Reply #11: Do you understand the concept of base load capacity? [View All]

Do you understand that the inherent intermittance of wind, PV and tidal mean they cannot supply base load? Neither can they supply peak load, due to the fact that they cannot be throttled off and on at will. They have a role for sure, but a recent study in the UK determined that wind can't supply more than 25% of the total capacity without destabilizing the grid.

There are two problems with most alternative energy sources - variable output and high energy input costs (low EROEI). The uncontrollable variability (as with wind) is what makes the source difficult to integrate in our current grid in anything but small quantities, regardless of how much energy may available overall. The higher input costs means that we not only need to replace the energy currently in use, but a delta on top of that to account for the increased energy of production.

Biomass has logistical and EROEI problems. It's very expensive to transport, so must be used close to its point of origin, requiring a very decentralized and thus capital-intensive generating capacity. It can be gasified at source and the gas transported, but you then lower the EROEI ratio, making it much less attractive as a large scale solution. Here's an interesting look at cellulosic ethanol and biomass gasification by a couple of thoughtful guys in the industry.

Conservation will be the main weapon against oil depletion for the next ten years or so. Beyond that, if we (speaking globally here) want to switch to an electrical economy, the requirement for additional invariable base load generating capacity is going to have the world looking at its traditional sources - coal, hydro and nuclear. Hydro is my first choice, but most of the suitable locations are already in use. I believe that for expanding our base load we really only have have two options. Renewables will play a large role, but we need to be realistic about their potential contributions due to their various inherent constraints. For peak load we have only one: natural gas. God help us if we start to run out of that..