'll need to make sure they stay moist. Dry shredded leaves in a pile will still be dry shredded leaves in a pile next year without moisture and air (meaning you'll need to mix the pile periodically, like weekly).

Adding other materials to the pile will also speed things up. Grass clippings would be great. Even a few shovel fulls of soil. Blood meal or other nitrogen source.

Depending on the size of your bins, one bin will not be enough to spread 1/4 inch deep over an acre. Compost shrinks a whole lot and you might end up with a wheelbarrow or two of finished compost from a 3-foot by 3-foot bin.