Do We Know what "Renewable Energy" means?
Do We Know what "Renewable Energy" means?
For example, I have deployed thousands of PV solar panels on remote wellsites over the years. When I'm doing project economics I expect to replace 1/3 of the panels every year and 1/2 of the batteries every year. This is because birds and reptiles are incontinent and their waste on the warm surface tends to short out the electronics. Further, covering a panel with dust or sand reduces its effectiveness towards zero and the first sand storm sandblasts the surface to the point that the electronics can't tell night from day (and cleaning the panels shorts them out about as often as it doesn't). No matter what metric you use, Solar PV does not ever generate as much energy as went into the mining, raw material transport, fabrication, and finished product transport. The industrial units I've deployed return under 5% of the energy required to make them appear on site. Project economics reflect that and the economics often favor Solar PV over bringing in grid power, but the only part that is "renewable" is that fuel cost for operation is zero. The popular literature uses a 25-30 year life for solar panels. Fires and sand blasting experience at large solar arrays seem to make this number laughable if you actually take the panels out of the box.
Forbes Magazine had an article a while back that claimed that grid-scale wind power units get about 83% government grants, subsidies, and tax credits (i.e., a company desiring to install a $500,000 wind turbine would have $415,000 covered by federal programs, state programs would further reduce the cost in most states). Then the federal government has mandated a price that the utility must pay for any power generated beyond the company's need (which is retail price, not the wholesale price that they pay for other power). Expected actual power generation from a unit that size would be worth (both in sell back and in avoided power purchase) about $30k/year which is not enough to service the debt on a $500 k loan. In this case Forbes is using dollars as a surrogate for energy input and energy output, but that is usually a reasonable surrogate--bottom line is that without the government involvement wind energy would not pay for itself. Most "information" available on this topic is like Science Daily that uses nameplate hp, 24-hour/day, 366 days/year operation at 100% capacity and subsidized sales prices to say that the turbines pay for themselves in 5-8 months. This analysis assumes energy storage that has no energy cost (and that it exists, it doesn't). When you factor in back-up power supplies for calm days, and fuel needed for standby plants the 5-8 months becomes laughable, but that is the number that "researchers" in this field continue to use.
Geothermal (where is is a viable option) is likely significantly "renewable" in that you get more energy out of it then you put into it. New research is linking industrial-scale geothermal energy to significantly increased seismic activity (both frequency and severity), but it is renewable.
Hydro-electric represents a love-hate relationship with the environmental movements. The narrative around evil fossil-fuel shows hydro as a huge win (it represents about 6.8% of the U.S. electricity usage), but the land that is taken out of service, the changes to the eco system by changing fast moving rivers to slow moving lakes, and the absence of flooding in river bottoms is depleting soil. Dams silt up and require maintenance/repair. Still, hydro is renewable in that it provides many times the power required to deploy the technology.
Solid biofuels like wood chips and vegetable debris have serious delivery problems (and ash-removal problems and particulate matter pollution problems) that caused the Province of Ontario to have to derate their coal fired plants by half when they were converted to solid biofuels.
Liquid biofuels to date have primarily been oxygenators like ethanol. Adding 10% ethanol to gasoline (petrol) will reduce total fuel efficiency by about 13%. This means that a trip that would have taken 100 gallons of fuel will take about 113 gallons of fuel--101.7 gallons of gasoline and 11.3 gallons of ethanol. In other words it is significantly energy negative. Bio-diesel has about 77% of the specific energy of diesel and tends to gel, absorb water, and requires higher compression ratios. In general without government intervention, this is an idea who's time will never come.
That brings me to gaseous biofuels. Methane comes from anaerobic biological activity on organic waste. In a recent article I computed that contemporary methane sources are on the order of 5 TSCF/day (the world uses about 0.3 TSCF/day). The organisms on this planet generate so much organic waste that we don't even have to get a lot more effective at re-processing organic waste to supply the world's power needs forever--truly renewable and sustainable. The only hurdle is that the contemporary narrative has methane listed in the "evil fossil fuel" category and not in the "renewable" category. That is it. A small shift in the narrative and the world will turn the engineering community lose on this problem and very shortly we will have unlimited power for an unlimited number of future generations. There are already hundreds of small and medium sized dairy farms, chicken farms, pig farms, and feed lots that are harvesting the animal waste to generate heat and methane for power generation (you get methane from anaerobic digestion which requires a small power input and generates horrible smells, taking the last step in the process into an aerobic digester, which is exothermic, provides heat for the anaerobic process, and gets rid of the worst of the smells). Everyone with knowledge of this process knows that there are a number of things that could be done to improve yields and recover more of the biological energy, but with an EPA focused on "eliminating methane emissions", there is no incentive to commit the engineering effort required.
Does anyone have any ideas on how to change the narrative from "methane causes global warming" to "retail harvest of contemporary methane can be a big part of the solution"?
David Simpson, PE
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist