Introduction

Many governments are providing support and subsidies for the development of renewable sources of energy. As a result, thousands of companies, some funded by venture capital, have been founded to tackle this problem. The incentive, how­ever, is always commercial. The world runs on money, and nothing gets done without the possibility of profit. This incentive, however, is artificial. What mat­ters more is the fossil footprint of each technology. That is, how much fossil energy is used in manufacturing and maintaining the equipment, including the mining of the raw materials, their transportation, and the assembly and installa­tion of the power units.1 After all, the goal is to replace fossil fuels, not to buy more of it to buildup a new business. “Green” energy has to be self-sustaining energy-wise. This seems obvious, but only the wind people have been brave enough to calculate their fossil footprint and publicize the results. This chapter also describes new inventions and ideas which give hope for the future but are as yet untested on a large scale.

Electricity is the kind of energy that our modern lifestyle depends on. Making elec­tricity from fossil fuels requires going through a heat cycle. As explained in Chap. 2, the thermodynamics of heat cycles puts a limit on efficiency. Power plants have to be carefully designed to approach even 40% efficiency. Sixty percent of the energy in the fossil fuels that we burn up is lost in the production of electricity. Most of the renew­able energy sources, however, can generate electricity directly, without going through a heat cycle, thus avoiding that 60% loss. This is the case for hydroelectricity, wind power, and solar power. The bad news is that these sources are local, or intermittent, or have their own inefficiencies. Hydro is well established, but not everyone has it. The realities of wind and solar will be covered next. The possible backbone energy sources, fission and fusion, still have to go through a heat cycle. The second or third generation of fusion reactors, however, could possibly produce electricity directly in so-called “mirror machines.” These advanced systems will be covered in Chap. 10.