This blueprint book contains 3 blueprints:
<li>43MW Undefended layout <li>37MW Defended (lasers) layout <li> 10MW base unit (borrowed from Yoann's excellent blueprint found here: https://factorioprints.com/view/-Kk_ig4QqWEmcT8Al4FV)The blueprints can be butted up adjacent (zero space) or up to 2 spaces without breaking the logistics network connections. That way you can run between them if desired.
The 43MW Undefended layout is simply the 10MW version times 4, but with a radar in the middle to provide visibility remotely on map view.
The "37MW Defended" layout is based on the 43MW design, but with lasers at the perimeter. I put them inside the outer ring of accumulators to act both as a wall from attacks but also to prevent players from "snagging" when running next to the solar layout (if the lasers were the outer edge, you can catch one and get stuck).
The rationale behind the "Defended" blueprint is that you can remotely drop the blueprint in map mode next to a logistics network and it will be built out with defenses, allowing you to build out into the remote areas without building a defense system.
The "Defended" blueprint includes a buffer chest requesting enough lasers and substations to allow future solar farms to get up on power and defended quickly (supplied by the farm next to them) while the solar panels and accumulators will come from the logistics network as supplies and distance permit.
The 43MW layout is the same size and logisitics layout as the 37MW Defended, so as you grow your defended solar farm larger, you can replace the "inner" areas with the non-defended version, saving on new lasers and adding significantly more power.
2018-07-14: Fixed some missing panels and rearranged a few entities on the 37MW Defended. Added the power to the BP icons for the 43 and 37MW BPs. Added a request for 4 Roboports to the buffer chest on the defended model.